76 series LC dual <span class="highlight">battery</span> + camper <span class="highlight">battery</span> setup

Submitted: Thursday, Dec 01, 2011 at 21:09
ThreadID: 90404 Views:13516 Replies:6 FollowUps:29
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Hi all,

I have searched heaps of 12 volt threads and cant seem to find an answer. ill explain my setup so far. I have a projecta 150 dual battery isolator hooked up to a century 100amp deep cycle battery. I wish to run from that 6 b+s cable to the back to connect via an anderson plug to charge a 100amp agm battery in the camper.
The 76 series landcruisers alternator puts out 13.8 volts. I understand that agm batteries need a higher charge than the alternator puts out. Also i was in a 4x4 shop today and was told that in my model there can be a huge problem with dual battery systems and was told of a letter sent to him from an automotive authority. I was also told that the only was to do it safely was to use a redarc bcdc.
My question is 1: has anyone else heard of such a problem?
2: If i was to get a redarc bcdc, can i scratch the projecta 150 and use the redarc instead mounting it under the bonnet and will it charge the 100 amp century and the agm in the camper?
3: Will it charge the agm properly over that distance?

Any help would be much appreciated

Cobsy
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Reply By: Member - Frank P (NSW) - Thursday, Dec 01, 2011 at 21:42

Thursday, Dec 01, 2011 at 21:42
Hi Cobsy,

Read thread 90310

It pretty much deals with your question. I have pretty definite views, you'll see them there. Others differ.

The choice is yours :-)

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Follow Up By: Member - Frank P (NSW) - Thursday, Dec 01, 2011 at 21:47

Thursday, Dec 01, 2011 at 21:47
Also see thread 90358 It's probably better.

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Follow Up By: Cobsy - Friday, Dec 02, 2011 at 14:41

Friday, Dec 02, 2011 at 14:41
Gday Frank,

I had a read of those threads and am starting to get my head around things. I think its important to get it right with the power stuff as im taking the little family to the kimberleys and wa coast next year and I want to have things set up right.
I read with interest about a reputable installer selling a diode to rectify the low alternator output. I think its the same people who tried to sell me a very expensive system including this $20 diode. I would hate to fit something like this and fry the trucks computers and have Toyota tell me bad luck!

Thanks for your help
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Follow Up By: Member - Frank P (NSW) - Saturday, Dec 03, 2011 at 10:06

Saturday, Dec 03, 2011 at 10:06
G'day Cobsy,

These low output charging systems really make life difficult (and expensive) if you want to do the job properly.

The way I see it, you NEED something like the bcdc in the camper to look after that battery. You've already mentioned big cabling to get power pack there to run it, so I think you're on the right track there. There are other products that would be worth a look. One of the guys in our club has had good success with a Ctek dc-dc smart charger that can also take solar - ideal for a camper.

That leaves the second battery under the bonnet. The situation is really no different for that battery either if you want to get max life out of it. I can't help coming back to the idea of a second dc-dc smart charger for it.

If you choose chargers that are also isolatores (the bcdc is one such. Not sure about the Ctek) then you don't need the Projecta 150 as the chargers would self-sense the crank battery coming up and switch themselves on.

However if one or both chargers you choose do NOT have the isolator funtion, then you will need to retain the Projecta.

In both scenarios, power the chargers from the engine battery. If you have to use the Projecta, just use it as a smart relay so that when it detects the engine battery coming up and switches "on" all it does is switch power on to the charger that doesn't have the isolator function. I had one of these on another vehicle and that is how I used it.

You might also consider a load switching relay in your truck, wired so that when the engine is off your camping accessories (car fridge, etc) are running off the second truck battery, but when the engine is running they are running off the charging system. Reason being its always better (better, not essential) to have the smart chargers charging an unloaded battery.

Cheers mate

Frank
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Follow Up By: Member - Captain (WA) - Saturday, Dec 03, 2011 at 17:27

Saturday, Dec 03, 2011 at 17:27
I have the same alternator low voltage in my 200, but have only found it to be a problem for the camper battery - the vehicle batteries seem to get fully charged, both main and starter battery. I would check and see if you actually do have a vehicle battery charging issue before going to the expense of another dc-dc for the vehicle aux battery.

The new landcruiser alternators are actually temperature controlled. Upon a cold start, the alternator will put out up to 14.3V (by my scanguage). If its a cold day it will slowly drop to 13.8V, but if its a warm/hot day it will get to as low as 13.2V quite quickly. Typical voltage is around 13.4V, but it does vary quite a lot with the ambient temperature, and the speed you drive at (underbonnet cooling effect).

IMHO this is actually a better design as it ensures the vehicle battery does not lose too much electrolyte by over-charging in warm/hot conditions. But it does make it harder for those of us who want to charge camper batteries.

