Bestechpower BMS

[dnmun]

83.8 is close enuff.

 

[virtuhal]

yes, you connect the charger and the controler negatives in those two holes on the outside edge and the negative terminal of the battery goes to the B- spot.

I made all the conections and everything ok.

Now im trying to charge the pack but i´ve found a problem. I left one group of battery with 4.00v and the others with 3.6v. When the stronger group gets to 4.2V, protection is kicking in and disconnecting the charger. And it only starts charging again if i disconnect all the bms wires and plug it again.
Should i plug the charger negative directly to battery negative?

 

[dnmun]

no. discharge the channel that is climbing to 4.2V with a power resistor or lamp bulb to bring it down even to the other cells in voltage.

 

[virtuhal]

Im already doing that.
But probably it will never balance the pack cause it will disconnect when the first cell reaches hvc.

 

[dnmun]

i do not know which BMS you are using so it is difficult to explain how yours operates without information.

but if you assembled a battery from cells that are not balanced before you assembled the battery it is gonna be a very difficult task to make it balance. the only way is to continue monitoring the cell voltages and drain voltage off the high channels as fast as you can to get them down to the level of the others. you can stop charging while you do that since it is gonna limit the charging in any case.

this is not how you should assemble a battery. you should always bring all the cells into balance before ever assembling them into a battery.

 

[crossbreak]

did 2 charges now. Just checked, all cells are within +/-0.01V. I'll keep an eye on that.

 

[virtuhal]

i do not know which BMS you are using so it is difficult to explain how yours operates without information.

but if you assembled a battery from cells that are not balanced before you assembled the battery it is gonna be a very difficult task to make it balance. the only way is to continue monitoring the cell voltages and drain voltage off the high channels as fast as you can to get them down to the level of the others. you can stop charging while you do that since it is gonna limit the charging in any case.

this is not how you should assemble a battery. you should always bring all the cells into balance before ever assembling them into a battery.

im using the D167.
I assembled the pack with balanced cells. I made this test now to find out if the bms would balance the pack in this situation.
If the BMS cuts out the current from charger to battery if one cell hits HVC, i think something is not working properly. I was expecting the bms would start draining (what it did) and the charger would still send current to battery (what it didn´t). It will start charging again only with a ¨reboot¨.

 

[dnmun]

no, that is the way it works. if you look at your data sheet you will see that it has a reset voltage you have to lower the cell voltages below in order for it to restart the charging cycle.

this is lipo, not lifepo4 so it is made to prevent you from accidentally overcharging the cells. under normal conditions a lipo cell never reaches the HVC.

what voltage did you ask henry to set the LVC and HVC at?

 

[virtuhal]

i asked for 4.20V.

 

[crossbreak]

can you plz post a high res pic of your board like i did?

 

[999zip999]

Do they have the right type of charger ?

 

[MAGICPIE3FOCUSPOWER]

Waauww luckily I have found this nice topic.
I am considering to buy 20S BMS for 20s lipo pack.
I would like to play safe, so no need to charge and discharge packs to max. and min. specifications.

So what are recommended settings for safe playing?

Thank you!

1.Over charge detection voltage 4.2V~4.35V(Adjustable) ?

2.Over charge release voltage 4.0V~4.2V(Adjustable)?

3.Over discharge detection voltage 2.3V~3.0V(Adjustable)?

4.Over discharge release voltage 2.3V~3.0V(Adjustable)?

5.Over current detection voltage 0.1V~0.2V(Adjustable)?

 

[dnmun]

use the standard settings that henry offers. you know nothing about BMSs so you should use the setting the people who do know offer as standard.

 

[MAGICPIE3FOCUSPOWER]

Thank you! 8)

What are the standard settings?

 

[izeman]

just a short notice: 'adjustable' as stated by henry is a bit misleading. YOU can not adjust it. lvc/hvc etc are set by them during manufacture based on parts (comperators) used. and those values are not freely chooseable. one affects the other. so it's either a quite low or quite high lvc to choose. my rc lipo one is set to 4.28 hvc and 3.0 or 2.8 lvc and 4.2 balancing if i remember correctly.
dnmun can surely help with correct values.

 

[MAGICPIE3FOCUSPOWER]

Thanks for your info 8)

Yes will wait for dnmun post :lol: 8)

 

[NeilP]

OK, before i start my question..I am being a lazy bastard here. Just come back from another afternoon explaining the options of e-bike building to a numpty that I knew was a time wasting bastard./.and i should have just told him to piss off as he does not have the money to build a bike, but no ..me being me and trying to be nice and helpful I wasted a good part of my afternoon. Go to leave the workshop and randomly I now have a dodgy throttle...it just randomly works or not...usually starts again just as you have it wound out to full throttle. But is not a loose wire...suspect water ingress but can't pin it down...Ok so what is the wittering leading to...yes I have been too lazy to work out my question for myself in case someone has a 'ready to go answer...



