Dual Battery Setup - Basic Advice Needed.....

Submitted: Monday, Jan 09, 2006 at 16:52
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Hi everyone,

have been a long time reader of the posts on this site and they have provided invaluable information but this is my first post so please be gentle, especially as I am (very) new when it comes to things electrical!

I know there have been inumerable posts on dual battery set ups and what the best option is, but I was hoping that someone might be able to give me some'high level pointers' as unfortunately I will probably have to rely on the expertise of one of the main 4WD operations in Perth (ARB/ Opp Lock/ TJM) to set me up and I know from the posts I have read on this site that this can be dangerous if, like me, you dont have a huge amount of mechanical or electrical knowledge! I have done some research but unfortunately I have found it hard to compare what you are getting and I was hoping someone may be able to help. Hopefully my questions are fairly simple (and wont cause a huge debate!!)

Basically, I am after any comments on which of the mainstream 4WD outlets will provide a DB setup that will:

1. Run an Engel 40ltr for at least a couple of days (I know this is weather dependant but main usage will be average summer conditions for south west WA). At the end of the day I dont want something that it going to run out of juice after a day (unless of course temperatures and therefore usage are extreme). Ie what type and capacity battery should I ask for?
2. Has some sort of system to let me know when the auxiliary battery is getting low and therefore that we need to go for a drive
3. Whether there are any pitfalls/ specific requests that I should be making to whichever company fits it in terms of cabling, what can be plugged.

In terms of research so far, the Opposite Lock system appears quite attractive in terms of the management system (easy to read flashing lights!) and the fact that they run a decent cable down to the back. However, they just seem to use a normal cranking battery whereas the guy at ARB sounded fairly convincing when he was talking about the hybrid type. When I asked both of them about deep cycle batteries they basically said that they arent necessary for what I want them to do but the posts on this site would appear to disagree?

Apologies if this is a fairly common questions but am just looking for some 'no-nonsense' advice on the systems put in by the main operators in the market and whether they do the job.

Any thoughts gratefully received.

PS I have 3ltr GU4 so have plenty of space under the bonnet

Cheers
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Reply By: Mainey (WA) - Monday, Jan 09, 2006 at 17:23

Monday, Jan 09, 2006 at 17:23
Darren,
What part of Perth do you live or work in?

If you read any Australian battery suppliers web site they will explain for you the reasons why a Deep Cycle battery is superior to a Cranking battery for powering a constant low drain item, like a 12v fridge, and the real benefits of using a Cranking battery as the Start battery in the vehicle, the batteries that are made "in between" these specifications and by the same manufacturers, do a bit of both jobs probably reasonably well, but not as good as the battery that is specifically built for the job intended.

You say you want "no nonsense" advice on the systems used, then you should also ask about the WARANTY supplied and the technical specifications of the unit and installation materials used also.

Mainey....
AnswerID: 147436

Follow Up By: Darren C - Monday, Jan 09, 2006 at 17:43

Monday, Jan 09, 2006 at 17:43
Cheers Mainey - work and live pretty centrally but have been going to suppliers in Osborne Park for advice.......will push them more on deep cycle as they just dismissed it for some reason.....hence my confusion

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Follow Up By: Notso - Monday, Jan 09, 2006 at 18:57

Monday, Jan 09, 2006 at 18:57
What you say is true, but there are some other considerations. Unless you buy one of those expensive AGMs or similar, a deep cycle battery will not take much in the way of charging AMPs. Most of the standard deep cycles won't take more than 8 amps per hour. If you flatten it significantly it will take hours of driving to whack any decent charge into it.

The hybrid type is a good alternative as it takes a high charge rate and has a pretty good resistance to charge discharge cycles.

Other things are that if you run a standard sort of smart isolator then most auto electricians will say match your batteries.