Cheers

Captain
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Reply By: Sand Man (SA) - Thursday, Dec 01, 2011 at 22:01

Thursday, Dec 01, 2011 at 22:01
Hi Cobsy,

To overcome your problem you may well need a dc-dc charger to boost the voltage.

Without necessarily attempting to change your mind on the brand, you may like to take a look at the CTEK solution.
Either a D250S dc-dc charger, or a D250S coupled with a SMARTPASS would efficiently charge both the remote battery in your camper, but the deep cycle battery in your vehicle. 6 B&S cable would be suitable.
The most effective location for a dc-dc charger is at the end of a circuit, close to the remote battery, however, if you cannot justify the cost of both, just the D250S, installed in your vehicle between your starting battery and the auxiliary battery, would be a good compromise. This would definitely maintain the auxiliary battery and also the remote battery in the camper, subject to adequate cable size to overcome voltage drop at the remote end.

The reason why I am suggesting the CTEK product is cost.
The CTEK D250S ($320) or D250S Dual ($359 - includes Solar support) can be purchased from Kulkyne Kampers, while the cheaperst price I found for the Recarc product is in the order of $600.
Thus, you could buy a CTEK D250S and a SMARTPASS, or two D250S chargers for about the same cost as the Redarc equivalent.

Bill


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Follow Up By: Cobsy - Friday, Dec 02, 2011 at 14:29

Friday, Dec 02, 2011 at 14:29
Gday Sand Man,

Thanks for your reply,

I like the idea of the cetk 250 dual mounted under the bonnet as it would charge the second battery properly and have the bonus of adding a solar panel later. With this unit in place do i still need to keep the projecta isolator? Or does the ctek 250 dual provide the isolating function as well?

Having the unit closest to the battery makes sense. Properly charging the battery in the car is important firstly as the camper is not finished yet and i run the fridge in the car all the time.

When the camper arrives I think i will monitor the charge rate at the camper battery via a Turnigy watt meter ( i already have one in the car) to see if im getting a charge close to 14.4 v.

I can also top up my batteries with a projecta 25 amp 7 stage that is on the way.
If the charge at the camper is not sufficient then another 250 dual at the camper as you suggest is a great idea as if gives me flexibility with a portable solar panel when camping with or without the trailer.
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Follow Up By: Sand Man (SA) - Saturday, Dec 03, 2011 at 09:32

Saturday, Dec 03, 2011 at 09:32
Hi Cobsy,

The D250S and D250S Dual chargers have built-in isolator funtionality to keep the starting battery and Auxiliary battery separated.
When the voltage has reached 13.1V in the starting battery that gives a signal for the D250S to charge Auxiliary battery. The auxiliary will be charged to 100% and the multi-mode charging will then maintain the auxiliary with a maintenance "pulse" charge.

The D250S Dual contains a MPPT controller and if desired, both solar and alternator input can be input at the same time and the controller will determine which input is best. (This may be an advantage if fixed solar panels exist on a caravan or camper while travelling.)

I have a bi-fold solar panel I use when camping and have rewired it to include a direct cable for the D250S dual, which bypasses the cheap on-board regulator.
The original cable connected to the on-board regulator is still available if I wish to use the panel to charge another battery not connected to the D250S.
The original cable has a Merit style plug on it and the unregulated cable has an Anderson connector.

I am really happy with my investment.

The way I use my setup is in two possible ways.
I have two separate circuits wired up from the starting battery to the rear of my dual cab. Both have isolators built in to their charging kits.
One is for my Thumper portable battery pack.
One is for my Sidewinder Flyer pack containing a 100Ah Remco AGM. This is my auxiliary battery I use to run the trusty Engel fridge.
When I hook up my camper (which has another two 80Ah Remco AGM batteries to support an upright Waeco compressor fridge, I connect the camper charging cable
to either the Thumper circuit, or the output connector on the Flyer.

In either case, both circuits are protected each end by fuses or circuit breakers.

I may add a Smartpass management system at a later date if I need it, or another D250S in the rear of the vehicle to provide a smarter charging function to the battery packs in the rear.
I have yet to test the current setup on a prolonged trip, but I'm hoping I will get extended Amp hours and a longer battery life from the camper batteries for the Waeco fridge.

Bill


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Reply By: Mick O - Thursday, Dec 01, 2011 at 22:48

Thursday, Dec 01, 2011 at 22:48
Cos,

I'm driving the 79 series supporting both a Dual Battery system under the bonnet and 2x 140AH Powersonics in the rear for the camper. I'm using the Redarc BCDC under the bonnet and the BMS system for the Camper batteries.

The BcDc will comfortably support your AGM's with the charging profile required by the battery. I've covered it off in a couple of blogs covering the build of the whole unit (electrical section is about half way through) and with a review on the Redarc products. Both are linked below.


