36V parallel and 72V serie using switch

[Doctorbass]

I just bought this 4pdt switch on ebay:

http://cgi.ebay.ca/ws/eBayISAPI.dll...304956&translate=no&ssPageName=LanguageToggle

I seen this schematic on a previous post.. (see below)



I will try to parallel 2 x DPDT with that switch.. to get 2 x 20A... my controller already draw 40A at 36V... i just can't imagine at 72V when my new 4110 will be at my door!

Doc

 

[sabrewalt]

Looks small to be rated for 20 amps.

 

[fechter]

Most switches can handle quite a bit more than their rating if you don't switch under load. Having two sections in parallel will help. If it burns up, not much is lost (it doesn't look too expensive).

One problem is when switching, the main capacitors in the controller will cause a huge current surge that can sometimes weld the contacts. If there is any way to disconnect the controller when switching, it will save the contacts.

 

[Doctorbass]

Fechter, that's exactly what i was thinking about the 160v caps.. that's the erason why i prefered a switch with off in the middle position. maybe i will put some resistor to pull up to 72V or to pull down to 36V before engage ON in both 36 or 72V position... I just have not make a circuit for that from now... .. this switch is heavy it seem... it is 3.6cm by 3.3cm!... and it have 16 contact screw!

Doc

 

[giveahoot]

Check out this one, sold as part of a major buyout for $10 each. Salzer H240 Switch 600VAC 40A.

http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=069-025&FTR=&CFID=23469124&CFTOKEN=45960548

 

[rf]

So how would you go about safely switching back and forth between 36 and 72 volts electronically?

I charge at 36-volts and run at 72. Would be nice if I could just plug in the charger and have the electronics handle everything. The human sometimes forgets and smokes things ...

 

[Pete]

If you always run at 72 volts, bring your drain and charge wiring into the same multi pin connector, then you can put the series link in the controller side of the connector.

Not sure if you have two chargers ? If so, wire them both into a single charger connector and all the switching is done for you.

Only down side is multi insert/removal operations which will wear the connectors over time.