# Chargers - Can I use 12/24/48v charger for a 72v setup?



## Micah (Apr 13, 2008)

I'm looking at either a 48v or 72v electric motorcycle conversion, and I'm unclear about the charging. If I get a 12v charger, will it just take longer, or will it not work at all? From my (very limited) understanding, it seems that lower amps means it takes longer, but lower volts means it won't work at all?

On that note, do they even make 72v chargers? Or, do I have to buy a 48/24 charger and charge 4 batteries, then switch and charge the other 2?

My ultimate goal would be to have an on-board charger. There are some 12v chargers that are small enough to fit in the space I (will) have left, but the higher voltage chargers look too big. It would be sweet if I could stow an on-board charger and extension cord in order to top-off whenever in range of an outlet.


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## MalcolmB (Jun 10, 2008)

Hi Micah
Yes, you've got it right. More amps means you charge faster, but you need to get the voltage just right. The good news is that with the right type of charger you can connect several smaller chargers side by side (in series) to give the voltage you need. On my motorcycle I have five small 12V chargers underneath the seat, each of which charges a 12V battery in a 60V series string. The important thing is that the chargers have isolated inputs and outputs, so they just ignore each other and get on with charging their "own" battery.

You can get 72V battery chargers, but they tend to be expensive and bulky. By using individual 12V chargers for each battery you also ensure that each battery is charged to its full capacity, so the pack remains balanced.


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## locoo (May 6, 2010)

Nice topic can i use 6x 12v cargers to use on my 72v pack .
Is it posible to do this ad kep them conected while driving the car od do i have to disconect the chargers befoer conecting the batterys to series.

Tnx for your help


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## sourcefinder (Dec 17, 2010)

I think this is difficult to say, depends on the chargers....


> The important thing is that the chargers have isolated inputs and outputs, so they just ignore each other and get on with charging their "own" battery.


I would not charge the batteries when they are connected in series to the controller and I would not connect them unless I did not remove the chargers.....

I think best way would be to buy a 72V charger.


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## locoo (May 6, 2010)

http://desmond.imageshack.us/Himg715/scaled.php?server=715&filename=dsc00897nw.jpg&res=medium

http://desmond.imageshack.us/Himg193/scaled.php?server=193&filename=dsc00894tc.jpg&res=medium

This is the charger it sooo cheap 6 usd and it works ok i tested it .

I prefer 6 cheap chargers , since a 75v charger costs a bit more and this way i chan keep them balanced


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## sourcefinder (Dec 17, 2010)

I understand.
As the charger seems to be very small, I guess you have little capacity?
What is your charging current?

If yu think it`s a good way to use this chargers, invest some money in fuses to be sure if there is something going wrong it does not damage your controller or the cells.

Problem is you have a lot of circuits using more than one charger and it depends of the inside construction of the charger how the circuits behave.

You can measure between the first and the second minus-pole in your closed serial batterie pack 12 V. So if chargers are bad, they cause a short circuit over the AC-circuit.


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