Creating the Dream Off-Roader

Redarc BcDc review


Hope that gives you something. I'm very happy with my choices and don't reckon you'll go far wrong with Redarc.

If in doubt, I'd always suggest giving Redarc a ring in Adelaide and asking them direct. Their tech boys are very helpful and only to willing to discuss and answer your questions.

Cheers Mick
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Follow Up By: Cobsy - Friday, Dec 02, 2011 at 14:34

Friday, Dec 02, 2011 at 14:34
Gday Micko,

Thanks for the info.

Had a look at your blog. Your truck is looking awesome, I love the custom work on the tray!

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Follow Up By: Mick O - Sunday, Dec 04, 2011 at 16:39

Sunday, Dec 04, 2011 at 16:39
Cheers Cobsy, it's coming up well. Marco and the boys did a great job. Always more money to be spent though lol.

Mick
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Reply By: Member - Captain (WA) - Friday, Dec 02, 2011 at 06:35

Friday, Dec 02, 2011 at 06:35
Hi Cobsy,

I have a similair setup to you and can confirm that the latest cruiser alternators will struggle to properly charge a camper battery. I use a Redarc isolator between my dual batteries in the vehicle and then use a Redarc BCDC 1240 to charge the camper 2xAGM batteries. With this now in place, I can easily charge all my batteries.

With regards to your specific questions;

1. Yes - is definelty a problem if you want high SoC.

2. No, keep the Projecta isolator for your vehicle batteries but run the 6 B&S cable from the aux vehicle battery to your camper.

3. The dc-dc will not charge properly from under the bonnet to the camper, it needs to be as close as practical to the batteries it is charging. Mount the dc-dc in the camper otherwise you will get voltage drop ito the camper batteries.

Cheers

Captain
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Follow Up By: Member - Frank P (NSW) - Saturday, Dec 03, 2011 at 20:41

Saturday, Dec 03, 2011 at 20:41
G'day Captain and Cosby,

The problem with this is that if you camp, say for an overnight, and leave your trailer connected, the DC-DC charger hooked to your vehicle Aux battery will run all night and drain the aux battery as it tries to charge the camper battery.

Yes, you can say you will unplug your Anderson, but one day you'll forget ...

Because the DC-DC chargers we have been discussing (such as Ctek and Redarc) have an in-built isolator function it would be better to have such a charger in the camper powered directly from the starter battery. This means your Anderson would be live all the time, which I think is a safety/security disadvantage, but you might find it convenient as you can plug into it any time with the engine off.

If you would like to switch the Anderson off with the engine and don't want to go to the expense of a second DC-DC charger for the truck's second battery then use your Projecta to isolate that battery and get a second isolator or simple solenoid to switch the power to the Anderson only when the engine is running.

Cheers

Frank
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Follow Up By: Member - Frank P (NSW) - Saturday, Dec 03, 2011 at 20:47

Saturday, Dec 03, 2011 at 20:47
PS. I meant to say that I agree totally with Captain's recommendation for 6B&S to the Anderson and locating the camper's battery charger in the camper, not in the vehicle.

(You CAN put in in the vehicle, but it's way better not to. It's much better to have a long cable with a voltage drop in the supply to the DC-DC smart charger because it will compensate for that. If there's a long cable with a voltage drop on the output side, most chargers cannot effectively deal with that. At high outputs that these chargers are capable of, there WILL be voltage drops in long cables, even 6 gauge.)

F
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Follow Up By: Member - Captain (WA) - Saturday, Dec 03, 2011 at 21:01

Saturday, Dec 03, 2011 at 21:01
Umm... Frank the Redarc has an inbuilt function that checks the alternator is on (every 100 seconds it measures the no-load voltage, must be above 13(?)v for dc-dc to run) so no need at all to unplug the Anderson plug or install a secondary isolator for the dc-dc charger, its all bult-in :)

No real difference which vehicle battery you connect the dc-dc charger to, but often people tap into this cable for accessories at the rear of the vehicle, so IMHO best to use the aux battery and leave the starter battery for that - starting.

Cheers

Captain
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Follow Up By: Member - Frank P (NSW) - Saturday, Dec 03, 2011 at 22:00

Saturday, Dec 03, 2011 at 22:00
"Umm... Frank the Redarc has an inbuilt function that checks the alternator is on (every 100 seconds it measures the no-load voltage, must be above 13(?)v for dc-dc to run) so no need at all to unplug the Anderson plug or install a secondary isolator for the dc-dc charger, its all bult-in :) "

Crikey, Captain, that's so basic, I'm embarrassed I forgot it :-( Thanks for your gentle follow-up!

