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I could use a little help for my friend with the JBD BMS selection with battery heater pad support

sidpost

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Mar 27, 2021
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Location
Texas, USA
My friend was looking at some YouTube video with a JBD BMS that had an output to drive a couple heater pads for the LiFePo4 batteries. It appeared the heater pads that were attached to sides of the batteries were connected directly to the BMS. Searching Ali Express has turned up some BMS options listed with a Heater but, the instructions I got from them showed only a single line out so, I'm thinking it is some sort of TTL switching signal.

A related question is what type of heater pads should I/he be looking for and how are they driven?

Other data points, he wants BlueTooth and RS485 output and a nominal 200A rating for 16x160Ah LiFePo4 batteries. I think the biggest problem we have is finding and understanding how to use the "heater" function and where to source the heater pads along with how to connect them to the BMS.

TIA,
Sid
 
The common 16s BMS that I can think off off the top of my head are more like 100 amp, not 200 amp. A contactor-based BMS (not FET) would handle more amps.

As I recall, the 120 amp JBD 4s BMS does not have any support for heating pads. The 150 amp version is newer and that might be the one that has heating pad support, but that's a 4s model.

For heating pads, you don't need many watts. On my 4s battery I use two pads, each one is 12 watts. But I maintain a temperature 24/7 that allows the charge to proceed at any time (> 32°F). The BMS that runs heating pads won't power the pads unless a charge is present, meaning that the battery is likely to fall below the 32°F threshold which means you'll burn daylight hours just warming the battery before you can charge the batttery.
 
Regarding the burn through the night, his smallest battery pack is 160Ah x 16 so ~20W/hr should be manageable.

He has fish that will die in cold weather if he can't keep the power on. We have unreliable power locally, going 'off-grid' protects his fish. The new battery pack won't take cold weather like his old Lead Acids so, he needs to keep them warm enough to work where they are located, which is at ambient to outside temperatures which is next to his insulated room for the fish.
 
There is masive confusion on the heaters of the JBD BMS's. The 4S versions have a nice M4 bolt as a connection and is wired as an open drain, so I use ceramic resistors as they are far cheaper than the pads, I derate them to about 25% so they don't get too hot to cause trouble. My cells are made with alum sheet so I just glue them to that. The 6S-22S SP22S001 BMS's are a lot more trouble as JBD have not made it simple, they basically have something like a 2.6V-3V output so you need to use either a saturated fet or smart fet like the BUK100 that I use, as the gate threshold needs to be really low. The supplied cable is confusing as it can be used in either the switch connector or the heater connector, but if used in the heater then the polarity is incorrect, the red cable goes to pin1 which in the manual says is the GND. So wire the red to the FET source pin, the black to the Fet gate pin and the FET drain pin is then connected to your positive battery through the heater resistors.
To test and trigger the heaters to 'ON' just raise the 'Charging under temperature' to a temperature greater then your three sensors are reading and importantly apply a charge on the battery or else it wont trigger!
If enough people are struggling I'll do a vid on youtube?
I've asked JBD over 20 times for further info but I don't think they know them selves as they haven't replied with any sensible answers!
 
There is masive confusion on the heaters of the JBD BMS's. The 4S versions have a nice M4 bolt as a connection and is wired as an open drain, so I use ceramic resistors as they are far cheaper than the pads, I derate them to about 25% so they don't get too hot to cause trouble. My cells are made with alum sheet so I just glue them to that. The 6S-22S SP22S001 BMS's are a lot more trouble as JBD have not made it simple, they basically have something like a 2.6V-3V output so you need to use either a saturated fet or smart fet like the BUK100 that I use, as the gate threshold needs to be really low. The supplied cable is confusing as it can be used in either the switch connector or the heater connector, but if used in the heater then the polarity is incorrect, the red cable goes to pin1 which in the manual says is the GND. So wire the red to the FET source pin, the black to the Fet gate pin and the FET drain pin is then connected to your positive battery through the heater resistors.
To test and trigger the heaters to 'ON' just raise the 'Charging under temperature' to a temperature greater then your three sensors are reading and importantly apply a charge on the battery or else it wont trigger!
If enough people are struggling I'll do a vid on youtube?
I've asked JBD over 20 times for further info but I don't think they know them selves as they haven't replied with any sensible answers!
@Gary did you ever make that youtube video? I'm working on exactly this scenario. I've got the SP22S001, and I'm trying to wire it to a relay, but I can't get it to go high for anything. I set the low temp cut offs and thr BMS is working correctly for that, but when it switches the battery off, the voltage across the pins is still 0. Appreciate the help!
 
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