Anyhow I have run matched batteries for for nearly 6 years now and just replaced both in the past few months.
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Follow Up By: Mainey (WA) - Tuesday, Jan 10, 2006 at 14:08

Tuesday, Jan 10, 2006 at 14:08
Darren,
Contact
Bryan Mc.
Opposite Lock, 35 Welshpool Road, Welshpool

or
for Batteries, Chris at 'Challenge Batteries' Ossie Park!

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Follow Up By: Mainey (WA) - Tuesday, Jan 10, 2006 at 14:47

Tuesday, Jan 10, 2006 at 14:47
Notso,
are you aware where can I read confirmation of your post "Most of the standard deep cycles won't take more than 8 amps per hour" from a battery manufacturer?

I'm sure my Delkor Calcium Deep Cycle batteries accept far more than a lousy 8 A/h.

Not seeking an argument, just clarification :-)
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Follow Up By: Shaker - Tuesday, Jan 10, 2006 at 15:32

Tuesday, Jan 10, 2006 at 15:32
I don't think the Delkor Calcium is a true deep cycle battery, I have one in my CT & when i bought it I was told it was actually better than a deep cycle for my use.
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Follow Up By: Notso - Tuesday, Jan 10, 2006 at 18:51

Tuesday, Jan 10, 2006 at 18:51
http://www.lakecomm.com.au/batteries.html

The reason why they won't take a fast charge is that the plates are less porous than the cranking type batteries and they quickly build up a surface charge and resistance builds up limiting the amount of amps passing into the battery.

The only way to fully charge a deep cycle battery, other than "the more expensive ones" like AGMs ,is to do it over a longer period at lower amps. Auto electricians I have spoken to basically say the same thing, even going so far as to say that Alternator charging will kill them quickly. Apparently Gell Cells are also damaged in a Vehicle Environment as well.

There is a special charger that is used in Caravans that takes the voltage supplied from the vehicle charging system and then converts it to a suitable charge rate and voltage for your house battery. Basically a 12 Volt smart charger.

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Follow Up By: Notso - Tuesday, Jan 10, 2006 at 19:12

Tuesday, Jan 10, 2006 at 19:12
http://www.trojanbattery.com/Tech-Support/BatteryMaintenance/ChargerSelection.aspx

Check this out as well. They recommend between 10 and 13% of the Deep Cycle Batteries 20 Hour rate. EG a 75 AH battery would take between 7.5 and 9.5 Amps.
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Follow Up By: Mainey (WA) - Tuesday, Jan 10, 2006 at 20:05

Tuesday, Jan 10, 2006 at 20:05
Notso, the first web site shown is the Battery CHARGER selection for Trojan Batteries.

"CHARGER Selection:
Most deep cycle applications have some sort of charging system ALLREADY installed for battery charging, (e.g. SOLAR panels, inverter, golf car charger, ALTERNATOR, etc.)
However, there are still systems with deep cycle batteries where an individual charger must be selected. The following will help in making a proper selection. There are many types of chargers available today. They are usually rated by their start rate, the rate in amperes that the charger will supply at the beginning of the charge cycle. When selecting a charger, the charge rate should be between 10% and 13% of the battery's 20-hour AH capacity. For example, a battery with a 20-hour capacity rating of 225 AH will use a charger rated between approximately 23 and 30 amps (for multiple battery charging use the AH rating of the entire bank).
Chargers with lower ratings can be used but the charging time will be increased. Trojan recommends using a 3-stage charger, also called "automatic", "smart" or "IEI" chargers, these chargers prolong battery life with their well programmed charging profile. These chargers usually have three distinct charging stages: bulk, acceptance, and float" {coppied in full}

Notso,
I believe the basis of the original Post was more relevant to an alternator charging the Aux battery, not an external Solar panel or a 240v 3 stage battery charger.