I suppose, on that basis, you could run it off either battery because whichever one its connected to, it will turn itself off when that battery drops below 13(?)V.

And if it's connected to the aux battery, which is in turn connected to the starter battery when the isolator (Projecta) is on it will draw off both until it shuts itself off. If the Projecta drops out first, then it will run off the aux battery alone, again until it shuts itself off.

I reckon it's now 6 of one and half a dozen of the other because either way both start battery and aux battery are protected.

I remain not keen on leaving the Anderson live at all times, but that's a matter of personal preference.

Cheers

Frank
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Follow Up By: Member - Captain (WA) - Sunday, Dec 04, 2011 at 00:07

Sunday, Dec 04, 2011 at 00:07
Hi Frank,

I too agree about not keeping the Anderson connected so I have actually gone one step further. I have a switch that turns on/off the Anderson point, that way I can isolate it or keep it live at the flick of a switch under the dash. As there is many times the vehicle is in use with no van, no point in having a large capacity connection live if not needed. I have seen these fill up with sand/mud and when wet, blow a fuse.

Cheers

Captain
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Follow Up By: Cobsy - Sunday, Dec 04, 2011 at 11:51

Sunday, Dec 04, 2011 at 11:51
This is very helpful info Blokes!

I have found on ebay ctek 250 dual for $276. This would go in the camper and sort out voltage drop, charging and future solar.
For the anderson lead, I too agree that not having it live when driving around without camper is ideal. I am thinking another anderson plug under the bonnet near the battery would do the trick to disconnect the lead when not in use.
Frank, how did you set up the switch on such heavy cable under the dash? What type of switch did you use?
As for the 2nd battery on the truck... Im not convinced that it is holding much charge as after 3 to 4 hrs driving the battery ran down to 6.5 v after running a 40lt engel set on 1 in two days.
I think a dc to dc under the bonnet would give the battery a better charge. Fully charged I should be getting 4 to 5 days running the fridge.
I looked at the spec on both the ctek 250 dual, redarc bcdc1220 and the redarc bcdc1240 with MPPT. Costs were $276, $335 and $440
Temp wise the redarc is rated to 80 degrees and the ctek to 50 degrees. I think it would get to over 50deg under the bonnet. Have any of you blokes got the ctek under the bonnet or had any issues regarding temp?
As for unloading the 2nd battery whilst it is charging, I have installed a switch in the truck to select between cranking and aux, after the switch i have a volt meter to read what the fridge is drawing and what levels the battery is at.
I like the idea of a relay to put the fridge onto the aux when the engine isnt running but i have no experience with them, ill hunt around for some diagrams.
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Follow Up By: Member - Frank P (NSW) - Sunday, Dec 04, 2011 at 13:51

Sunday, Dec 04, 2011 at 13:51
Cobsy,

"Frank, how did you set up the switch on such heavy cable under the dash? What type of switch did you use?" That wasn't me, mate, that was the Captain!

I use a Redarc SBI to switch power to the Anderson, and also to the DC-DC charger for the vehicle's AUx battery.
----------------------------

"As for the 2nd battery on the truck... Im not convinced that it is holding much charge as after 3 to 4 hrs driving the battery ran down to 6.5 v after running a 40lt engel set on 1 in two days. "

I think that pretty much confirms what you can expect with a conventional setup (simple paralleling of batteries with an isolator) and a late model vehicle with low output charging system. As you seem to have identified yourself, I think you need a dc-dc charger for that battery.
--------------------

With a 50deg temp limit, I don't think the Ctek will survive under the bonnet. A couple of people here have posted about measured battery temps in excess of 60 deg, which means the environmental temp had to be higher than that - way above the 50 deg limit for the Ctek. My DC-DC charger (Ranox) is not designed for the under-bonnet environment. I mounted it under a seat and ran cabling through the big grommets in the firewall. Toyota give you extra space in the grommets for that sort of thing - very thoughtful!
---------------------

"As for unloading the 2nd battery whilst it is charging, .... I like the idea of a relay to put the fridge onto the aux when the engine isnt running but i have no experience with them, ill hunt around for some diagrams."

Though it's desirable, you may not need to do that. Some smart chargers can sense a load on the target battery and compensate. Best you check with the manufacturer.

Nevertheless, I'll see if I can knock something up and post a link to it in a follow-up.

Cheers

Frank
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Follow Up By: Member - Frank P (NSW) - Sunday, Dec 04, 2011 at 16:30

Sunday, Dec 04, 2011 at 16:30
Cobsy,

Here is a schematic of my system.

I'm not an electrical engineer, so please forgive the non-standard symbols I have used.

As discussed, I use a Redarc SBI to switch power to the Anderson and to the rest of my system. If you use a DC-DC charger ith an in-built isolator function, then you can replace the SBI with a simple relay or solenoid (about 100 amp should do) The Jaycar SY4073 is rated at 150 amp. You'd activate it through a circuit that is live when the key is on.

