Charge e-Golf VW Batteries for Cityel


Surfer71

Mitglied
08.10.2019
105
Southampton, UK.
Hi, I'm sorry for English, but I don't speak German, but I'll use "Translate from Google" in every answer.
I have a Cityel .. and I have lead acid !! but i now have VW EGolf lithium batteries 36v 110ah as a set that i can double .. to 36v 220ah ..

but let's take the 36v 110ah first ... i would like to understand how i can get a charger that can come from the home network , and then can charge those batteries to say 41V MAX and then turn off.
So I know I can't use my standard lead-acid charger. So HELP !! What do I need?

thanks, people
 

Kamikaze

Mitglied
24.08.2020
268
Are those cells Lithium-ION or Lithium-POLYMER?
Those two types have entirely different voltage levels.
As you are suggesting a maximum Voltage of 41V, I assume those are Lithium-Polymer-Cells.
For that chemistry you may use either the ELs original LiFe-Charger (if you are able to obtain one) or use some generic LiFe-Charger from the web.
I'm using this one currently: https://www.akkukaufhaus.de/ladegeraete/fuer-lifepo4/6695/36-volt-10a-lifepo4-ladegeraet-fuer-life-akkus?c=2175
I hear that there are numerous vendors like that and some chargers might even have adjustable voltage-settings (mine cuts off at around 42,5V).

Very important is that you double-check if there is a BMS (Battery-Management-System) already included in your Packs and if so whether it is working properly.
The BMS will make a great difference in the lifetime of your cells. If it is working (and adjusted) properly, you will get most likely years of fun out of your Batteries while if you use them without a proper BMS they will most likely die within a short time.
Also check if it is possible for you to manually get all the cells' voltages aligned initially - that takes load off the BMS and thus adds to the lifetime of your batteries.

Also: there is no need to apologize for writing in english. Firstly almost everybody in germany speaks english (some better than others), secondly we also are able to use some translator-tools if necessary. Just don't junge spelling mistakes or weird wordings. :D
 

Surfer71

Mitglied
08.10.2019
105
Southampton, UK.
BRILLIANT thank you... yes and yes... I had a look under the plastic cover and I could see a circuit board still connected to the battery.. so I assume that is a good thing?
I don't have any other parts from the car.. sadly.. but I am keen to get the right set up for the cityel as these batteries fit so well in the old battery trays ... like... they are made for it!!!

so I will look to follow your link.. I was told 41v but also told 42v so if I can find one that stops at 41v even better I will look.. ref BMS I don't have one... so any recommendations would be great I am learning electrics it's all new to me I am a mechanical person so it's all up hill learning but I am keen to learn..

thanks for the reply.. and help
 

Surfer71

Mitglied
08.10.2019
105
Southampton, UK.
ok looked at that ... that looks ok.. 10amp looks a decent charge rate.. and the price is not too bad either..
now I need to make sure it cuts out at a decent voltage
I will ask about this 42.5 is that works ok.. is that the charger that cuts out or the circuit board under the seat? As I have just had that altered so that it cuts out at 45v as before ( original ) it cut out at 50v
 

Kamikaze

Mitglied
24.08.2020
268
I will ask about this 42.5 is that works ok.. is that the charger that cuts out or the circuit board under the seat? As I have just had that altered so that it cuts out at 45v as before ( original ) it cut out at 50v
I got my charger strapped under the aluminium seat-plate. ^.^'
Sadly not much of the original Electronics is left in my EL - so I don't really know what you have there. Maybe a photo will help clear things up as the pros here told me exactly what was original after I posted a snapshot in another thread.
In my case it's the charger itself that stops working at roughly 42,5V(the cells reset to around 41,6V shortly after) and restarts at around 41,3V. (Measurements taken during operation in my EL so those may vary on different batteries.)
In my case the original BMS "only" does the balancing of the cells and the general surveillance (current, voltage, temperature, charging-state or rather used Amp-hours, etc.)

