Battery Questions

dpgllg wrote:


I'm curious why the Optima's are not a good choice for RV's?

Optima. for any given footprint (Size) have about 60% of the capacity of other types. I mean look at them. See all that SPACE Empty Space. with non-optima batteries that empty space is filled with BATTERY so you get more power storage.

NOW.. For say Wave runners or 4-Runners that go slamming over rocks. ruts. waves logs and so on.. Optima is the boss.

But if you drive your RV that way.. Batteries are NOT going to be your main worry.

KD4UPL wrote:

dpgllg wrote:

KD4UPL wrote:
You say you checked the charge level using your charger? How does that work? Have you checked the battery's resting voltage? If it's 12.6 or 12.7 it should be fine.
In my opinion Optima batteries are overpriced for what they are. I've installed hundreds of Deka batteries over the years along with lots of Rolls and Lifeline. I've had very good results form all of them.
You have just one battery but use it to power an inverter running a coffee maker? That is very hard on that battery. If you have a 1,200 watt coffee maker I would think you would want at least 600 AH of battery hooked to the inverter.

My battery charger has a gauge that indicates the battery strength when connected. It has a 12 volt deep cycle setting to charge the RV battery. When fully charged it indicates the amount of charge ( I can't remember exactly what the numbers are). It is probably not real accurate but enough to let you know that when you hook up the battery the amount of charge in it.

When I say making coffee we make two cups on a Kurig and that's it. We have only done this twice with this battery. I can turn the inverter off so it is not running all of the time just when I need it.

You say that you have installed hundreds of batteries over the years. Are you in the business? If so what battery and size would you go with and why?

My wife's Kuirg uses 1,425 watts AC. Pulling that thru an inverter will likely be about 140 amps. That is an enormous draw on a 100 AH battery. It's best to not draw above about a C/5 rate; that is the Capacity in AH divided by 5. So, for a 140 A draw you would want 700 Ah. It's not that you can't do it with less, it's just harder on the battery, the voltage sags more, etc.
I'm an electrical contractor who specializes in solar systems, particularly off-grid homes and cabins. I would install 2 6v golf cart batteries in series rather than 1 or more 12v batteries. That will give you about 220 AH. If you want more I'd use 2 sets of 6v GC batteries for 440 AH.

Good info, I have a Keurig and two 6v's in series (220Ah). I Run a single 365 watt solar panel and 40 amp 3 stage charge controller. I have been trying to find out what caused my battery to boil over after using the Keurig. I'm not sure if the quick discharge or solar charge was the culprit... or a combination of the two. My digital volt meter in the trailer drops down to 11 when the Keurig is doing its thing of a minute or two while making coffee but, then pops right back up after it is done. Didn't mean to highjack the thread but, thought it might provide usful info. for the OP.

I would get Lifeline over Optima.

https://batteryguys.com/collections/lifeline/products/lifeline-gpl-27t

186 minutes for $320 shipped (shop around)

More power in the same space.

Putting any faith, whatsoever, in a charger's state of charge display % in unwise in the extreme.

It is entirely based on voltage, nothing else, and full charged resting voltage varies from 12.6v to 13.2 depending on teh battery and its temperature. If you even can trust the vltage display on sime chargers is another huge factor. My 2007 purchased shumachers 'intelli' charger's voltage display was off by close to 0.2 volts, when the display still worked.

So dismiss any percentage your charger reads, it is completely inadmissable in any logic driven decision.

Also completely dismiss any garage charger's decision that the battery is indeed fuly charged. Almost all of them will stop in the 92 to 95% range and that last 5 to 8% of charge can take several more hours at absorption voltages to achieve.
Automatic 'smart' chargers, do not fully charge the battery, they are desiged primarily to NOT overcharge it. It is safer to underchaarge than overcharge or fully charge, and Lawyers......... and the brainless hyper entitled entitled dimwit of today's population, see $$$$ in this day and age of automatic everything and fingerpointing fabricated outrage.

It is utterly Unwise to believe the green light on any charger that was attached to any aged battery that has seen more than a few cycles.

A hydrometer will easily prove that the bttery was not fully charged when the 'smart' charger said it was. But nobody ever bothers and just assumes the green light is incapable of not telling the truth.

A six pack style spiral cell battery excells over other batteries, ONLY in cases of extreme vibration and when physical strength of the case is important. They have lesser capacity per battery group size. Beware of marketing.

Water any flooded battery and its voltage will soon read lower than before watering and its performance will seem to decrease, as the electrolyte/ acid solution is now weaker and not homogenous. A battery low on water will seem to retain voltage when resting and under load significantly better than one recently filled, even if the level was below the tops of the plates.

I find the 'reserve capacity' rating to be nearly useless, unless one is subjecting a single battery to 20 amps and draining it to dead flat, something wise battery owners avoid.

Self discharge of batteries is directly related to their temperature. the hotter they are the more they self discharge. the more impurities in the lead plate paste the faster they self discharge, the more impurities introduced when watering, the more they self discharge. the more aged and abused, the more self discharge there is