DPDT Switch diagram for turning parallel batts into series

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swbluto
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DPDT Switch diagram for turning parallel batts into series

Post by swbluto » May 18, 2013 11:12 pm

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Useful for doubling the output voltage. Hook up two 24volt batteries, and you have the choice between 24volts and 48volts at the flick of a switch. The lower voltage is good for long-distances as it encourages a less energy demanding speed (And more pedaling), and the higher voltage doubles the speed and raw power.

Please see Amberwolf's warnings below before using this idea.
Last edited by swbluto on Aug 12, 2013 1:24 pm, edited 1 time in total.

swbluto
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Re: DPDT Switch diagram for turning parallel batts into seri

Post by swbluto » Aug 12, 2013 2:07 am

The lower voltage is good for long-distances as it encourages a less energy demanding speed (And more pedaling)
I found out from experience that this isn't universally true. With my particular bike, the hub motor would start to regen at 15 mph at 24v, so I was using the throttle to sustain 14-15 mph, but I found if I switched to 48 volts, I was able to pedal at 15-16 mph with no problems as the motor wasn't fighting me and using no power at all, so it turned out that running at 48volts was more energy efficient in my situation (I was trying to minimize energy usage on my long distance trip by using the least amount of throttle).

However, the 24v mode is useful for bulk-charging with my 6s turnigy balancer.

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amberwolf
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Re: DPDT Switch diagram for turning parallel batts into seri

Post by amberwolf » Aug 12, 2013 12:46 pm

Please note that you can't use just any switch for this: you must use a "break before make" type of switch. Some switches are "make before break", and would create a short vaporizing contacts and possibly damaging the batteries/etc. as well.

Most switches will probably work--but check that what you want to use is "break before make" before you use it for this. ;)


(BBM means it will break all connections during switching, then make the new connections. MBB means it will bridge across all the connections on that pole before it breaks the connection being switched from.)

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