And from the http://www.lakecomm.com.au/batteries.html web site:
“Delkor, now a well established battery throughout the world, brings a NEW technology, highly reliable battery. For most low current consumption applications, the maximum rated A/H capacity is FULLY USABLE. The use of Calcium alloy grids and low resistance envelope separators means that Delkor batteries have 20 % improved charging ability, when compared to other batteries even during intense heat or cold”

I believe I've previously stated my Aux battery is a Delkor Calcium Deep Cycle battery, and your website above has stated “the Delkor Calcium Deep Cycle battery has a 20 % improved charging ability over other batteries” Yes they're their words, not mine, and they are a Trojan dealership.
Delkor DC batteries are a 'quality' battery, for the reasons the website states!
‘Challenge batteries’ in Ossie Park can show you the technical specs for the batteries.
{and I don't really work for either company}
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Follow Up By: Notso - Tuesday, Jan 10, 2006 at 20:11

Tuesday, Jan 10, 2006 at 20:11
Yep,

20% better that 10% is 12%. Or 20% better than 13%, well better work that out for yourself, it's beyond my mental capacity

Thats a lot less than a Hybrid type will take?

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Follow Up By: Mainey (WA) - Tuesday, Jan 10, 2006 at 20:56

Tuesday, Jan 10, 2006 at 20:56
"Yep, 20% better that 10% is 12%. Or 20% better than 13%, well better work that out for yourself, it's beyond my mental capacity ???
That’s a lot less than a Hybrid type will take"

Notso, Look at it another way, lets call it the BIGGER picture shall we :-)

A Deep Cycle battery, and as your website has stated, the Delkor in particular, can be discharged far, far and even more far than any Cranking battery, any 'Marine' or any ‘Hybrid’ battery, for the same reason you are using to say they recharge slowly they also DIScharge more slowly than ALL other battery types.
They require far less frequent recharging over any given time.
If you recharge them daily, then because the Delkor DC has actually discharged far less than any other ‘standard’ battery given the exact same use, it requires less recharging, and will probably go a few more days before it requires or it even gets recharged, taking it down to below the useful service level of a ‘non-DC’ battery.

You say “It takes a lot less than a Hybrid type will take” but it also needs less than a Hybrid!

Do you understand what I’m trying to say? {all said very nicely}

A [test] idea;
Fully recharge a (?type?) battery
Next day at 6.55PM measure the battery voltage
Connect a fridge and turn on at 7PM, run fridge @ -1 degree internal temp, 25 ambient.
Disconnect the fridge next day at 7PM (24 hours)
Measure the battery voltage the following day at 7AM. (to eliminate ‘surface’ voltage measurement)

Does the Cranking, Marine and Hybrid batteries all show less voltage than a Deep Cycle battery of the same case size?
I believe the answer is a resounding, yes!
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Follow Up By: Notso - Tuesday, Jan 10, 2006 at 21:36

Tuesday, Jan 10, 2006 at 21:36
Yep,

The thing i,also said wiv a smile, is, Lets take another example.

You pulss up afetr a nice long drive at a nice camp. Battery starts discharging. Say for 12 Hours at a nominal say 2 amps per hour. Thats about 24 Amp Hours ignoing inefficiencies and other stuff like bias etc. Then the next day you drive say an hour or so looking around the place. That puts say as an optimist 12 amps into a deep cycle battery or up to 40 or so into a Hybrid or cranker. Now do the sums and see how long the battery will las.

Nother thing, your delkors cost a lot more than a cranker or Hybrid, Nother thing the warranty on a cranker or hybrid is longer than a deep cycle. Don't know about a delkor cos I can't afford one to find out.

Last thing, my final out if you do manage to convince me is that I reckon your Delkors fit into My "Expensive AGMs or similar" Nuff Sed
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Follow Up By: Mainey (WA) - Monday, Jan 16, 2006 at 13:45

Monday, Jan 16, 2006 at 13:45
Shaker posted this followup
-> "I don't think the Delkor Calcium is a true deep cycle BATTERY, I have one in my CT & when i bought it I was told it was actually better than a deep cycle -> FOR MY USE"

Now I'm really confused :-)
what's "your use" ??