I think you need to do something like this to get automatic switching of power to the Anderson.

The load switching is done by the relay at the bottom of the diagram. The Narva and the Jaycar 4070 are rated at 30/40 amps, the 4073 at 150 amps and the 4074 at 60 amps. Choose one to suit the total likely load on your second battery.

I think I have this right. If anyone thinks it's wrong or could be better please post a follow up

Cheers

Frank
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Follow Up By: Cobsy - Sunday, Dec 04, 2011 at 17:15

Sunday, Dec 04, 2011 at 17:15
Frank,

Thanks heaps for the drawing
So with the relay... when the sbi kicks in, the dc-dc starts, the anderson livens and pin 30 automatically connects to 87. When the sbi is off, anderson is dead and pin 30 automatically switches to 87a which is the relays normal position.

Am i getting it?!

This is exactly the setup that suits my needs,
Thanks for your help!!
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Follow Up By: Member - Frank P (NSW) - Sunday, Dec 04, 2011 at 18:05

Sunday, Dec 04, 2011 at 18:05
Cobsy,

You've got it.

In effect, if your dc-dc charger has an inbuilt isolator function you will have two isolators in series. Not necessary but it won't do any harm. You're basically using the Redarc SBI as a dumb solenoid, but it's not dumb.

So when the start battery voltage comes up, the SBI will kick in and power the dc-dc charger. If the charger has an isolator function it may take a little while to have a think - mine does - and then kick in.

You may find that if your camper battery is low and its charger is pulling amps, then if you're in traffic and idling with low alternator RPM (and thus low current output), the SBI may drop in and out as the start battery gets some of the load and its voltage drops until alternator RPM come up again. Normal behaviour, particularly if you have other loads on the primary system such as lights and aircon. My system in my Prado does it.

A dumb solenoid in place of the SBI would stop that, but then if the dc-dc chargers have the inbuilt isolator function, they would be doing that internally anyway. However your fridge would be getting steady power.

I think for the sake of $30.00 or so a dumb solenoid in place of the SBI is probably better PROVIDED both your dc-dc chargers have the inbuilt isolator function.

In fact, that circuit I gave you will only work properly with your camper hooked up if the camper charger has the isolator function. If it doesn't there will be a back voltage from the camper through the Anderson and the camper battery will try to run everything, which you don't want to happen.

I just had a quick look at the Ctek Australia website. The 250s Dual has the isolator function, so two of those at the right price would work in the circuit I gave you.

Cheers

Frank
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Follow Up By: Member - Captain (WA) - Sunday, Dec 04, 2011 at 19:51

Sunday, Dec 04, 2011 at 19:51
Hi Cobsy,

Frank has given some very good advice and I agree with it. I would suggest though that your vehicle aux battery is likley stuffed if you have run it down to 6V on a few occassions. If that is the case, it doesn't matter what you are charging it with (dc-dc, alternator, 240v charger), you will never get the life out of it you want.

I would try charging the aux battery on a good 240V multistage charger so you know its fully charged, then apply a known load like a spotlight (not a fridge, they cycle too much - or keep the lid open) and run the battery down to 12V and measure the time it takes. 12v is approx 50% State of Charge (SoC) and thus you can work out just what capacity your battery now has.

If you have a N70Z battery, it will likley have a 75a/hr rating, or in that order of magnitude. If you use a 100W spottie as the load, that uses approx 8a/hr so it should take aprox 4.5 hours to get down to 12V.

I am guessing that it will take a lot less time to get down to 12V and thus the nominal a/hr rating of your battery is way down due to running it down to 6V occasionally. If that is the case, I suggest you replace the battery and in future try to minimise the time it is below 12V and definetly try and avoid lower than 11.5V as you will impact battery life.

Now, a dc-dc charger for the camper is a must IMHO for the new cruisers due to voltage loss over the distance. However, I do believe that a dc-dc charger for the vehicle aux battery will not give the same benefits - provided you use big cables between the main and aux battery. There is certainly no harm using a dc-dc charger for the aux battery, but the cost benefit is not the same. I have found in my 200 that the aux battery remains fully charged and have not required a dc-dc charger.

The Ctek 250s is a good dc-dc charger, but the MPPT solar controller has a few limitations. It cannot run panels smaller than 80W in low light conditions and some users have reported troubles with even 160W panels in very low light. For this reason I went with the Redarc bcdc1240 charger in my camper and have found no issues with it in low light conditions - bit I do have 160W panels. I spoke to Redarc before buying my bcdc and they gave some good technical reasons why their MPPT controller can handle lower rated panels. If not running solar, no problem with the Ctek but if buying it for the MPPT capabilities then please be aware of its limitations.

