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BMS Warning from Andy Off Grid Garage

I really don't know what to do with the newer JK BMSes I purchased. I have the older style which is tried and true. I bought the newer style at the same time as Andy awhile back and I've been scared to hook them up because of things like this.

Im sure I'm way out of return period and I'm also sure there is no way JK is going to help me out. Sitting on 5 of these with lcd screens! I hope they fix the bugs soon...
 
Skypower said:
Why should JK wait to introduce a product when they have Andy and diysolarforum find every possible glitch for free???
Click to expand...
Only problem is no one here or Andy found the glitch. Someone told him about it and he made a video about it basically from my take on watching the vid.
 
42OhmsPA said:
I think @nebulight was the first to report it here.
Post in thread 'Anybody tried new JK BMS with inverter communication support?' https://diysolarforum.com/threads/a...erter-communication-support.68964/post-971720
Click to expand...
I was playing with my BMS just connected to a power supply so I would do some testing with the app, updating the firmware, turn it off, turn it back on ect. I assumed the issue was when I connected to the PC software, but it was actually when I was powering down my power supply. My test rig is only 12v so I ordered another 4 cells to leave it on full time for more long term testing before I install in my camper van. I switched from REC-BMS Active 12v because I decided to go 24v. Probably a mistake. If only REC made a 24v Active.
 
As a software engineer who has written code for the same types of chips used in these systems (ESP32 and the like), it sounds like a simple bug that doesn't write the user parameters to EEPROM when saving. So it retains the values while the power is still on but they get reset to default when power cycling again because nothing was written to recall from.
 
Cronix said:
As a software engineer who has written code for the same types of chips used in these systems (ESP32 and the like), it sounds like a simple bug that doesn't write the user parameters to EEPROM when saving. So it retains the values while the power is still on but they get reset to default when power cycling again because nothing was written to recall from.
Click to expand...

It's an STM32 clone (at least on the old version) so they would just store them on a dedicated Flash region (no real EEPROM as such, only emulated in Flash - just like the ESP32 really).

As I mentioned somewhere else, the previous versions of the firmware for this same device did not have the same bug, so it should be a simple fix. What I really wonder is, why was it introduced in the first place.
 
Okay, new question.

Why would a person remove the BMS power?
Is there a chance it can happen under normal operating conditions?
It seems to me that a BMS should always be on unless you are... perhaps moving?

Someone's gotta be the dude with the dumb questions! TIA
 
30mA * 24hr = 720mAh per day. a 100ah battery will be drained in around 139 days just from the BMS. It happens all the time in the boating/RVing world that store their rigs inside.

This BMS does have a sleep function. I'm curious if coming back from sleep also resets the settings. I'm going to test that right now! Lowest setting I can set for sleep is 1 hour, so I'll report back later.
 
Last edited:
nebulight said:
30mA * 24hr = 720mAh per day. a 100ah battery will be drained in around 139 days just from the BMS. It happens all the time in the boating/RVing world that store their rigs inside.

This BMS does have a sleep function. I'm curious if coming back from sleep also resets the settings. I'm going to test that right now! Lowest setting I can set for sleep is 1 hour, so I'll report back later.
Click to expand...

It was only asleep for a few about 20-30 minutes, but the settings were still there with a sleep.
 
ChrisG said:
Crowdsource Testing!
Click to expand...
Yep… it’s a real thing since the advent of over the air updates or software fixes ..they push for quick release of a product ….they hear about quirks ,so they release a fix for it… then they hear about a vehicle full of gerbils randomly steering off a cliff into the sea and then they fix that.

WE the real world testers … WE pay upfront to be the the test crash dummies for new products.

just my skewed opinion…
J.
 
I believe that Andy has all of the older firmwares still available if anyone wants to see if this didn't happen before and would like to revert back.

That is assuming you can go back.
 
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