House Battery Dies Quickly

[paulgreenwood1]

I own a 2004 Coachmen Mirada class A. Last year I replaced the house battery. Now my battery won't run my lights for more than a couple of hours before dying. As I live in Florida, I figured maybe the heat was killing the battery, but, after further reading, I'm not so sure. Can anyone suggest why my battery dies so quickly? Is there a way that I can check if it is being charged sufficiently when rv engine is on? I do alot of boondocking, so my HB is usually only being charged when I drive. I have noticed, however, that when I camp and am plugged in, the battery also does not last long after disconnecting from shore power.When the rv is not in use, I make sure to push the battery disconnect, so it is not in use when sitting for long times idle.Maybe just a bad battery? It is deep cycle marine battery. I also read that completely discharging the hb will cut down the life. In future, should I turn lights off when battery reads 1/3?

[Yankee_Clipper]

What some of the other posters have hinted, but not said, is you have to pull the batteries periodically and re-fill the cells with distilled water. I also take that time to pull material I keep under the batteries (non-skid drawer liner) and re-paint the base of the battery compartment to keep corrosion under tight control. Remember that these deep cycle batteries are a bit hefty, and come out at an awkward angle for your back, so be careful to support yourself carefully lest you add the cost of a good chiropractor!

[dougrainer]

Your Genset does NOT charge the batteries. Your Genset supplies the 120 volts to run the CHARGER for your batteries. If you have only a CONVERTER (you do since you have just 1- 24 series battery), then to fully charge a discharged battery that is below 50 percent discharged, it would take at least 4 to 8 hours(maybe more) to fully charge a 24 series battery. It all depends on what TYPE Converter you have and what its charger section is rated at. If you post what brand and model Power Converter, we can help you understand the charging parameters for that model. Doug

[MrWizard]

start using the generator and a good converter for charging
what charge/converter do you have now
a few hours is not enough for a Good battery to fully recharge from very low
much less recover a damaged battery

[CA_Traveler]

50-90% SOC cycling is common for boon docking and that's what deep cycle batteries are designed to accomplish. Check out bulk, absorb and float stages and you'll find that charging beyond 90% is not practical with a gen due to the many hours required.

Your mechanic may be excellent with the chassis but he certainly knows little about deep cycle batteries.

[paulgreenwood1]

The battery that is there is a Carquest marine battery, group 24. After alot of research since this morning, I am fairly convinced that I killed that battery, due to over-discharging, and maybe not recharging fully. That particular battery is a hybrid battery. The battery holder is significantly larger than the battery, maybe 2-3 inches larger, so I am guessing the original battery was larger. I contacted my mechanic and ordered a group 27...don't think anything larger would fit.I told him about what I read online and the advice I received on this post. He didn't even know that there is a hybrid deep cycle and a pure deep cycle. Made me feel better about being ignorant on the subject. Anyway, a pure deep cycle battery has been ordered, and hopefully that will work well. I read that these type of batteries should not be discharged past 80%, and after each use should be charged fully. That may be my problem in the future, as I do alot of boondocking/dry camping, and don't always have access to shore power. In any case, thanks everyone for the help.

[gbopp]

Why not just replace the battery with the same size? Unless it's not the original size that was installed at the factory, it should serve you well.

Check the voltage while the engine is running and/or on shore power. Maybe you're overcharging the battery?
Make sure the charging system is working properly.
Don't allow the battery to discharge too far.

If you want to upgrade, and have the space, consider two 6 volt golf cart batteries.

[darsben]

Did you ever maintain the battery?

[CA_Traveler]

Stop guessing. Load test the battery. Buy a $10 digital voltmeter and get some voltage numbers and/or a hydrometer.

What charger do you have? Unfortunately some are not very good for charging batteries so 2 hours may not be enough and possibly less that 90 percent SOC.

You probably have a 90Ah. If 2 GC2s fit you would up it to 230Ah. And yes larger batteries require longer to charge or a larger charger.

[paulgreenwood1]

gbopp, thanks for the link. It explains many things I didn't know. So, assuming I have killed my battery by discharging too often, how do I find the proper deep cycle battery for my rv? As mine currently is most certainly a hybrid, I would want to change that out. I read that a bigger battery might not be so good as it would take longer for the alternator to charge? Any thoughts?

[gbopp]

paulgreenwood1 wrote:
Sorry, guess I forgot to turn on the brain switch this morning. Let me rephrase....battery does not run lights for a few hours before dying. Even after using generator for air conditioning for a couple of hours, my battery dies quickly when generator is off and battery is powering lights/fridge.I figured a few hours with the generator on would have charged the house battery fairly sufficiently...

Thanks for explaining it, we were wondering what type of battery you had that would run the A/C for a couple hours.

Check the voltage at the house battery with the engine off. Then again with the engine running. You will see the voltage going into the battery.
But, first have it checked. You could have sufficient power going into a bad battery.

Also, have you ever read The 12 Volt Side of Life?
Good information on your batteries, etc..

[paulgreenwood1]

Yeah, realized that 2oldman...will repost...Thanks 🙂

[2oldman]

OP..you may want to change your original post as it appears people don't read all the replies.

[CA_Traveler]

If a A/C uses 10A AC then it will draw about 110A DC from the battery with the inverter. If nothing else the battery will soon be toast.

[WILDEBILL308]

paulgreenwood1 wrote:
I own a 2004 Coachmen Mirada class A. Last year I replaced the house battery. Now my battery won't run my ac for more than a couple of hours before dying. As I live in Florida, I figured maybe the heat was killing the battery, but, after further reading, I'm not so sure. Can anyone suggest why my battery dies so quickly? Is there a way that I can check if it is being charged sufficiently when rv engine is on? I do alot of boondocking, so my HB is usually only being charged when I drive. I have noticed, however, that when I camp and am plugged in, the battery also does not last long after disconnecting from shore power.When the rv is not in use, I make sure to push the battery disconnect, so it is not in use when sitting for long times idle.Maybe just a bad battery? It is deep cycle marine battery.

What is AC if you are saying airconditioner I think I can help. STOP trying to run the AC on one 12v battery. You can only run the AC from shore power or when the generator is running. You have probably ruined that battery by over discharging it repeatedly. The only way to know is to charge it fully charge it then load test it.
You say you do a lot of boondocking I would upgrade to at least two 6v golf cart batteries, if you have room I would try for 4. You still won't be able to run the AC on battery power but the batteries will last longer boondocking.
Bill