Finally, I think that expecting 4-5 days from a 75 a/hr battery (assumption here!) is too much if you want long battery life. Even at a setting of 1, the Engels would draw over 1 amp and likley closer to 2 amps per hour (I have 2 x 40L Engels plus an 82L Evakool and have measure power draw over different conditions). Lets just say 1.5amps for the Engels and thats 36 a/hr for a 24 hour period. And thats about the max you would want to run your battery down to (50% SoC) if you want long battery life. Sounds like you may need the solar sooner than you think!

Cheers

Captain
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Follow Up By: Member - Frank P (NSW) - Sunday, Dec 04, 2011 at 20:47

Sunday, Dec 04, 2011 at 20:47
Thanks Captain.

I concur with your analysis of Cobsy's battery, 100%.

You also said
"The Ctek 250s is a good dc-dc charger, but the MPPT solar controller has a few limitations ......" etc.

I have no experience of that device, but I did note on the Ctek website that you cannot series up your panels to overcome losses in long panel leads. Same with the Redarc BCDC. I see that as a disadvantage - not huge if you use big copper, but a disadvantage nonetheless.

Also, using an all-in-one solution you are tending to put all your eggs in one basket. If the Ctek or Redarc fails you've lost the lot. I prefer a bit of diversification, with a portable MPPT solar reg to accompany the solar panels. My 240V charger, the car charger and the solar system are all stand-alone. Not as neat, but much more redundancy, which is particularly important if you are in a remote area and some part of your system goes pear-shaped.

So Cobsy,

Would you be interested in dc-dc chargers with no solar input (cheaper), then have an external MPPT solar reg that can take, say 60 solar volts (ie, panels in series, typically for campers 44 volts or so), which you can then plug into/onto either vehicle aux or camper batteries with dedicated Andersons direct to battery or alligator clips?

Whatever you do you're going to have a lot of connections. To maximise reliability, do very good crimps or solder, ensure terminations have strain relief and cable support, use heat-shrink and cable ties to help that. If you're crimping, hold the crimp really hard for 5 to 10 seconds then pull it to see if strands move. If they do, cut it off and do it again, or solder. Then apply heat-shrink.

Do not tin the end of a wire then crimp or clamp it. The solder will flow, the connection will get loose and then problems will occur.

More grist for the mill ...

Cheers

Frank
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Follow Up By: Member - Captain (WA) - Monday, Dec 05, 2011 at 04:12

Monday, Dec 05, 2011 at 04:12
Unless you are putitng a huge amount of solar panels, the 32V limtation of the Redarc is not a big limitation IMHO. Also, while I agree redundancy is a good when travelling remote, the chance of failure is low.

However, in my particular scenario, as well as the Redarc dc-dc / MPPT, I also have a Ctek 25A charger (240V input). So, in a worst case issue, I simply fire up the Honde 2iu and recharge of the Ctek. Now, lets say the Ctek fails, then i simply recharge off the 12V off the Honda. Now, if the Honda fails (3rd failure!), I now bypass the faulty redarc dc-dc and recharge of the alternator only. Ok, the alternator now fails, I am finally really stuffed :)

I also agree mostly on Franks method of cable crimping. Only thing is, I always avoid soldering as it can lead to fatigue failure of the joint. But when you have your own hydraulic crimpers, its easy to preach the right thing to do.

Cheers

Captain
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Follow Up By: Member - Frank P (NSW) - Monday, Dec 05, 2011 at 09:21

Monday, Dec 05, 2011 at 09:21
I mentioned the solar input voltage limitations on both units because I have what I believe is a fairly common set-up - multiple panels joined together.Mine is 4 60W panels in two pairs. You see lots of 2 and 3 panel systems too.

They were all in parallel, 22 solar volts, going into a simple reg, but when I got my MPPT to improve performance I found that the MPPT function dropped out below 18 volts - which happened quite frequently - passing cloud, etc. I put each pair in series (44 solar volts) and then paralleled the pairs (still 44 solar volts). It works very well now, and the 15 metres of panel-to-reg cable that I use is not an issue due to the higher voltage.

You wouldn't have those options with an MPPT reg that doesn't take the higher solar voltage.
------------------------

"But when you have your own hydraulic crimpers, ......"

Ha! I wish. For me just simple crimping pliers for small terminals and solder for lugs. I agree re the limitations of solder, but you can minimise the risks with technique and the right amount of heat.

Cheers

Frank

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Follow Up By: Member - Frank P (NSW) - Monday, Dec 05, 2011 at 18:20

Monday, Dec 05, 2011 at 18:20
Cobsy,

A couple of last things,

If both chargers are going hard (ie, second vehicle battery and camper battery both well down) then depending which ones you choose they could be drawing up to 90 amps in total. That's a lot of current.

