Adding a reserve battery in the helmet compartment


Since getting my CE-04, I've thought a lot about the challenge associated with longer-distance touring and dealing with the possibility of arriving at a broken charger. While I've opted for the BMWMOA towing plan, I'm not the sort of person who asks for help often.

After being impressed with the size of the helmet compartment, I realized that the should fit in the helmet compartment if you remove the handle (which happens to be hollow plastic).

There are some caveats with the Jackery 1000 and the CE-02 to be aware of though:

- Max sustained AC output is 1000W (with 2000W peaks). On paper, the CE-04 will draw 1100W. If this is a problem, the workaround would be to set the CE-04 to use a 7A draw (770W).
- Max helmet compartment weight is 18lbs (8.16kg). The Jackery is 22lbs (10kg). I suspect if the load is evenly distributed, it shouldn't be a problem.

Given that I use the helmet compartment for stowing a helmet on most days, I'd only use this reserve battery for longer tours, like a fuel reserve switch on pre-FI petrol motorbikes.

I suspect that such a device could conceivably charge a CE-04 from 0 to 9% (~0.8kw of the 8.5kw usable) in about 25 minutes. In Eco mode, this would yield an extra 6-7 miles to head to another charger

Has anyone else tried something similarly insane?


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I received a Jackery 1000, but so far no luck: both the BMW charger and the Tesla charger detect a fault, even before I plug it into the scoot.

After reading through the manuals, I think this is because, unknown to me at ordering time, the Jackery 1000 does not have an actual grounding pin. I'll reach out to support to see if there are any recommendations from them. The Jackery 1500 has a different ground slot, so maybe it's better for this use -- but it won't fit in the helmet compartment without serious modifications.

I suspect there is a way to fake out the ground fault check. I've ordered a portable GFCI outlet, as well as contacted Jackery support, to see what if anything I can do next.


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Active member

As temporary alternatives, until you get the extra battery situation worked out, to cover eventualities such as broken charging stations you might try one of these solutions:

1) Pull a generator, e.g.:

motorcycle pulling generator on trailer.jpg

2) Install a generator on the scoot itself, e.g.:



Just as an update here: I've yet to make this work. The Jackery 1000 has an empty plastic slot where the grounding pin of a 120V power plug would normally go. Both the Tesla and BMW mobile charging adapters detect the lack of ground and refuse to do anything. I've tried using a portable GFCI adapter to no effect.

I imagine if I was using a system where you can disconnect ground monitoring that this idea could work.


I found an interesting video where someone worked around the same issue, albeit with an inverter and a Nissan Leaf charger cable:

My current thought is taking apart a portable GFCI outlet and running a ground clip to wherever BMW says the grounded location on the BMW CE 04 is. I'll run the idea past some folks who know more about electricity than I do first. :)

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