# What are people using as a battery backup?

• In October I had this 400W invertor I'd had laying around for awhile hardwired to my car's electrical system (like you would an amplifier for a subwoofer) so I can charge when driving from trail to trail. It sits in the passenger seat well and has a long enough chunk of cord on it that I can pull it to the back seat if needed. That ended up only costing me about \$80 since I already had the inverter. You might consider going that route if you plan on doing most of your adventure riding out of your car.

I really like this idea. That's a great alternative to carrying a battery in a backpack.

Thanks for the feedback everyone. I'll consider my options again once I actually possess a OneWheel.

• I bought a spare supercharger that I take on longer trips. Seems like the most practical option if you go where there'll be power.

• https://www.amazon.com/dp/B018GE8JPY/ref=cm_sw_r_cp_apa_HCOBybQDM4WCP

Do you think this one would work?

Nope. The OW charger is rated for 300 volt-amps which means you should look for a power source that can output at least 300 watts. The watts required is equivalent to the volt-amps multiplied by a factor that is always less than one. Since we don't know what the "power factor" is for the charger, you are better off getting something that can output 300W, even though the current pulled will be some amount less than that.

• @bmtka Thanks! That explanation helps a lot

• 199.8 watt hours, and only 2.19lbs. It can output up to 250 watts, which is enough to power the Onewheel ultracharger.

@bmtka You calculate the wattage by multiplying the amps by the volts. These are listed as 58V and 3.5A on the charger, so the power draw is approximately 203 watts.

• @NextGenDan looks awesome, about how many times could it charge a OW?

• @No It should be good for 2-3 charges (probably 2).

• @NextGenDan thanks, sold. I think the rest of the forums would really like to know about this battery, might be worth posting in it's own thread

• @NextGenDan That thing looks cool! Let me know how the "plug" works for you! I am looking for a good solution to increase the range of my OW+.

• @NextGenDan Yeah, that would have been easier [derp], but I was at work and could only remember that the charger is rated for 300VA.

That battery pack looks amazing. I can't find a way to preorder it, though. Got a link? Or did you mean you're an indiegogo backer and "preordered" as reward?

• @bmtka it looks like it's a reward for certain packages, I backed the 255\$ one and it says I should be getting my battery next month

• @NextGenDan Also, 58*3.5 is the wattage outputted. Given that energy is always lost via heat during the AC/DC conversion and we don't know how efficient the supercharger is at that (I'm guessing not much better than 80%); you are not going to want to go any lower than 250W for an AC power source. That is, of course, the rated max and the battery might not even accept that much power unless it is drained beyond a certain point.

I've got a digital wall-outlet wattage meter. I'll see if I can drain my battery a bit and see what the charger pulls in a real world situation. It might not happen today, though.

• Okay, so I was only able to drain my battery down to 76% riding around in the garage. I tried going outside but the snow presents a triple threat of wheel slip, lack of lateral grip, and the smallest bit on your shoe renders the grip tape instantly useless so I can't do a full charge cycle right now.

I plugged it in and the charger immediately began pulling 222W at the outlet and held steade for most of the charge. Oddly, when the battery was close to full around 96-97% this went up to 227W before it began tapering down slowly at around 98%. I doubt it would pull much more wattage beyond that for a more fully drained battery but I'll have to wait until the snow melts for a day or two before I can test that for sure. Assuming that's true, a 250W power source should be just fine, though I'd prefer to have a little more wiggle room for hardware variances and such. I'm usually pretty conservative with these things and like to have a power supply that exceeds my expected usage by 20-30%. That's why I suggest matching your wattage to the input volt-amps.

I will be interested to hear how the Charge Tech "Plug" works for you guys. It's the first UPS-type battery I've seen that I would consider buying for the purpose of extending OW range.

• I use a solar charge controller(about 1 lbs) and pretty much any battery. Currently I use a 36v lipo pack out of a hover board and a 32v LiFepO4 pack out of a scooter. I get 1.5 charges out of the lipo and 2-3 out of the LifepO4(higher capacity)

There is a "convince Andy to build this sh*t" thread that has info from the guy who came up with it. I'm just an adopter.