Delkor, is the brand
Calcium, is the material used with the "lead/calcium" plates
Deep Cycle, is the 'type' of use the battery is designed & manufactured for

the Delkor Deep Cycle battery has the initials DC written on the side
the Marine battery has M
followed by the number relevant to the battery capacity
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Reply By: Member - John - Monday, Jan 09, 2006 at 18:54

Monday, Jan 09, 2006 at 18:54
Darren, have a chat to the 12 Volt Shop in Kewdale. They may be able to help you out better than the Major 4 WD Stores. http://www.12volt.com.au/ Hope this helps.
John and Jan

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Reply By: Member - Glenn D (NSW) - Monday, Jan 09, 2006 at 19:26

Monday, Jan 09, 2006 at 19:26
Hows it going Darren,

Made my own dual set up using the REDARC smart solenoid, I got an Exide extreme to match my cranking battery.

Went round oz the year before last and the only problem I had was after we stayed at Katherine Gourge for 5 nights the battery was fully discharged. It was running a 40lt Engle in high thirties every day plus fluro lights at night.

It is not ideal to totally flatten a cranking battery every day and they would soon die if you did , a deep cycle battery handles this ok. The reason I got a cranking battery was that it was about a quarter the cost of a deep cycle battery and I thought that we normally wouldnt spend 5 nights without even starting the vehicle.

Get a price off a local auto electrician , you may be surprised.

Hope this helps

Glenn
AnswerID: 147459

Follow Up By: Member - Luxoluk - Monday, Jan 09, 2006 at 20:05

Monday, Jan 09, 2006 at 20:05
I'm with you Glenn. I'd suggest an ARB battery tray, Redarc solenoid and a matching starter battery. I've done all the deep cycle bullsh#t in the past and are now over it!! I want to travel, not spend my life pre-occupied with how well the deep cycle is taking charge!! Cheers
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Follow Up By: Leroy - Monday, Jan 09, 2006 at 20:24

Monday, Jan 09, 2006 at 20:24
My exact setup also Darren as well as a few friends. No nonsense reliable beer cooling setup. I'd also recomend getting an auto elec to install as he has the proper gear for crinping cables etc. I use an exide extreme n70 and it will cope for a couple of days and for the cost of this batt you can afford 2-3 for the price of a deep cycle.

Leroy
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Follow Up By: Nick R - Monday, Jan 09, 2006 at 23:16

Monday, Jan 09, 2006 at 23:16
I did my own too, done 2 now, happier with the latest one. Went to the auto electrician and got all the bits, voltage sensitive relay (140 amp), battery tray & battery isolator, went the battery isolator so I can jump start if i need to or if I get a winch and feel the need for 2 batteries. went for a deep cycle, my understanding is they handle a major discharge (like the fridge and lights for 4 days) better than a cranking battery, not sure if that is true or not.
I also bought solder on connectors, had heaps of wire around so used 25 sq mm.
NickR
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Reply By: Member - Andy Q (VIC) - Monday, Jan 09, 2006 at 21:52

Monday, Jan 09, 2006 at 21:52
G'day Darren, Yeah man! go with the set described by Glenn, luxoluk and Leroy. There is some doubtful statements though as far as price of cranking batteries and if these guys are right, exide batteries are overpriced. Do what i did and go to your local Battery World and price them, I have never had trouble with the Century batteries I've used, both Deep Cycle and Cranking.
Just a word olf advic...shop around for the best price on batteries, whatever brand you go with.
andy
ps my system runs 40L fridge(non stop), compressor, accessory lights, chargers for sat phone, mobile phone, camera and when the camper is towed, lights, fridge and other accessories.
AnswerID: 147496

Follow Up By: Mike DiD - Monday, Jan 09, 2006 at 22:58

Monday, Jan 09, 2006 at 22:58
Isolators
- don't spend too much money on the Isolator - no matter which one you buy, they ALL charge the Auxiliary Battery simply by connecting it to the Main Battery.
- features that are useful are indication of Auxiliary Batt Voltage and selectable load cutout voltage to protect the Battery.

