Battery Balance Light

[grantracy]

I am getting a "Batt Bal" light when I crank the bus. it stays on for around 20-30 seconds and goes out. Is this a problem or impending problem?

[Kenneth Brewer]

Do you have a 24 volt chassis system? If so, I occasionally have the indication as well, and it goes out after a few seconds. Others will weigh in on this, but in my view at this point, I think what happens is the 12 volt equipment, including clocks and miscellaneous other 12 volt equipment that runs when the coach is shut down tends to unbalance the 2 banks (of 2) chassis batteries by pulling down the side those 12 volt loads are connected to.

[Jon Wehrenberg]

Sounds normal Gran. Mine will do that on occasion and it is just the 12 volt side or the chassis batteries trying to get to within 1 or 1.5 volts of one half of the 24 volt side. That is the monitor spread that trips the light. The equalizer maintains it to within .5 volt of one half of the 24 volt side

[grantracy]

ok guys, that sounds about right...just never noticed it before.

[Joe Camper]

I was asked to look at a battery imbalance light issue and found this.

The chassis Batts show 26v and the starter just clicks.

Long ago when they first bought the bus they had installed a 24v marine battery tender, a small 5amp trickle charger for the chassis. It's green light also showed on, no red light all good.

Then I stuck both separate 12 volt pairs of batteries and 2 were at 15v and 2 were at 11v. Amazing to me that the little trickle charger could get the good 2 overcharged enough to make up for the weak 2. Or, is this charger gone bad too??

After separating the bank and leaving it overnight 2 were at 12.9v and 2 were 10.8v.

If there were 2 separate 12v trickle chargers instead of 1 24v on the chassis batteries the bad battery would have possibly surfaced sooner.

[GoneCrazy]

My balance light will come on for a few seconds after startup, then goes off. It never used to come on , So when it started a few months ago. I was hoping that the equalizer was not going out. My chassis batteries are 4 years old however. And have never had a tender charger on them. I suspected that it might be an early indication that the old chassis batteries are coming to the end of their life. Time to test them and replace most likely ..........

[Gil_J]

Not knowing where the 2 low voltage batteries were in the bank, it could be an equalizer problem. If the low voltage batteries were both on the lower 12V half bank, I would check the equalizer.