Heres what inverter/chargers do to batteries...and battery holders

[davecampbell]

Guess what happens when a 100 Amp charger is put on inverter batteries when the batteries can only take 20 amp or so on a good day?

Battery death by severe overheating and case rupture.

Recipe for destroying battery banks:

1.) use a 100A charger (we used to use 50A for boost starting engines...)
2.) power some house loads with it too, lets say 75A total.
3.) turn the loads off and sock all 75A to the batteries.
4.) wonder why batteries need replacing every year.

This one was so bad the battery cases exploded up around the terminals. Acid leaking out and off gassing ate through the steel expanded metal grate.

[Uncle Dave]

Quote:

Originally Posted by davecampbell Guess what happens when a 100 Amp charger is put on inverter batteries when the batteries can only take 20 amp or so on a good day? Battery death by severe overheating and case rupture. Recipe for destroying battery banks: 1.) use a 100A charger (we used to use 50A for boost starting engines...) 2.) power some house loads with it too, lets say 75A total. 3.) turn the loads off and sock all 75A to the batteries. 4.) wonder why batteries need replacing every year. This one was so bad the battery cases exploded up around the terminals. Acid leaking out and off gassing ate through the steel expanded metal grate.

Hmmm- good point,

I have a somewhat alterate view of the 1 year battery bank problem

Most Rv's I've been around have 4 house batteries usually "100 AH" interstates/die hards- standard Johnson Controls product.

Wouldn't a 100 AH charger effectively drive 25 amps a-piece then? Typically the charging starts there then quickly tapers off.

I think they die more from being flattened constantly than from 100ah charger because they rarely get the full 100amps into all of them for very long before the charger drops in output considerably.

People seem loathe to fire up a genny for an hour a couple of times a day to "save " fuel, so they drive their batteries to an early grave with continuous deep discharges.

False economy in my observation.



Uncle Dave

[RV Wizard]

Here are some links to help in research:

U.S.Battery/Leader in Deep Cycle Batteries
Frequently Asked Questions (FAQ) - DC Battery Specialists
Deep Cycle Battery FAQ
http://www.rvsolarelectric.com/sources.htm
Car and Deep Cycle Battery FAQ, Battery Manufacturers and Brand Names List, and

There are many more sights and discussions on this very often misunderstood topic.
The chargers of today are pretty good at doing the job correctly if all the cells in a battery bank are in good condition and the right charging voltage is used for the various types of batteries.
Maintenance ( I consider this to also be proper usage) is always going to be key to getting maximum life from batteries. Example:
I got 10 years out of my 4 Interstate U2200 batteries before I replaced them. I had to add water only 4 times in the 10 years.

[Gary RVRoamer]

Kind of depends on the battery charger, Dave. Sure, a flat 75-100 amps direct into a single battery might cook it, but my 120A charger is well managed by its controller microprocessor and maintains the charge at a level my 4 batteries (440 AH worth) are willing to accept. Been doing that for several years now and my Trojan AGM deep cycles are still happy.

[hamguy]

A 100A charger is only capable of driving 100A into a system that can use it. Most battery systems only draw 30-40A when severely discharged. You have other problems.

Quote:

Originally Posted by davecampbell Guess what happens when a 100 Amp charger is put on inverter batteries when the batteries can only take 20 amp or so on a good day? Battery death by severe overheating and case rupture. Recipe for destroying battery banks: 1.) use a 100A charger (we used to use 50A for boost starting engines...) 2.) power some house loads with it too, lets say 75A total. 3.) turn the loads off and sock all 75A to the batteries. 4.) wonder why batteries need replacing every year. This one was so bad the battery cases exploded up around the terminals. Acid leaking out and off gassing ate through the steel expanded metal grate.

[somekevinguy]

I had a 2000 watt inverter with a 100 amp charging section with 4 Costco golf cart batteries and it frequently charged at over 90 amps and the batteries were about 5 years old when I sold that rig and they were still working great. I even let the water run really low one time and exposed the plates. I ran the generator probably about an hour a day so they never got deep cycled probably below about 50%. Which is what is recommended.