Difference between revisions of "Charging on-the-go"

Revision as of 18:05, 18 February 2018

Use at your own risk. I am not responsible if you break your Onewheel, injure yourself, someone else, or burn your house down.

Overview of options

You have to choose what’s most important to you. Every option has tradeoffs on price, weight, capacity, and safety.

Option	Pros	Cons
DC battery pack (e.g. solar charger)	- Lightest solution - Most energy efficient (DC->DC) - Lots of battery choices - Offers the greatest control over capacity and rate of charge	- The cheapest DIY solution is the most technical. Requires soldering. - Safety is dependent on batteries used - May require separate charger for portable pack depending on configuration
AC battery pack (e.g. Chafon)	- Most common solution - Safe - Includes multiple USB ports and outlets	- Heavy (7lbs w/ battery and charger) - You must carry charger too - AC->DC is inefficient from energy perspective - Expensive ($300+) - Battery capacity readings are wildly inaccurate
Car inverter	- Lots of options on the market - Don’t have to carry anything while riding - Safe	- Must be at your car to charge - Need to make sure it can handle 300W load

Onewheel specs

Charger output: 58V 3.5A
Charger capacity: 130Wh
Wattage required to charge: 250-300W

Commercial Solutions

DC Battery Pack

DC Charger from Carvepower- https://carvepower.com/products/dc-charger-for-onewheel

This charger uses a 36v 4.4ah hoverboard battery to charge the Onewheel. A solar charge controller boosts the output of the battery to the 58V 3.5A required by the Onewheel. One battery provides one charge, and the Onewheel wall charger is not necessary. A separate AC charger is provided to recharge the portable battery. The controller is attached to a mount which slides on to the battery case, making it easy to switch between multiple batteries. The total weight of the controller and one battery is 4lbs.

The battery itself is not included in the kit, but can be purchased separately. Currently the best price available is from this EBay seller- http://www.ebay.com/itm/NEW-SAMSUNG-18650-36V-4-4AH-BATTERY-EBIKE-VAPE-POWERWALL-BATTERIES-20-CELLS-BMS-/201895735309?epid=1621923126&hash=item2f01ec700d:g:Mh8AAOSwSypY9Y7d

Carvepower DC Charger instructions- https://www.dropbox.com/s/hkt86dyslpq5cyb/DC%20Charger%20Instructions.pdf?dl=0

AC battery pack

The idea is to use an AC battery pack with the standard Onewheel charger.

Tested solutions

Option	Pros	Cons
Chafon CF-UPS008 $290 for 2 charges (288Wh)	- Most common option in community	- Modified sine wave - Heavy - 7lbs
igoeshopping $311 for 2 charges (288Wh)	- Pure sine wave	- Heavy - 7lbs
AMSU $300 for 2.5 charges (330Wh)	- Pure sine wave	- Heavy - 7lbs

Incompatible with Onewheel

ExpertPower Omega 453

DIY DC battery pack

The idea is to use a solar charge controller to upconvert a portable battery’s voltage to the 58V that the Onewheel expects. The solar charge controller is typically used to charge a battery via a solar panel. However in this case, your portable battery takes place of the solar panel and your Onewheel is the battery you’re charging.

See photo from @timvp below:

Make sure you protect your battery with something soft in case you wipeout while riding. I suggest packing foam.

