Using a flooded starter battery for dual battery install and some deep cycling

[DaveInDenver]

Have you ever used a starter battery for occasional deep cycling? What kind of life did you see from it?

When I had an Odyssey die in spring about 2 years ago I bought the cheapest 12-month warranty Walmart battery I could find in the size just to keep my battery system intact for camping season. It was I think about $45, made in Spain. It ran my Engel for a few months while the warranty situation was sorted. After that it became my portable ham station battery, so it got deep cycled a few more times.

About a month ago the battery in her Subaru started taking a dive and it just so happened to be the same size, so now it's running her car daily, this being the first time actually being used as a starter battery and it's doing its job still. It gets charged and kept topped, so that helps. I'm not really demanding on the second battery, it's just an Engel (no lights, no devices) for a day or two. So it's not getting run down to 0% routinely and asked to fast charge every day.

It's not ideal but I don't think you're completely nuts. Will a starter type have less useful capacity than a true deep cycle? Yup, definitely. Will it age quicker? Yup, no doubt. Is sharpening the pencil and determining that periodic replacement is doable? Maybe. If you're buying a battery and the cost is a wash, get the deep cycle for deep cycle application. It'll work better and last longer.

As a true house bank doing starter batteries isn't a good choice, though in this case if you already have a spare battery or the cost difference is truly significant between a true deep cycle and a starter type you might be able to make it work if the price-vs-performance-vs-life curves meet at a reasonable point. In light use like this (which is really dual use or redunancy) you might go a year, it might go three.

 

[highwest]

Good on you @OllieChristopher. It’s refreshing to see decision-making that doesn’t involve every top-of-the-line item (and associated bills). If it doesn’t work out, you can always get a more exotic battery next time. I’m looking forward to seeing your experience/results of this case study.

 

[billiebob]

Why are you comparing 1 $140 battery to 2 $300 batteries and why are you replacing the starter battery?
CCA for starting an engine are not the same thing as the slow steady draw on an RV battery.

Smart choice is pick the correct battery for the application.

And I doubt anyone will let you scam them on the warranty.

 

[john61ct]

If the **only** location to add a House bank is inside the engine compartment (wut?)

them my apologies I missed that detail

 

[john61ct]

I did not claim that these GCs, the cheapest possible worldwide that are still true deep cycling, could go over a decade.

EoL is supposed to be 80% SoH, but 70-75% is acceptable for consumers and non mission critical applications.

If you aren't measuring SoH then claims about longevity are meaningless.

But yes absolutely common for some lead banks to last 10-14 years, and that's with daily deep cycling, although on the shallower side, not all the way down to 50%.

That factor alone can extend lifespan by 2-4 times. Obviously to get there need meticulous care on all the other factors as well, all of which are only worthwhile starting out with a large bank worth many thousands, and a mission critical context.

My point in all that is **not** pushing any one regime, just that **only** FLA out of the lead chemistries can do this.

No AGM can.

And that FLA is easier to care for, its longevity does not require as much meticulous precision.

And it starts out as much cheaper up front, only getting more so every year after AGM would have reached EoL.

Yes of course LFP is "better" for many reasons, especially the top cell makers proven over decades,

but in NA price value is not one of those reasons, really is better to keep as a completely different topic from comparing the various lead deep cycling options.

By the way GEL is a sealed type that "can" last much longer than AGM, but not as long as FLA, not cheap, and requires **very** precise care nearly as much so as LFP.

Sonnenschein and EPM are the two good makers selling into NA.

And actual GC **usage in a propulsion context** is completely Oranges to low C-rate House bank usage, not a relevant point at all!

 

[OllieChristopher]

6v golf cart batteries are great but OP doesn’t have room for an extra pair of largish batteries under the hood of his pick up truck.

If the **only** location to add a House bank is inside the engine compartment (wut?)

them my apologies I missed that detail

Yes that is correct. If you look at my thread on my dual battery install, you will see the second battery location is in a factory tray I purchased. Some of the GM trucks had a dual battery setup from the factory. Mine is going to serve the same purpose as OEM ones except a lot more robust with 1/0 wiring throughout.