Batteries
- people who get good peformance per dollar use the Exide Extreme or the Chinese AGMs (Remco, Fullriver). Both of these are Hybrid Starting/Deepcycle.

Mike
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Reply By: South - Monday, Jan 09, 2006 at 23:07

Monday, Jan 09, 2006 at 23:07
I would suggest getting a price list for all the products the stores are going to use and compare them to obviously get the best deal. By doing the work yourself or with the hand of a mate you can easiy save 50%.

These figures are from our installation roughly 2 years ago. Piranha battery tray $90, 75A Deep Cycle battery $150 (should have shopped around on that one, but I was being impatient) and Redarc Solenoid $145 (that was the best price in Perth, the easties get them around $90-100). Couple of circuit breakers, wiring, connectors etc would add up to about $50.

You can always buy the parts seperately and have a go at doing it, once you lay down a plan its pretty straight forward. Even if it takes you a weekend its still good practice for future installations and if your up the duff out in the middle of nowhere because of a battery issue, you may be able to rectify the situation with your new found knowledge...
AnswerID: 147513

Reply By: Nick R - Monday, Jan 09, 2006 at 23:21

Monday, Jan 09, 2006 at 23:21
I recently learned something more about batteries.
Some come withsecondary posts with wing nuts, the current you can draw off these is less than 1/2 of the battery's potential. I now have very little connected to those terminals preferring to use the main posts.
NickR
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Follow Up By: Mike DiD - Tuesday, Jan 10, 2006 at 12:11

Tuesday, Jan 10, 2006 at 12:11
"the current you can draw off these is less than 1/2 of the battery's potential."

For the typical 4WD size battery, that would be about 200 AMPS.

Mike
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Follow Up By: Mainey (WA) - Tuesday, Jan 10, 2006 at 14:28

Tuesday, Jan 10, 2006 at 14:28
Nick,
the (generally) stainless steel bolt you refer to is actually attached to the base of the battery post in "quality" batteries, maybe in elcrapo, discounted low priced batteries your information could be partly correct, but that is what you miss out on when you don't buy quality products !!!
Sure you will save some money initially, but, as you say, you will have an underperforming battery, and that's just a waste of money.
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Reply By: pac374 - Monday, Jan 09, 2006 at 23:26

Monday, Jan 09, 2006 at 23:26
Hi Darren
i have a Arb dual battery system in my Patrol GU 3ltrIII and has worked perfectly for three and half years. I have a Delkor M27 Battery which is a marine battery (calcium)sealed. I ran my 40l engel of it for days (only on 1.5 setting) and i now have a 80L engel which will run it for a few days in hot weather. The battery has work well for me, but i have now just bought a honda gene and battery charger to charge my aux battery so i dont have to turn my car over on our week long fishing trips.
I am only new to this forum thing so i might get shot down in flames with this method, but i am only really experimenting myself at this stage.
Hope this helps you out a little
Pac
AnswerID: 147523

Reply By: Mainey (WA) - Tuesday, Jan 10, 2006 at 02:07

Tuesday, Jan 10, 2006 at 02:07
Buy the best "technology" you can afford.......

If you want good advice on batteries go to a specialist who sells only batteries!!

If you buy a solenoid system that is rated as NOT suitable for two 'different' types of batteries then you are restricted to using two 'identical' cranking batteries to run a fridge.

If you get (?????) brand Electronic Isolator that is guaranteed to work with two 'different' types of batteries you can use a Deep Cycle battery, and they will both recharge fully and correctly, as I originally bought a Smart Solinoid system, it did not fully recharge the DC battery fully, so I replaced it, and now I have no hassles.

Read the forum replys, check the guy's who have problems recharging their batteries and you can put together your own idea.

I believe you will find most who use two identical cranking batteries will also use a solenoid system, and many if not all of them say they can NOT use a Deep Cycle battery because it will not fully charge.

Most of those who use the top end technology use Deep Cycle batteries as Aux batteries, and appear to have no problems....

