[Astro]

Originally Posted by Ryland

The main contactor should be on the battery pack and there for should be a DC contactor, non that I have seen care about positive or negative and work fine for regen.

I use an Albright Contactor.

http://www.albrightinternational.com...ct%20Range.pdf

I had a look at the Albright site. They talk about polarity sensitivity and magnetic blowouts.

Blowouts enable the contacts to switch D.C. voltages of 48v or higher. Fitting of blowouts usually makes the contacts polarity
sensitive and where this is the case the positive markings ‘+’ on the top cover of the contactor must be observed. Magnetic Blowouts
can be used with certain ‘P’ type switches, but we do not advise them suitable for frequent current switching applications. The suffix
’B’ denotes the fitting of magnetic blowouts.
Note:
The SW200 series is fitted with magnetic blowouts as standard therefore the option is to not have blowouts, this is indicated by
the suffix ‘N’. Also relevant to the SW200 range is the suffix ‘R’ which denotes non polarity sensitive blowouts are fitted.

So if i read that correctly they put in the magnetic blowouts to help deal with voltages over 48v. This normally makes the contact polarity sensitive unless non polarity sensitive magnetic blowouts are used.