Now, say your coming home on a wet night - lights on, heater and maybe aircon on for de-misting, wipers on. How's your alternator capacity? Prado has only an 80 amp alternator, so I have a switch so I can switch all my extra loads off if I have to. I just switch the earth on the SBI coil so it doesn't come on.

Also, I don't like the idea of 90 stray amps hunting for a return path shortcut through the chassis and maybe, if an earth connection goes bad, through the engine and cooling system. If that happens your aluminium radiator can become a nice sieve in fairly quick time. I've heard of a water pump impellor almost dissolving. To eliminate that risk, all those earth points on the circuit diagram are wired back to battery negatives, and the two battery negatives are cabled together and they both also go to factory chassis earth points.

Cheers

Frank

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Follow Up By: Cobsy - Monday, Dec 05, 2011 at 21:46

Monday, Dec 05, 2011 at 21:46
Frank,

projecta 7 stage charger came today and ive started playing around with it. ill charge and check to aux battery to see if its ok, as mentioned above discharging it with a constant load to 12 v and timing it.
All the connections i have put on the aux battery are grounded to the battery negative via a bus bar.
Thanks a lot to everyone for their advice and when ive done some more work ill try to post what the setup with some tests and results, hopefully some pics as well

Cheers,

Cobsy
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Follow Up By: Member - Frank P (NSW) - Monday, Dec 12, 2011 at 20:27

Monday, Dec 12, 2011 at 20:27
Cobsy,

How did the tests go?

As an aside, but relevant to this discussion, I have read on a couple of other forums a recommendation to be kind to the Redarc bc-dc unit and place it under a seat or somewhere else other then the engine bay. That's not always the best way.

The Redarc charger should be located near and in the same environment as the battery.

Charging systems should be temperature compensated (ie, the applied voltage is reduced as the temperature rises above a chosen standard temperature, usually around 22-25 deg C) to stop the battery overcharging or getting into a thermal runaway situation. Similarly, voltage will be increased for temperatures below the standard. That's what many smart chargers do, and that's what these new low output vehicle charging systems do - reduce the output as things warm up in the engine bay.

The Redarc units don't have direct battery temperature monitoring. Instead, they monitor their own internal temperature, which may rise because of heat as a by-product of their operation, and also because the environment is hotting up, with the assumption that the battery will also be hotting up. This serves two purposes:

1 It protects the unit against over temping itself.

2 If it lives in a hot environment with the battery, by approximating the battery temperature it compensates and adjusts its output accordingly to avoid overcharging or thermal runaway in the battery.

If you put the Redarc in a remote cool environment with the battery in a hot environment you run the real risk of overcharging your battery. In extreme circumstances you could get a thermal runaway which can result in a cooked battery.

I believe the Cteks you're considering have a battery temp probe. So do both my DC-DC charger (Ranox) and my mains charger (Xantrex). On the basis that these reputable products provide temp compensation, I believe it is more than a theoretical consideration.

Cheers

Frank


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Follow Up By: Member - Captain (WA) - Tuesday, Dec 13, 2011 at 01:07

Tuesday, Dec 13, 2011 at 01:07
In my camper, I have both the Redarc bcdc 1240 and the Ctek 25A charger. Frank is right in that the Redarc has its temp sensor within the unit while the Ctek has a remote probe that simply clips onto the battery lead.

While there may be a theoretical advantage, in reality for my setup, the Ctek simply measures the temp some 300mm away - no difference for all intents and purposes. While they call the probe a battery temp probe, it can only be mounted externally so is really only a remote mount air temp probe.

Also, the newer vehicles that have temp sensing alternators (like my 200) are not actually "low output" systems, rather they are designed to prevent electrolyte boiling by reducing voltage. They are fully capable of "normal" voltages, but then reduce voltage as the engine bay (and thus batteries) warm up. While it helps battery life, it doesn't do camper battery charging any favours, hence the increasing widespread use of dc-dc chargers.

Cheers

Captain
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Follow Up By: Member - Frank P (NSW) - Tuesday, Dec 13, 2011 at 21:01

Tuesday, Dec 13, 2011 at 21:01
Captain,

My camper's Xantrex mains charger's temp sensor is quite large. It has a substantial metal tag to bolt onto a battery terminal. It is bolted to a positive battery post. The camper batteries are reasonably well insulated from the environment - they live in a closed box within a larger compartment.

The Prado's Ranox sensor is simply a thermistor which I have taped to the negative post then covered with a quite large carved-to-shape block of styrofoam that seals to the battery with foam plastic tape in an effort to insulate the sensor and the battery post from the direct heat of radiator fan blow-by. It's about the best I can do.

