Battery Isolation Manager 2017 Miramar

[FEZ]

Does anyone has a wiring schematic on BIM in a 2017 Miramar? I think mine was wired incorrectly from the factory which burned it out. I emailed with Thor this week and they said it doesn't exist, but I know better that. So any help is appreciated, thanks!

[Jdb]

Thor has been using the BIM 160 since at least 2018 - likely back to 2017. I confirmed this by getting the electrical schematic TEE2937-00, which clearly shows the BIM 160. Previously they used the BIRD, and the tech rep I spoke with told me that my unit had a BIRD from the factory; however the schematic they sent me shows the BIM 160

Dave

[FEZ]

Dave, thanks for the information. Any chance you could email that schematic? I would greatly appreciate it, thanks!

[Jdb]

FEZ, Thor sent me 4 files of schematics. Their customer service rep was extremely good and sent the files within 5 minutes of ending the call. He pulled the specific schematics for my VIN.

I shouldn't forward those since they are marked with IP protections. Call them and you'll be pleasantly surprised - I was!!

Dave

[Jdb]

FEZ - the Thor support number is 877-855-2867

Dave

[FEZ]

Thanks Dave, will do!

[revjeffrey]

https://precisioncircuitsinc.com/pro...ion-manager-2/

[Jdb]

Thanks for posting the link. My BIM is wired with the battery banks reversed from their diagram. I called Precision yesterday to ask if that is OK - they assured me that it won’t matter. My Thor schematics show the battery banks are to be wired with coach batteries to the Battery A terminal

Dave

[Judge]

Originally Posted by Jdb

Thanks for posting the link. My BIM is wired with the battery banks reversed from their diagram. I called Precision yesterday to ask if that is OK - they assured me that it won’t matter. My Thor schematics show the battery banks are to be wired with coach batteries to the Battery A terminal

Dave

I'm not convinced the wiring doesn't matter even after Precision told me the same thing.

I have a 2020 Magnitude SV34 with the BIM 160. I have been having issues with the house batteries charging while driving coach.

The BIM 160/225 datasheet's terminology is all screwed up. They call the battery connected to the engine alternator the "coach" battery and they call the battery hooked to the coach converter / charger the "chassis" battery.

The there wiring diagram shows the Ignition terminal on the BIM connected to their version of the "chassis" battery, which we would call the house (coach) batteries.

When I look at the BIM version for Lithium batteries it specifically says the left post is for the starting battery and the right post is for the house batteries. The Lithium battery unit looks identical to the BIM 160/225 so the only difference with this model is how the microprocessor controls the Lithium battery charging.

I also found a Forest River site that specifically shows the BIM 160 wired with the left post going to the starting battery and the right post going to the house batteries.

During my last trip the FireFly panel started reporting the chassis battery at 0V when the engine was running and then normal voltage when the engine was off. The BIM was also not boosting the house battery voltage when the Inverter was on for the fridge and the voltage dropped below 12.5 volts and the chassis batteries were showing 14.7 volts on my dash voltmeter.

Today I decided to switch the BATT-A and BATT-B wiring the way the Forest River site showed and the way the Lithium battery version shows. I moved the chassis battery cable to the BATT-A post and the house battery cable to the BATT-B post.

After doing that I started the engine. After a couple minutes I could hear the relay engage while the engine was running and my house battery voltage went up.

I'm still not going to rule out that I have a bad BIM 160 and maybe it just started intermittently working. But after seeing the Precision Circuits documentation being screwy and other indications that it might matter which post goes to the chassis battery and which post goes to the house battery, I figured I had nothing to lose and for the moment it seems to be working.

Here are pics I found from the Forest River site....