That's a mighty big statement...

John, generally your advise is solid, but come on - What was that again? 10-14+yrs with FLA in a vehicle app and a 75% SoH? Ok...your numbers are growing with time/posts.

Lithium batts in overlanders is taking over - it's been over for LA in my professional life for several years now (mobile and stationary apps alike). If 10-14 yrs were even remotely viable, I'd be knee deep in acid...

I have to agree with you on this. It is extremely rare to see any battery regardless of type to last over 10 years even with proper maintenance. I do like the idea of a nice deep cycle battery. I don't think it's needed in my case. At least for now. As soon as they wear out then I will think about getting a set of true deep cycle batteries.

Smart choice is pick the correct battery for the application.

And I doubt anyone will let you scam them on the warranty.

I'm picking the right battery for cost vs application. Why would you even mention a scam? AAA batteries have a 36 month replacement warranty. If the battery tests bad in that time then it will be replaced. It is going to be in a factory location under the hood and will be used no differently than a single battery with electrical demands of any truck with high amp accessories.

 

[Joe917]

Yes that is correct. If you look at my thread on my dual battery install, you will see the second battery location is in a factory tray I purchased. Some of the GM trucks had a dual battery setup from the factory. Mine is going to serve the same purpose as OEM ones except a lot more robust with 1/0 wiring throughout.




I have to agree with you on this. It is extremely rare to see any battery regardless of type to last over 10 years even with proper maintenance. I do like the idea of a nice deep cycle battery. I don't think it's needed in my case. At least for now. As soon as they wear out then I will think about getting a set of true deep cycle batteries.






I'm picking the right battery for cost vs application. Why would you even mention a scam? AAA batteries have a 36 month replacement warranty. If the battery tests bad in that time then it will be replaced. It is going to be in a factory location under the hood and will be used no differently than a single battery with electrical demands of any truck with high amp accessories.

You are planning to deep cycle a starter battery.
That is abuse the manufacturer should not be expected to cover.
A truck with a single battery and high amp demands is usually supplying those demands from the alternator.

 

[DaveInDenver]

You are planning to deep cycle a starter battery.
That is abuse the manufacturer should not be expected to cover.
A truck with a single battery and high amp demands is usually supplying those demands from the alternator.

If it's AAA the automobile club we're talking about they stipulate that "When a passenger car battery is used in a commercial application truck over one ton, marine service, recreational vehicle, etc. and is defective in material or workmanship and not merely discharged, it will be replaced free of charge within (6) months from the date of purchase."

Who's to say what exactly they have in mind with this disclaimer? Dual batteries in commercial trucks aren't just there to crank diesel engines. They're expected to run electrical stuff, pumps, winches, radios, lights, etc. So "abuse" is kind of contextual.

If they are willing to back it for 6 months with this application then why not take them up on it? This is telling as to what the manufacturer thinks of using a starting battery like this, though. Going from 36 months to 6 on the warranty.

 

[OllieChristopher]

You are planning to deep cycle a starter battery.
That is abuse the manufacturer should not be expected to cover.
A truck with a single battery and high amp demands is usually supplying those demands from the alternator.

I know without a doubt that AAA will honor replacing a failed battery. I'm not concerned in the least with a warranty claim. Bottom line is it is a 3 year free replacement and additional 3 year pro rated warranty (total of 6 years). And yes my battery demands are being supplied by a 250 amp alternator and charge controller.

If it's AAA the automobile club we're talking about they stipulate that "When a passenger car battery is used in a commercial application truck over one ton, marine service, recreational vehicle, etc. and is defective in material or workmanship and not merely discharged, it will be replaced free of charge within (6) months from the date of purchase."

My truck does not meet any of the criteria you have mentioned. It is a daily driver 1/2 ton truck.


Boy this thread sure did go sideways!! It went from me mentioning a way to save some money to scamming the battery manufacturer, to denied warranty claims before I even got the battery. Some of you members are speculating some outrageous scenarios with nothing to back it up. I appreciate the feedback but geez.

