Ctek 250S Dual Solar Input - information

Submitted: Saturday, Sep 14, 2013 at 18:10
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Some months ago there was a discussion on MPPT and Solar and such chargers, and I suggested there shoul dbe no reason you could not use a high current power source of any descrition for the solar input - not just solar.

So just as a follow up on this and for information to anyone that may be interested, I recently tested my 250S with a high current supply for charging the batteries via the solar input and it appears it will charge at a max of 20 Amps the same as the alternator input (if the power source is capable).

The supply I used is not stabilised and starts about 17.5V at 0 Amps and ends up at about 12.5V at 16 Amps into the Ctek on initial charge, and I am assuming this is the best point determined by the MPPT of the Ctek. Should the supply be capable of more I would expect I would see 20 Amps into the Ctek at initial bulk charge.

Given there are 13.8 high current power supplies "off the shelf" these may be suitable for such use rather than messing around with additional multi stage chargers for people that have unused solar inputs and want to mains charge their batteries when at home.

This came about for me because I tried a couple of multi stage mains chargers directly connected to the batteries with the Ctek also connected and the chargers tended to get "confused" and not charge. So rather than have to mess about disconencting the Ctek, or buying the specific Ctek charger to do this, I decided to look at a different way.

Ken
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Reply By: gbc - Saturday, Sep 14, 2013 at 18:16

Saturday, Sep 14, 2013 at 18:16
Isn't that what the smart pass is for? To supply consumers separately and handle charge at up to 80 odd amps in conjunction with the 250s?
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Follow Up By: Nomadic Navara - Saturday, Sep 14, 2013 at 19:34

Saturday, Sep 14, 2013 at 19:34
No, the Smartpass is used to allow more than 20 A to be supplied to the battery when they are very flat. The Smartpass bypasses the D250S until the battery charge current drops to 20 A. When that point is reached the D250S takes over and boosts the alternator voltage to maintain a charge current of 20A or a charge voltage of the set absorption voltage.

Keith was talking about using a fixed voltage power supply to drive the D250S and using the D250S to provide the multi stage charging function.

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Reply By: Nomadic Navara - Saturday, Sep 14, 2013 at 19:38

Saturday, Sep 14, 2013 at 19:38
Keith, I would be more inclined to use a power supply with a minimum of 25 A output and feed it into the alternator input. Use a changeover switch to switch between the two inputs. That would leave the solar panels to be permanently attached to their input.
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Follow Up By: KenInPerth - Saturday, Sep 14, 2013 at 20:32

Saturday, Sep 14, 2013 at 20:32
Peter

There are of course lots of ways if doing pretty much the same thing.

The reason I am looking at this option is that I don't have solar at the moment and this involves no mecahnical devices as "weak points".

Also I think the alternator input will probably start cutting in and out with my current power supply which as I said is down to about 12.5V at 16 Amps - a better power supply would fix that problem.

If I add solar I envisage I would look at isolating the devices with diodes or do similar to what you suggest.

I figured when I bought the Ctek I would be crazy not to purchase the Dual even though I was not going to use Solar initially.

Ken
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Reply By: Member - GeeTee (NT) - Sunday, Sep 15, 2013 at 07:37

Sunday, Sep 15, 2013 at 07:37
Hi Ken, I have recently fitted a 250S Dual to my Patrol. Standard wiring and no problems. If I need to charge either battery, for whatever reason, is the system going to get confused if I hook my Ctek 15000 up direct to the main or second battery ? I have solar connected to the solar input. Should I disconnect the panels and use the solar input to charge the batteries and leave the system to sort it out ?

GT
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Follow Up By: KenInPerth - Sunday, Sep 15, 2013 at 11:33

Sunday, Sep 15, 2013 at 11:33
I would rather you ask Ctek those questions than give you information I am not 100% sure on. I played with my system knowing I was "experimenting" and may blow something up. The actual design parameters seem hard to come by even from Ctek tehmselves.

1300 605 499 or submit an email from their web site http://www.ctekbatterychargers.com.au/contact-us.html

I have always found them helpful but only within the limited information they seem to have on their own products (which is why I had to experiment a bit myself). You might only get a "that is not supported" answer so as to protect any warranties you have and their bums.

The D250S Dual manual shows the use of a Ctek M300 directly connected to the secondary battery with the D250S output - but nothing in regard to charging the main battery in these situations.