[Jdb]

Judge thanks for your info and the pics. I’m curious - do you have both coach and chassis Lithium batteries? Seems to me that we have to do all or none because they are tying the charging circuits together at times

Dave

[Jdb]

Judge thanks for your info and the pics. I’m curious - do you have both coach and chassis Lithium batteries? Seems to me that we have to do all or none because they are tying the charging circuits together at times

Dave

[Judge]

Originally Posted by Jdb

Judge thanks for your info and the pics. I’m curious - do you have both coach and chassis Lithium batteries? Seems to me that we have to do all or none because they are tying the charging circuits together at times

Dave

I do not have Lithium Batteries. I was just searching online for wiring diagrams and came up with the Lithium version of the BIM and it has labels on the battery posts as to which battery gets connecter to which terminal.

I would assume that if you use the Lithium version of the BIM, both sets of batteries should be Lithium so it could charge each bank properly.

[howzball]

Here is the information from the Lithium BIM specifically.

http://precisioncircuitsinc.com/wp-c...i-BIM-Rev1.pdf

It's designed to charge your Lead acid/AGM truck battery and Lithium Coach batteries independently.

Lithium batteries can tolerate a huge charging amp load, so if you were to reverse your battery connections on this it could probably damage your starting batteries.
I haven't converted to lithium coach batteries yet but I plan to so I've done some reading on this device.
I don't want to risk burning the truck alternator up from over-amping from the lithiums.

[Judge]

Originally Posted by Judge

I'm not convinced the wiring doesn't matter even after Precision told me the same thing.

I have a 2020 Magnitude SV34 with the BIM 160. I have been having issues with the house batteries charging while driving coach.

The BIM 160/225 datasheet's terminology is all screwed up. They call the battery connected to the engine alternator the "coach" battery and they call the battery hooked to the coach converter / charger the "chassis" battery.

The wiring diagram shows the Ignition terminal on the BIM connected to their version of the "chassis" battery, which we would call the house (coach) batteries.

When I look at the BIM version for Lithium batteries it specifically says the left post is for the starting battery and the right post is for the house batteries. The Lithium battery unit looks identical to the BIM 160/225 so the only difference with this model is how the microprocessor controls the Lithium battery charging.

I also found a Forest River site that specifically shows the BIM 160 wired with the left post going to the starting battery and the right post going to the house batteries.

During my last trip the FireFly panel started reporting the chassis battery at 0V when the engine was running and then normal voltage when the engine was off. The BIM was also not boosting the house battery voltage when the Inverter was on for the fridge and the voltage dropped below 12.5 volts and the chassis batteries were showing 14.7 volts on my dash voltmeter.

Today I decided to switch the BATT-A and BATT-B wiring the way the Forest River site showed and the way the Lithium battery version shows. I moved the chassis battery cable to the BATT-A post and the house battery cable to the BATT-B post.

After doing that I started the engine. After a couple minutes I could hear the relay engage while the engine was running and my house battery voltage went up.

I'm still not going to rule out that I have a bad BIM 160 and maybe it just started intermittently working. But after seeing the Precision Circuits documentation being screwy and other indications that it might matter which post goes to the chassis battery and which post goes to the house battery, I figured I had nothing to lose and for the moment it seems to be working.

Here are pics I found from the Forest River site....

I'm becoming slightly more convinced that which battery gets connected to the BATT-A and BATT-B posts might matter on the BIM 160.

Every time I start the coach now the house battery voltage gets boosted after the engine has been running for a few minutes.

I'm also seeing a difference in the the way the converter / charger is working after I plugged into shore power at home. It looks like both the house and chassis batteries are being charged once the relay kicked in. I have a hardwired Progressive EMS installed and with nothing else running I am showing a current draw of 12 amps on Line 1 where the converter / charger circuit is located. I typically don't see the type of current draw after plugging in but it makes sense since the house batteries were drained down a bit and I also had drained down the chassis batteries a bit doing my troubleshooting.

From what the Precision Circuit guys said the relay kicks in if it senses the voltage of one battery bank drops below 12.6 volts and there is an adequate charge on the other bank.