Ask for breakdowns of different Battery and isolator systems ?
with the result of a fully charged Aux battery as the priority....

What do you believe the results will tell you???

AnswerID: 147532

Follow Up By: Leroy - Tuesday, Jan 10, 2006 at 08:29

Tuesday, Jan 10, 2006 at 08:29
'Most of those who use the top end technology use Deep Cycle batteries as Aux batteries, and appear to have no problems.... '

And everyone I know including myself who uses a solenoid isolator (ARB/Redarc) with an Exide Extreme have no charging problems at all and are powering 40l and 60l Engels and lights.

Leroy
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Follow Up By: Mainey (WA) - Tuesday, Jan 10, 2006 at 13:51

Tuesday, Jan 10, 2006 at 13:51
Leroy, Yes that's what I'm saying
but ....
have you attempted to use a Deep Cycle battery ? ?
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Follow Up By: South - Tuesday, Jan 10, 2006 at 16:37

Tuesday, Jan 10, 2006 at 16:37
Mainey, we are using a deep cycle with a Redarc and have absolutely no problems with it getting a full charge. Handsfree, radio, uhf, fridge, lights dvd player and TV all run off this battery and it shows no sign of deterioration...
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Follow Up By: Mainey (WA) - Tuesday, Jan 10, 2006 at 20:13

Tuesday, Jan 10, 2006 at 20:13
South,
That's the best news I have read here today.....
Can you inform me as to what Brand and size of DC you use?
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Follow Up By: Leroy - Wednesday, Jan 11, 2006 at 10:09

Wednesday, Jan 11, 2006 at 10:09
Not used one and don't intend to. don't feel it necessary for what I and most people do. Refer to my reply further up.

Leroy
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Follow Up By: Mainey (WA) - Wednesday, Jan 11, 2006 at 12:36

Wednesday, Jan 11, 2006 at 12:36
Leroy, yes point taken
however, for those who camp for long periods in one place, a Deep Cycle battery will deliver low current for much longer periods of time than a cranking battery will, which are designed for quick shallow burst, as is used in starting the vehicle, which is then quickly charged as you drive, whereby the "long term" camper generally has a portable Generator or Solar system to recharge their (deep cycle) Aux battery system.

As you have said above you "have not used, or intend to use a Deep Cycle battery" so I understand and believe you would not really be able to comment on any perceived effectiveness or otherwise, of a Deep Cycle battery, either positively or even negatively, other than what you have read, or had the opportunity to observe of other peoples Deep Cycle battery systems, as you have also stated above :-)

The battery manufacturers themselves actually state the technical specifications of a Deep Cycle are far better for powering a fridge and all the associated auxiliary electronic camping equipment, whereby the Cranking battery is designed specifically for and is superior at starting the vehicle.

Leroy, as you suggest, it’s a case of 'horses for courses'
what’s good for one, is not suitable for all, for many & various reasons.
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Follow Up By: South - Wednesday, Jan 11, 2006 at 13:45

Wednesday, Jan 11, 2006 at 13:45
Mainey,
I think its a Century and its a 75A jobbie.
I will confirm these details when I check later...
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Follow Up By: scottp - Thursday, Jan 12, 2006 at 20:05

Thursday, Jan 12, 2006 at 20:05
Mainey,

do you beleive that a quality deep cycle battery will be better suited to camping for 4-5 days than an agm

I have a couple of CAT PHO batterys. One of them is a 190 ah which will run my 40 ltr engel for 6 days in the sunshine coast summer heat set to below 4deg C. It ran completely dead and took over 24 hours to recharge with a 50 ah automatic charger when I got it home. The charger thumped 40-45 amps into it to start with but spent moast of the time set at 10-20 amps. (Charger has needle guage showing output into the battery)

Knowing that this battery is a said Hybrid that is built to withstand full discharge and re charge cycles I was still dissapointed with its recharge time.

Should simply wait till our current batterys are caput and buy agm's regardless of the expence.

Is this the advice we should be giving darren?

