24V Series Parallel System Charged by 12V Charger

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MB-1-E
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24V Series Parallel System Charged by 12V Charger

Hi All,

I've got 8ea 12V AGM Batteries.
I'll be using these in Series Parallel to supply 24V
to my motor (This is on a bicycle that I'm converting to electric).

I only have a 12V charger.
It's an Iota 12V-15A with QD4 three stage charging, so I'd like to use it to maintain my AGMs.

I made this drawing on AutoCAD and the translation to JPG didn't turn out very well, but I think you can still see it.

Please take a look at it and let me know if this will work to do this. It appears to me that I can do this with one DPDT switch, what do ya think?

Oh, one more question, will this hurt a 24V controller or do I need to disconnect the controller when charging.
It's a Navitas 100-36 (24V or 36V) Controller?

SeriesParallelSwitch.jpg

Thanks for your help!

Dave

chas_stevenson
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Re: 24V Series Parallel System Charged by 12V Charger

I think you are right on with your diagram. I would add 1 more wire as shown in this modification of your diagram. When the switch is in the 24-volt position it will also connect the battery pack to the controller. This will also disconnect the controller when charging the batteries in the 12-volt position.

Here is the modified diagram, note the added red wire.
12_to_24_batteries.gif

Chas S.
My Bicycle Pages

MB-1-E
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Re: 24V Series Parallel System Charged by 12V Charger

Great Idea Chas!
Now why didn't I think of that ...
I like it!

Now, my question would be, where can I get a DPDT that will handle the Amperage?

I did some searches and did check out Digi-key and McMaster Carr and didn't have much success.
I got the impression that this was going to be an expensive item.

I won't be switching it under any load, so perhaps you have an idea of what type might work here. Do you think this might work?

http://tinyurl.com/3yawgu

... or maybe an standard AC type would be ok.

My inclination would be an old DPDT, knife type switch but that's probably way off base.

Thanks for looking at my diagram and perfecting it.
This project is proving a bit of a challange to me, at times.

Thanks,

Dave

Dave

MB-1-E
Electric - Bridgestone MB-1 Mountain Bike
Icon Photo of lighning striking Eiffel Tower Jun 3, 1902, taken by MG Loppe'

Dave B

MB-1-E
<a href="http://visforvoltage.org/book-page/996-mountain-bike-conversion-24v-3-4h... - Bridgestone MB-1 Mountain Bike</a>

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