# Charging Leaf Modules



## benjylafond (Apr 22, 2014)

I have a 36v Leaf Module pack (5 modules - 60ah) on my golf cart. I'm currently charging with a Quick Charge onboard charger with voltage cutoff at 41v. It has a Li-on algorithm but the Charger seems to be a bit of overkill. I have been looking at some of the small Li-on chargers on Ebay that run about $60. They all seem to say they are for 20 or 30 AH batteries. Would this make a huge difference or would it just take longer to charge my batteries (the Quick Charge is a 15 amp charger)?


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## Yabert (Feb 7, 2010)

It will be just longer if the power of the charger is lower.
In fact, a 10S (10 cells in series) li-ion balancing charger will charge your battery pack and protect each cell from overvoltage if you connect it correctly.


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## dcb (Dec 5, 2009)

15 amps is good. If none of the cells exceed 4.2v while charging then you are golden.

Note, leaf cells are typically charged to %80 and not discharged below %20, so you might need to turn down the termination voltage a bit for best lifespan.

But you can charge em with like 35 amps from a 120v 12A socket, not a problem. Just keep an eye on the temperature.


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## Kyle (Apr 28, 2015)

Yabert said:


> It will be just longer if the power of the charger is lower.
> In fact, a 10S (10 cells in series) li-ion balancing charger will charge your battery pack and protect each cell from overvoltage if you connect it correctly.


Could you please explain in detail how to connect it correctly? The balance lead on these chargers has a positive for each cell and then a single negative. So in this example the plug would have 11 wires.


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## dougingraham (Jul 26, 2011)

Kyle said:


> Could you please explain in detail how to connect it correctly? The balance lead on these chargers has a positive for each cell and then a single negative. So in this example the plug would have 11 wires.


Yes, 11 wires. You have to use the center taps on the leaf cells to connect to the balance wires. Each leaf module contains two cells in series as viewed from the outside world. (There are actually four cells in each module.)

With one module you need three wires. One to positive, one to center tap and one to negative. With two modules you need five wires. With three modules you need seven wires. And so on.

With two modules wired in series you have the positive of one module connected to the negative on the next. That connection between the cells gets a single balancing wire. So if you count the terminals you have


Most negative terminal
Center tap on most negative module.
Positive terminal connected to the next module.
Center tap on the second module.
And finally the most positive terminal

Each of those gets a balancing wire. Additionally you need a heavy wire from the most positive terminal to the positive lead of the charger and a heavy wire from the most negative terminal to the negative lead of the charger. Each additional module in series adds two more connections.


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## Kyle (Apr 28, 2015)

dougingraham said:


> Yes, 11 wires. You have to use the center taps on the leaf cells to connect to the balance wires. Each leaf module contains two cells in series as viewed from the outside world. (There are actually four cells in each module.)
> 
> With one module you need three wires. One to positive, one to center tap and one to negative. With two modules you need five wires. With three modules you need seven wires. And so on.
> 
> ...


Thank you so much for your reply. So, If I understand you, In the example above. I would have the pack positive and neg. I get that. For the balance plug I would have number 5 as the first and 4, 3, 2 ,1 in that order from right to left.


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## dougingraham (Jul 26, 2011)

Kyle said:


> Thank you so much for your reply. So, If I understand you, In the example above. I would have the pack positive and neg. I get that. For the balance plug I would have 4 postive and one negative. And that is lead 1 as the negative and 2-5 as the positive leads?


You need the heavy wires to the most positive and most negative of the charger. Those are the charge and discharge connections. You can charge and discharge the battery without any other connections. The little wires are the balance wires. On all the chargers I have seen the most negative one must connect to the battery at the most negative terminal. You need this wire to get an accurate reading because of the voltage drop across the heavy power lead. The rest of the balance wires must be hooked up in order or it wont work properly. The wire next to the negative one goes to the next terminal and so on until you have all the balance wires connected for the terminals you have. But they must be connected in the correct order. Calling them positive is not correct. Each one must connect to the next cell tap in order. I hope this ASCII art will clarify. This is five leaf modules which is actually a 10S pack of cells.


+-++-++-++-++-+
| || || || || |
|1==3||1==3||1|
|2||2||2||2||2|
|3||1==3||1==3|
| || || || || |
+-++-++-++-++-+


Leaf modules come in two types that stack together. One has the positive on the top terminal and the other has the negative on the top terminal. This allows them to be placed in series with a simple strap to the adjacent cell. The + symbols represent the corners of the modules. The == symbols are the cell interconnect straps. The 1 represents the positive terminal and the 3 represents the negative terminal. The 2 is the center tap on that module. If the leftmost cell is A and the rightmost cell is E then A3 connects to the charger negative power lead and E1 connects to the charger positive power lead. Your balance wires must connect in the following order from most negative to most positive.

A3
A2
A1B3
B2
B1C3
C2
C1D3
D2
D1E3
E2
E1

Note the A1B3, B1C3, C1D3, D1E3 on the same line. These terminals need only one wire because they are already connected to each other. And that is your 11 balancing wires.


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## Kyle (Apr 28, 2015)

Ha Ha, I think we were both typing at the same time (My edit I mean). 

Thank you very much. That does make sense to me.


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