Battery SOC minimum %

[wingnut771]

It is actually a good practive
By the time you hit that voltage the battery is full anyway

Cell manufacturers actually suggest that the charge amps has to taper off when ad uoj get to the top

Which most bms's can't do

Lowering the charge voltage accomplishes this

Shoto does the same thing
Or it does on my 15s shoto anyway
Limits pack voltage to 54v

But then they allow cells to pop way above 3.65v and well below 2.5v

So yea most of these batteries
That uses these pace type bms's is just cheap chinese crap imo

Marketed as premium brands

Imo they are all just ****

Sure well known brands may spend more effort in cell selection and pre balance

But hardware wise they are all ****

Just a fire prevention device nothing more

Yes, this is africa, nobody got time for "best practice".

 

[Zuner]

BMS minimum hey?

I actually haven't tried lower, The risk is too high imo, once cutoff happens and it switches to Eishkom it still trickles for some reason, so i've seen it go below what i set, and I don't want to risk complete shutdown and needing a jump as i'm unsure if teh inverter will activate the charger if it can't detect a battery, so not worth it since It's so rare that i go that low SoC.

Edit: Beyond building a 48v temp battery by pooling random 12v batteries together I don't have a means of getting 48v to jump it.

 

[wingnut771]

I actually haven't tried lower, The risk is too high imo, once cutoff happens and it switches to Eishkom it still trickles for some reason, so i've seen it go below what i set, and I don't want to risk complete shutdown and needing a jump as i'm unsure if teh inverter will activate the charger if it can't detect a battery, so not worth it since It's so rare that i go that low SoC.

Edit: Beyond building a 48v temp battery by pooling random 12v batteries together I don't have a means of getting 48v to jump it.

Sounds like you need to do a test for humanity.

 

[AchmatK]

UP5000



US3000C

 

[B-1]

I actually haven't tried lower, The risk is too high imo, once cutoff happens and it switches to Eishkom it still trickles for some reason, so i've seen it go below what i set, and I don't want to risk complete shutdown and needing a jump as i'm unsure if teh inverter will activate the charger if it can't detect a battery, so not worth it since It's so rare that i go that low SoC.

Edit: Beyond building a 48v temp battery by pooling random 12v batteries together I don't have a means of getting 48v to jump it.

There is always a risk the BMS safety kicks in and then you need to open the battery and charge individual cells, balance everything etc. Not something I feel like doing. I've seen the same on mine where the inverter draw over a couple of days on a flat battery is several percent.

 

[wingnut771]

UP5000

View attachment 1872495

US3000C

View attachment 1872496

Perfect

Now tell me how things go wrong from here?

 

[wingnut771]

There is always a risk the BMS safety kicks in and then you need to open the battery and charge individual cells, balance everything etc. Not something I feel like doing. I've seen the same on mine where the inverter draw over a couple of days on a flat battery is several percent.

Dont these server rack batteries keep going even after 40V? IOW, no need to jump start them like a dumb 12V LA LFP replacement?

 

[wingnut771]

There is always a risk the BMS safety kicks in and then you need to open the battery and charge individual cells, balance everything etc. Not something I feel like doing. I've seen the same on mine where the inverter draw over a couple of days on a flat battery is several percent.

I remember @TheChamp having this issue with a mates pylon or similar. Never found out the outcome though.

 

[TheChamp]

I remember @TheChamp having this issue with a mates pylon or similar. Never found out the outcome though.

It ended up going back to the supplier, they said they had to replace the BMS.

Some feedback, according to the supplier it seems the battery was overloaded at some point and damaged the BMS. It has been repaired and it will be delivered soon, but with a strict warning that damages from overloading are not covered by the warranty.

We will have to review the circuits connected on it and think of some circuit breaker to limit the output of the inverter to a power draw that doesn't put a strain on the battery, technically limit it to around 1500W or thereabouts.

Thanks everyone for the assistance.

 

[leon.davibe]

I actually haven't tried lower, The risk is too high imo, once cutoff happens and it switches to Eishkom it still trickles for some reason, so i've seen it go below what i set, and I don't want to risk complete shutdown and needing a jump as i'm unsure if teh inverter will activate the charger if it can't detect a battery, so not worth it since It's so rare that i go that low SoC.

Edit: Beyond building a 48v temp battery by pooling random 12v batteries together I don't have a means of getting 48v to jump it.