How the 15000 would react either being directly connected to the main battery or the secondary battery with the dual battery system in place I would not want to predict - as per the next paragraph.

I would not suggest using the Solar input for the 15000 because 1. the charger may get "confused" as to what it is connected to and 2. the alternator and solar inputs are in my mind designed for basic constant power sources such as alternator, solar, or as I suggest a basic "unintelligent" DC power supply. I don't think you would blow anything up but you may not get the result you want - like the recent post about the Ctek and the Fridge.

If I use a smart charger for the main battery I disconnect the other systems downstream, but others with much more experience than myself in this area may have a different answer. A manual isolation switch between the systems is always a good idea anyway and simple then to disconnect (but just as easy to forget to re-connect).

Ken
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Follow Up By: Member - GeeTee (NT) - Monday, Sep 16, 2013 at 07:07

Monday, Sep 16, 2013 at 07:07
Thanks Ken for your reply. I think I may just disconnect the D205S if the occasion ever arises that I need to charge the batteries with the 15000.

GT
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Follow Up By: Nomadic Navara - Monday, Sep 16, 2013 at 14:59

Monday, Sep 16, 2013 at 14:59
Just hook your mains driven charger direct to the auxiliary battery. The D250@ and the 15000 will have slightly different set voltages for the absorption charging. The one with the lower set voltage will simply go into its float setting when the other charger brings the battery terminal voltage higher than the lower one. The first charger to go into its float voltage will take no further action and the one still charging will finish the job off. There will be no conflicts.
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Follow Up By: KenInPerth - Monday, Sep 16, 2013 at 15:20

Monday, Sep 16, 2013 at 15:20
PeterD



Admittedly I was not using a Ctek charger, but when I did this with a couple of non-Ctek smart chargers they both stopped charging with indications like "faulty battery" or other erroneous errors.

Given he has a Ctek charger it may well work OK, but I was being cautious in not suggesting it would or could work with the 15000 as the manual for the 250 only shows the M300 as an installation option.

Hopefully it does if GT decides to try it, or hopefully Ctek would be able to confirm it would or should work.

Ken
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Reply By: Member - LeighW - Sunday, Sep 15, 2013 at 18:13

Sunday, Sep 15, 2013 at 18:13
I would assume the reason they say don't connect a high power supply to the solar input is that the mppt chargers works by loading up the solar panels till it finds the most efficient load it can apply to the panel for the most amps it can generate out to the battery.

I you connect the mppt to the high power regulated voltage supply as the mppt ramps up the supply will maintain a constant voltage and the mppt will keep ramping up as it will see no decrease in the input voltage.

If you have a large battery connected to the charger you could end up overloading the ctek, I know the the ctek DCDC charger from the alternator side is current limited to 20A but from the solar side using the mppt the charger might not be that smart to protect itself.

As Ctek are reluctant to release specs of their products due to supposedly protecting the technology from other companies the only way to find out would be to ask them.

From what I have been able to ascertain, it appears the inbuilt mppt controller in the ctek is not that good so I would suspect overloading would be the issue.

Connecting an unregulated supply of less the 20A output should present no problem to the ctek assuming it is within allowable voltage limits. However you might find that the ctek will then overload the unregulated supply if it pulls the input voltage to low.

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Follow Up By: KenInPerth - Sunday, Sep 15, 2013 at 23:33

Sunday, Sep 15, 2013 at 23:33
Leigh

Valid point.

I know this is a bit "out of the realms of probability", but the same could apply if you had enough solar panels such that you could obtain more than 20A before it found the optimum power point. For that reason I would expect they would protect the solar input as well. But admittedly that is an assumption.

That is a test I have not done yet and will post the result if I find out
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Follow Up By: Nomadic Navara - Monday, Sep 16, 2013 at 15:04

Monday, Sep 16, 2013 at 15:04
Quote "If you have a large battery connected to the charger you could end up overloading the ctek, I know the the ctek DCDC charger from the alternator side is current limited to 20A but from the solar side using the mppt the charger might not be that smart to protect itself."

It is known that the solar charging will not deliver any more than 20 A to the battery. It does not matter how large a solar array you hook onto the input the D250S will only take sufficient current from the array to charge at a maximum of 20 A.
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Reply By: Member - bungarra (WA) - Monday, Sep 16, 2013 at 10:01

Monday, Sep 16, 2013 at 10:01
My question refers to this charger but not the specific topic....however I am posting because obviously those contributing have experiences with this charger and I am keen to hear their observations:

I have recently fitted this charger under the bonnet of my 4.5L Land cruiser 79 series. The temperature probe was originally placed as per recommendations (on top of and adjacent to the terminals of the aux battery....{solar panels are also in the system})..........problem is that no matter where I placed the probe in the engine bay the charger went into temp overload warning.