I have to get an new battery that will fit under the bonnet of my new hilux as the 100ah is just that little bit to big. So I find myself asking the question- "AGM, DC, or another hybrid" Leaning towards AGM.

What do u rekon?
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Follow Up By: scottp - Thursday, Jan 12, 2006 at 20:08

Thursday, Jan 12, 2006 at 20:08
"should we simply wait......."
Sorry! typo!
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Follow Up By: Mainey (WA) - Saturday, Jan 14, 2006 at 13:46

Saturday, Jan 14, 2006 at 13:46
scottp, you asked "Mainey do you beleive that a quality deep cycle battery will be better suited to camping for 4-5 days than an agm"
You really have to compare Apples with Apples, what A/H capacity batteries??
as any old fashioned 150 A/h 'Deep Cycle Wet cell' battery will for sure outlast in single use any 75 A/H AGM battery, AGM is only a design/specification name and any two Deep Cycle batteries of the same Amp Hour rating "should" last the same time in a single use situation, it's when you have to recharge them that the AGM battery wins.

scottp, you then say "I have a couple of CAT PHO batterys. One of them is a 190 A/H, which will run my 40 ltr engel for 6 days"
Yes, as you say the battery is rated in Amp Hours, so I then have to assume it's general purpose as it's rated by the battery Manufacturer in Amp Hours, is as a Deep Cycle battery, or you would have said it's a 750 CCA 'Cranking' battery but you say it's an A/H rated battery, not CCA, and you get 6 days from it, so is your point that you think you would less days from a Cranking AGM battery?
What does is Retail for $$$ ??
and what physical size is it ??

My next battery system will be a Deep Cycle AGM battery.......
not a Cranker or Hybrid AGM, as many companies will sell all AGM's as suitable for a Deep Cycle batteries, when in fact some are not, as some are Cranker batteries with high cranking amps and low a/h, their main benefit is, as you have correctly stated, is they recharge very quickly, but the Deep Cycle AGM cost big dollars when compared to a conventional 'Wet cell' Cranker battery.
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Follow Up By: scottp - Saturday, Jan 14, 2006 at 14:34

Saturday, Jan 14, 2006 at 14:34
The battery is rated as a 1300 cca 190 ah.

527mm x 218mm x 248mm

Weight = 54kg

http://www.cat.com/cda/layout?m=37407&x=7

part number 9x9730 If you want to have a look at the
-" Battery Product Line Specifications" link at the above page

retail: guessing around $350.00 - $380.00

I didn't buy it. The truck it was in melted one of the terminals and the battery was replaced under warranty. I just reshaped the terminal and good as gold.

The point was to tell darren c that deep cycle AGM's are the way to go.
Just spend the extra dollars so that when you are camping and the battery goes flat, you know that the agm will charge of the alternator in a hurry, and get you through another night.

There is only one thing worse than warm beer, and that is having to put up with the missus complaining about warm wine.

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FollowupID: 401773

Reply By: tonysmc - Tuesday, Jan 10, 2006 at 09:56

Tuesday, Jan 10, 2006 at 09:56
Darren, After years of experimenting with dual batteries, I have to agree with the 2 starter batteries and the kiss method. "Keep it simple" I think you anwered your own question when you said that you "dont have a huge amount of mechanical or electrical knowledge!" By keeping it simple, in a way you understand how it works, if something goes wrong you can get parts and fix it yourself or any mechanic could. All these electronic gismos look flash, but if they stop working you can bet its out somewhere remote and its not fun opening a fridge to that wonderful smell of your food going off!!!
The only thing I would add and I believe you must have (no matter what type of battery you get) is a low voltage cut out switch. There is no use trying to get more power out of a battery once it is flat.
Good Luck. Tony
AnswerID: 147551

Reply By: Darren C - Tuesday, Jan 10, 2006 at 11:42

Tuesday, Jan 10, 2006 at 11:42
Thanks for all the common sense replies guys, based on your replies it sounds like deep cycle may not be the way to go and that a simple cranking battery as the auxiliary will be sufficient for our needs. I just didnt want to end up kicking myself for not getting deep cycle or missing something else fundamental without some impartial advice which is what this forum is great for especially when you are shelling out a reasonable amount of cash.