Step 1: choose a battery and charger

Battery options	Specs	Pros	Cons
36V 12.5Ah Lithium Scooter battery	$209 for 3.5 charges (450Wh) @ 5lbs	Most bang for buck in terms of cost and capacity AC charger included Safe since it's LiOn	No BMS
36V 4.4ah Lithium batteries from eBay	$60 for ~1 charge (158Wh)	Cheap ($60) A couple folks in the community have had luck with this	Lots of fakes
LiFePO4	$35 for ½ charge (42Wh?) @ 1lb	Safe. This is the same kind of battery that the Onewheel uses.	Less than one charge
52V Mighty Mini	$230 for 2.5 charges (300Wh) @ 3.3lb	Safe It should be possible to charge it with stock OW charger (to be confirmed)	Unsure how to upconvert 52V to 58V as the solar charger doesn’t support 52V as input
Lithium battery from Jet.com	$129 for ~1 charge (158Wh) @ 2.6lbs	Safe (UL certified supposedly) Can be charged with LunaCycle charger	No BMS
36V LiGo	$150 for <1 charge (98Wh) @ 1.3lbs	Safe w/ BMS Lightweight Can be charged with LunaCycle charger Designed to be rugged	Less than one charge
Lipo Bricks (RC packs) (Good Value: MultiStar)	$140 for 3 charges (444Wh) @ 2.6lbs	Low cost Offers fast charging of OW (0-100% under 20 min) Can be recharged quickly with external charger Packs are modular (Recommended configuration is two 6s packs with series connection for 12s (50V output)	Requires occasional balancing Packs are sometimes defective (low charging speed or dead cells) Hobby-grade charger is recommended for balancing, cell health monitoring, and fast charging Packs require protective case for safety, should be charged in a safe location etc.

You also need a way to charge your portable battery.

Charger options	Pros	Cons
LunaCycle charger	Cheap ($60) Safe because it auto-shuts off XT60 connector
AC → DC charger	Uses off the shelf power supply	Requires DC Barrel to XT60 connector
LiFePO4 charger	Cheap ($30)

To be safe, buy a battery pouch and only charge when you’re near the charger and awake.

Step 2: buy the other parts

Solar charge controller - $40

2x XT60 pigtails - $3 each

XLR plug - $3

Step 3: configure the solar charge controller

The output of the solar charge controller must match the output of the Onewheel charger. Your settings should look something like the photo below.

The first line is for monitoring your supply battery, it is not critical if this is incorrect. Set the first line (where it says 32.5V) to the minimum voltage of your battery. 32V is generally a safe setting for a 36V-rated battery.

The critical settings are on the second and third lines (Target voltage (58V) and Amp limit). If the voltage is set incorrectly, the battery will overcharge or may not fully charge.

The stock charger supplies 3.5A. If you are using a 36V battery, you will not be able to exceed 3.5A. If your supply voltage is 50-60V, you will be able to charge the OW at a higher rate. Limited testing has been done on fast-charging, but there do not appear to be any major drawbacks (cycle life and warranty may be affected).

Remember! The battery pack should be on the solar panel label and OW on the battery label on the solar charge controller.

Never charge your batteries while they are cold!!!

The manual can be found here.

Lipo Pack 12S running at 8A

Step 4: solder the wires to the XLR plug

The Onewheel’s XLR plug requires a different wiring than the off-the-shelf XLR plugs. Unfortunately, that means you have to do some soldering.

Below is the correct configuration. Notice the positive wire is connected to *both* pins 2 and 3 of the XLR plug. If you want to verify this yourself, you can easily open the Onewheel charger’s XLR plug.

Step 5: hook it all up!

Portable battery → male XT60 pigtail → solar charge converter → female XT60 pigtail → male XT60 pigtail → soldered XLR plug → (wait until voltage reaches 58V before plugging in!) Onewheel

Sometimes the OW does not go into its charge mode automatically. Simply press the power button in this case.

When you’re done charging, I suggest turning off the solar charge converter first before unplugging anything. Then disconnect the battery. Then unplug from Onewheel.

Charging Onewheel to 100% is safe. You’ll see the amps ramp down on the solar charge converter display as you enter “trickle charge” mode. But you’ll want to disconnect soon or it’ll just slowly drain your battery.

@@ Line 235: / Line 235: @@
 '''Never charge your batteries while they are cold!!!'''
-The manual can be found [http://www.mhinstek.com/pdf/User's%20manual%20of%20MPT-7210A.pdf here].[[File:Fast charge.jpg|thumb|371x371px|Lipo Pack 12S running at 8A|none]]
+The manual can be found [http://www.yampe.com/images/pdf/2907.pdf here].[[File:Fast charge.jpg|thumb|371x371px|Lipo Pack 12S running at 8A|none]]
 === Step 4: solder the wires to the XLR plug ===