Battery Isolator Question

[newRVer]

Seems I had to start a new thread as other related threads where to old to reply too.

After reading the BIM documentation that's been previously posted and more specifically these paragraphs, It would seem that the chassis and house batteries can be connected together through the BIM even when the ignition is off? (under certain conditions) Am I reading that right? If so, that might explain why I saw what I did when recharging batteries this past weekend. I.e. My solar was charging my house batteries and I was seeing a volatage across the chassis battery terminals even though they were disconnected from the battery.

If this is what is happening, would that mean that the solar panels are charging the chassis battery as well?

[fobagbob]

Yes, that is exactly what happens with my 2017 2861. I installed a digital volt monitor that I can switch between house and chassis batteries, and I can see that the chassis battery gets charged at times when the house is plugged into shore power and the ignition is off. It appears to follow the conditions described in the documentation.

[Tombsy]

The solar controller I have (Go Power) is connected to the chassis battery as well, after the house batteries are fully charged it will charge the chassis battery. You can switch the display to monitor 1 (house) or 2 (chassis).

[newRVer]

I can see where this might be a good thing when the RV is in storage i.e you may not have to worry about charging the chassis battery separately if it gets low because the solar for the the house batteries will be doing that, but are there situations where this may actually be detrimental? I may need to consider putting in a cutoff switch between either the house or chassis batteries and the BIM just so I can have more control over the flow of power.

[RamblerGuy]

With reference to your question about possible detrimental effects with the battery isolation system, I have worried about the convertor continuously charging the chassis battery when plugged in for weeks. Since the original battery in our 2010 E450 is still good I don't worry about it anymore.

[fobagbob]

Originally Posted by RamblerGuy

With reference to your question about possible detrimental effects with the battery isolation system, I have worried about the convertor continuously charging the chassis battery when plugged in for weeks. Since the original battery in our 2010 E450 is still good I don't worry about it anymore.

Thanks for that data point. I have had my 2017 plugged in continuously when stored in our garage for the past 18 months (except for 4 months on the road) and it hardly uses any water, now I am even less concerned about overcharging.

[newRVer]

Some good thoughts on the lack of possible detrimental effects. Maybe there will not be much to be concerned about and just let the BIM do its thing....

[brucemc]

Our old 2000 Four Winds didn't charge the chassis from the house converter/charger, so when we got our new 2016 Sunseeker, we were pleasantly surprised when the modern BIM took care of the chassis battery as well.

With the unit plugged full time in over the first winter, I've had a little liquid bubbling over on the chassis battery in the past and had some corrosion in the engine compartment at the battery base to clear up that spring. Now I leave the unit plugged in for a few days, then off for a couple-three weeks.

My monthly maintenance schedules over the winter include starting the MH engine & running for a period of time, ideally with a quick run to town & back. I also start the generator & load it for an hour or so with either the roof air or a portable heater. The engine start is around the first of the month, and the generator start is around the 15th. This way both exercise & contribute to the maintaining of the batteries, if only for a short time.