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Chargery BMS now with Low Temp Cutoff

Hello,

The SOC issue was confirmed by Jason to be a bug (I'm thinking this other cut off delay is another one). Jason also told me to wait for the new and improved v4 of the firmware (whenever that comes out and if it fixes these problems) Its been like that since I got them. Problem occurs when you disconnect the LCD and reconnect it at a later time (I don't have the LCD connected at all times). Sometimes, by cycling the switch (for the delay board), it starts to give a reading.

The 5Hz cycling is due to the 5s setting of the "delay cut off time" Currently, its not doing the cycling of the relay. I had to switch the "delay cut off time" from 5s to "NO" and then back to "5s" Since my SOC doesn't work reliably, I'm thinking of just setting the "delay cut off time" to "NO" I just want to make sure that I still get LVD, HVD protection.

So, if SOC is set at 0%, will you still get LVD? I just want to remove the buggy SOC portion and possibly not deal with this "cut off delay time" mess

I'm kicking myself because I never go this route (buying the cheaper product). I was set to purchase the BMS123, but the wifey suggested we "save" some money. haha.
 
The BMS started cycling the discharge relay again. Had to set "cut off delay time" to "NO" to get it to stop. I guess I am going to have to run the batteries down to see if LVD is triggered.
 
diysolarman said:
So, if SOC is set at 0%, will you still get LVD? I just want to remove the buggy SOC portion and possibly not deal with this "cut off delay time" mess
Click to expand...
On mine, when I set SOC to 0%, LVD did not trip. I set SOC smaller than actual battery size. Then I watched it discharge with displayed SOC dropping to 0% and then it stayed at zero while discharge continued. Later when cell voltage dropped to the LVD setting, LVD did trip, correctly.
 
Airtime said:
On mine, when I set SOC to 0%, LVD did not trip. I set SOC smaller than actual battery size. Then I watched it discharge with displayed SOC dropping to 0% and then it stayed at zero while discharge continued. Later when cell voltage dropped to the LVD setting, LVD did trip, correctly.
Click to expand...

Hello Airtime,

Thanks, I'm confused though. when you say that you are setting SOC smaller than actual battery size, do you mean "battery capacity?" I see "SOC battery gauge" I set that to 0%. I have battery capacity set to 200.0AH.

I (now) also set "cut-off delay time" to "NO" from the manual, it says that LVD/HVD and temp will still trigger but Jason said that it wouldn't
 
diysolarman said:
Hello Airtime,

Thanks, I'm confused though. when you say that you are setting SOC smaller than actual battery size, do you mean "battery capacity?" I see "SOC battery gauge" I set that to 0%. I have battery capacity set to 200.0AH.

I (now) also set "cut-off delay time" to "NO" from the manual, it says that LVD/HVD and temp will still trigger but Jason said that it wouldn't
Click to expand...
Yes I meant battery capacity, sorry. I set it lower so that displayed SOC would go to 0% early, before the battery was actually drained. Then set the 'SOC battery guage' to 0%, and then discharged the battery. As I mentioned it did not disconnect when SOC meter went to 0% during discharge, just stayed at 0% and kept discharging which is what I wanted. And then LVD did trip when cell voltage reached set limit.

I did not try changing the "cut-off delay time" so can't comment there.
 
I'm a little confused by the "cycling at 5 HZ." That would be 5 times per second ... and pretty hard to count. Did you mean it cycles every 5 seconds?
 
You are right I should have said period or 1/5 Hz. sorry about that
 
Last edited:
Okay, so it doesn't LVD despite what it says in the manual. Discharge P V: 2.9 Discharge R V: 3.0 Battery dead V: 2.75. it let the battery go down to 2.55V

This whole thing is disappointing
 
diysolarman said:
Okay, so it doesn't LVD despite what it says in the manual. Discharge P V: 2.9 Discharge R V: 3.0 Battery dead V: 2.75. it let the battery go down to 2.55V

This whole thing is disappointing
Click to expand...
This should not happen mine always turns off discharge at the P voltage. What are you using to turn inverter or loads off?
 
diysolarman said:
Okay, so it doesn't LVD despite what it says in the manual. Discharge P V: 2.9 Discharge R V: 3.0 Battery dead V: 2.75. it let the battery go down to 2.55V

This whole thing is disappointing
Click to expand...
Sorry I jumped in the middle of this then read backwards. Can you give us a list of all your settings I know it is a pain in the rear but usually I find a bad setting and that cleans things up a bit.
Or you can post your parameters and I will go down the settings line by line and post what I think things should be.
 
Hello Craig,

Here are my settings. Jason just told me that the problem is when my cell voltage diff goes above the setting value, it turns the discharge relay off. This is odd because it normally doesn't do that. Maybe my batteries are bad, but I constantly have been getting cell voltage differences of over 200mV when there is a load and none of the BMS disconnect the discharge relay.

Also, I was experimenting with setting "cut-off delay time" to "NO" in order to avoid these problems, but it seems like it doesn't work

Here are my settings:
 

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I have my delay set at 10 seconds and it still shuts off when any parameter is met. So yours at 30mV differential should shut down when you hit the 200mV difference for sure Which is a huge problem in itself but should not stop the shutdown,

I would not set the cut off delay time to No. Can you refresh my memory as to why you tried this. Sorry like I said i got in on the middle of this.
 
If you are not worried about SOC I would unplug the shunt if you do not want to keep calibrating it. Then calibrate to 0 for all 3 settings. once we figure out the first problem maybe we can then fix the shunt. I know it should just work but obviously something is whacko.
 
Hello Craig,

Thanks again. I tried the "NO" setting in order to prevent the random cycling of the discharge relay. The interesting thing is that my differentials, under load or heavy charging, go over 400mV and it never shuts the discharge relay. Maybe it randomly started working for one of the BMS (when I started getting the cycling of the discharge since the differential was 52mV at the time). Maybe I should set the differential really high? Maybe my batteries are bad, but when the load is removed or I stop charging, the differential quickly goes back to 80-120mV and settles at around 50mV after an hour. Oh, I forgot to mention that I'm using deltec 50mV shunts
 
I would try setting everything high enough to make it work then start making things where they should be to see if you can isolate the problem.
Possibly after a few weeks the batteries may come into balance but 400mV is pretty huge difference and will throw all kinds of flags to the BMS. I think the NO stops anything from shutting on or off set it back to 10 and then go from there. but that 400Mv swing will definately cycle the cell diff shut off like you described.
Honestly on my BMS the most important settings are the cell high cut off and the cell low cutoff. I do not worry too much about the rest because this is all that really matters in my system. I do also have it set to balance in all 3 states as well as have the differential to 5mv. with the balance voltage parameter at about 90% of my cells max V protection value
 
Is it possible the shunt is wired wrong so that charge and load are being confused?
 
May Steve can talk to Jason at chargery. I suggested that maybe having a setting where the red button is held for 3s to force shut the BMS (and turn of the charge relay) could be an option. He says its illegal. But having a switch, with the delay board, to turn off the discharge at random is not :/

anyways. I don't know about how accurate the current is for you guys, but mine drifts +/- 1A and doesn't let me turn the BMS off.

Thanks for all your help
 
Bob B said:
Is it possible the shunt is wired wrong so that charge and load are being confused?
Click to expand...

I don't think so. Red going to battery side. When I have a big load (50A or more), I get a negative reading. When I'm charging, I get a positive reading. Now I'm not getting much of a reading since I have to calibrate it again.
 
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