Current limit

[vogelkristofistvan]

I received a firmware version from the Longgood developers that limited the maximum charging current.
Would it be possible to limit the maximum charging current to 20 amps, and then increase it by pressing the button while charging?
For example: 25A, 35A, 50A, 70A, 100A, 125A, 150A, 200A

The car's BMS can still limit the charging current, this would only be the maximum the car can get.

Nissan Leaf battery cells are destroyed by overheating. A constant lower charging current results in more predictable heating.

[osexpert]

Stop button during charging is already taken as stop button, I rather want to keep it like that..
It is possible to add a special mode (set right after power on) that limit to some fixed amps eg. 100.

[osexpert]

Or if you build yourself, I think you can just change this line in main.cpp
Param::SetInt(Param::MaxCurrent, 200);
and set the max current you want.

[osexpert]

"Nissan Leaf battery cells are destroyed by overheating. A constant lower charging current results in more predictable heating."
At least for my car, 2018 Leaf 40kwh, in this summer, when in was 30 deg. Celsius, the battery temperature was pretty high all the time, and it did not increase at all during charging. The car typically requested around 30kw max, or worse. Limiting this to even lower, was the last idea in my mind:-)
But maybe the older Leafs are worse and not as good at limiting the amps as the newer leafs. Personally, I think my Leaf is limiting waaaay too much, but I guess it knows better than me:-)

[vogelkristofistvan]

<style> </style>

													20%->80% SoC calulated time	calculated temp increase
50kW	Time	Amper	Volt	SoC	Minutes	Bat Temp	Celsius/minutes	SoC/minutes	Temp Rear Central	Temp Front Right	Temp Mid Right	Ambient
Shell	8:21	125,00	366,60	40,10	11,00	25,6	0,673	1,527	26,4	25,5	25	19	39,3	26,4
Tritum	8:32	124,00	377,00	56,90	11,00	33			33,8	33,3	31,9	20
42kW	Time	Amper	Volt	SoC	Minutes	Bat Temp	Celsius/minutes	SoC/minutes	Temp Rear Central	Temp Front Right	Temp Mid Right	Ambient
Lidl	9:01	122,00	345,00	20,30	10,00	33,5	0,60	1,84	34,1	34,4	32	22,5	32,6	19,6
	9:11	122,00	365,00	38,70	10,00	39,5			40,1	40,8	37,7	23,5
17kW	Time	Amper		SoC	Minutes	Bat Temp	Celsius/minutes	SoC/minutes	Temp Rear Central	Temp Front Right	Temp Mid Right	Ambient
Lidl	10:21	46,00		38,70	60,00	27	0,148	0,783	27,4	27,6	26	21,5	76,6	11,4
Szekszárd	11:21	46,00		85,70	60,00	35,9			37	36,5	34,2	26
12,7kW	Time	Amper	Volt	SoC	Minutes	Bat Temp	Celsius/minutes	SoC/minutes	Temp Rear Central	Temp Front Right	Temp Mid Right	Ambient
CCS	19:11	31,00	350,00	35,80	40,00	37,4	0,068	0,513	36,8	37,6	38	35,5	117,1	7,9
Adapter	19:51	31,00	365,00	56,30	40,00	40,1			39,4	40,5	40,5	33,5
8,6 kW	Time	Amper	Volt	SoC	Minutes	Bat Temp	Celsius/minutes	SoC/minutes	Temp Rear Central	Temp Front Right	Temp Mid Right	Ambient
CCS	19:21	23,40	348,00	30,40	41,00	33,2	0,032	0,385	32,9	33,1	33,6	31,5	155,7	4,9
Adapter	20:02	23,40	358,20	46,20	41,00	34,5			34,2	34,6	34,8	29,5

[osexpert]

I am not sure what to conclude from these numbers, but I see when charging on 12,7kW the final temperature was almost the same as when charging on 42kW (40.5-ish), so its kind of a loosing game in all cases:-) This was also my experience in a long trip this summer, no matter what I did, the battery temp was way too high all the time, rapid charging or not:-) So IMO its best not to worry about it, it will break down eventually regardless:-)

[vogelkristofistvan]

45 amps raises 10 degrees.

[osexpert]

It would also be possible to add a special mode eg. 5 that change how the stop button works to how you suggest. But it seems like a very narrow use case, that would generally be usable only for a very few, so I will not involve myself into this. But being open source, its possible to make own special versions.