2018 Axis 25.2 - Does the BIM charge chassis battery from shore power?

[keefd]

I have a 2018 Thor Axis 25.2 and I'm having trouble with the chassis battery charge. When I plug into shore power, the chassis battery does not get charged but the house batteries seem to be fine. Chassis battery was charged last weekend, but it's dead now.

I don't think I have a BiRD/Trombetta, but I do have a BIM 160. When I push the emergency start button the radio powers up and the chassis battery seems to be getting power. Also don't think I have a BCC as there isn't one near the fuse box in the driver's side outside compartment.

My question is - when working normally, does the BIM allow for chassis battery charging when plugged into shore power? It allows house battery charging when driving.

I'm wondering if the BIM is mis-wired or if the system's not designed to charge the chassis battery from shore. The chassis battery was replaced at some time before I got it. I checked the 100A breaker and the 15A fuse going to the BIM, both are good.

[lwmcguire]

Get out the VOM and see how yours is wired. Sounds like the banks are connected by a solenoid for certain. BIM can certainly connect both banks and what its purpose is.

http://www.precisioncircuitsinc.com/...ger-Rev7-1.pdf

[Judge]

The BIM160 is designed to allow the Converter to charge the chassis batteries when on shore or generator power and for the alternator to charge the house batteries when driving.

I have the BIM160 on my 2020 Magnitude SV34. I have had many posts about it being wired incorrectly and causing issues with charging the batteries in my coach. You may want to do a search.

In my case, Thor had the chassis batteries connected to Post-B along with the chassis battery voltage monitor wire and the house batteries connected to Poast-A when the chassis battiers and voltage monitoring wire should have been attached to Post-A and the house batteries should have been attached to Post-B.

[keefd]

On mine the BIM 160 seems to be wired correctly. The dead chassis battery is wired to the "A" post, the house/coach batteries are wired to the "B" post.


Judge, I read through all the thread about your BIM issues - I'm glad your problem got resolved.

I wonder if my problem is because the chassis battery was dead before I plugged into shore power. I parked my RV in my driveway and it was about 3-4 days before I connected it to shore power. In that time it seems the parasitic loads drained the chassis battery down to about 5v, and when I plugged in shore power it just didn't charge it up.

I've got the chassis battery on a charger now, I'll have to test it to see if it was a too-low voltage on the chassis side problem.

[MJC62]

Have you checked that the chassis battery is indeed still good? Either via a load test or with a hydrometer. If you have the OEM battery in a 2018 coach it may be done in. My 2018 ACE the battery had a bad cell after two years of service. Remember your 2108 is built on a 2017 chassis and the battery is at least 4 years old at this point.

[keefd]

MJC62 - I believe that the chassis battery was installed recently as the dealer mentioned replacing a battery and the house batteries look old. I'll have to check the date code.

I threw it on a car charger and it seems to have charged up, but I'll have to check the resting voltage. This is the second time it's died like that, last time I charged it up and it lasted for a weekend trip.

I wonder if the aftermarket radio I installed recently has accelerated the chassis battery issues. The car charger shows about a constant 1A draw, I don't think the radio draws that much by itself and radio accessory power is tied to the house batteries as from factory.