Lithium Battery Upgrade 2020 Minnie Winnie 31K

[thistlesmith1]

I thought I had this all worked out. Add 2 100AH lithium batteries. Upgrade converter to lithium profile. Add Vectron 700 BMV. Replace Battery solenoid with Progressive Circuits LI-Bim 225. Now I am not sure the BIM will do the job of protecting the alternator. I also have a boost switch in the mix but I think I have that figured out. The BIM has a signal terminal that I don't know what it does. Progressive hasn't been much help. Anybody used that BIM in this application. Thanks. 2020 Minnie Winnie 31K.

 

[ptronus31]

Do you have solar? If so, you may not need DC-DC (alternator charging). I have 350W of solar and just disconnected the DC-DC via a switch that I can turn on if I need the boost switch.

Also, you may not need to change the converter. The stock LA converter may not fully charge your new batteries, but it will probably get them in the 90% state of charge range.

 

[Bnystrom]

I didn't replace the boost solenoid when I installed a DC-DC charger. The charger bypasses the solenoid, but you can install a switch to enable boost mode if you need it.

 

[creativepart]

I’m pretty sure your 2020 Minnie Winnie 31K doesn’t have a BIM but a Mode Solenoid. That’s why the connections don’t exactly transfer to the LI-BIM. It probably could be made to work, but my feeble brain can’t figure it out to provide any real help. You might try speaking to support folks at Precision Circuits.

Also there is at least one YouTube installation video which details the “mystery wire.”

 

[Morich]

In this case and where the mode solenoid is installed, I would not consider it worth the effort to add a switch for the odd occasion when a boost feature might be needed.
One of my first points would be how rarely I need a boost, as I don't remember ever running the start battery down, once the kids were all out of the RV!
So if I only use something hardly ever, I do little work to maintain easy function of the feature. As long as the alternate is pretty simple.
Keeping in mind that why we kill this is to keep the coach and chassis batteries separated and only want it connected on very rare occasions, I go for having a backup plan but don't feel it necessary to go to much work to be able to flip a switch.
Since the two batteries are normally connected together by putting battery on wire LR at the mode solenoid and that solenoid is pretty handy under the steps, I go for simple---if it's ever needed!
The drawings show the solenoid under the steps and next to the batteries. So if you disconnect wire LR from the solenoid, the feature is dead and there will be no concern about overworking the alternator driving down the road.

You should have chassis battery on one big post and coach on the other big one with a small lug in the middle. That small center lug should have LR on it. Disconnect it and the boost or connection to charge while driving are dead, until LR gets battery to operate the coil in the solenoid!
Taking LR off, kills the feature but if we suddenly need a boost, all we need is a small strap placed from one of the big lugs that is alive over to the small center lug! This strap is only going to carry the same current as wire LR and that may only be a 16 gauge wire!
This can be a simple as getting a strap with alligator clips on the ends and tying it near where you might/might not ever need it!

Yes, it is a bummer that it can't be done from the driver's seat with the switch but maybe you never need it anyway? And if you DO need a boost start, get out, open the battery box and put the strap between the big lug and and the small center lug! That powers the solenoid coil and connects coach and chassis for starting!
Try it and see if you hear the solenoid thump as it moves?
Start the engine and then remove the strap!
I consider that a pretty easy thing , especially if I never expect to use it!

 

[ptronus31]

