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Battery charging using generator

1991 Unihome U225 W/ onan LP generator
Need to charge batteries
How do i proceed?
Coach has been stored for over 1 year w/ batteries disconnected

Re: Battery charging using generator

Reply #1 –
Off the top of my head suggestions.  Others will chime in, I am sure. 

1.  Check physical condition of all batteries.  If conventional "flooded" design, check electrolyte level, add water if necessary.

2.  Check all battery cable connections.  Remove cables from batteries, clean up the connectors and posts, reinstall cables.

3.  While battery cables are disconnected, using a multimeter, check and record "resting" voltage of each individual battery.

4.  Fire up the generator.  Coach battery charger should begin charging of house (coach) batteries.  Confirm charging voltage with multimeter.

5.  If you have a "BOOST" switch, activate the switch - engine start batteries should begin to charge.  Confirm with multimeter.

6.  If you don't have "BOOST" switch, use appropriate portable battery charger plugged into available AC outlet to charge starting batteries.

Re: Battery charging using generator

Reply #2 –
Good answer from Chuck.

Be aware that if the batteries have been left totally discharged for a long period, they are likely DEAD.

And many chargers, particularly the smarter ones, will not charge a totally dead battery.

Re: Battery charging using generator

Reply #3 –
X2 what they said, however I would not expect the batteries to be useable. You might invest in new start batteries from the get go.

Re: Battery charging using generator

Reply #4 –
Expanding on Brett's and Bruce's comment about batteries possibly being "dead".  If you check the "resting" voltage as suggested, then you will (hopefully) read some voltage value.  If you read ZERO volts, no need to go any further.  Replace the battery.  If you want a second opinion, take the battery to any local auto parts store and ask them to test it for you.

If you read some voltage value, then compare to the little chart in the first link below.  It will give you a idea of how to proceed, and what to look for in a battery that has been severely abused.  Some batteries are worth trying to save - some are not.

If you have AGM batteries, and you read a voltage value above ZERO, but less than about 10.5 volts, then you might want to try one of the three suggestions listed in link #2 below.  However, even if the battery takes a charge, it is living on borrowed time.  Even if it shows good voltage after charging, it may still fail a "load test".  For peace of mind, replacement batteries would be recommended.

Tech Tips & Tricks | How to Tell if Your Battery is Bad in 3 Easy Steps

Resuscitate a Deeply Discharged AGM Battery | Support | OPTIMA® Batteries

Re: Battery charging using generator

Reply #5 –
I'd find an old fashioned transformer based (heavy) battery charger, connect it to the batteries, then plug it in while standing back. After an hour or so put a new "smart" charger on them & see what you get. As suggested, I'd spring for new start batteries though.

Re: Battery charging using generator

Reply #6 –
the old chargers work well but the new digital ones have a cut off.. a good old fashioned charger will put the charge down on a dead battery

Re: Battery charging using generator

Reply #7 –
Agree with the other comments, except a battery can not be load tested (if you want valid results) unless it is fully charged.  So, taking a dead battery to them for testing will only work if THEY have the time and equipment to fully charge it.

Re: Battery charging using generator

Reply #8 –
I have a schuamaker smart charger that if battery is dead it will start desulfication process. I only do this with battery out of vehicle and in a safe location. This feature does not appear to be available any more. 67% success rate but takes a long time, sometimes as much as 24 hours or more on the large scissor lift batteries. I don't have any before or after data, but they crank really well. I've done neighbors batteries, and many equipment batteries at my workplace. Give the pros a shot. I could not revive a pair of 2003 batteries that we're a third Bank on my coach. 130 lbs got me $35 at the recycle place.

Re: Battery charging using generator

Reply #9 –

Here is a page of chargers with desulfurization: Amazon.com: desulfator battery charger

A friend has one and I've seen it work on dead batteries. Won't bring back shorted cells though.

Pierce

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Battery charging using generator

Reply #10 –
Quote from: Chuck & Jeannie –
Off the top of my head suggestions.  Others will chime in, I am sure. 

1.  Check physical condition of all batteries.  If conventional "flooded" design, check electrolyte level, add water if necessary.

From what I've read, on flooded batteries it's best to charge, then add distilled water a little at a time and allow the batteries to charge up between additions.  If they are needing charge and you top them off fully then charge, you run the risk of boilover.  At least that's what was recommended for our golf car.

Re: Battery charging using generator

Reply #11 –
One addendum to Michelle's advice.  Be sure the plates are covered/not exposed before charging.

But. reality is if battery has been dead for an extended period and plates exposed, it is only good for recycling.

Re: Battery charging using generator

Reply #12 –
Quote from: Michelle –
From what I've read, on flooded batteries it's best to charge, then add distilled water a little at a time and allow the batteries to charge up between additions.  If they are needing charge and you top them off fully then charge, you run the risk of boilover.  At least that's what was recommended for our golf car.
Good point Michelle! When you start the slow charge with the desulfator, the plates should be just covered and not filled to the top of the ring. I like to charge with the caps off as it's easy to see the level. Don't disconnect or connect with the charger plugged in as the hydrogen can violently explode in the area above the electrolyte level or in a confined space. Smart to wear goggles during the operation.

Pierce

Re: Battery charging using generator

Reply #13 –
Maybe the batteries are not dead as the original post was that the coach had been parked over a year, but the batteries were disconnected.

Re: Battery charging using generator

Reply #14 –
I agree with Reply #1. Check the voltage go from there.

see ya
ken
 

Re: Battery charging using generator

Reply #15 –
On Desulfinators, Alistar Couper, has plans for a desulfinator that is very inexpensive to build and it does work. I have built two and use them quite frequently. This is not a fast process, but it is efficient. I watch my battery voltages, when the charge voltage drops down to around 13.6 volts, I hook up the desulfinator and the charge rate, after a couple of days , is back to over 14 volts... It will not work on car batteries with waffle plates, but sure likes the heavy plates of a deep cycle !

Save Travels
Dave