Add-on battery (non-Specialized) for longer trips?


New Member
I recently purchased a base Turbo, mostly for commuting, and the standard battery seems just about ideal for my commute -- so far I seem to use about 80% of the battery round-trip (~20 miles, mostly flat) in turbo mode. But I'm starting to think about longer rides and battery options.

Before I purchased the bike, I read about Marissa Muller's cross-USA ride and how she was able to directly plug in solar panels with a charge controller to the charging port on her bike which would power the bike and charge the battery on the move (

It seems that an additional power pack that could temporarily attach to the bike or the rack and be plugged in for longer day-rides might be more convenient and significantly less expensive than buying and carrying around a second Specialized battery. For example, I remember seeing a 36V, 1030Wh battery pack for $499, vs. $999 for the Specialized Turbo SC battery at 691Wh.

So, I'm wondering if anyone has tried plugging in an additional 36V battery to the charging port to supplement the normal battery? If so, what were the results?

I would be very interestd to see if this would work. My guess is that you would have to have a higher voltage battery connected by the rosenberg plug. Not clear if you need some kind of regulator for the Amps.
sounds too easy to be able to plug in to the charging port, but i would certainly like to have a connection that i could connect a spare battery to to increase my capacity and not have to swap out batteries.

Ann M.

Well-Known Member
Folks, the charging port idea is interesting; however, the wiring harness behind that port is not designed to handle the high output amps of a full size battery for long periods of time or when the bike is under load from high speed or climbing. That port is built with wire gauge to match the output of a charger, just a few amps. And the BMS of the original battery will balk too, since lithium batteries can overheat and catch fire with too high or too fast of an input.

Do a wiring harness with connectors designed to handle the higher voltage and amps and perhaps add in a switch which also matches in voltage capability, too. A lot safer design.