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Latitude · 01-08-2008, 10:30 AM

When boondocking how low could you let the 6V House batteries go??? I have 4 220 Amps.

I read 12v could go to 11.9 before hurting them!! Is that correct???

Thanks Rick

Latitude · 01-08-2008, 10:30 AM

When boondocking how low could you let the 6V House batteries go??? I have 4 220 Amps.

I read 12v could go to 11.9 before hurting them!! Is that correct???

Thanks Rick

BOB E · 01-08-2008, 11:30 AM

#1 Check manufacturers website for spec's

#2 It's my understanding that lead acid battery plates build a layer of sulfate over a period of time which ultimately destroy's their ability to take a charge.
When a battery sits in a discharged state, the sulfate will accumulate faster and harden to where it won't dissolve when attempting to recharge.
Therefore, keeping them fully charged & maintaining their voltage level as high as possible is the key to a long lived battery.

I have let my house batts get down to 11.5 volts (over night) but attempt to recharge & top them off daily when boondocking.

When sitting at home, I keep a small trickle charger on them (on a timer) where they get aprox 2 hours a day. I usually get better than 5 years out of a set before replacing.
Also, keep an eye on electrolite levels - use distilled water to maintain.

BryanL · 01-08-2008, 12:06 PM

It is easiest to check the house voltage and not the individual components of the battery bank. Look at individual batteries in the bank only for differences between them. (differences between batteries in a bank generally are not a good thing)

Check voltage on a resting battery. This means no charge current and no loads for at least a half hour. (same conditions as for hydrometry which tell you the same thing - state of charge - but in a more dangerous way)

The halfway point is 12.2v for a 12v system (half or double that for 6v or 24v). That is usually considered as deep as you want to go for optimum battery life. With only a half hour rest, 12.0 is usually close enough as, depending upon your last load, it might still be coming up to a rest voltage.

For any lead acid battery, discharging below halfway shortens their life and the deeper the discharge the more the impact on battery life. Any good RV battery should be able to handle a few real deep discharges with no significant effect. Just keep the average!

As Bob says, don't let batteries sit around without being at full charge. Recharge promptly. Make your discharge cycles at least 10% down to 50% down to properly exercise the battery.

What usually kills batteries isn't an occasional deep discharge, it is a failure to recharge promptly and completely and then not taking care of them when not using them for a couple of weeks or more.

Once your batteries get down 50%, the voltage will start to drop rather quickly. The first 50% is a half a volt, then next 50% is a full volt plus.

In normal use, you can learn from experience what the voltage should be. A furnace or water pump, for instance, will draw the battery voltage down just a bit on a full charge but a much larger bit when the battery is down.