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Discussion Starter · #1 ·
So I'm Stuck in a Dilemma, It's finally time to start thinking of replacing the hybrid battery. Since I want to keep this car alive for as long as possible, (almost one of a kind- 10 inch ground clearance, great awd, 33+ city still, taxi's used past 400k mi with no issues, etc.), The battery replacements are absurdly expensive $3800 for a 3yr warranty from greentech or $4000 for a "lifetime warranty" from a company I think my car will outlast.

I've rebuilt the battery myself already, with limited success, as I don't have quite the NiMh testing facility of proper shops! -But that leaves me a second complete hybrid battery
Now to stop Rambling:

I'm planning a 100s Lifepo4 conversion, using 1p100s Headway 38120HP for $1600 (if not cheaper due to bulk buy)
(note- I can easily fit 2p100s but that's out of the budget for now)
An Orion BMS 2 108 Cell $1,285
That leaves over $1k, If I want to stay in budget
I'll be reusing most of the stock pack, Including precharge contactors, safety disconnect, Fans and a/c control

Now since this car is so old, there's surprisingly little in the way of CAN messages and other control (literally only 24 messages for the whole car)
It looks like the orion BMS can easily handle most of the CAN control,

However here's my current problems with this:

  1. Emergency signals, I need to generate a 2hz 50/50 square wave for emergency control, and be able to change that to 6hz for problems
  2. Need to figure out what these two pins do, It's not quite written in the best way
  3. Be able to precisely control the timing of the precharge resistor contactors, and send the confirmation back if normal.
  4. Figure out characteristics for outside thermistor, Control the stepper motor for air source selection, and control A/C solenoid
  5. Modify CAN information, (I want 30%-90% DOD for normal operation of the pack, but the car will only work properly if it thinks its 42%-60%)
  6. PID's <- Do i need to keep the stock ones, i'm not sure if the radio display for example reads just CAN data or requests stuff
  7. R-mode enable- The car enables this every 10k miles at random just to balance the battery Probably can respond with a fail state CAN message to prevent it starting
  8. Jumpstart module- I don't think I'll need this and would replace this in the future with a charger for a bit of PHEV use (80% DOD gives me 2048wh of capacity- an easy 5+ city miles)
I'm pretty sure I can solve most of these issues with an arduino, use it to control the contactors, Emergency square waves, Stepper motor control, and modify CAN messages
I dont think theres an automotive grade version, however its in a climate controlled box and would probably have its own power supply isolated from the car's 12v

Has anyone attempted anything similar? I heard in the past Insight owners swapped in LTO packs.

And any good contacts of people willing to help or hire in the southwest US would be great! (AZ-CA area)
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