A 12v dc power supply and a boost converter to 50v shiuld dk the trick

It does not realyhave to di any significant amps

Have seen a video where skmeone jump starts a 12v lifepo4 with a 9v battery

It just needs to see the voktage

 

[wingnut771]

It ended up going back to the supplier, they said they had to replace the BMS.

It wouldnt even jump start?

Because these batteries dont need to be jump started?

What was the diagnosis? Just some random fault from out of the blue? What was wrong with the BMS? Was it a pylon?

 

[wingnut771]

A 12v dc power supply and a boost converter to 50v shiuld dk the trick

It does not realyhave to di any significant amps

Have seen a video where skmeone jump starts a 12v lifepo4 with a 9v battery

It just needs to see the voktage

I'm sure it would. Who has that **** lying around?

 

[wingnut771]

A 12v dc power supply and a boost converter to 50v shiuld dk the trick

It does not realyhave to di any significant amps

Have seen a video where skmeone jump starts a 12v lifepo4 with a 9v battery

It just needs to see the voktage

I cant see a 48V BMS going dead. Too much voltage range to work with imho.

 

[leon.davibe]

Dont these server rack batteries keep going even after 40V? IOW, no need to jump start them like a dumb 12V LA LFP replacement?

No i think all the lithium batteries with a bms uiu always have a risk of bms shutdown

Tjennit just depends what hey set the recovery voltage at

If it has n nice recovery voltage
And you can manualy switch of inverter and it can reach recovery voltage when load is gone would be a bonus

 

[TheChamp]

It wouldnt even jump start?

Because these batteries dont need to be jump started?

What was the diagnosis? Just some random fault from out of the blue? What was wrong with the BMS? Was it a pylon?

Yes Pylontech, besides saying the BMS was damaged from overload there wasn't much, the supplier had to send it to somewhere as well.

 

[wingnut771]

I actually haven't tried lower, The risk is too high imo, once cutoff happens and it switches to Eishkom it still trickles for some reason, so i've seen it go below what i set, and I don't want to risk complete shutdown and needing a jump as i'm unsure if teh inverter will activate the charger if it can't detect a battery, so not worth it since It's so rare that i go that low SoC.

Edit: Beyond building a 48v temp battery by pooling random 12v batteries together I don't have a means of getting 48v to jump it.

Apparently the Deye inverter has a battery initialise mode or whatever that is supposed to wake up a dead battery, but I've never seen a youtuber having to wake one up before. Plenty of 12v examples but thats not what we're talking about here.

 

[wingnut771]

Yes Pylontech, besides saying the BMS was damaged from overload there wasn't much, the supplier had to send it to somewhere as well.

So it didnt go flat, the BMS failed doing its job randomly?

How was the warranty process?

Stories like this reafirm my strategy of buying cells and bms and assemble it myself. I have no fear of electricity, but I know of a few peeps that have it, like spiders and thunder, but thats their problem.

 

[leon.davibe]

I'm sure it would. Who has that **** lying around?

Yea butba buck converter is cheap

Would rather plan for worst case scenario

As i have landed in thiis situation once struggling to get it out ofvthe state

The jkbms has a nifty feature emergency

So it ignores all low voltage safegaurds

And fhus ifbyou have one battery with a jkbms yoj can easily jump start your system

Think i have had a few jump start scenarios

4 in total
1 without jkbms luckily i had not taken the gel batteries in for scrap yet

So had to drag them all back into the house tk jjmo it

The other 3 was done via emergency setting

 

[wingnut771]

Yea butba buck converter is cheap

Would rather plan for worst case scenario

As i have landed in thiis situation once struggling to get it out ofvthe state

The jkbms has a nifty feature emergency

So it ignores all low voltage safegaurds

And fhus ifbyou have one battery with a jkbms yoj can easily jump start your system

Think i have had a few jump start scenarios

4 in total
1 without jkbms luckily i had not taken the gel batteries in for scrap yet

So had to drag them all back into the house tk jjmo it

The other 3 was done via emergency setting

but takes 9 days to arrive from geewizz.

Anyway, this topic is moot as I refuse to believe a 16S bms will shut down at 39.9V.

 

[leon.davibe]

I cant see a 48V BMS going dead. Too much voltage range to work with imho.

Yea butnif you arent awake or home

It switches off revivers auto starts
Eat a but more capacity
Switch off auto recovees

Rinse repeat
And eventually even with load gone it can't reviver enough to hit recovery voltage

Precisly why i had to jump/emergency

Showed the kid of this **** happens again do manual switch off

Training wasn't good enough still happened once after that