In this case and where the mode solenoid is installed, I would not consider it worth the effort to add a switch for the odd occasion when a boost feature might be needed.
One of my first points would be how rarely I need a boost, as I don't remember ever running the start battery down, once the kids were all out of the RV!
So if I only use something hardly ever, I do little work to maintain easy function of the feature. As long as the alternate is pretty simple.
Keeping in mind that why we kill this is to keep the coach and chassis batteries separated and only want it connected on very rare occasions, I go for having a backup plan but don't feel it necessary to go to much work to be able to flip a switch.
Since the two batteries are normally connected together by putting battery on wire LR at the mode solenoid and that solenoid is pretty handy under the steps, I go for simple---if it's ever needed!
The drawings show the solenoid under the steps and next to the batteries. So if you disconnect wire LR from the solenoid, the feature is dead and there will be no concern about overworking the alternator driving down the road.
View attachment 1112015
You should have chassis battery on one big post and coach on the other big one with a small lug in the middle. That small center lug should have LR on it. Disconnect it and the boost or connection to charge while driving are dead, until LR gets battery to operate the coil in the solenoid!
Taking LR off, kills the feature but if we suddenly need a boost, all we need is a small strap placed from one of the big lugs that is alive over to the small center lug! This strap is only going to carry the same current as wire LR and that may only be a 16 gauge wire!
This can be a simple as getting a strap with alligator clips on the ends and tying it near where you might/might not ever need it!

Yes, it is a bummer that it can't be done from the driver's seat with the switch but maybe you never need it anyway? And if you DO need a boost start, get out, open the battery box and put the strap between the big lug and and the small center lug! That powers the solenoid coil and connects coach and chassis for starting!
Try it and see if you hear the solenoid thump as it moves?
Start the engine and then remove the strap!
I consider that a pretty easy thing , especially if I never expect to use it!

I did just this, only I put a 10A switch between the LR wire and the center lug. Normally the switch is off (open), but when I need a boost, just switch it on, start the engine, then turn it right back off. Way easier than straps and clips.

 

[Morich]

If one wanted even easier than a clip but wanted more work to set it up, going with a switch near the driver would do away with time involved with getting out and going to the solenoid and all that walking. Of course the downside is that it may take an hour or more to run the wiring from the solenoid to the driver. But then that is where we each need to look at what WE want to do. If the work is better for each as it cuts all that time walking to the solenoid, that certainly is an option.
Making it only require connecting one end of the wire instead of all the super tedious effort of connecting both ends will certain save a vast amount of time and effort , especially if we use it every three years instead of every five years?
I find flipping that sort of switch once each five to ten years will certainly increase the odds of my nails becoming worn down, so there is that to consider. It really does need to have some thought given to how we each might like to set up our RV for this super important item, especially if we ever use it!

But when looking at easy, the labor can be cut down some if we just cut the loop connection off Wire LR and add the type which fits snuggly on the center connection post. Take the wire off and it is dead, stick it back on the post and it is good to go.

I find I have never used the boost feature, so spending any more effort to plan for events that never happen may also be a total waste of time.

But that is what RV are for in most cases as we certainly have a problem if we want to make a case for them being efficient!

 

[ptronus31]

If one wanted even easier than a clip but wanted more work to set it up, going with a switch near the driver would do away with time involved with getting out and going to the solenoid and all that walking. Of course the downside is that it may take an hour or more to run the wiring from the solenoid to the driver. But then that is where we each need to look at what WE want to do. If the work is better for each as it cuts all that time walking to the solenoid, that certainly is an option.
Making it only require connecting one end of the wire instead of all the super tedious effort of connecting both ends will certain save a vast amount of time and effort , especially if we use it every three years instead of every five years?
I find flipping that sort of switch once each five to ten years will certainly increase the odds of my nails becoming worn down, so there is that to consider. It really does need to have some thought given to how we each might like to set up our RV for this super important item, especially if we ever use it!

But when looking at easy, the labor can be cut down some if we just cut the loop connection off Wire LR and add the type which fits snuggly on the center connection post. Take the wire off and it is dead, stick it back on the post and it is good to go.

I find I have never used the boost feature, so spending any more effort to plan for events that never happen may also be a total waste of time.

But that is what RV are for in most cases as we certainly have a problem if we want to make a case for them being efficient!

I put the switch in the compartment with the solenoid. It was a 10 minute job.

 

[Bnystrom]

Our switch is mounted under the passenger's seat, which is where the boost solenoid switch is. To use it, I switch it on, press the OEM "Battery Boost" switch on the dash, start the engine, then turn off the switch. I can reach it all from the driver's seat.