M.L. Toys
M.L. Toys
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for 12v vehicles that NEED to be upgraded to 18v
Total newb here. I found a lot of great info in the faq about 18v conversions using three 6v batteries in series for 18volts. Problem is I don't have a 6v battery charger. Would the attached diagram work to allow for two 6 volt batteries to be connected in parallel with one another, then connected in series with another 12 volt battery to make 18 volts? I could then connect the 6 volt batteries in series to make 12 volts, then connect them in parallel with the 12 volt battery so they could all be charged at the same time with the same battery charger. If this would work as illustrated, I'd likely wire it all to a 6 square plug and have two different connections for running vs charging.

Would this work? If not, is there a way to make this type of setup work?

12vCharge18vPower.png (60.69 KiB) Viewed 1631 times

There are a couple of problems with the circuit.
First, you would need some type of switch/switches to open the series parallel circuit prior to charging. They need to be separated for each requirement (driving and/or charging).
Second, you do not want to charge batteries of different sizes/capacities (amp hour/AH ratings) in a parallel configuration. The smaller batteries will charge faster and you will either overheat/damage the smaller batteries from overcharging or your larger battery will not fully charge.

You can charge the 12v 12ah battery alone and then charge the 6v 7ah batteries (in series for a virtual 12v 7ah battery). Again you would need to disconnect the batteries from the series parallel circuit in the vehicle prior to charging. It is also good to charge batteries separately from time-to-time so you would really need to get a 6v battery charger eventually . Batteries tend to decay at different rates so the 6v 7ah batteries will need a 6v charger. Walmart sells schumacher auto chargers that charge both 6v & 12v batteries and are fully automatic (so no overcharging) for just under $20. They are handy little chargers and well worth the money.
Last edited by wired on Sun Jun 21, 2015 8:00 am, edited 3 times in total.
+1 what wired said :lol:
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Rob222 Thanks for that.


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