Jump to content

Solowheel Xtreme repaired!


Phunny

Recommended Posts

Thank you @edwin_rm for the wheel, I'm thrilled with it, and it is working again.

This wheel was DOA, due to a deeply discharged battery. 20.45 volts total. That's 1.46 volts per cell, lower than the roughly three volts that would be "empty". The two halves were within .1v of each other

I charged the battery on an RC charger one half at a time, at 100ma for an hour, then 500ma to completion. For the first hour of each pack, I sat with it watching like a hawk, primarily for any signs of heat. The pack took 2720mah from 1.45v to 4.05v. After I put the wheel back together, plugged in it's charger, to top up and balance the pack.

After putting it back together, it wouldn't work. The wheel would balance itself, then go to full power in an instant. I took it apart, double checked all wires (correct) and put it together again, being careful not to let any connectors pinch the control board.

It worked now, but the pedals were tilted way forward. After recalibrating it several times, I've got the pedals level, and it's made it through an initial ride of two slow sidewalk miles.

It will come apart once more, to replace all the hot glue I removed, and anchor the batteries so they don't rattle. At this point the insides will likely get a spray of Boeshield T9 for water proofing. This is my waterproofing plan for my MCM5 as well if/when I open it up. 

This ride mode is so soft. Drops are nerve wracking. Third person looks like nothing, but first person it's blind trust or fail. First foot on was easier than the stiffer ride of the MCM5, and I could see someone with zero experience maybe picking it up a bit easier because the wheel doesn't shoot away with accidental input. It climbs my hills without issue and feels confident off-road. I think it will be a good trainer as it kind of encourages a very smooth style. My "Tishawn" carve is fun on the small wheel, but epic on the big one. 

  • Upvote 2
Link to comment
Share on other sites

After another 3-4 miles, it dropped one battery bar, and started tilting back and vibrating. I turned it off and back on, and went slowly home. Doing a lap of my house, going up a steep hill, it did the vibe and tilt back again. I finished the hill, then stopped. It buzzed a few more times, then shutdown itself, no lights and won't turn back on. Now it's on the charger, and will turn on again. I'm thinking it will stay on charge, so it can balance overnight. As I had most of the battery left (or so it looked), and this happened at the top of a steep hill each time, am I looking at an overheat, or a low voltage issue?

Link to comment
Share on other sites

It's most likely a dead battery. Sure, it's 4V without a load, but may start dropping to 2V when under heavy load, freaking out the electronics.

Can you maybe connect a voltmeter and measure the voltage when you're clibming a hill? :-)

Link to comment
Share on other sites

On 5/4/2019 at 12:58 AM, Phunny said:

 This wheel was DOA, due to a deeply discharged battery. 20.45 volts total. That's 1.46 volts per cell, lower than the roughly three volts that would be "empty". The two halves were within .1v of each other

There is no guarantee that the different series cells inside have the same voltage - so some below this 1.46V.

According to batteryuniversity.com cells with less the 1.5V for longer than a week can be considered dead and can be disposed.

On 5/4/2019 at 12:58 AM, Phunny said:

I charged the battery on an RC charger one half at a time, at 100ma for an hour, then 500ma to completion. For the first hour of each pack, I sat with it watching like a hawk, primarily for any signs of heat. The pack took 2720mah from 1.45v to 4.05v. After I put the wheel back together, plugged in it's charger, to top up and balance the pack.

Afain there is no guarantee that all cells charged again "normally". There a "good" chances of some bad battery cells inside with too low voltage and the whole pack cannot be balanced anymore.

The whole pack should have much less capacity than normal, with low ability to deliver higher burdens like for going up hills.

And the risk of venting/fire rises with each use...

Of course you could have incredible good luck and all cells "regenerated" somehow in sync - i would measure each cells voltage to be on the safe side.

On 5/4/2019 at 1:21 AM, Phunny said:

As I had most of the battery left (or so it looked), and this happened at the top of a steep hill each time, am I looking at an overheat, or a low voltage issue?

That's "normal" behaviour of a "dead" battery - "breakdown" once it is burdened ...

But i don't know the solowheel extreme - it should have some alarm before it shuts down due to overheat?

Link to comment
Share on other sites

Actually, looking at the specs it seems that the battery is 14s1p. Which means that there needs to be only 1 broken cell in series for the battery to be dead.

Just replace the cells in a battery with a new high-amp cells [for example Sony VCT5A] - a 1p battery is as strong as the weakest cell, and thus mixing new with old cells will result in bad performance.

