I’d previously purchased some Deans to Tamiya battery adaptor cables with the intention of using them with vehicles that still had Tamiya battery connectors if I bought batteries with Deans, or vice-versa, but didn’t find the need to use them until now. I’d recently purchased a new battery that came with a different type of connector all together, but it came with an adaptor to Deans which was fine because I had wired up my new Trail Finder 2 for Deans, however I’d also changed the connector on my only other LiPo to Deans which meant that my Axial SCX10 would need to use one of the adaptors. With me so far?
I plugged in the adaptor to the SCX10 but as soon as I tried to connect it to the Deans plug on the battery it sparked like crazy, like there was a short; I checked to make sure the battery was OK on the charger and also tested the connector on the SCX10, all looked to be fine – no shorts, charges and balances OK, so I tried it again this time with the Deans end already connected to the battery, the connector in the adaptor actually burned out from the brief moment it was touching! Handy fuse-like protection, which made me think that perhaps an in-line fuse wouldn’t be such a bad idea, but it still didn’t make any sense.
A quick google for sparks when connecting Tamiya revealed others that had experienced the same thing – it transpired that, like a forum poster I found, the adaptor was wired incorrectly, rather scary that these items are sold for batteries that pack such high current.
Fortunately I was able to push out the connectors in the Tamiya plug on the adaptor and swap them over, it all worked fine after that (luckily no damage was done to battery or model). The moral of the story is that Tamiya connectors have positive (red) to the square hole, negative (black) to the half-rounded hole.