I have been asked to look a 4 year old bike...with a on its way out battery. Re pack price for a 'drop in ' insert is about £300 ($450 USD) so she does not want to pay that, All E-bikes should be sold with a big banner warning "these are not cheap toys..don't buy if you can't afford me"

So again I said I'd see what I could do.


24 volt 10 Ah Lithium is the current pack.
If it were mine, a pair of 7 series LiPo blocks and job done..but she wont want to handle the charging of that sort of LiPo pack..so it needs a BMS

I got as far as here:
http://bestechpower.com/296v8spcmbmspcbforli-ionli-polymerbatterypack/

and lost the will to live

It s a flat rear rack pack

What shall I go for 6 series? 7 ? 8 series?

and what BMS ...any one got any idea...OK I am being lazy bastard,
Looked at 8 headway 10Ah cells, but the BMS board from Jim is 12mm ..so that won't fit with the cells in the outer case.


But a couple of 7series 5 ah packs in parallel, stripped if necessary should be able to fit in here..but what BMS?


Cheers guys.

 

[dnmun]

not sure if you are asking me for advice. you are trying to see if you can fit some HK lipo into that aluminum box and need a 7S BMS to do it?

24V is absurdly low voltage, could she use a 36V lifepo4 pack? she could buy a 36V10Ah lifepo4 pack from sunthing guy for less than $250 i would expect. that would last longer and be more reliable/less risky imo.

one of the things i have become more thoughtful of is the risk that something goes wrong with a battery built for someone else and they have no clue or if there is a fire or some other event which causes significant financial losses so the liability would come back onto the battery builder.

that is hard to put off. no matter how good your intentions, when the shit hits the fan it will be pointed at you.

 

[NeilP]

Yes, a BMS for 7s Lipo 15 amp
All to fit in that. Box
No chance to use a different voltage or shape battery. I am just not prepared to do that much work. A straight electrical job, stick it in the box and go is fine. Not getting involvolved in fabrication,changing racks , potential voltage issues etc.

It is a 24 volt bike , she is happy with it, it is legal,and al she needs.

 

[dnmun]

if the controller is limited to 15A then look at the smaller BMSs than the D167. i have used the D126 at 15A continuous but it will burn up in excess of 22A continuous. i just ordered another one for a 13S li ion calibike pack called the D127v2 which has a cover over the circuitry and is 15A. i get good deals since i order a buncha stuff at the same time and he charged me about $20 as i recall.

 

[k1jahan]

Can someone explain me how this works in a channel for one cell. So how does the temperature sensor and off the circuit. thank you.Thanks a lot

 

[k1jahan]

hi. Except resistor 101 (smd 2512) What is the code of rest resistance....smd? What is the capacity of capacitors and their code? thanks

 

[k1jahan]

hi. Except resistor 101 (smd 2512) What is the code of rest resistance....smd? What is the capacity of capacitors and their code? thanks

 

[NeilP]

if the controller is limited to 15A then look at the smaller BMSs than the D167. i have used the D126 at 15A continuous but it will burn up in excess of 22A continuous. i just ordered another one for a 13S li ion calibike pack called the D127v2 which has a cover over the circuitry and is 15A. i get good deals since i order a buncha stuff at the same time and he charged me about $20 as i recall.

thanks for that info,

She never got back to me about doing to , so i am not going to chase it up!




I have a Stealth Bomber here in my shed at the moment. I have not seen the original battery, , but a cell, the original BMS or the charger died and the battery 'melted' is the best I have got out of the owner.


So I am back on the search for another BMS.

Over the the last 18 months with these BMS units, how reliable have you found them? Are they really gogin to work as a good plug and play system that I can build a pack for, for some one that wants plug and play, Are they reliable?

Thinking of one of the 80 amp units for the Bomber and the 150 amp unit for myself.

Any recommendations as to which 80 amp unit to go for? or should I go for the 100 amp for the Bomber?

 

[izeman]

... Over the the last 18 months with these BMS units, how reliable have you found them? Are they really gogin to work as a good plug and play system that I can build a pack for, for some one that wants plug and play, Are they reliable?

yes they are. it's a plug and play system. very convenient. the only drawback they have is that they don't sense if one of the balance leads falls off or looses contact to the cell. so it could be that one balance lead is broken and this cell group will not be monitored. don't ask me why that can happen, but it can. another question is how likely that is?! every 10 charges i check the cell voltage directly just to be sure - there's never been an issue on both of my bikes. for my 4.2kw klein bike @80v i use the 80a bms and never got nearly warm.