Newbie with some questions


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krawcu

New member
Joined
Feb 2, 2022
Messages
4
Did you managed to rearrange this battery?
I'm thinking about Hyundai Kona EV battery right now and It looks like I will face the same issue with it.
 

ManxViking

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Joined
Dec 24, 2021
Messages
24
Depends on the year but i would expect we are facing the same issues KRAWCU. I have had some info but with everyone saying i'm going to set fire to my house on various forums has put me back into research.

I understand the issues around charging etc but as i have each pack as separates ( 48v ), the only real issue is, do i need a BMS as the cells are all linked, so therefore balancing?
Do i just need some sort of Lithium-ion charger?
On top of this i have 2 x 72v packs that i can't split to 3 x 48v easily, they are stuck together somehow and i'm not brave or stupid enough to attempt it just yet.
No one has that info to support any conclusions i have come up with and i've spent months of research going in circles.

So there is a way, i just am no further ahead. Someone somewhere must have figured this out and has already done this but i cannot find anything anywhere using these specific cells. Charging / discharging controllers are a minefield, useable capacities is straighforward, 20-80% will extend the life by a decade.

I'm only stuck on how to monitor each cell and charge each pack.

If you do find anything please share so we have a chance to work on this together (y)

David
 

krawcu

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Joined
Feb 2, 2022
Messages
4
I understand the issues around charging etc but as i have each pack as separates ( 48v ), the only real issue is, do i need a BMS as the cells are all linked, so therefore balancing?
I would recommend using BMS for sure despite that all cell are same.

I looked for second hand batteries and cells from Hyundai and it seems that people managed to disassemble those packs into separate cells.

I still have some doubts if I should go for pack from Hyundai - it is the cheapest option for 1kWh, or should I look for pack from Tesla M3 SR+ that should have (in some cases) LFP (LiFePo4) batteries - this should be much safer at home.
 

ManxViking

New member
Joined
Dec 24, 2021
Messages
24
I have researched to find a way of splitting them but I cant find a way. They have not become so mainstream as the old 18650's so that is an advantage cost wise still. I am going to leave them as they are with the exception of the 2 x 72v packs.

I can get a bms without an issue but understanding what size i need is a starting point I'm working out. Can anyone advise please. If i had 48v x 30Amp would give me 1440w max draw from each pack x 7 = 10kw max. I only use around 12-16kw overnight so I'm wondering if that's overkill or a safe amps to run? If i went for a smaller BMS, like a 15 or 20amp would that, in reality be a better / safer / longer life place to be?
Then the final and biggest question before i order and build, how can i charge these from the mains? I want to run a diverter to recharge these during the day when i have excess solar.
In order to charge these packs i am non the wiser? The BMS will take the same current i can draw to allow the returning dc to charge right? So that means i need an AC to DC charger of what amps? Does it need to be a charger that i can adjust to set for lower and upper limits on voltage? And how would the charger know the cells are fully charged? Simply from the voltage? If yes, do i need smart bms to show me what each pack is doing?

Any advice as always gratefully received.

David
 

ManxViking

New member
Joined
Dec 24, 2021
Messages
24
Hi all,

I have got the BMS's from China ( and the hybrid inverter charger has arrived ) and have attached them as per what I've found on the internet. I have received 13s bms's when i need 12s bms's.
I have scoured the internet to find out whether or not ive just been had for £600 as i will never get the money back, but alot of people have said their DALY BMS can have the last wire also placed on the last cell in order for the BMS to 'wake up'.
When I connected originally the B- on the BMS and the main + on the battery showed 48.8 volts going across but only 21.3v when connected to the P-?? No one seems to know why, except most have commented about shorting the P-and B-, didn't work, connecting it to the PC, done but doesn't read the bms.
I've definitely got the connections correct and in the correct order as checked on the bms plug in. I've tried 2 other of the 7 BMS's I received but they show the same result.
If I need to 'wake it up' are there any suggestions please? I take it I cannot connect it to my hybrid inverter to charge them as the voltage is only showing 21.3v and so might cause some damage to the inverter charger or the bms or the battery pack??
So close and yet so f...king far :ROFLMAO:
Any help always grateful.
David
 

ManxViking

New member
Joined
Dec 24, 2021
Messages
24
Well, thanks to various people I have confirmed that I cannot use the 13s bms's. I have reordered 7 12s bms's.

I now will try to get some of my costs back by selling the 7 13s 100amp 48v.

I will have a look and see if I can post them on here for sale maybe. DM me if anyone interested.

Many thanks to everyone who has helped and advised.

David
 
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