Li-BLM working correctly?

VISTACA · 10-07-2022, 10:13 AM

I have the Lithium battery package. I've been watching the chassis and coach battery voltages. They are always the same. If I am plugged into shore power they both read 14.6 volts. Seems like that will burn out my chassis battery. How do I test the Li-BLM to make sure its functioning correctly?

**bclemens** · 10-07-2022, 10:19 AM

here is the information on the Li-Bim.
https://www.precisioncircuitsinc.com...i-BIM-Rev1.pdf

It would help if you put your model and year in your signature.

For example, if it is a 5 Series, I would suggest you verify that the "Aux Button" was properly set up as a momentary switch and not a latching switch.

VISTACA · 10-07-2022, 11:24 AM

Ok, I figured out how to update my signature. (2022 I3 RW) The switch is a momentary type and always returns to the "start" position. When I press it to the "aux" position I do hear a click somewhere.

Desert Boat · 10-07-2022, 03:28 PM

If the cross-connect signal is verified to not be on, then it sounds like the LI-BIM has failed or is miswired. The chassis battery should not continuously sit at 14.6

One check is to carefully lift and tape the wire labeled SIGNAL on the BIM, then see if the voltages drift apart.

If they do drift apart with "signal" removed, then you need to investigate the signal wiring. Either ground or +12V on the signal line will cause it to connect. Signal needs to be "floating" for normal operation.

If they do not drift apart, then the BIM is suspect.

There is a functional test procedure for the regular BIM posted on FRF, but not the LI-BIM. I do know that while driving, with some load on the house, the LI-BIM seems to follow a 15 minutes connected, 15 minutes disconnected cycle. If your house just tracks the alternator voltage continuously for greater than 15 min driving, then that would be a second indication that it is not functioning. Again, with signal removed and safely taped, to isolate any switch effects.

VISTACA · 10-07-2022, 03:29 PM

Well after clicking the switch 4 or 5 times it now seems to be working correctly. 12.8 on the chassis and 14.6 on the batteries. Maybe the solenoid stuck?

twp5253 · 10-12-2022, 06:21 AM

Quote:

Originally Posted by VISTACA

Well after clicking the switch 4 or 5 times it now seems to be working correctly. 12.8 on the chassis and 14.6 on the batteries. Maybe the solenoid stuck?

Yes, might have just needed a good kick. Mine seems to work pretty well but when I put RV in long term (2 month or greater) storage, I disconnect the starter batteries and put a Optima AGM charger on for them. On my Magnum Advanced Remotes, I set the Li voltage to 13.2 so they will be closer to 50% SOC as per most Li battery instructions. I have two inverters and both now have advanced remotes. Stores in my GarageMahal nicely on a 50amp circuit.

VISTACA · 12-06-2022, 04:23 PM

I contacted the manufacture of the BI-BLM and this is what was said.

(me) I have an RV with 2 Lithium batteries. I've noticed many times while on shore power or generator the voltages for the chassis and coach battery are the same. Usually in the 14 volt range. If I press the aux start switch (we have a Sprinter chassis) it seems to separate the chassis and coach and the chassis will drop down to about 12.9 volts. Not sure why they seem to "stick" together. I think eventually this will burn out my chassis battery if I don't catch it. Do you have any ideas as to why this happens?

(them) The Li-BIM is bidirectional so if you are charging the Lithium coach batteries and the chassis battery gets to 12.7v or less the LI-BIM will connect so both battery banks can charge together.

(me) Ok, so at what voltage does the "Manager" stop charging the chassis battery but continue to charge the lithium batteries because they are a higher voltage?

(them) Once the LI-BIM connects both battery banks will have the same charge voltage. It will stay connected for an hour then disconnect and only reconnect when the chassis battery gets down to 12.7v again. If you have a draw on the chassis battery or if the battery is weak the Li-BIM will be connecting more often to charge it.

So I will watch it for a while. Maybe my concerns were for nothing.

Sabu · 12-09-2022, 12:36 PM

Following. I have the same going on. Isata 5 30FW.

VISTACA · 12-09-2022, 01:57 PM

So this is how they told me to test it.

It is possible the BIM is working as designed you may just be seeing it connect more often then not. You can run a test to verify, if the BIM is connected press the AUX start switch and verify the coach and chassis batteries have separated voltages. If the coach batteries are charging and the chassis battery gets to 12.7v the BIM should connect, wait for it to connect on its own then set a timer. The BIM should stay connected for one hour then disconnect, after 2 minutes if the chassis battery gets to 12.7v it will connect for another hour.

I turned on the headlights radio and dash fan to run the battery down. About ten minutes went by and then the system started charging the chassis battery again. After an hour it did shut off. I'm going to test it again on solar power this time.

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