I guess the circuit-board included in your packs might be a balancer (maybe it was able to communicate with the original vehicle somehow, but I guess that doesn't matter as the EL has no means for using this communication).
So if I were in your position, I'd check if the balancer is working properly by measuring (and documenting) the individual voltage of each single cell. Theoretically these numbers should vary only in the 100ths (0,0X V). If it varies more, then you should charge the Pack fully and see if the balancer-board gets warm/hot. That would mean that the resistors are discharging single cells to even out the voltages. This could take several hours. After that the voltages should be almost identical in each cell.

Be careful on the first charge though - if the balancer and/or one or more cells are damaged already there might be risk of fire. I think it would be best to try that outside or in a garage or some other place that can be well ventilated and has nothing in it that might catch fire and is sealed off agains the living-areas so possible smoke can't get there.

Other than that the BMS-board should theoretically provide safety against deep-discharge, overload, over- or undertemperature charging or discharging an overcharging as well as shut off the pack if a single cell is defective to prevent damage to the rest of the pack.
Unfortunately I can't think of a low-tech possibility to check those functionalities without risking severe damage to the pack so I guess we'll have to trust that board if the balancing works properly. (Maybe someone else here has some ideas..?)
Alternatively it's of course possible to switch the old BMS-board for a new one with the specifications of your liking.
You should be able to find BMS-Boards on Aliexpress or the like quite easily.
 

Surfer71

Mitglied
08.10.2019
105
Southampton, UK.
https://www.akkukaufhaus.de/ladegeraete/fuer-lifepo4/6695/36-volt-10a-lifepo4-ladegeraet-fuer-life-akkus?c=2175 I am about to buy this one you mentioned I states it cuts off a 43v but are you saying it cuts off at 42.5v if that's the case then I will be happy to buy this.. yes I agree I would like to look at the Blancer on the batteries but I am not a electronics guy so I have seen a BMS from China ( I know sorry ) but it has leads that comes off and works as a BMS to each battery.. but sure if I can get the original battery ones working then even better!! let me know on that charger and I will buy one.. I need to get it bought this week.. ( Brexit )
 

Surfer71

Mitglied
08.10.2019
105
Southampton, UK.
BTW that company selling that charger I asked for some details and they responed with this

Now way to help you out. IT is LiPo , we do not sell that kind of chargers, Bye!!

Helpfull... not so they are saying that charger you posted doesn;t work but I am sure it does other wise you wouldn't be posting it..
 

Kamikaze

Mitglied
24.08.2020
268
Of course I can not guarantee, that another charger cuts off at the exact same voltage as mine.
As I have no further connection to this seller, i can only assume, that those chargers are all (at least almost) equally made.
With my charger I measured the cutoff-voltage basically by accident: I had the multimeter connected while charging and by chance looked at it when the charger stopped charging. The multimeter showed 42,5V prior and the voltage dropped to ~41,6V right afterwards.
To be safe, the only way I can think of would be to get a programmable BMS which cuts off at the desired charging-voltage. without that your guess is as good as mine, as to which exact voltage the charger will shut off.
Nontheless - even at 43V the voltage would be well within the charging-parameters for 12 LiFePo4-Cells in a row. My guess is that 43V is the guaranteed maximum-cutoff-voltage for those chargers.
 
Zuletzt bearbeitet:

Anmelden

Neue Themen

Adblock ?

Wir verstehen, dass Werbung nervig sein kann!

Der Adblock macht einen großartigen Job bei der Blockierung von Anzeigen, aber er blockiert auch nützliche Funktionen unserer Website. Für die beste Website-Erfahrung deaktiviere bitte deinen AdBlocker.

Alternativ wird die Meldung wird nicht mehr angezeigt, wenn du angemeldet bist.
Als Mitglied kostenlos registrieren
Login für Mitglieder

Ich habe meinen Adblock deaktiviert!