Edited by atdlzpae
Link to comment
Share on other sites

On 5/3/2019 at 6:58 PM, Phunny said:

This ride mode is so soft. Drops are nerve wracking. Third person looks like nothing, but first person it's blind trust or fail. First foot on was easier than the stiffer ride of the MCM5, and I could see someone with zero experience maybe picking it up a bit easier because the wheel doesn't shoot away with accidental input. It climbs my hills without issue and feels confident off-road. I think it will be a good trainer as it kind of encourages a very smooth style. My "Tishawn" carve is fun on the small wheel, but epic on the big one. 

Glad you were able to revive it! And yeah, comparing it to the MCM5 is like night and day. MCM5 is rock-hard, while the SW Xtreme is quite possibly the softest wheel ever made. But with that softness comes GREAT maneuverability. No other 18" wheel comes close to its agility.

By the way, when the wheel was brand new, the range was 10 miles on a full charge. That was back in 2015.

Link to comment
Share on other sites

@edwin_rm the current range feels like 5 miles. My terrain is all hills, but the pack has lost capacity for sure. I put in 2720mah of the packs nominal 4000mah. That's 68% capacity, which, being below 80% is textbook "dead". The pack is 3.5 years old, and set low for a week (or two). I don't think to much damage happened just now. I consider this a weak, still safe battery.

What I did was with special precautions. There is a very real chance of a fire, and that fire is INTENSE! Since it bears repeating, don't do this in your house, or anywhere that could burn down.

The danger of sitting at low voltage is the electrolyte can dissolve metals(copper), which precipitate out to form dendrites when recharged. This can potentially create an internal short. This effect is most noticeable after negative 1.5, a much lower voltage. For a week at +1.5, and a slow gentle recovery, the realistic result is slightly reduced capacity and slightly increased self discharge. The damage is cumulative though, and if it won't hold it's charge I'll know soon enough. When I open the pack I will check each cell individually, but until then, it's been behaving well.

@atdlzpae, the Xtreme has 28 Sony VC3 cells in a  14s2p pack, arranged as a row of 14 cells on the left side of the wheel, and 14 on the right. Each row of cells is wired as 7s2p. There's also different spec sheets in circulation for the VC3 cells, one says 20amp/2000mah, and another says 18 amp/1900mah.

  • Upvote 1
Link to comment
Share on other sites

  • 2 weeks later...

Experimental follow-up!

Tldr: a day at deep discharge cost about 1% capacity of an 18650 cell. This damage is cumulative.

I took a matched pair of LG HG2 cells, charged one, and discharged the other to 1.46 volts. I waited 24 hours, then charged the low battery. I then discharged each cell at 500ma to 2.8, then charged at 500ma to 4.2 volts. The damage caused by being low for a day was 31mah capacity permanently lost. These two cells are being retested, if there's a change I'll update.

  • Like 1
Link to comment
Share on other sites

8 hours ago, Phunny said:

Tldr: a day at deep discharge cost about 1% capacity of an 18650 cell. This damage is cumulative.

 

8 hours ago, Phunny said:

The damage caused by being low for a day was 31mah capacity permanently lost

Yes - there is no way to "heal" damages to li ion cells. Imho the damage it takes should be "random" - same "chaotic" process that forms the ?dentrits? inside...

Just out of curiosity - your pack still charges to full voltage or somewhere below?

Link to comment
Share on other sites

  • 5 months later...

Hi, I also have a Solowheel Xtreme that is pretty much new, except the battery does not charge. I've tried charging over night and also charging by spinning the wheel manually for a long time.

Do you have any suggestions on how I can repair mine? Do you have a source for a replacement battery?

Thanks!

Link to comment
Share on other sites

Don't use it. Trying to revive dead cells is NEVER ever a good idea. There may be dead cells in the pack. Or let me say it like this. There are dead cells in the pack, or there will be. At this point anything could happen. It could spontaneuosly catch on fire. At any time. 

Link to comment
Share on other sites

  • 2 weeks later...

18650's can be sold for a few $ a piece.
Open the pack, desolder the cells, check their health (voltage), charge/discharge them to measure their capacity, measure their internal resistance and sell them on ebay.

Or maybe some companies buy whole second-hand batteries for a small price... IDK. :)

There are some people who buy used/broken wheels for spare parts... But don't expect too many $ obviously.

Edited by atdlzpae
  • Like 1
Link to comment
Share on other sites

  • 3 years later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...