# Simple Battery Charger from TP4056 in Series



## dima (Dec 1, 2015)

Hello All battery experts,

I was planning to to make a simple charging system for e-bike from TP4056 lithium boards connecting them in series with the batteries.
Plan is to make 10 cells in series, no discharge protection (being handled by the controller 20A)

It seems simple but I cannot wrap my head around how current flows to make sure there are no possible shorts. I came up with this "newbie" design.

Also I wanted to have manual toggle switches to turn on/off individual live connections to the charging boards for long storage/safety.

*Question:* Do I need those big 20A Schottky Diodes?


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## dcb (Dec 5, 2009)

those are not isolated, meaning you are creating a lot of "shorts", even with the diodes. And all those diodes are going to waste lots of energy as well.

"proper" chargers push current through all the cells in series. Some folks use multiple chargers, but they know what they are doing.

No offense, but this is really a bad idea for more reasons than I care to get into.


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## dima (Dec 1, 2015)

Hmmm and here I was attempting to reinvent the wheel.

Schottky diodes 0.55v x 8 (for 10 cells) = 4.4v wasted. That's why I was wondering is they are even needed.

As for charging diodes I can crank 5 volts a bit. I guess I just have to try small scale.


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## bigmotherwhale (Apr 15, 2011)

dima said:


> Hmmm and here I was attempting to reinvent the wheel.
> 
> Schottky diodes 0.55v x 8 (for 10 cells) = 4.4v wasted. That's why I was wondering is they are even needed.
> 
> As for charging diodes I can crank 5 volts a bit. I guess I just have to try small scale.


My advice to you would be forget about this and buy something ready made before you start a fire.

each of these stages needs to be on a separate ISOLATED power supply or it will likely blow fuses let out smoke or cause a fire... the diodes wont help at all.

just buy a hobby charger and connect a balance plug, ive seen them for so cheap it would probably cost less than the tp4056 modules you are using and WILL burn out on the first try.


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## dima (Dec 1, 2015)

Ahhh I think I spotted the short.  ... a bit discouraged now. But any possible solution other than separate power-supplies? ...or give up.


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## dcb (Dec 5, 2009)

bigmotherwhale said:


> just buy a hobby charger and connect a balance plug





dima said:


> But any possible solution other than separate power-supplies? ...or give up.


:/
endlesssphere has endless discussions on chargers.


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