Battery problems?

[nrhareiner]

I think I know the answer to the question, but want some conformation. My coach batteries are almost 5 years old and I had scheduled the change for October. 2 days ago when it got plugged in after 6 hours unplugged, the inverters did their thing and both showed 8 amp draw of the chargers. Inverter one then went into float mode while #2 stayed in bulk drawing 15 amps to charge (maximum allowed by my setting). It has not come out of this charge mode. I have 8 8D batteries in two banks. One bank running 10 degrees hotter than the other measured by infrared.

I think one battery has fried and getting a large draw through that battery. The batteries are only measuring 25.8 volts on 24 volt system not the normal 26.6. Is that a good guess? I am ordering the new batteries through Lifeline today if people agree with this post. Only slight problem is that the coach is in OKC not at home.

Thanks to everyone for help.

[Jon Wehrenberg]

Kim,

That sounds logical, but as you describe it you imply each inverter handles a portion of the batteries. Are you sure? On my coach each inverter handles all of the batteries. The way yours appears to be set up any inverter charger section failure takes out 1/2 of your coach unless there is a switch that allows you to merge both battery sets into one bank.

[dalej]

Kim,

It sounds like you have a good understanding of your batteries and the way they have been handling your coach.

Your at a point in the battery life that most would think it's time for a change. I think if it were my bus, I would break down each bank to get a better understanding of the condition of each battery. If they are all resting at the same or close voltage rate then I would be prone to start looking at the charging system.

You didn't say if your current batteries were Lifeline but to me that is a short service life if they are. My last Lifelines were in 9 years.

[Jon Wehrenberg]

I know for sure that as Kim stated a failed battery will ruin a set. I think in Dale's case his betteries held up very well, but I think we all know that if a battery fails at any time in its life we are going to be replacing the set.

There are a lot of factors which determine the life of batteries ranging from manufacturing defects which may ultimately create internal shorts, to just wearing out batteries by the number of discharge cycles and the depth of the discharges.

We can screw up battreries all by ourselves by charging them improperly (often without realizing it), exposing them to a high temperature environment, or something as simple as letting them go dead.

I am at my five year life right now on both house and bus and although both seem to be working perfectly I also know from previous battery failures that when they do fail, they can fail quickly and without warning so I am torn between premature replacement, or risking a trip that ends up with a bad set of batteries. Hard choice.

[nrhareiner]

It seems that when the problem started the one inverter goes to charging (as many amps as I allow the charger to draw). The other one is in float mode, and in fact may be allowing some draw from the batteries if the limit of amount of draw is reached from the electrical plug. I was set at 40 amp draw max from shore line. I was running many of the a/c units since 105 out side. With the unit drawing 15 amp charging the other inverter was actually showing a negative charge amount to accomadate the over all draw.

That may not have been written correctly, but I hope all of you understand what I am trying to say.

I was wondering if the problem was the inverter. However, then something is causing a large draw of amps from one of the chargers. It may not just be one battery, or as Jon says the charging of every battery is connected to both inverters, and one is just picking up the load.

[truk4u]

Kim,

Your drawing 15 amps for the charger, but take a look at the inverter that's doing the charging and see what DC amps are being put in the batteries. The bulk and absorbtion DC amps should slowly go down until hitting float. If the charger is putting 100+ DC amps into the battery bank and is not gradually reducing as the batteries get charged, you may have a bad battery like you suspected. If you end up testing the batteries, they each need to be unhooked and load tested individually.