If you completly deplete the house batteries, are they toast?

[IMPULSE DRIVEN]

Can I just plug them in and recharge them and recover, as they dont have enough power to start the generator, did I ruin them? I left the house batteries switch on and depleted them.

[akadeadeye]

Originally Posted by FLIGHTSIMMER

Can I just plug them in and recharge them and recover, as they dont have enough power to start the generator, did I ruin them? I left the house batteries switch on and depleted them.

I did the same thing over a year ago. Plugged in, they were recharged and everything is fine. However, they may not last as long as they would have and they show 13.2v when float charging. I believe they showed 13.5v before.

Don

[IMPULSE DRIVEN]

Originally Posted by akadeadeye

I did the same thing over a year ago. Plugged in, they were recharged and everything is fine. However, they may not last as long as they would have and they show 13.2v when float charging. I believe they showed 13.5v before.

Don

I hope there ok as they are brand new.

[CraigAllegro]

No they are not toast. It is somewhat mathematical. Batteries die over time the amount percentage you deplete the battery on average over time determines the rate of decline. If you run your batteries to zero all the time they won't last long. Here is a bit of clue though a fully charged 12V will register 12.66V assuming there is no input or draw, as a battery deteriorates it gets harder to reach that level.
I have consulted with Midtronics a couple of times and from an engineering perspective and no one has come up with a way to determine where a deep cycle battery is in its lifecycle that can be taken to the bank. If there was a tester that could determine how much life is left in an industrial battery they would be a very rich man.

[BryanL]

re: "If there was a tester that could determine how much life is left in an industrial battery they would be a very rich man." -- the issue here is 'life left' - that depends very much on future use and conditions.

You can determine current battery condition (which is different from state of charge). Traditional load testing is somewhat destructive. Modern methods use conductivity and impedance (see batteryuniversity.com). You can also use the smartgauge.com approach and determine battery condition by seeing how it responds to loads.

There are two primary risks from running a battery flat. One is that you can reverse charge a cell and the other is that you can prematurely age the battery. If you do in a cell, the battery is indeed toast. But if you can successfully recharge the battery then you'll be OK for a while, usually.

As for battery voltage, that stays the same over a battery's age. What happens as a battery ages is that its capacity fades and its resistance increases. An aged battery just acts like a smaller battery for all intents and purposes. Full charge is still 12.6 volts as measured after surface charge has been depleted.

What I do is to recharge a flat battery as soon as possible. I sometimes need to use another battery to get it juiced to where the charger will take over. I give it time to get a full and complete charge. Then I check the electrolyte levels before I see how it does with a load of 100 watts or so for a couple of hours. If no cells are destroyed, it will keep a good voltage so I know I can still use it.

[DCPakaMOM]

I just did the same thing this past weekend. Felt rather dumb actually. :(

Recharged and so far (knock on wood) they appear to be working fine. There is so much to learn, so much to remember for this Newbie. I do now know to remember to hit the battery switch to off!

[wa8yxm]

House batteries are usually DEEP CYCLE types.. Generally.. I stress GENERALLY, if you do not leave them sit in a depleted state for more than a day or so they have a tendency to recover fairly well.. Yes, you've lost life, but it's not a complete disaster. Charge them, Depending on your converter you may need to initalize that charge with an alternative charger. But charge them (Put a volt meter on them and plug in, if the meter looks like it's charging come back in an hour, if it's looking bettery let 'em sit for at least 24 hours if you have a smart 3-stage converter (That sit and charge)

Starting and Marine/Deep Cycle.. are more likely to be toast at this point just so you understand the advantage to DEEP CYCLE batteries. From MY point of view. that is the big difference (There are several which I know about but that is the one that bites me in the backside,, right where I keep my wallet)

[garym114]

You just hurt their feelings.

[pwf16129]

i would put them on a slow charge until they are topped off and then keep an eye on them,they should be fine but they will lose many charging cycles,oops part of life just try not to do this too often any time a battery is discharged below 10.3 it is rough on them but it will happen. we have all done it from time to time they make a device called a lvd low voltage disconnect that can be wired into the circuit that will prevent ruining the batteries by cutting off the voltage at a safe level and then reconnecting automatically when the charge rate exceeds 13 volts. we run them in our fleet trucks with great success you can google it for a vendor.
happy traveling

[JimM68]

they'll be ok.

Now if you let them go flat and then they froze... that would be bad.

[BryanL]

re: "House batteries are usually DEEP CYCLE types.."

oh no, not this again! ;-)

if you can find any objective, pertinent measure for batteries commonly used in RV's that will distinguish a 'deep cycle' battery from any other please let me know.

the labeling on batteries is marketing. differences are a matter of degree, not kind. the impact is mostly seen in warranties.

[wa8yxm]

Bryan.... One "pertinent measure" is the battery's ability to recover from such a disaster.

Every time I've taken my starting batteries below 11 volts, EVERY TIME it was time for a new battery (Why would you take it that low.. Well it was 17 miles home from work at night with the lights on and it was Sunday evening shift and the alternator died as I left the company parking lot.. That's why)

Every time I had to replace the battery as well.

The U-2200's have hit bottom a few times and still tested good.

[BryanL]

re: "Bryan.... One "pertinent measure" is the battery's ability to recover from such a disaster." -- where do you find this in a spec sheet or warranty or other such promise that the manufacturer or retailer will put his money on?

I understand personal experience but I also know that it is why statistics is often used to guide decisions involving measures that have many variables or other influences. That is why I suggest anyone looking at things like batteries take all stories and anecdotes with a grain of salt and instead depend upon what someone will put their money on.

Your example of an alternator death is another good lesson. Correlation is not causation. Whether the alternator caused the battery failure or vice versa is sometimes difficult to determine and the multiple failures in close proximity may just be coincidence.

Battery failure is particularly sensitive to environmental conditions and usage patterns. This shows in warranties. It is why one person's experience can be a rather poor guide as small samples can be depending upon many unknown things. So I recommend that folks only rely on things that are clear objective measures that are pertinent to their need and are backed by warranty or other such value.

[larrydp]

What if the house battery is a "maintenance free" one and the water level can't be checked.....(or can it?)