A question:

Given the shortcomings of a temp sensor taped or bolted to a terminal post rather than being immersed in electrolyte, which is the better post to use - positive or negative, or does it not matter?

Cheers

Frank

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Follow Up By: Member - Captain (WA) - Tuesday, Dec 13, 2011 at 21:47

Tuesday, Dec 13, 2011 at 21:47
Hi Frank,

The Xantrex sounds like a better temp measurement setup than the others, it should give a closer battery temp reading than the rest.

As for which battery post, I really think it would not matter. Probably best to choose the battery post based on physical location and influence by indirect heat like a radiator fan than whether its a +ve or -ve terminal.

Cheers

Captain
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Reply By: Mickfrom983 - Thursday, Dec 08, 2011 at 21:47

Thursday, Dec 08, 2011 at 21:47
Hi Cobsy.

I have been through a fair amount of research on this topic as I have just taken delivery of a new vdj76r myself.
The 76 alternators are ecu controlled to drop charge requirements when thre is low load on the system. Typically about 13 v under minimal load. The maximum charge I have measured under load is about 13.8v. I am lucky enough to have friends that are auto electrical specialists and are in the manufacturing field for high output alternators for emergency vehicle utilization that have suppplied me with info regarding the shortcomings of the 76 alternator.
On the vdj76r's alternator, there is a 4 wire plug on the side of the alternator. If the wire that has the prefix of 'M' as per the detail on the side of the alt. mysteriously becomes disconnected, the alternator performs as per normal (13.3-13.95v). However, trying to charge a number of batteries as you are indicating is going to be a large job for any alternator.
DC-DC devices will upstep dc voltage but it is an extremely complex system that i'm not going to gamble on when i'm in the middle of the desert with my family.
If you are interested I can supply you with the details of the company that custom CNC's alternators for the services. These are expensive but have outputs of 100-200A. As an aside to this, I have been advised that running standard lead acid type cranking and deep cycle batteries is definitely the go.
Expanded calcium grid types will take longer to get to full charge and provide relatively little in amp hour capability. More often than not, they never reach full charge, which shortens their working life.
I myself am running a redarc smart start isolator and that red (did I say that colour?) wire has fallen off the alternator, but I have the luxury of 160w of solar panel to charge up things when we pull up for a spell.
Best of luck.
AnswerID: 472005

Follow Up By: Member - Captain (WA) - Tuesday, Dec 13, 2011 at 12:08

Tuesday, Dec 13, 2011 at 12:08
Hi Mick,

Are you sure the 76 alternator is load sensitive? I was pretty sure that the 76 had the same type of alternator as the 200 and thats a temperature sensitive alternator. It varies the voltage based on underbonnet temp to ensure that the battery electrolyte does not boil under warm/hot conditions. If it was load sensitive, would it not increase the voltage when you applied the higher charging load of the aux battery?

I know my 200 alternator will vary from ~14.3V to 13.2V depending on temp, it is not load sensitive at all as I can switch on loads of ~50A and it makes no difference to the voltage, but the same load under different temp conditions result in a different voltage.

While diconnecting the M terminal will give a higher voltage, it does so at the expense of vehicle battery life, its why Toyota went to the expense of designing and installing it. Its your choice, but I think you are gambling more with your family in the desert by potentially overcharging the battery in hot conditions than any dc-dc failure, one that can be easily identified and overcome for the short term by simply charging direct with a lower voltage - or by simply using your solar panels.

Cheers

Captain
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Reply By: Mickfrom983 - Tuesday, Dec 13, 2011 at 18:39

Tuesday, Dec 13, 2011 at 18:39
Generally most lead acid type batteries will withstand 14v DC with no ill effect of boiling electrolyte. Calcium types will cop up to 14.5 max charge with no ill effect. The standard range of charge is 13.8-14.2v for most common type batteries. Granted that if your reg is letting the batteries have 14.2 all day long there will be some degree of electrolyte loss, but as i said, the vdj76r system maxes out at 13.95-14v dc no load. I am keeping a close eye on levels as I am only setting this one up at this point in time. The alternators being temperature compensated is a great lot of you know what as alternator zener diode packs have been "temperature compensated" for the last coupe of decades as have external regulators on the older type cars. It is definitely not a new phenomenon. Toyota have been asked why this system was designed as ECU controlled and the silence has been deafening. General concensus amongst automotive electronic personnel that I have spoken to is that apparently is that a lot to do with screwing the last bit of emmision control possible out out of an already efficient motor. Somewhere in the Euro III-IV range? I will post further down the track if I find anything to the contrary. Having worked in remote qld areas in drilling camps I try and live by the "KISS" rule especially when it comes to setting up vehicles that have to perform day in, day out.
Cheers,
Mick.
AnswerID: 472452

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