AGM Cranking Battery

Thanks Mountainman. I have an AGM deepcycle and thats still going well and it was intalled in July 2006. Hope to get a few more years yet. I'll take on board your Cat suggestion, Have heard good reports of them. I seem to get 2 1/2 -3 years max from the Crankers so just looking at the options.

CAT stopped making their own batteries back in the mid 2000's if I remember. Now they appear to be just rebranded products from various battery makers.

Just be careful you are not paying extra for the yellow.

Hey Mountainman,

Where do you buy CAT batteries from other than a CAT dealership of which there are too many.
Cheers

lyn id like to see you buy a 1000 CCA battery for 140 bucks..

I didnt buy it because its got a CAT sticker, or the fact you think its yellow.. ha ha

i bought it because you CANNOT BUY A BATTERY THAT SIZE.. FOR THAT PRICE, AND ALSO get a decent warranty..

as for buying it for the yellow, their actualy BLACK..

yellow is optima, and there prices are a joke.. and still cant beat the CAT 1000CCA.

and as i said, its CAT. and being for the price, you get excellent bang for your buck, as well as the best warranty on the market for price.

CAT have specifications on all products they sell.

from the steel used in making their equipment, its to the CAT standard..
even they have their own bolts, to their specs..
batteries are the same.

whether or not some things are made by CAT or not, it has to meet their specs before it can be sold under the CAT name



yes their are a quite a few dealerships now..
either WESTRAC, or CAT itself.
i had the battery delivered from newcastle to gosford, and total cost ended up being 175, still even if it was for 250..
its still the best buy on the market.
by a country mile............................

man its got SOME GRUNT..
what more do i say, its AWESOME.

Thanks Phil, I'll check out the Optima website.

Thanks Allan, My deep cycle is mounted just behind the headlight and does'nt seem to be affected by heat although I intend to fit a heat shield around the engine side when I get a chance.
I'll keep my options open but I wouuld like to get a longer life from the Cranking battery.

Des,

I don't know what it is with batteries. Some claim 4 years, 5 years, even 7 years of useable life. I never seem to get more than 3 years no matter how I manage things! I cannot find a common denominator for this claimed longevity in lead-acid batteries.

I know, and generally follow, the rules for battery maintenance but to no avail. I hold hope for my recently revised charging setup for my auxiliary batteries but it is yet to be proven.

The embarrassing part is that as an electrical engineer, I should get better results. Are all those extended-life claims authentic or am I just a underachiever?

Alan B , the problem that you have with batteries is that you are an "electrical engineer" ,, automotive 12/24v is one thing ; yes a speciality; that does not mean knowing the be all and end all of batteries either , battery technology has moved leaps and bounds BUT the basic principals have NOT changed ,that being you can only get out what you put in charge wise of a storage unit ,,,problem is that soooo much conflicting information is available that the actual basics are forgotten ,,, and yes some get what may seem unreal 'life' from their battery , I still have the first AGM that I ever bought in 2002 , still going strong , been abused a few times in 4 different vehicles but never ever discharged BELOW an actual 12v ,,,,,

Allan I've had different types of Crankers over the years and I don't think that any have lasted more than 3 years regardless on how they have been maintained.
Alloy I hope my 2006 AGM will go for another 4 years too. I'd be wrapped

Yes Alloy, the other problem I have is that some people believe that I couldn't possibly have an understanding of any particular aspect or "specialty" of my vocation and lecture me accordingly.

Hi Allan,

having sold a couple thousand AGMs over the years, with zero defective returns for the last 3 years (except for two or three pieces which were chronically under-charged but which we were able to revive), I'd love to see you getting better service from your batts.
If you like you can post the answer to the following questions here.
That way I can try to identify any weak spots in your system.

battery type
mounting location
alternator voltage and current rating
wire gauge/length between alternator and aux battery
depth of discharge before recharging
how often per year do the batteries get cycled
any other charging sources
what's the charging voltages of these, possibly multi stage
does the battery get to see the absorption voltage for some time regularly
if yes, what is the absorption voltage in your charging setup
concurrent loads during charging
any chance of these loads upsetting the multi stage charging sequence, e.g. through prolonging the absorption stage
how do your batteries die: gradual loss of capacity or sudden cell short

cheers, Peter

Thanks Peter for your interest.

The battery performance (or lack of it) that I was referring to was the cranking batteries over a number of vehicles and more particularly in my current 2002 Troopy which has returned a life of no more than 2 years. I think that was an Exide Extreme N70Ex and was replaced with the same model just 2 years ago. It is still performing and I hope it continues to do so. It is used only for cranking and vehicle essentials.

I cannot recall the model of the original deep-cycle auxiliary charged directly from the alternator via a solenoid isolator. It also lasted about 2 years. That has now been replaced with two Exide Stowaway AGM ST27DC105 batteries individually charged by two Redarc BCDC1220 chargers which seem to be maintaining those batteries in good condition. I am hopeful of an extended life for them.

I can answer some of your more specific questions but the hour is now too late to examine the vehicle, so off the top of my head:

Battery type: As above
Mounting location: Cranker in engine bay, one aux in engine bay, other in cab.
Alternator specs: 14.58v hot, 130A max. Ripple 35A.
Alt/Batt cable: Original Toyota (whatever that is) with remote voltage sensing.
Depth of discharge (Auxiliary Batts) Never lower than 50%, 12.2V
Cycling per year: (Aux) 50 or 60 cycles to 30-50% discharge.
Other charging sources: Multi-stage mains charger several times per year. Voltage is as per CTEK 15A multistage.
Absorption: Yes, as per Redarc & CTEK chargers.
Concurrent loads during charging: Only a 4A max fridge and some phone charging. This does not appear to affect the charging algorithm.
Batteries have suffered capacity loss not catastrophic failure.

Hi Allan,

Alternator specs: 14.58v hot, 130A max. Ripple 35A - holy moly this is high voltage stuff :)
Do you know the output voltage when cold (25 degrees)?

Your crankers are all dying prematurely due to accelerated grid corrosion this high float voltage will cause.
I've attached a diagram which gives you an idea how severely battery life is affected by float voltage and temperature mismatch.
The apparent battery life reduction @ 35 degrees and 2.3V/cell is five fold.
And that's for 2.3V/cell but your cells float even higher at 2.43V, so depending on the amount of driving you do, it's no wonder your crankers don't last.
Chances are that by simply reducing your alternator voltage down to 13.6V you double the life of your cranking battery.



cheers, Peter

Thanks Peter for that useful information.
Whoops, typing error.....the alternator voltage spec should have been 13.58V so cell = 2.26V, somewhat better.
The premature failed battery was with a previous alternator of unknown specs so not really assessable. The specs quoted above are for the replacement (current) alternator and I have not validated them. I will do so when time permits and possibly makes some adjustments using the information you have provided.

Chisel, A mate bought one of those at the last 4WD show. Must ask how he is finding it.

Thanks Alloy. I checked wifey's Compass and the battery doesn't look anything special.

Thanks Peter, I'll have a look at your site a bit later.

Thanks Ajay. I'm sure that there are many who found your input helpful.