Lithium Battery Wiring Diagram

[Rich-MLsRV]

Folks,

I am converting from lead acid to lithium batteries. Attached is how I plan to wire in the Lithium batteries. Let me know if you have recommendations as to what I should change.

thanks

 

[Gronk]

Pulling power from the batteries the way your diagram is is the correct way. That helps ensure both batteries share the load. I cannot see ant issue with your plan.

 

[Rich-MLsRV]

Pulling power from the batteries the way your diagram is is the correct way. That helps ensure both batteries share the load. I cannot see ant issue with your plan.

Good to point out balancing current flow out of the batteries. Subtle important point to make. Thanks for commenting on this.

 

[Kevin D Pem]

Quick question. Do the 3/0 cables go thru any walls that may have metal? If so a fuse on the battery side is in order.

 

[Rich-MLsRV]

Quick question. Do the 3/0 cables go thru any walls that may have metal? If so a fuse on the battery side is in order.

Any changes I am making do not pass thru metal walls. It's all contained within the enclosed battery bay. Thinking about it, a fuse would be a good idea. I'll add a 300A fuse between the batteries and the disconnect switch.

 

[Gronk]

Excellent idea!

 

[Kevin D Pem]

My guess is you will have the terminals covered as well. Lithium is kind of a dangerous capacitor. A wrench welded between terminals would produce quite a fireworks display. Ttat is the kind you run to the closest phone and call 911.

 

[jmltech]

You may want to look at the cables between the batteries and your house connection. AM Solar shows 4/0 cable:

AM Solar 300Ah x 2

 

[Rich-MLsRV]

You may want to look at the cables between the batteries and your house connection. AM Solar shows 4/0 cable:

AM Solar 300Ah x 2

Thanks for the recommendation. Looking at the current carrying capacity of 3/0 and 4/0 ga wire

it makes sense to go w/ 4/0 ga wire. It's interesting how the current carrying capacity is so dependent on temperature. I am not expecting wire temp to reach 140F. If this is the case then something is very wrong.

 

[Kevin D Pem]

The very wrong happens in raceways. I would not worry about 3/0 cable unless your running the inverter at capacity for long periods. You could grab your IR thermometer and see how hot the wires are getting. As an incite the rating on wire is mostly because of the insulation not the copper capacity. Short runs will not see much of a voltage drop so should not make problems with the inverter operation.

 

[Rich-MLsRV]

Here's an almost complete picture. I used the existing lead acid battery bay. I thought removing the lead acid tray would be difficult. It turned out to be relatively easy since Newmar had the tray bolted rather that welded. As far as enclosing that battery area I wanted easy access to the slide motor so the bolts can be torqued as part of regular maintenance. Currently, I have not completed enclosing the batteries. With some screws and warmer weather I'll be able to complete. It's been cold here in CO.

I ended up going with Battleborn batteries as the LifeBlue were back ordered until end of December if not later. Battleborn had a Black Friday sale so that helped with the price.

I still have tape on the negative terminals. When installing I had tape covering both positive and negative as I was paranoid about shorting while connecting wires.

The 6 awg across the front of the batteries is the solar pre-wire. Next project will be installing solar.

 

[Chuggs]

First thing...remove the ME-BTS. Lithiums do not need temperature compensation.

You should consider swapping the BIM you have with the Li-BIM, or a manual tie relay...dc-dc Charger.

https://www.amazon.com/dp/B07DY8S815/?tag=rvf01-20

Lastly...some method of keeping them above 32 degrees...

I just replaced my batteries with AGMs...I am watching for better development of methods to incorporate Lithiums into a MotorCoach with two battery systems. If nothing else good developes...I am looking at doing some things to prep...

1) Remove the 10w Zamp Solar panel...and replacing it with a 200w panel and Victron SmartSolar MPPT75/15 controller. I want the chassis to be self-maintaining.

2) Figure out where the Oasis loop fluid lines going to the dash area are...splice another heat exchanger in...with coin thermostat like the wet bay has. This to be used only for cold wax to prevent Lithiums from shutting down.

3) When I installed the Lithiums...enclose and insulate the bay. Remove the BIM, and place a cross tie relay for BOOST feature...and two DC-DC chargers to allow the Alternator to share amperage while driving. Mainly so I can run a rooftop a/c with my Inverter while driving.

 

[Rich-MLsRV]

@Chuggs - Thanks for your thoughts.

I did install the LI-BIM.

I am on the fence as to whether install a method to heat the battery bay. The Battleborns operating temp is -4F to 140F. BBs won't charge below 25F. I have a Govee WiFi temp sensor in the battery bay to monitor temperature. I typically don't camp in these temperatures. Later I'll decide what to do.

 

[Chuggs]

Nice job!


I didn't know they could operate that low. With the ME-ARC, you can set AC-IN to a time range...so, if you know temps are going to dip at night...the Magnum Inverter will disconnect for a time...and no charging would even be attempted. With Victron Solar, you can set a temperature relay. So charging wouldn't be an issue. And wow...I think 10 F is the lowest I've seen. Guess those Battleborns are good stuff. I have a friend that had eight of them in his Ventana. I loved looking at the operating voltage. Cuts down on amps used...when the voltage helps make up the wattage.

Battery Porn... my Lifeline getup.

 

[Kevin D Pem]

Like @Chuggs said. Nice Job! Also his concern about temperature. Lithium develops dendrites when charged at freezing. The problem with saying you will not be camping at those temps is the solar can still be charging at those temps. Insulate and heat(even if that means a incandescent light fixture and lamp in the bay. Put the light on a thermostat.