Hi I have purchased VW e-Golf Batteries.. :-) but now I am in need of charging them



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Surfer71

Mitglied
08.10.2019
112
Southampton, UK.
Hello I have bought some lithium ion batteries. From a VW e-Golf. nice Samsung 108ah batteries and 1/2 battery 55Ah The idea is to use two of the larger ones and one half unit. making 4kw .. But I am struggling to find a charger that will do this .. Does any one know how i can charge the batteries. I had heard some one had used a computer power supply and altered it? but I can't find any of that information... Any help would be great thanks as I am struggling.. I have all this power here to really push my cityel along but do not want to use the batteries till I have a charger and a BMS.. HELP!!! :)
 

Bjoe10

Neues Mitglied
03.10.2020
44
i think we need mor informations...

does the battery have a bms? can you access it? you should first have the cells under control before you think about charging.
 
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Wertungen: Kamikaze

Kamikaze

Aktives Mitglied
Also we need:
> Voltage (cell-wise)
> Number of cells (per series)
> exact cell-type
> Data of the used BMS

Otherwise there is little chance that someone knows exactly what type of battery you need help with. :)
 

Surfer71

Mitglied
08.10.2019
112
Southampton, UK.
Ok lets try and fill you guys in with some data.

the Batteries as I understand it are 3.75v cells and there are two types of cells I have.

1 Cell as 15v capacity of 4 cells at 3.75v x 4 = 15v I will call this the large battery

the next battery is a 1/2 battery and it just that.. 2 cells made up of 3.75v = 7.5v

I have in total 4 large batteries
and I have 2 1/2 batteries

My calculations using the wha rating all 6 batteries give me 8kw

1/2 a pack ... 2 large 1 of the 1/2 batteries gives me 4kw

I hope to run the cityel on the one half

and the mini el on the other half

The amp hour rating for the large battery is 108ah and the 1/2 size battery 55ah

there is a circuit board on the battery but I would ignore that.. as i feel that it would be more hassle than it is worth..
I will need to some how get a BMS made up so that the discharge cuts the power when it gets to 3v per cell and the same the other way when it charges to 4.1v or a max of 4.2v

I understand the basics needed on paper to protect and prolong the life of the batteries

but sadly that is where my knowledge stops.. I feel if any one has an ideas how I can go forward that would really help.. I think I need to get a simple BMS that I can connect up and monitor each cell..

Now... there is a small issue but i think it's best ignored in favour of I think others have had the same problem..
I said there are 4 cells to a large battery that is correct ... how every they are in series? ( I hope I got that right ) there are in fact 3 smaller cells to each bigger cell... so to make up one cell of the 4 in the large battery... there are infact 3 small cells.. to that one..
so to be really accurate there are 12 small cells to one large battery.. I think to monitor all 12 cells on one BMS would start to over complicate things and I am best just ignoring that and going for a BMS that monitors the 4 larger cells to 1 large battery...

does that make sence?

Cooling.. well I could add fans but I think being as it's a small car with open air to the batteries and really not needed but .... I could add fans later if when working I can see that I need to keep the temp down..

take a look at this listing to show you more details.. this is for the large battery .. I have 4 of these..
it shows the spec and you can see from the one photo that the battery is formed of 12 smaller cells.. http://rover.ebay.com/rover/1/710-5...0001&campid=5338536215&icep_item=293734777987
 
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Bjoe10

Neues Mitglied
03.10.2020
44
what voltage do you want? 36V or 48V

I think you need 10-14 cells in series (37.5 - 52.5V)

you can only connect batteries with the same capacity (Ah) in series to form one battery

you cannot connect 108Ah + 55Ah in series
but you can connect 108Ah +( 2 * 55Ah in parallel) in series (2*55Ah ≈ 108Ah)

you have to understand the configuration of the cells, the same will be inside the cells as you described.

Your big pack will really be 4S3P (4Cells in series and 3 each in parralel = 15V 108Ah

you have to connect cells of the same size in series

cooling won't be a problem i guess

In addition to the whole cells, you will of course need a BMS that monitors and balances the cells
 
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Surfer71

Mitglied
08.10.2019
112
Southampton, UK.
well yes the BMS is where i am stuck the most.. I really am struggling what to use for this that is reliable. 36v but I think it really comes out at 38v
 

Kamikaze

Aktives Mitglied
38V would be quite an odd nominal-voltage.
Maybe that's the resting voltage in unknown SOC? (That might result in 36V nominal voltage.)
To be sure which setup you really have, there seems to be no other way than to really open up the batterypacks and look, what really is inside.
Then you can choose which BMS you want to use. Without this exact knowledge there's always the risk to choose the wrong parameters and thus damaging the Pack(s) or as worst case set fire to the system.
 

saxobernd

Aktives Mitglied
23.07.2020
962
Maybe, I find the same batteries in my new Seat Mii. But neither I nor any serviceman in the region here is allowed to get a look into, You are more lucky.
Where did you get the battery? I would like to get one or more, too.
I have some HP-chargers, 2,8 kW which would fit in and I have the idea to test an BMS, not before next month.
But first You have to answer the question, if there is an battery managing system in Your battery boxes, for neither the servicemen of VW , nor I, are allowed to look inside. Please, have a look. Maybe, You will find only a part of a BMS, or none.
I plan to use such a battery in a Citroen Berlingo, or, maybe Saxo. There are , more electric drivers waiting for it.

For the cityel , there is no difference, if left or right hand traffic. On the street, I fear, it is.
Ferry cost is 39Euro, one way. I see, much cheaper than in former times. 680km, England is now in my range. Perhaps more comfortable than by hitchhiking, in 1965. Once again bathing under palm trees near Bangor/Wales? I had three weeks without any rain, sun only.
I have got my vaccination. My only fear, the weather may have changed.
 

saxobernd

Aktives Mitglied
23.07.2020
962
No problem, You need a low voltage. I have some of Compurer-Chargers for up to 54 Volts. 2500 or 2800W. I think, I could help You. I am constructing an active BMS, too, which would fit in.
 

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