multiple temperature sensors.

P

paulie

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Hi all, I am using a JK BMS on my 80p7s li ion setup. I am going to increase the system to 160p7s and I would like to increase the temp sensors from 2 to ideally 14. Is there anyway to do this? 2 sensors does not seem enough.
thanks in advance
 
7s160p, as I'm sure you only have 1 BMS, not 7.
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What does S and P stand for? What is Xs, Yp or XsYp with X and Y being numeric digits?

What does S and P stand for? What is Xs, Yp or XsYp with X and Y being numeric digits? This is the notation for the configuration of the battery. S means Series, P means Parallel. XsYp means X cells in series (to get the desired voltage) and Y cells in parallel (to get the desired capacity). If...
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Sure, you can put as many Temp probes as you want. Problem is will the BMS handle them? Probably not. Best option here is to install a custom solution with an ESP32 or similar and you can single wire temp probes. Technically they are 2 wires, but they can be daisy chained.
Then input the data into InfluxDB or similar time based database.
 
thanks Korishan, I got my p's and s's arse backwards. As the 2 temp probes that are presently fitted with the JK bms will 'cut off' the battery pack at selected temperatures, I would therefore like to put temp probes all over the place and have the JK Bms 'watchdog' over them. How would I daisy chain these 2 temp probes (into multiple probes) that are presently fitted. Cheers
 

incl a relais suited for your pack voltage.
Make a extra circuit, daisy chain them. if one fuses blows then the whole pack will be without power.
So, let's say your trigger is 12v to keep the relais in "on" position so the relais will continu to give and receive power.
One cell is going to heat up abose 65C the fuse will blow and the relais will shut down.
140C is self-combustion btw
80C you dont want to cross this line.

A bms will not tell you which fuse or sensor detected a cell that was to hot?
And will restart when the cell is cooled down?

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Soldering them could be very tricky btw, when submerged in a glas of water will do te trick.
I hope this was helpfull.

With best regards Igor
 
great 100kwh-hunter, thanks for your answer. Being thick (although trained in radio and radar electronics) I cannot quite get it. I would need more information or a schematic.

I understand that the bms will not tell me which fuse sensor beyond the two that are fitted, but i have a thermal camera/mobile phone add on called a topdon which is very accurate and would show me any hot or even warmer cell. i I would recommend it to anyone who is thinking of a thermal camera.
 
Korishan said:
with an ESP32 or similar and you can single wire temp probes.
Click to expand...
I have had kind of the same thought - using an ESP32 or Arduino with 14x DS18B20 temp. sensors - they can be connected in parallel - each sensor have a serial number. If the ESP32 is connected to InfluxDB it would be possible to watch / analyze each batterypack. Another thought was to use a relay like this one: TE Connectivity - to connect / disconnect the battery.
 
Use the ESP32/Temp-Probes in conjunction with the relay(s). the esp will trigger the relay(s) to turn off.

The added bonus is that the esp can actually tell you which temp probe triggered the alert

@paulie No, you can't add temp probes to the BMS give higher temp resolution and coverage. Unless the BMS is designed for such a task, which most are not, especially these 1 PCB board designed ones. If there's 2 ports for temp probes, then you can only have 2 probes.

Well, sort of. You *could* add multiple. However, you would need to make sure the overall resistance of the added probes has the same resistance of the single probe the BMS was designed for. Buuuut, this is a lot of work and probably no where near the effort. If it's even really possible to do so.
 
paulie said:
I would need more information or a schematic.
Click to expand...
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Your psu can be what your coil need to have regarding voltage.
With the fuses it is a separate circuit.
The relais is a switch that is always on(if power is provided), up to the moment a fuse is blown(no power is provided on that line.), then the coil will not have the power anymore to keep itself in the "on" position and will disconnect the pack/battery.

Choose a relais that can handle your DCV output!, if you draw 10A take one of 15A, if draw 100A take a really big one of 125A minimum, overrate voltage aswell.
A relais is nothing more than a voltage regulated switch.
For the fuses it does not matter if they have dc or ac, max 10A and max 250V.
Basically, you can put them even in your line between the packs, without relais and extra psu, but i am not fond of that idea due to resistance.

I hope this will clarify things a bit.
sorry for my bad English, i hope someone will chime in with propper translation of this mater.

With best regards Igor
 
I hope it will/can help you in your endeavors.
please let me/us know.

best Igor
 
Will do Igor. Have you installed thermal fuses? I did have a look at the ESP32/Temp-Probes set up but it fried my brain. lol I will probably end up with the 2 temp sensors for each JK BMS and have a look once a week with the thermal camera. Also the MPP solar is great for settings too.
 
Igor's idea about the thermal fuses is really good. I never thought about using them in a separate circuit. I think if they are used with a shunt release instead of a relay, the circuit would be minimal and almost all mechanical.

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great grundholm, thanks. Trying to get my head around this. How would this be wired up? Most of the ones I have looked at are 'switch off' when voltage applied.
 
paulie said:
Will do Igor. Have you installed thermal fuses?
Click to expand...
Yes i use 2 per 20 cells.
If the relais has tripped I must manually figure out with my dmm witch one it was.
With that done you also have the faulty pack, i can see nothing more as a win/win situation.
With propper testing your cells, heat fuses, glass fuses and the idea of @grundholm i dont think much can go wrong.
@grundholm you have a perfect idea, i am going to adopt this idea, this is really KISS and save.

Aaa heck....drown in it....i am going to say it----> this is the WAY (flies of now);)

With best regards Igor
 
and you can get the shunt in 24/48V - The only disadvantage I see is the relay must be always on (contacts die over time) - Maybe it would be better to use a 'depletion' MOSFET.
 
As far as I understand, the MOSFET is normally closed. As long as the gate sees 5V (from your circuit with the thermal sensors) there is no voltage for shunt. If one of the thermal sensors blow, then the circuit is open and there is no longer 5V on the gate and the shunt is triggered.
 
Do you know this type?
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I think it's possible to solder and they make them 'Normally closed' and 'normally open' - The circuit for the 'normally open' is really easy to make.
 
You still wouldn't know where the trigger was done at. Also, these will reset on their own once they cool down. So if there's a problem with a cell(s), this might not be a good idea. You want the system to stay disconnected until you can inspect what's going on.
 
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