Mission critical, life threatening, battery murder, foolish, etc. I think all of us can agree a whole lot of these comments are suppositions, innuendos, and false postulations.

Agreed, not expect them to cover. But if the seller (AAA) is willing to cover it without question as part of their advertising & PR budget, sounds good to me.

That sounds about right. I'm not so dishonest as to drain a starter battery below 20% capacity over and over and expect or even attempt to get a free replacement. OTOH if I do a normal campout every month or so and run on some battery power and it dies, then yes I most certainly would get a free replacement within the warranty period.

 

[vtsoundman]

Yes that is correct. If you look at my thread on my dual battery install, you will see the second battery location is in a factory tray I purchased. Some of the GM trucks had a dual battery setup from the factory. Mine is going to serve the same purpose as OEM ones except a lot more robust with 1/0 wiring throughout.




I have to agree with you on this. It is extremely rare to see any battery regardless of type to last over 10 years even with proper maintenance. I do like the idea of a nice deep cycle battery. I don't think it's needed in my case. At least for now. As soon as they wear out then I will think about getting a set of true deep cycle batteries.






I'm picking the right battery for cost vs application. Why would you even mention a scam? AAA batteries have a 36 month replacement warranty. If the battery tests bad in that time then it will be replaced. It is going to be in a factory location under the hood and will be used no differently than a single battery with electrical demands of any truck with high amp accessories.

Just a quick reminder, I'm running a Duracell Sam's Club AGM Deep Cycle under the hood...it is my starting and winch battery. My Jeep is a hell of lot hotter under the hood than your truck (know from experience). It is only a few dollars more than your FLA (like 40 maybe for a Grp 31). For your size, it maybe even be the same price. Sam's club will let you buy if you go to the desk to ask for a day pass... Just a thought.


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[OllieChristopher]

For your size, it maybe even be the same price. Sam's club will let you buy if you go to the desk to ask for a day pass

Right on thanks for the tip on that. I let my Sams Club Expire. I kind of prefer to keep the same battery type under my hood. I was looking at the battery you mention and boy that is a great price for a 140 bucks!! 2 group 78 AMG batteries for under 300 bucks is a hard deal to pass up......

 

[vtsoundman]

Right on thanks for the tip on that. I let my Sams Club Expire. I kind of prefer to keep the same battery type under my hood. I was looking at the battery you mention and boy that is a great price for a 140 bucks!! 2 group 78 AMG batteries for under 300 bucks is a hard deal to pass up......

Take a moment and see if you can't get a Grp 31 in one of the trays (or both of them!). A Grp 78 battery is only good for 60-70Ah (at least it isn't an Optima at a paltry ~50 ). A single 78 battery is only good for ~30Ah...you'll drive a starter batt into the ground pretty quick. Grp 31 is good for 110Ah or so.

Some flat plat bolted to the factory tray, some angle iron bolted/welded for a battery tray...and a new battery hold down bolt/bracket ...

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[vtsoundman]

One other thing...get a solenoid (nothing fancy) to manually disconnect / disable it when you turn the truck off (or starting). Energize it/close the solenoid after you start the truck to charge the AGM...run all your Aux from the existing Grp 31 AGM. Starter battery is kept happy, ya get MORE usable Ah, AND you're not throwing good money after bad.

Tie the power source of the solenoid (or solenoid control switch) to a 'run' source (only powered during engine run)...that will keep your battery from dying if ya happen to forget to switch it off.

If ya want to get real fancy, grab a 12V $6 time delay relay(Amazon) to supply power (to solenoid or manual switch) ... That way it will wait to charge the Aux/close the solenoid until after the truck is stable.

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[billiebob]

Why would you even mention a scam? AAA batteries have a 36 month replacement warranty. If the battery tests bad in that time then it will be replaced.

Wrong, only if it was used as intended. Otherwise it is scam. And you will need to be inventive to get a new battery under warranty,,, hence, scam

 

[billiebob]

You are planning to deep cycle a starter battery.
That is abuse the manufacturer should not be expected to cover.
A truck with a single battery and high amp demands is usually supplying those demands from the alternator.

THIS ^^^^
On the money.