EV Gas Can

https://www.youtube.com/watch?v=ygBf1wOx1X8

I'll caveat this by saying it's not for everyone in terms of cost/benefit.

This was more of an experiment, and I've yet to actually drive around with it.

You can accomplish the same thing by using the biggest AGM battery that will fit in the Leaf's battery holder - or make a slightly larger one. 150AH might give you enough of a charge to go a few miles. Interestingly, there is anecdotal evidence that as the Leaf gets very low on charge, it will pull power from the accessory battery through the DC-DC converter to go a few more meters. IF true that would eliminate the need for the inverter.

That *is* interesting (the two-way DC-DC conversion). I guess it could be proven by measuring the current on the connection to the 12V battery from the Leaf 'power module' as low traction battery condition developed.

The battery in the video is 150Ah, and I get 7-8 miles of range added before the inverter hits the low-voltage cutoff. An AGM battery should perform similarly, *if* you don't mind discharging it that far (90%?). Otherwise 3-4 miles seems more realistic.

Are you talking about actual range, or Guess O Meter range? 3-5 actual miles could be very helpful.

It's fairly consistent after close to a dozen cycles (I'm filling this battery up with a couple of solar panels pretty much daily). The SOC usually goes up between 7% and 8%. This is a 24kWh Leaf, and 8% SOC is 'about' 7 miles of range (hence the 84-mile EPA rating).

Another way to look at it is: at 4 miles per kWh (my readout is at 4.6mi/kWh so far for April), each 250Wh is one mile of range, and this 150Ah battery holds *nearly* eight of those (1920kWh). This is of course before conversion losses in both the inverter and the on-board charger, so maybe 6 miles is a more conservative estimate. This also assumes a charge cycle gets everything out of the battery, which isn't quite the case (low-voltage cutoff at 10.5VDC).

I have another battery that I assembled from four 200Ah LiFePO4 cells (so 2560kWh), and routinely see over 10% SOC increase when I try this with that one. Weight is only one pound more than the one in the video (36 versus 35). And way less expensive (sourced straight from the manufacturer). But no BMS on that one so a bit more care is called for when charging.

LeftieBiker said:

You can accomplish the same thing by using the biggest AGM battery that will fit in the Leaf's battery holder - or make a slightly larger one. 150AH might give you enough of a charge to go a few miles. Interestingly, there is anecdotal evidence that as the Leaf gets very low on charge, it will pull power from the accessory battery through the DC-DC converter to go a few more meters. IF true that would eliminate the need for the inverter.

Click to expand...

Since the inverter is doing DC to DC one way, seems the traction batteries would eat the power if it did switch in reverse instead of going to the motor. Unless it can cut-off the traction battery, up the voltage and then feed into the motor and still run all the 12 volt accessories, computer, etc without the voltage dip messing everything up, then you would have the ability to "creep" @ 500 watts maybe, but not sure how far or how long.

knightmb said:

LeftieBiker said:

You can accomplish the same thing by using the biggest AGM battery that will fit in the Leaf's battery holder - or make a slightly larger one. 150AH might give you enough of a charge to go a few miles. Interestingly, there is anecdotal evidence that as the Leaf gets very low on charge, it will pull power from the accessory battery through the DC-DC converter to go a few more meters. IF true that would eliminate the need for the inverter.

Click to expand...

Since the inverter is doing DC to DC one way, seems the traction batteries would eat the power if it did switch in reverse instead of going to the motor. Unless it can cut-off the traction battery, up the voltage and then feed into the motor and still run all the 12 volt accessories, computer, etc without the voltage dip messing everything up, then you would have the ability to "creep" @ 500 watts maybe, but not sure how far or how long.

Click to expand...

What I recall, FWIW, is that this happens only while the traction batteries are still above the low voltage cutoff, and the accessory battery gets drained in this brief window, after the "---" on the GOM, but before the BMS shuts the pack down. Again, I have not verified that this actually occurs, and I can't think of uncommon enough search terms to find the post(s).

Heh. I found it - first try! https://www.mynissanleaf.com/viewtopic.php?f=9&t=22405&p=468097

It's about a quarter of the way down the page.