extra battery backpack.

[matthall1135]

Has anyone ever thought about making some type of backup battery in a backpack that you can plug into it with a quick disconnect? Any ideas about how to go about it or if it is possible?

[thegreck]

@matthall1135 You could get one of these and put it in a backpack. It's just 7lbs and I hear it holds 2 OneWheel charges. That means if the OW is charged when you leave the house, you'd be able to ride 3x as far before having to find an outlet (that's a LONG ride):
https://www.amazon.com/dp/B00W3LS0ZG/ref=cm_sw_r_cp_awd_t8pUwbH21W3JQ

[matthall1135]

Thanks gonna have to look into one.

[DVO]

@thegreck yep I have the same one!! Works like a charm

[thegreck]

@DVO It was probably your post that I got the link from! I keep bookmarks of every link I see in here that I think might be helpful. Have you tried taking it with you in a backpack? Or is it too heavy?

[Apio]

@thegreck I bought this exact battery. When I ride I keep it with along with the ultra charger in my backpack and not much else. It's heavy enough to notice, but not too heavy to be cumbersome. It does shift your balance a little if you're not used to a backpack when you ride. I bought the @kolinko onebag which folds up really small and also fits in my backpack (and while his bag has a pocket for the charger this battery is too big for that pocket) so if I have to carry the OW I can sling it over my shoulder and charge it from my backpack. I'll admit I haven't used the battery a ton yet because I haven't taken that long of a ride due to the upstate NY winter. This summer I plan to go on some pretty long rides on some of the trails near my house and this battery dramatically reduces the chances of being stranded in the woods.

That was longer winded than I intended so I'll bottom line it: if you like to take long rides and push the range limits, this battery is really nice to have. If you ride in areas where you are never more than 100yrds from an outlet then it's not really worth the money.

[carvewell]

@matthall1135 this project has got to be on the table I would think. Meaning hopefully FM is designing and bringing to market a OW dedicated packpack that has 3+ charges, bluetooth speaker, nano refrigerator (dos cervesas), adaquate storage, and the all coveted OW dock, holster, cubby or whatever. Might as well throw in some solar panels. I have the power block that @thegreck @DVO mentioned and it works amazingly although I worry about it exploding or something weird after a high speed impact or contact with water being lithium ion (the sparky kind). I keep it in a lightweight dry bag inside my packpack. The weight is really not bad considering the added range. I've used mine a good bit 10+/- discharges and haven't had any issues. It has opened up some of the finest single track western NC has to offer to my OW!

[thegreck]

@Apio That's good info! I ride my OW in places where there aren't any outlets (parks, bike paths, hiking paths, etc) and always have to pack it up and head home when the battery, so this would be perfect.

[atl1wheelin]

A buddy of mine and I were talking the other day and think if we could get a few extra charges or some kind of solar charger it would be really fun to do a OneWheel ultra light backpacking trip for 2 nights. Just gotta make sure you plan it right with battery range and what not. How cool would that be?

[Apio]

@atl1wheelin I'll bet a lot of us would be all in for something like that, if only the airlines would let us fly with our onewheels.

[cr4p]

i am also looking for some kind of "range extender" (power bank), but for my purpose the 3.5kg thing from amazon is just too much to feel free when riding trails. therefore i am looking for something lighter. lets say it shoud have about half the weight and only one additional charge would be fine...any ideas on exisiting products that i could buy?

[germx]

@cr4p I've looked around a bit, but it's not easy. Most smaller I've seen looks nice, but they lack output power. That ultra charger is drawing too much power for those small banks that I've found. =(

[cr4p]

@germx : that´s exactly what I found so far:-(
i think in terms of durability and lightweight it also has to have LiFePO4 batteries.
the only thing that I found so far that comes close ist the following:
http://www.bioennopower.com/collections/mobile-power-station/products/120-watt-hour-power-pack

but it has only 120Wh (OW: 130Wh) and it only delivers 1,1Amper at 110VDC Output, which seems to less (OW: 3.5A?)
on the positive side it only has 3lbs (1,4 kg)

[germx]

@cr4p Yeah, I checked the charger and it says input 300 VA (so basically 300 W), which is quite a lot. (Or am I missing something?)
Then I found this http://www.powerportstore.com/litihium_ion_options.htm
That PowerPort 259 Lithium power, is supposedly a LiFePO4, and 400 W.
However, it also say 5 lbs and 108 Wh, which seems pretty sad :(

I guess you could technically get a low power charger, but a quick google only showed 2 A versions. Which is still a bit much. And the OW would charge quite slow as well.

Also I'm confused. I've seen 1,8 A chargers stating 110 W, and 4 A stating 120 W (that last one seems very wrong).
And 1 lbs 200+ Wh powerbanks. Which seems like way too much for the weight. But it only delivered 65 W.
All these numbers so early... don't makes sense.

[cr4p]

@germx I also did a lot of research with some of my firends who are developing technical stuff.
so far i think there does not seem to be a purchaseable finished solution for these requirements. the power bank from @thegreck seems to be the best ready-to-buy available device. all lighter devices are moreless for charging mobile phones and similar devices, which do not require as much power as the OW does. so either they provide not enough kWh or they are not able to provide enough power within the 20 minutes of charging time.

so if we want a device with less weight and less bulkier we would probably have to built it on our own.

so far I think there are basically 3 options:

1. buying something like a 110/230V power bank where we can plug the super charger in
   as stated above it seems that there are no such devices available. also from a technical point of view there are batteries in it which are transformed to a higher (110/230) voltage (power loss) just to be then transformed back down to 58V with the supercharger (power loss again) which makes it inefficient, heavy and bulky.

2. using an existing battery back + a separte transformer + super charger
   technically very simmilar to the first option, but instead of buying a finished product (which does not seem to exist) you would just use 2 separate (existing) devices. alltough this would be lighter (~2 - 2,5kg for 130kWh depending on the battery technologie) you would still have the same disadvantages (power loss/inefficiency resulting from 2 transformations)

3. using an existing battery back (e.g. 12V) + designing a specialiced circuit which transforms the voltage directly to 58V and limits the current to 3.5 A
   so basically the circuit makes sure that the output is exactly what the supercharger provides so you would not need the supercharger for this. technically this would be the cleanest solution, because it is very efficient, and therefore will be light and small (1-1,5kg). but of course one has to to some development and some good testing to make sure output is perfectly stabilized to avoid battery to be damaged. since the onewheel (not the supercharger) already contains all the electronics for balancing and overload protection, this should not be too hard.

for option 2 + 3 it has to be considered, that the batteries have to have more than 130kWh because of power loss due to transformation and because you can not discharge the supply battery completly (which would damage it). obviously option 2 would need much more capacity than option 3 (which I guess something like 150kWh would be fine).

keep me updated if you have any further ideas or if you find a ready-2-buy-product which does the job.
i am really looking forward for something like that to make those perfect trails more usable...

[germx]

@cr4p Yeah, I was thinking about those as well, and did quite a few searches on 1 and 3. With all the E bikes using 48 V Lifepo4, you'd think there would be more stuff available.
Option 3 would be great, just like an extra battery.

Fortunately for me, I'm a traffic light technician. I can charge my OW at pretty much any traffic light in town, as they have a 230 V service outlets. :D

[Franky]

If fm put out an external battery that would charge the internal batteries while riding, I'm guessing almost all owners would buy one or two....or 10:) That could be a real solution to people wanting more range or just range anxiety.

[cr4p]

@Franky : I agree, that would be awesome!