LOL, so all I had to do was hook the green wire to that? I suspect I am ok with what I did, but if the relay ever goes again I would change to that connector. I put a Panasonic in so I suspect it will work for many years. The charger is installed and I don’t want to take it out again…
Regarding dropping the voltage to the heater: I found some small ceramic heaters on eBay, if you search 12V ceramic heater 100W you will see some small square heaters with a muffin fan, I got 4 to play with. I hooked the heaters in various configurations parallel and even tried series and parallel. Best results in my opinion are three in parallel and it drops the voltage about 11.5V while producing heat themselves. Two in parallel dropped the voltage 15V however I felt the small ceramic heater might not endure this long since the terminals got too hot to touch. I burned out a 12V fan on the small heaters during my tests, I’d recommend attaching the fan power to the 12V fan on the Gem rather than using the main load power. I hope to eliminate the small additional fans and plumb one small heater into each of the three heater ducts to boost the heat from the system. At full charge the Gem heater coil will see a max of 87.4V, that’s with three small heaters in parallel added in series to the main heater, it will probably survive that fine (I hope). https://www.ebay.com/itm/100W-PTC-Car-Fan-Air-Heater-Constant-Temperature-Heating-Element-Heaters-Black/392805858872
I was able to pop the ducting tubes out of the heater and am using silicone to attach the 100W ceramic heaters. This can all be undone.
Heater is in, it works better than in my tests possibly due to the connections being soldered now. Main heater 83.6V, 3 parallel 100w ceramic heaters boosting the heat to the ducts hooked in series to the main heater coil, at 12.2V. Perfect!
To go over what I did.
Purchase three of the same 100w 12V ceramic heaters, 6cm x 6cm, remove the fans.
Remove the heater from the Gem, carefully push the plastic tubes that connect to the ducts inward, you have to push the ribs one at a time to get them to pop in. You’ll see the tubes are square shaped and they can come out the hole with some slight force at the correct sideways orientation. Start with the one on the face, then do the ones on the sides, the hole on the face is slightly larger so pull them all out this hole.
I sanded the plastic face of the small heaters flat on a disk sander to glue the original duct tubes to, I also cut off the mounting tabs.
I glued the small heaters to the big heater and the original duct tubes to the small heater using silicone. be careful not to cover the area where the mounting bracket mounts the main heater, I measured there is plenty of room.
I connected the wires in parallel with a loop terminal on red going to the relay, then I installed the heater and connected the black to the black wire loop from the heater.
This can be undone and put back to original with no damage, just clean off some silicone glue, but it might work fine on 72V as is. I hope the silicone glue is strong enough to stay, but I think it will.
There might be a 300watt 12V heater that can be separately mounted and much simpler, but I like that this just boosts the original heating system. If you use another heater I suggest hooking it’s 12V fan to the gems 12V fan power. During my tests there are some voltage spikes in the beginning which may burn out 12V fans.
I hooked up your 2N2222 thingy, works great thanks! Where is everyone placing the BMS24 display?
Dave made a plexy glove box door and placed it inside the glove box. I’m working on a angle cut 4s nema 3 j box to mount in front of the glove box.