diy solar

diy solar

Hankzor JK BMS with screen and power button

upnorthandpersonal said:
I just wanted to mention that the Hankzor store on Aliexpress has the JK BMS with a screen option. It also has a power button on the screen to easily turn the BMS on and off. This means no more messing about with 9V batteries or power supplies to turn on the BMS. It seem that Hankzor is the only store right now with this option. I've ordered two of them and I'll report the results here once I have them.
Click to expand...
That’s the ones I bought. They work good but limited information.
 
Messier11 said:
Hi guys!

Need urgent help. I installed a 48v system in my off grid cabin in the summer.

Just a couple of weeks after I left the cabin in the summer, it all of a sudden stopped charging. For some reason I cannot understand, I could see that everything worked but the MPPT just didn’t charge. I thought perhaps that the breaker between the MPPT and the battery had gone default, but I can see now that it seems to work.

Anyway, the system shut down itself eventually. Now, when I am back after what 6 months — the volt in the battery is low, like 12-13 volts. It’s cold like heck, minus 21 Celsius (hopefully not were the cells are stored, they could be below freezing but I doubt by much). Anyway I am warming up the cabin. I tried to start the JK BMS, but I get no reaction.

So my question is now — what should I do?

I have a gasoline generator and a MultiPlus 48/5000 that can charge the battery. But in what order should it be done? How do I charge the battery when the JK isnt starting? You think it would fire up if I start the generator? @upnorthandpersonal you have any thoughts?

A thread on my build:
diysolarforum.com

My 6k$ budget DIY Scaleable Off-Grid 15 kwh 48v LiFePo4 hybrid build with remote control and supervision function

v2. Introduction Hi everyone! I have always spent the summers and part of the winter out in the archipelago it the most northern part of the Bothnian Bay in Sweden (Finland is only a slap shot to the East). During summer time, we get sun 24 hours a day and, conversely, during parts of December...
diysolarforum.com diysolarforum.com
Click to expand...
First, make sure all your possible loads (other than the BMS) are disconnected and get the battery warmed up, if you end up having to disconnect or bypass your BMS for a bit, you'll have no under temp charge protection. Sounds like you're already heating the cabin, but I'd hesitate to go much farther until you've measured the temperature of your cells above about 5 Celsius.
Second, measure the voltage of the battery at the cells. i.e, directly measure the voltage from the negative of cell 1 to the positive of cell 16. Note that this could be different from what you measure in lots of other places in your system that would normally all show the same voltage... If your BMS shut down, everything downstream of it can show strange voltages; not necessarily zero, but also not pack voltage.
If your measurement above is still 12-13 volts, start measuring individual cell voltages at the terminals. If some (or many) cells are very low or zero, there may not be much you can do to save them. Maybe there are others on the forum would have some ideas on that.
If your measurement in step 2 above is more reasonable but still low, say ~40V, you may just be in a situation where your BMS did its job and disconnected rather than killing your pack. It would probably still be worthwhile to measure the voltage of each cell to make sure there are no big outliers. If there aren't, jump your 9V to start the BMS. If cell voltages are still below the Power Off Voltage, it should just shut right back down, but I'm not sure how much (if any) delay there would be before that happens. If there's a delay, you could quickly go into your JK App and turn on emergency mode to keep the BMS running and then start recharging the battery, but note that in emergency mode all the normal protections are shut off, so monitor closely. If there's no delay on the BMS shutting down but your multimeter shows that your cells aren't completely ruined, you may have little choice but to bypass the BMS to get some initial charge into the cells. Do so with great caution.
As for how to charge, my Inverter/Charger will run on AC power (e.g., a generator) and just complain about not having a battery connected, but it's not a Multiplus, so I'm not sure if yours will do that. It may need battery voltage to start.
There's already a few diverging paths here, so maybe report back some results, like pack voltage, cell voltage, etc., and we'll see where to go after that.
 
LakeHouse said:
First, make sure all your possible loads (other than the BMS) are disconnected and get the battery warmed up, if you end up having to disconnect or bypass your BMS for a bit, you'll have no under temp charge protection. Sounds like you're already heating the cabin, but I'd hesitate to go much farther until you've measured the temperature of your cells above about 5 Celsius.
Second, measure the voltage of the battery at the cells. i.e, directly measure the voltage from the negative of cell 1 to the positive of cell 16. Note that this could be different from what you measure in lots of other places in your system that would normally all show the same voltage... If your BMS shut down, everything downstream of it can show strange voltages; not necessarily zero, but also not pack voltage.
If your measurement above is still 12-13 volts, start measuring individual cell voltages at the terminals. If some (or many) cells are very low or zero, there may not be much you can do to save them. Maybe there are others on the forum would have some ideas on that.
If your measurement in step 2 above is more reasonable but still low, say ~40V, you may just be in a situation where your BMS did its job and disconnected rather than killing your pack. It would probably still be worthwhile to measure the voltage of each cell to make sure there are no big outliers. If there aren't, jump your 9V to start the BMS. If cell voltages are still below the Power Off Voltage, it should just shut right back down, but I'm not sure how much (if any) delay there would be before that happens. If there's a delay, you could quickly go into your JK App and turn on emergency mode to keep the BMS running and then start recharging the battery, but note that in emergency mode all the normal protections are shut off, so monitor closely. If there's no delay on the BMS shutting down but your multimeter shows that your cells aren't completely ruined, you may have little choice but to bypass the BMS to get some initial charge into the cells. Do so with great caution.
As for how to charge, my Inverter/Charger will run on AC power (e.g., a generator) and just complain about not having a battery connected, but it's not a Multiplus, so I'm not sure if yours will do that. It may need battery voltage to start.
There's already a few diverging paths here, so maybe report back some results, like pack voltage, cell voltage, etc., and we'll see where to go after that.
Click to expand...

