Switchable Series/Parallel Battery Setup

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laxplayer9009   1 mW

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Joined: Mar 22 2015 2:39pm

Switchable Series/Parallel Battery Setup

Post by laxplayer9009 » Apr 08 2015 4:39pm

I'm wondering how to go about a switchable series/parallel battery setup? I'm going to have (2) batteries and it'd be nice to be able to switch them between series and parallel. If its even possible assuming relatively even discharge between the 2 regardless of configuration (series/parallel).

I believe someone on here has already accomplished this using a 3-way switch ON(series)-OFF-ON(parallel). But i'm not sure how to actually power the board in that case, and ensure no spark on powering it on.

No small switches are capable of 80+Amps. Maybe some kind of MOFSET or SCR?

It'd be awesome to ride around in series then have a warning go off that it's under 20% capacity, switch it to parallel and then have double the capacity to make sure that you make it home.

Thanks in advance

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beto_pty   1 kW

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Re: Switchable Series/Parallel Battery Setup

Post by beto_pty » Apr 08 2015 4:44pm

just switch between
ScreenHunter_227 Apr. 08 16.46.jpg
series
ScreenHunter_227 Apr. 08 16.46.jpg (40.46 KiB) Viewed 756 times
http://www.hobbyking.com/hobbyking/stor ... _1pc_.html

and this
ScreenHunter_226 Apr. 08 16.46.jpg
parallel
ScreenHunter_226 Apr. 08 16.46.jpg (32.02 KiB) Viewed 756 times
http://www.hobbyking.com/hobbyking/stor ... _1pc_.html

however....

P = IV
and assuming P (power required) is constant... (your weight/friction /losses at 10 kph)
halving your V (parallel vs series voltage ) will double your I... negating the doubling of amp hours you just obtained...

i actually did try this once with 4s vs 8s at a slowish speed like 15 kph... actually i got a better run at 8s since my batts did not unbalance so much and the amp drain was lower... it was however a slight difference; nothing earthshattering maybe 5%... I stuck in my mind cause the improved range combination was in the opposite manner as i thought it would ...
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mark5   100 kW

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Re: Switchable Series/Parallel Battery Setup

Post by mark5 » Apr 08 2015 5:45pm

Same way as beto_pty said, you could use Anderson connectors as described here.

laxplayer9009   1 mW

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Re: Switchable Series/Parallel Battery Setup

Post by laxplayer9009 » Apr 08 2015 6:14pm

beto_pty wrote:just switch between
ScreenHunter_227 Apr. 08 16.46.jpg
http://www.hobbyking.com/hobbyking/stor ... _1pc_.html

and this
ScreenHunter_226 Apr. 08 16.46.jpg
http://www.hobbyking.com/hobbyking/stor ... _1pc_.html

however....

P = IV
and assuming P (power required) is constant... (your weight/friction /losses at 10 kph)
halving your V (parallel vs series voltage ) will double your I... negating the doubling of amp hours you just obtained...

i actually did try this once with 4s vs 8s at a slowish speed like 15 kph... actually i got a better run at 8s since my batts did not unbalance so much and the amp drain was lower... it was however a slight difference; nothing earthshattering maybe 5%... I stuck in my mind cause the improved range combination was in the opposite manner as i thought it would ...

I'll take your word for it, no need to over complicate it if un-needed.

Thank you for the response

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