As some of you have said, keeping it simple will work best but think I may still have to let the experts fit it - dont think my other half would appreciate (or trust) me ripping off panels etc to run cables down the back etc!! Dont worry though - I am on a mission to start looking under the bonnet more........

Cheers
AnswerID: 147567

Follow Up By: Mike DiD - Tuesday, Jan 10, 2006 at 23:01

Tuesday, Jan 10, 2006 at 23:01
I think most were suggesting a Hybrid (characteristics of Starting AND Deepcycle) rather than a starting battery e.g Exide Extreme.

Mike
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FollowupID: 401015

Reply By: Sand Man (SA) - Tuesday, Jan 10, 2006 at 12:06

Tuesday, Jan 10, 2006 at 12:06
Darren,

One point that hasn't been made clear to you is that battery capacity (available Amp Hours) will depend on the amount of "spare" room you have in the engine bay of your vehicle. This will largely determine the physical size of the battery you can fit and therefore the Ah (Amp hour) capacity it provides.

The 12 volt shop should be able to give you good advice to assist your choice.

Two recommendations I would suggest you look at seriously.
1. Use a Deep Cycle Battery as your secondary one, of AGM style if you can afford it.
2. Although a 75Ah battery should give you 2 days of operation on your 40L Engel without dramas I would include a Low Voltage Cutout device to protect the battery from draining down to full flat. I have found the Projecta Over Discharge Protector (ODP500) device to be a simple solution and available for about $30 from KMart, Repco, or maybe even the 12 volt shop.
Bill


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AnswerID: 147574

Reply By: Darren C - Tuesday, Jan 10, 2006 at 23:46

Tuesday, Jan 10, 2006 at 23:46
Ok, think I have it now

If I go for a hybrid battery that should serve my purpose and I should be Ok in terms avoiding any major charging problems caused by it not matching my starting battery. The Exide Extreme seems to be fairly popular so will probably pursue something along those lines.

Just out of interest and probably another stupid question but how do you guys know when you secondary battery is getting low and need to go for a drive? I know that there are a couple of systems (eg Opp Lock) around that visibly show the charge levels of each battery and thought that this would be useful but perhaps there is an easier way as none of you have mentioned having such a set up?

Thanks for all your help
AnswerID: 147703

Follow Up By: scottp - Thursday, Jan 12, 2006 at 20:27

Thursday, Jan 12, 2006 at 20:27
piranah battery monitor works great for me!
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FollowupID: 401400

Follow Up By: Mainey (WA) - Sunday, Jan 15, 2006 at 14:02

Sunday, Jan 15, 2006 at 14:02
Darren, a ($39) 12v battery guage will show you exactly what is available in your battery, IF you are not measuring the recently recieved 'surface charge' soon after recharging the battery, and that goes for ALL battery measuring devices.

The better one to get is one that only has the numbers from 10v to 15v showing on the guage, as the relevant numbers between 11.8v and 14.4v are more easily read.

As for what battery to use, I would be reading the relevant web sites of the battery manufacturers and companies who specialise in batteries for powering fridges etc :-)
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FollowupID: 401906

Follow Up By: Leroy - Sunday, Jan 15, 2006 at 14:21

Sunday, Jan 15, 2006 at 14:21
A 20 buck multimeter is a wise investment. You can use it for other things than measuring your batt voltage also.
To get a feel of how your batt is going you could measure the batt voltage in the morning, arvo and evening. From this you could decide if you need to go for a drive. Never let it discharge below 10.5 volts as it won't last long being discharged this low. Try keep above 11.5v. Do your measurments over a couple of days. I don't even check the batt. voltage much these days as I know it will be ok for 2 days. After this i may pull the multimeter out.

Leroy
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FollowupID: 401910

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