Thanks!

I wonder how it could get that low? Should be a closed circuit when the BMS shuts down, right? Unless of course the balancing cables let something through, but that would be odd. Anyway, I am heating up things right now, should get warm in there pretty fast but I recon the cells need time to heat up.

Gonna tear up the box they are stored in to get to the individual cells to measure them. Worst case I commission a chopper to get @upnorthandpersonal, he is only like 200miles away. ?

BTW, one odd thing, when I put the positive of the 9v batter before the BMS and the negative pole after it (like it should be done) — I get a buzzing sound. When the circuit was open, I also got a light on the MPII.
 
I removed the lid and all insulation from me battery, unfortunately I don’t have any thermometer that gives a direct reading, but they felt really cold. You didn’t want to hold your hand against them. Wouldn’t surprise me if they were minus 10c, doubt lower than that though.

The reading per cell is around 0.6v, in total 11v. Does that mean that the cells are beyond repair?
 
Please for goodness sake, do not go by the surface temp if they were frozen, the liquid electrolyte throughout the cells will be like a gel, a few hours of warming won't do. Give them at least 12 hours or so to thaw - patience ! Once thawed and "certainly" above 0C in their cores, readings etc will make sense.
Check each cells voltage with your Multimeter and note it down as well as the time. Check it a couple of hours later and note any difference, should get better as they thaw. This of course assuming they are still frozen solid.

BTW: Just prior to your posting about this, there was a quick discussion on making a start switch for the BMS if you didn't get one with it.
 
Messier11 said:
I removed the lid and all insulation from me battery, unfortunately I don’t have any thermometer that gives a direct reading, but they felt really cold. You didn’t want to hold your hand against them. Wouldn’t surprise me if they were minus 10c, doubt lower than that though.

The reading per cell is around 0.6v, in total 11v. Does that mean that the cells are beyond repair?
Click to expand...
Well, 0.6V sounds a lot better than 0.0V…
Steve_S said:
Please for goodness sake, do not go by the surface temp if they were frozen, the liquid electrolyte throughout the cells will be like a gel, a few hours of warming won't do. Give them at least 12 hours or so to thaw - patience ! Once thawed and "certainly" above 0C in their cores, readings etc will make sense.
Check each cells voltage with your Multimeter and note it down as well as the time. Check it a couple of hours later and note any difference, should get better as they thaw. This of course assuming they are still frozen solid.

BTW: Just prior to your posting about this, there was a quick discussion on making a start switch for the BMS if you didn't get one with it.
Click to expand...
Yes, agreed on all points here. Warming up the cells will take a long time!
Hopefully those voltages look better tomorrow morning.
 
This morning the overall battery voltage is up by 0.2v (11.8 instead of 11.6). Don’t think the batteries have completely warmed up yet, there was just 4c in that room when I woke up this morning.

I still can’t get the JK BMS to start, there is a distinct humming sound when I connect the 9v battery, but no beep and I can’t find it in the app…
 
I've had the cells in storage for the last 6 months, all disconnected in the box they came. Unfortunately the camper project got delayed quite a bit.
I've connected them to the BMS to do a cycle since it's been 6 months, they were all stores at 3.29V and balanced when I connect everything. Charged at 28V 10A with a bench power supply, watched for the afternoon and then left for the night, they were at about 30% soc when I stored them. This morning I found one cell very low, at 3.34V
What should I do? Top balance them again?
I checked all the connection and they are all torqued to 5NM, since I'm only working with low amps for this tests.

PXL_20230225_093404860.jpg
 
I left for the day yesterday and when I came back they were all at 3.37V, so the BMS did it's thing. Gave it a bit more charge at 28V, but in less than 1h it was getting below 1A and the same cell was lower then the other, again left them to balance and this morning they are all a 3.38V. today I'm trying a discharge. The JK works great so far
 
On wiring, I have B2A24S20Ps. I thought I'd read that unused balance leads after the last cell in series should be bundled to B+, which is what I did and seemed to work. On coming across wiring diagrams since then, it looks like most have the spare leads from B16+ (in my case) through to B24 left open circuit, with only the last B+ lead connected. Can anyone confirm which is proper for the longevity of the BMS?
 
I've always left any un-used balance leads disconnected in all my JK BMS's. I remove them from the plug to keep the cabling tidy.
 
weeman said:
I've always left any un-used balance leads disconnected in all my JK BMS's. I remove them from the plug to keep the cabling tidy.
Click to expand...
This is also what I have done. It is only just the last B+ wire that should be connected to the battery positive.
 
Thanks all. That's what I'll do for the new ones, and rearrange the one I did do.
 
Hi all. Can you please tell me if someone managed to connect the BMS 24S to the solar inverter using the CAN or RS485 protocol?
 
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