Battery Upgrades are very possible

[bkvszomorito]

Interesting. The BMS may also be measuring the total power draw or possibly the internal resistance of the module. 3.45V indicates that roughly 12Wh (22%) of the capacity is not being used. Have you tried charging the car for only a short time (1 hour) and seeing if driving it again would trigger turtle at a lower voltage?

What this means is that the 30 kWh BMS will likely not over-discharge the 40 kWh cells, so you are safe there. However, you're not getting the full possible range.

When you charge the 40 kWh modules with the 30 kWh BMS to 100%, what does Leafspy show when the charge to 100% is done? What is the min/avg/max voltage of the cells?

Good idea, I’ll try the one hour charge and drive.

Charging of the 40kWh modules with 30kWh BMS stops at 4.110/4.115/4.120 Volts. I think there might be unused capacity as well.

If I ‘ll never discharge below 22%, my battery should be very happy.

Regarding the internal resistance, it should be really different, as the Hx value with my healthy 40kWh modules is 74 according to the 30kWh BMS.

[Lothsahn]

Good idea, I’ll try the one hour charge and drive.

Charging of the 40kWh modules with 30kWh BMS stops at 4.110/4.115/4.120 Volts. I think there might be unused capacity as well.

Based on the curve, you're wasting ~3% of the battery on the top end. That means that overall, you're sacrificing 25% of the battery, between upper and lower bounds. Your 40 kWh battery is effectively a 30 kWh battery, but I would expect it to last LONGER because it's not being kept at either extreme.

If I ‘ll never discharge below 22%, my battery should be very happy.

It should help. However, cars are generally stored charged, not discharged, so I suspect the top-level charge cutoff matters more. Either way, you're going to have a small DoD on each driving cycle, which should allow your battery to last much better if you drive a lot.

Regarding the internal resistance, it should be really different, as the Hx value with my healthy 40kWh modules is 74 according to the 30kWh BMS.

I don't understand what the Hx value really means, but the internal resistance of the cells will affect the amount of regen braking, among other things. If the BMS is calculating a higher Hx score, you should get more regen braking.

[Dala]

I recently acquired the EVs Enhanced; HV Battery Pairing Tool: http://evsenhanced.com/products/hv-batt ... ring-tool/

My next step is to buy a salvage 30/40kWh pack, and make a frankenbattery. Then I will tackle the instrumentation and hopefully cutoff voltage with a CAN-in-the-middle board.

My end goal is to have a sellable product, battery swaps on the cheap, and also upgrades.

Considering that used 24kWh batteries go for 2500€, 30kWh go for 3500€ and 40kWh go for 5000€, it's even way way cheaper to upgrade than a new 24kWh battery from Nissan, that you pay 10000€ for !

[Oilpan4]

Hey I'll take one.
I will be at 11 bars any day now.
Probably be looking for a 40kwh pack next year.
I think I can get a whole crashed 40kwh leaf for under $7,000, hopefully around $5,000.
Take the battery, sell the rest piece by piece on ebay till its a hollow shell that I can drag to the scrap yard.

[Lothsahn]

My next step is to buy a salvage 30/40kWh pack, and make a frankenbattery. Then I will tackle the instrumentation and hopefully cutoff voltage with a CAN-in-the-middle board.

Best of Luck. I am rooting for you! There is a can intercept/logger someone posted in this forum. It logs all communication to a SD card. That will make your project much easier.

[yontyont]

Is it possible to put the slightly larger 2019 Plus battery in a 2015 Leaf ?

Thanks, Tony

[SageBrush]

I recently acquired the EVs Enhanced; HV Battery Pairing Tool: http://evsenhanced.com/products/hv-batt ... ring-tool/
My next step is to buy a salvage 30/40kWh pack, and make a frankenbattery. Then I will tackle the instrumentation and hopefully cutoff voltage with a CAN-in-the-middle board.

Good luck!
I hope you keep us informed of your progress.

[Lothsahn]

Is it possible to put the slightly larger 2019 Plus battery in a 2015 Leaf ?

Thanks, Tony

Currently? No. People haven't even gotten a way to get any battery upgrades, unless you swap the VCM on a 30 kWh pack.

[Dala]

Update, the Man-in-the-middle CAN boards from Muxsan arrived today. Purchased a 30kWh pack, gonna figure out shipping next, and I'm also always on the lookout for any 40kWh packs

Here is where the magic happens:

[LeftieBiker]

It looks well constructed. No questionable solder joints on the back?