I'll keep testing and see how things go but things sure seem to be behaving differently since I swapped the cables going to BATT-A and BAT-B on the BIM. It still could be the thing has an issue and is only working intermittently but it is a heck of coincidence that it started working more like it should once I swapped the battery cables.

[DadTimesThree]

Like Judge, my BIM was cross-wired. General RV spotted that problem today when they had the rig for 5.5hr.

While we all agreed that a cross-wired BIM should NOT be an issue as far as battery charging is concerned, it "fixed" another problem - the input voltage on the inverter control panel had ALWAYS matched the chassis voltage on the Firefly control panel prior to the wiring change.

Of course, the inverter input voltage matching the chassis battery voltage makes NO sense as the inverter is supposed to get its input from the house batteries.

However, it also makes no sense that changing the BIM wiring would change the input voltage of the inverter since the BIM is for providing current to the batteries not for siphoning it off.

Since General said "all is working correctly", I'm back to trying to get answers from Thor support. Also trying Precision Circuits (the BIM), Eaton (the inverter) and even Firefly to see if any of them can offer an explanation.

[Judge]

I still contend having the chassis battery and house battery cables has a negative impact on the BIM charging algorithm.

My proof is that after driving 6 hours, my slide would not extend because the house battery voltage was too..... even with the engine running to extend the slides. The BIM should have been providing more than enough voltage from the alternator to extend the slide! The first time it happened I thought I had a slide controller failure.

I had to start my generator so the Converter kicked into provide voltage to the house batteries to allow the slide to extend. Thats when I knew the problem had nothing to do with the slide itself.




The FireFly panel shows the wrong chassis battery voltage because there is a smaller gauge wire on the BATT-A post of the BIM where the chassis battery should be connected so it can monitor and report that voltage. Instead the house battery cable was connected to that post where the chassis battery voltage monitoring wire was located.

The voltage readings on your Inverter (and solar controller if you have one) will match the chassis battery voltage (and house battery voltage) when the BIM relay has engaged.

Now that I wired my BIM correctly, I can do an easy test to make sure it is working properly.

If I am plugged into shore power, I can turn the headlights on to drop the chassis battery voltage and once it hits ~12.6V, I can hear the relay engage to send voltage from the house batteries via the Converter / Charger to the chassis batteries. At that point the voltage on the Inverter and Solar Controller match the voltage of the chassis battery within 0.1V.

I can also do the reverse test and take the coach off shore power and start the engine. The I turn up the fridges and other items on the Inverter to drop the house battery voltage to 12.6V until the BIM relay engages to charge the house batteries from the alternator. Again the battery voltages will math within 0.1V at that point.

[DadTimesThree]

Thanks, Judge. Those 2 tests to prove the BIM is properly wired AND working are brilliant in their veracity and simplicity.

[The_Breeze]

For anyone who may not have heard or wants to investigate further: https://static.nhtsa.gov/odi/rcl/201...9V609-6943.PDF

"It has been discovered that on certain model year 2020 Chateau, Daybreak, Four Winds, Freedom Elite, Outlaw, Quantum Motorhomes, a loose connection exists between the Battery Isolation Manager (BIM) or the Battery Isolation Relay (BIR) and attached battery cables.

-Recalled products do not have lock washers on isolator relay studs.
-140 Chateau units are a part of the recall population."

[tgsmith4845]

I just installed a battery monitor on our 2018 ACE 30.4 in anticipation of replacing the 2 12v wet batteries with three 12v AGM batteries, and noticed readings similar to those in this thread. The house batteries weren’t charging with the engine running and the chassis battery wasn’t charging on shore power. Sure enough, the chassis and house battery leads were misconnected on the BIM 160. Switched the leads and all good now. I’ve been driving this for three years thinking the house batteries are charging when we’re driving. Luckily most of the places we visit have shore power to plug in to.

[Judge]

I’ve posted many times on this topic. Thor wired my 2020 Magnitude incorrectly and it caused all sorts of 12V issues.

At least I figured mine out in 3 months.... 3 years is a bummer.