Lithium Upgrade v0.4 - WIP for Comments

[Stormy98]

I'm in the midst of a LiFePo4 upgrade. I'm calling it "v0.4" because I have at least 6 things I still need to do:

• Secure the batteries. I'm thinking threaded rod to tee nuts in the plywod base and a metal strip that runs under the battery cables.
  
• Protect the battery terminals. Possibly an acrylic sheet mounted over the 3 batteries.
  
• Upgrade the Inverter case ground wire. I'm currently using the SMB wire but my understanding is the recommendation is one size below the largest cable, so that would be 3/0.
  
• Secure the various wires with cable clamps and protect them with loom where abrasion is a factor.
  
• Remove the isolator. Could use some advice here. Still need to trace the wires from the isolator and confirm where they go. Also interested in the best way to connect and protect the 4AWG wire that will go between the starter battery and the DC-DC charger. Maybe a fuse holder on the battery terminal? Or a separate fuse holder mounted in place of the isolator?
  
• Install the DC-DC charger and MPPT charger. I will likely remove the DC distribution panel and Starcool relay plate and move them to a new board that has those panels on one side and the DC-DC charger and MPPT charger on the other side. The GFCI outlet would also live on this board. I'm considering replacing the SMB DC distro panel with a Blue Sea 7748 Panel to avoid having two connections at the Lynx distributor (the Starcool plate would then connect to the Blue Sea Panel instead of running back to the Lynx). But not sure if it's worth the extra expense.

No doubt there is more that can be done to make this better, so any and all comments are welcome. Photos and a schematic are attached. The schematic is a bit vague around the alternator and starter battery because I still have some investigating to do there. I've also attached a wiring diagram from a SurePower manual that I believe matches the SMB install.

Kinda wish I'd saved space by going the DIY battery route and using the existing 2-battery bay, but that will be a project for another time!

 

[mjcleland]

I am in the middle of a similar project. What software are you using to do the schematic drawing?

 

[Stormy98]

I'm using Adobe Illustrator. Tell me a little more about your project, maybe we can compare notes.

 

[mjcleland]

Similar overall - using separate inverter and LiON charger, don’t have a starcool to factor in.

My use case includes freezing temps so I am including battery heaters. I am adding the complication of keeping the existing AGM house battery and a selector allowing power for the LiON battery heaters and diesel heater until I can get the LiOn batteries up to temp and keep warm.

Could have bought self heating batteries, but dead batteries would mean no charging until made warm anyway. If you see this differently, I can use the help.

I will end up with 520 AH of liON, 90 AH AGM, and 2 starting batteries. I will keep original charging from alternator (plus intelligent charging from solar - Renogy MPPT w/ alt). Only expect 200-300 watts solar.

AC needs are minimal, but I want option for power tools and potentially a portable small AC unit.

Your schematic layout is about identical with the exception of the selectable battery source.

For context - the van is a 2001 7.3 Diesel 350EB

 

[Stormy98]

What battery heaters are you using? I don't encounter freezing temps that often and my batteries are inside but I have considered rigging up heaters and a temperature triggered switch to keep them above freezing if needed.