OK, I decided that I am going to join in the switch to lithium batteries. I will be using Leaf modules, I haven’t decided on 10 or 11. Since they are 7.6V/module my nominal voltage would be 76 with 10 modules or 83.5 with 11. Electric Conversions in CA says they can modify my Zivan charger to work. Since I have a T2 controller, would the 11 module be too much?
I am considering upgrading my front brakes with larger drum units, similar to what Rodney did. If I do the brake conversion, I will start another tread and add pics, if I am tech savvy enough to do that.
I guess by the way you say it is hard to mount the batteries in separate locations that lithium works differently than lead acid ???
My thought was to connect the packs just like the 2 12v batteries in my motor home for the coach batteries. Positive to positive and ground to ground that way you still have only 12v but the total amps of both batteries. 2x1000 = 2000 right.
If that will work for lithium I should only need to monitor 1 pack, the packs should balance each other out is my thinking.
I may be way off base here, thats why I am asking these questions, in hopes someone more advanced than I, will have the answer.
I can build anything from steel, I built my own hot rod from steel stock and 4 pieces of a 1932 chevy body.
I am not a rich Guy so every dollar I can save my self is a dollar earned, plus I can say I did it, and not bought it that way.
Thanks for taking the time to answer my questions.
The packs “may” stay balanced just fine.
Problem is, that with lithium, unbalance can be catastrophic.
At best damages battery, at worst fire or explosion.
The only way that I know to be safe is to monitor each parallel set of cells.
That means monitoring all 20 p-cells in a Leaf pack. Adding another pack in parallel is 20 more to monitor.
If your plan is to parallel at the module level, then still just 20 to monitor.
With no bms, each 10s parallel pack can be monitored separately.
A bms requires 11 wires from each 10s battery location. These are high power cables. Not easily extended safely.
I got these last year so figured I would throw this out there an another option for other lithium conversion folks. Got these from Nick at Hybrid auto center. More expensive that the earlier models ~$1700 but higher Ah. 5 New Nissan Leaf modules combine for a 76v nominal, 82.5Ah battery pack. They are 4 cells per module x 5 modules =84v max. They are the current generation of leaf cells. They fit nicely beneath the back seat of my 4 seater 1999 GEM. I haven’t actually tested the mileage since I do mostly hills but they work extremely well. I don’t have BMS but they do stay very well balanced. I’m still trying to find a good monitor for 20 cells if anyone has any suggestions. I’m using a DeltaQ that Travis from EMF reprogrammed for me. Next step for me is installing a Victron Battery monitor BMV-702.
Shout out to this forum. I couldn’t have done it without you!!! Thanks Y’all.
See my posts on bms-24.
This will display all 20 cell voltages on on screen. Indicating high and low cell.
Shows soc and total pack voltage.
Comes with 300A shunt that shows amps in and out. Also kw in and out.
Interfaces using the white wire from Travis’s charger.
Inhibits charger when high cell reaches set point. If. 4.15v.
Yes, runs from battery power when over 8s.
When connected it automatically counts cells. Select battery type and it goes to work.
Comes with all cables, sensors, and alarms.
Outputs can drive ~60v relays.
I can make, or show you how to make, a simple open collector interface to DQ white wire.
This display does it all.
Balances 1.2 amps peak.
If you leave connected to charger, it will stop and balance, when one cell is “full”, then restart. Continues till all cells are within the balance set point. ie. 10mv-100mv whatever you select.
I’m guessing the high voltage $50 option is necessary for it to function on 72-84v GEM?
I guess I’ll have to figure out what to do with the Victon battery monitor I already have. This looks so much better.
No, it works as is up to 24s *4.2volts.
Plug and play.
You can change all the limits, timers, and settings, but the defaults work fine.
Only things you might need are things to control charger or shut down car. Optional!
I just got my low miles Leaf lithium cells since my Trojans were dying.
My cells read 7.58 volts but have probably been sitting around for a few months. 72V divided by 7.58=9.5 cells.
So I figure I will need 10 of the Leaf cells in series; though I might want to add a couple more in parallel.
IS THIS BLUE BMS WHAT I SHOULD USE?
ANY ASSISTANCE WOULD BE GREATLY APPRECIATED; I AM IN SOCAL.
Thanks,
Jeffrey 8189160787 TEXT OR CALL; TEXT IS BEST
I know it has been a while since I checked in, but I’ve got 11 Leaf modules mounted in the front of my 2 seater where battery #5 and #6 used to set. I don’t have a BMS yet (INWO) but would like to know more about their function and method of operation. I found a place that will modify my Zivan charger to charge the lithium modules and will be sending it in this week. The eleven modules should give me around 83V from what I have learned on this forum that should work well with the GEM.
I will answer any questions I can until a few users start reviewing.
Most important function is the display that shows all cell voltages on one screen.
Also highlights hi and load cell voltages and shows the difference.
If difference is more than you like it loads the hi cell an brings it down.
During charging it can turn off charger when any one cell reaches set point. Then turn it on again after balancing. This makes sure you get all cells charged.
Can be connected to slow or stop motor when battery is low.
