[Antman]

I'm in the process of converting a classic car to an EV. I have basic knowledge but not quite sure how to sort out my battery and contactor setup.

So I have two battery boxes running 6s and plan to join them together before they get to the inverter. I'm trying to work out whether I need two contactors per battery box or whether I can just run one in each and have one on the +ve and one on the -ve of the other half?

Then I'm trying to work out where the precharge resistor and contactor would be best in the system? Or whether I need to double up on these also?

Finally, to join the two packs together would people use a HV junction box? There will be service disconnects on both battery boxes.

TIA
Antman

 

[Immo1282]

Assuming some kind of lithium batteries, 6s is really not very much voltage. What motor and controller had you planned to use with only 19-22V nominal from your batteries?

I'll be building my batteries into two dissimilar sized groups when I do my conversion but instead of paralleling strings together, I will split a series pack across the vehicle - with XsYp notation making my battery "92s1p".

 

[Antman]

Yes using lg chem 60v lithium cells for 360v and giving 32kWh.

 

[brian_]

This is six of the common LG modules for the Chrysler Pacifica Hybrid in series, not six cells, so the overall configuration will be 2p96s, and the nominal operating voltage will be 360 V, just like the Pacifica and most current EVs and plug-in hybrids.

While the grouping of the modules into packs is different, electrically this is the same as snowdog's Electric Supercar project.

 

[Immo1282]

My mistake then; 6 of the LG modules is plenty of kick.

Snowdog's setup is closest to what you are trying to do, definitely. Putting a pair of contactors on each sub-pack seems like overkill to my intuition, but definitely hang around for the opinions of the diy ev veterans around here...

 

[Antman]

I'll have a look at Snowdog's build thread then guys. Thanks for the advice so far!

 

[brian_]

XS_MotorWorks' Project Split Decision is also similar: it uses Chevrolet Volt modules, but it has two parallel strings of 90S each.