I gave up and placed the probe in the grill to get some air flow so at least the battery got some charge. Placed anywhere else the charger is shut down over temp

The aux battery is about to be replaced ( no longer holds charge...this happened prior to installing new charger)....I have purchased a marine battery already for that role....waiting to install


I have also boosted the alternator charge with the diode......so I have two options to consider before I replace the aux battery....
Do I
1) Use the ctek with the probe at the grill.....using as designed...alternator + solar to mange the aux battery
2) Use the increased alt diode booster together with the dual battery controller (originally in use and still fitted but disconnected temporarily) to manage alternator charge and have only the solar side of the ctek to the aux battery

It is obviously damn hot under the bonnet and so others must surely have had this problem with the temperature probe.

Thanks



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Follow Up By: Member - LeighW - Monday, Sep 16, 2013 at 10:17

Monday, Sep 16, 2013 at 10:17
I think you'll find the over temp is because the charger is getting to hot, not the battery.

From memory don't Ctek state that the charger shouldn't be mounted under the bonnet or am I confusing that with the Redarc?

Anyway, you'll find that most if not all DCDC chargers when set to AGM will bulk charge at around 14.5V @)20C ambient, that is 97% of the charge is done at that voltage. Only the last 3% or so is done at a higher voltage to shorten the recharge time of the last 3%.

You'll probably find your alternator with booster fitted will charge at around 14.4V so your really not gaining much using the Ctek anyway.

The alternator will charger quicker at the start the Ctek quicker at the end of charging.

I would simply remove the Ctek and if the basic system works ok leave at that.

If you still want to use the Ctek re-install it somewhere cooler when you can.

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Follow Up By: Member - bungarra (WA) - Monday, Sep 16, 2013 at 10:46

Monday, Sep 16, 2013 at 10:46
Thanks for your reply...you well be correct although I am not sure as there is no alternative to placing the Ctek under the bonnet simply because the probe lead limits the charger to being within roughly 1 meter of the probe itself...which is stated as being at the battery receiving charge
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Follow Up By: KenInPerth - Monday, Sep 16, 2013 at 11:33

Monday, Sep 16, 2013 at 11:33
I have not had any experience with this problem (as my system is not under the bonnet of the vehicle).

May pay to give them a call (Ctek) or email as per one of the repsonses above and see what they can offer - I would not think you were an orphan in thsi regard.

Just looking at the installation guide for the unit it does not specifically mention anything I can see about not mounting it under the bonnet, and if I remember the sales video that is what they show.

The only thought I could add is that if you move the sensor to the grill and the battery gets some charge, then maybe that indicates the location of the aux battery is in a very hot spot (not gettig enough air flow itself for some reason) and not perhaps the best spot for the battery either - but not sure if you get any choices do you as to where to mount it, and surely the location would be a design consideration by Toyota ??

Hope you can sort it out - might also pay to post a new thread as some people will have given up looking at this one now and you will draw some more comment.
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Follow Up By: Member - bungarra (WA) - Monday, Sep 16, 2013 at 12:53

Monday, Sep 16, 2013 at 12:53
I have emailed Ctek......and will post their answer for all to see

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Follow Up By: Member - bungarra (WA) - Thursday, Sep 19, 2013 at 12:06

Thursday, Sep 19, 2013 at 12:06
As promised here is Ctek's email answer......firstly read my query...then their response

as you can see whoever answered the query didn't fully read/understand and do their homework on the questions.....cant be bothered answering them if that is the quality of there feed back and they don't fully understand what was asked (or they don't know their product they are agents for?)

Comment
Hi have a D250S Dual charger. I have mounted it under the bonnet in the only practical location (drivers side of Land Cruiser 4.5 diesel V8 79 series).

In this location the temperature probe lead reaches the aux battery (this battery adjacent to and immediately behind the OEM battery)....passenger side

Your unit shows over temperature and the only way I can get this charger to work is to shift the temp probe to the front grill area to get a cooler spot.

