Battery balance light

Driving I-95 yesterday, battery balance light started flashing then stayed on full time. Pulled in next rest stop. Checked all connections, all were tight and no signs of heat. Checked both Vannor's (chassis & house), chassis one was OK, house green led on Vannor was not lit and voltage reading were 27.1 & 14.3. Started generator, balance light went out, but Vannor still had same readings as noted.

Recently had all the house bank of batteries out to replace a R-14 relay valve. Check all the 4 year old batteries at that time, all but one checked OK. The one that was weak was still good but not as good as the others.
Do I have a bad Vannor or maybe that one battery is giving up. On the road an no time for in depth diagnosis right now. Not sure why running the generator makes the balance light go out but the voltage is still not within proper parameters.

Chuck:


Are we talking about the balance light on the dash? I always assumed that this would monitor the chassis batteries only. I would think that the house battery Vanner would have its own monitoring system. If it is the dash light, and the chassis vanner has a green light, then it might be the monitor that is bad. I have read that these fail more than the Vanner itself.

To check the Vanner you need to have the green light on. If it is not on and it is working properly, turn on some larger 12 volt loads and the green light should illuminate. With the green light on, check the voltage between the 12V and GND terminals. Then check it between the 12V and 24V terminals. The 12V/24V measurement should be equal to or not greater than +0.1V compared to the 12V/GND measurement. As an example, if the 12V/GND reading was 13 volts, the 12V/24V reading should be between 13 and 13.1 volts.

So, let us know what balance light was on and how the above test works.

BTW, with the readings you provided, I assume that the engine was running? I would do the test without it running.

Hi Mark:
Have done the test with the Eng running and off, Same results. Featherlite said they do tie the house Vanner into the dash light too.
Called Vanners custom coach and bus division, they said most likely a bad ground or one of the batteries in the bank is going out. Have arranged to borrow a AGM battery tester tomorrow. Will update once I know more.
Chuck
P.S. Hope it is a battery, that’s cheaper than a Vanner LOL
Also green LED on Vanner has never come on.

Good to know. Let me know how the batteries check out.

Checked the house batteries with a tester this afternoon. One of the 8 houses batteries was in bad shape (9.4Vdc), the rest tested in great shape. Replaced it and will check the system tomorrow after the batteries have a chance to equalize tonight.

Chuck

Everything is back to normal this morning. Vanner voltages are back to within.01 volts difference.
Phew, dodged a $1k bill on a new Vanner.

Chuck

That is great news. Now you can have an awesome weekend.

I wonder how many converters tie the dash balance light to both the chassis and house battery systems?

Don’t know, but it was quite helpful in my situation

Never gave it much thought, but now that I do - my house and chassis are both tied to both battery lights (red and yellow). It uses a high current solenoid (24v coach) rather than an isolator which connects chassis/house/alternator output together once coach (alternator) is running.

If coach has been unplugged for awhile and I start engine and turn on shore power (or probably generator also) the inverters immediately ramp up briefly to a voltage high enough the red battery light will illuminate. Once I see that I either turn off engine or shore power. If starting and coach has been plugged in and in float mode, no battery light.

Had never seen yellow battery balance light. Changed monitor a few months back from the old original EM70 to the later EM70D (from memory but I think that's correct) and discovered during the changeout that the ground wire was not connected on the old unit. Don't know if this was intentional or accidental. Installed new monitor and now yellow battery balance light illuminates for a few seconds after engine start and then goes out. Assuming this is normal.

I guess I should start paying attention to the color of my lights LOL. To my knowledge, I have only seen red.

Ha! As luck would have it, we left Nashville this morning with the sun coming in the drivers toll window ... low and behold I do have an amber balance light :-) Now all I have to do is see if it ever comes on!