Given that the OEM battery is under exactly the same operating temperature as the aux. battery I am disappointed that your charger appears

a) either unable to operate under normal under bonnet operating temperatures or
b) is it that it considers the battery it is charging is at too higher temp to charge
c) if so then how is it that the OEM battery is being charged quite happily under that same temperature?
d) if it is the charger unit itself that is too hot (as against the battery temp with the probe at the terminal) then a longer lead is obviously required to allow the battery charger to be housed some distance away from the under bonnet it is currently limited to

I would appreciate your comment as to how to over come this situation as in purchasing this unit I thought I was purchasing the perfect unit.....and something is clearly limiting its operation under what I consider a normal operating / installation system

Their Response:
THanks for your email, Graeme

The D250s is subject to temperature the same was as your current alternator is,e.g reduces charge rate
as temperature of the battery increases.This is to stop the averse over charging and damage to he battery
that occurs with rise in temperature. External cooling in our extreme temperature variations is important for
long term life of our batteries.

As you most likely have notices that current battery installations have a cooling chamber round the battery vented
and a cool input duct to the front of the vehicle to try and over come the 50deg C temperatures experienced
in under bonnet temperature levels.

So the best way to over come charge difficulties withe the D250s is to provide cooling for the batteries and mount
the D250 is a cooled position possibly under the dash with the temp probes adjacent to the battery location.Do not
leave the temp probes under ha dash as this will cause improper charging as the cab is cooler than the engine
compartment.

As Ctek has not released any information on this, we have come to our own conclusions regarding the temp range that the
Ctek can operate under and as per the spec 50 Deg c is the maximum range it can extend to.

Hope this helps,

Regards
Peter
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Follow Up By: Member - LeighW - Thursday, Sep 19, 2013 at 12:28

Thursday, Sep 19, 2013 at 12:28
Yes they didn't really indicate if it is an other battery temperature or the Ctek charger is getting to hot ie over 50C.

It would seem they believe you should either force cool your batteries or move them to a cooler location, and do the same for the charger.

Bottom line would appear that the unit is not suitable for the intended application and if so desired you should receive a refund.

Else you could try heating the temp probe above 50C with the engine bay cold and see if the charger throws a wobbly, if it doesn't then only other option is to relocate the charger, try a different charger or charge method.

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Follow Up By: KenInPerth - Thursday, Sep 19, 2013 at 15:12

Thursday, Sep 19, 2013 at 15:12
Bungarra

Have you had a look at the video on the web site

http://www.ctekbatterychargers.com.au/ctek-d250s-dual.html

At about 23 seconds in it shows what is probably very similar to what you have .... so maybe we can track down the guy in the video ??

As you found out they seem to have very little published information from Ctek themselves and have to rely on what they know from experience or be very guarded in their answers.

I found it interesting the comment "As you most likely have notices that current battery installations have a cooling chamber round the battery vented and a cool input duct to the front of the vehicle to try and over come the 50deg C temperatures experienced in under bonnet temperature levels." Do you ??

Gvien you said you could re-locate the temp sensor and get some charging it does not sound like putting the Ctek itself in the cab will fix the problem.



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Follow Up By: Member - LeighW - Thursday, Sep 19, 2013 at 16:07

Thursday, Sep 19, 2013 at 16:07
Normal temperature compensation for a lead acid battery is around .005V a degree C, therefore if the temperature under bonnet rises from 25C to 50C your looking at a reduction in charge voltage of around .125V

The Ctek if similar to most other chargers, will bulk charge at around 14.5V therefore its output voltage at 50C should be 14.37V approx, this should voltage will still result in considerable current flowing into the battery.

If the Ctek stops charging above 50C it is because it is programed to, either because the battery probe has exceeded its allowable temperature range or the charger is to hot, not because of temperature compensation.

I have read that it is not desirable to charge a battery that's temperature is above 50C, to be realistic I would expect under bonnet temperature in Australia to be mainly above 50C in summer.
What does surprise me though is that I can only ever recall reading of one similar issue.

Still think you need to isolate to either the charger or probe. Try dropping the probe below the car or cooling with a damp cloth when the problem occurs and see if that helps, should prove or disprove the probe temperature is the issue.

If its the charger and assuming you can find a mounting position a cure should be achievable, if its the battery probe and you want to maintain temperature compensation as accurate as possible then perhaps mounting the probe on side of the battery facing the front of the car might help. At least you'll get an accurate reading for that side of the battery:)

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