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Did I destroy my battery?


jaytee
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Last summer I purchased a Luffy for my SO.

It was our first entry into the EUC world and super excited after researching for months. Anyways, for various reasons she tried it a few times but didn't quite get the hang of it. Then winter came and we packed it in the closet.

 It sat in there till a few days ago after we decided to give it another go. So after I pulled it out it was completely dead. I remember vaguely reading about a dude that killed his Tesla by not keeping it plugged in or something.

Anyways, plugged it in and been charging for 2 days now and managed to get to 50%/40% (it oscillates between displaying those two levels on the app).

How badly are we screwed? :(

 

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There might be another option before you consider getting a new battery. That would be to fully deplete the energy you managed to gain. After a second, or even a third, recharge from dead doesn't fix your issue, you might have a battery issue. Do what Warped said first though. check if your charger is working.

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51 minutes ago, kasenutty said:

What happens when you ride around and drain the battery and then try charging again? 

It could possibly be bad cell balancing. Discharging it completely could 'reset' the battery levels to be more equal. Similar to charging a battery then leaving it plugged in for a little longer but on the opposite end. At least, that is my mindset on it. It really doesn't hurt to try though.

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It seems from what everyone is saying, the next step is to stop charging it now. Then drive it around until it runs flat, then recharge again.

Will test that out this weekend and see how it goes.  

Thanks for the ideas and the sliver of hope!

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My knowledge of batteries is very limited. If allowing a battery to die is a bad idea, maybe that is exactly what happened in the first place. The battery was unused and the battery was damaged from being allowed to fully deplete. 

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In my experience, some cycles might help for the next couple of rides but you don't need to drain it down all the way, at least charge IMMEDIATELY after the first low battery warning signal and DON'T PUSH IT FURTHER. It was my first Chinese generic one which came new without any battery charge (I wish I had more knowledge to return it back). What I also noticed though is that first, it improves the range (after the first 2/3 cycles) then soon after distance was fairly reduced and some cells seemed to got shorted a few months after, after storing it for a couple of weeks more later. To my understanding, those 2 cells probably got a higher resistance and got over-discharged during that storage time but battery life was evident to have come near the end of life before storing it. PS. that battery only lasted a year for me

As @WARPed1701D and @Keith suggested check the charging voltage first but be very careful if you see a pattern like mine. Getting 2 shorted cells at the end and the battery was not fully charging (I remember both chargers I had for this wheel were switching red-green continuously) and got me hurt at slow launch. I would rather look for a new wheel or change the battery if so (after some tests to make sure the battery only is the issue). For charging time you can check the manual, but a few hours is normally required. Also, protection gear (Minimum; Helmet& wristguard Then; Elbow and knee pads) is suggested for trying it out with such a battery.

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Measure charger voltage. If it's at the rated voltage you might want to let someone have a look at your battery.

Maybe they can hook it up to a hobby charger and help you charge the unbalanced cells, if any.

At the very least just measure the individual voltages and see how many groups are off and how much they deviate.

/a

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Hi Folks

Thanks for the suggestions.

Here's a video last week demonstrating this was meaning to upload. Apologies for the jerkiness.. bit tricky with arthritis and juggling the camera.

Subsequently, I noticed each day the Luffy was left charging the % went up by about 10%. So now (July 27th) it reads 90%-100% battery charged. But this is only when it's plugged in. When I unplug it, it beeps like crazy and battery shows 0% on the app.

I've ordered a multi meter and also emailed a local Luffy supplier (UK) - maybe they can help. Also a bit concerned as to how far one can go from a safety POV along the DIY route

Hope this serves as a reminder... keep those PEV's charged!

 

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Another small update: Ian from speedyfeet asked me to check something.

"When you turn the Luffy on at the wall switch, does the LED on the black charging brick flash red briefly before going green?"

So I tested and it does flash red briefly... apparently this means battery is indeed dead. kaput. game overs

ah well...

Also from my googling it doesn't look like anyone supplies spare luffy battery packs.

So if anyone wants some spare parts.. let me know. Maybe someone else can find some use.

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12 minutes ago, jaytee said:

Another small update: Ian from speedyfeet asked me to check something.

"When you turn the Luffy on at the wall switch, does the LED on the black charging brick flash red briefly before going green?"

So I tested and it does flash red briefly... apparently this means battery is indeed dead. kaput. game overs

ah well...

Also from my googling it doesn't look like anyone supplies spare luffy battery packs.

So if anyone wants some spare parts.. let me know. Maybe someone else can find some use.

With some time, a little reading, some youtube videos, and help from some people on this forum, you may just be able to replace the battery on your own. This may even ultimately grant you a larger battery than you had before.
If you don't want to go this route, I remember seeing someplace online that makes custom 18650 battery packs with connectors and everything. I can take a look online and see if I can find it if you want to pursue this method. It would be more expensive than making your own.

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I actually hit this problem months back with my home-built battery pack and was able to fix it. One of the cells went down to nearly 1 volt due to a missing wire, this mistake also costed me a BMS. I fixed that by paralleling the battery with a fully charged one with two small long wires, keep doing that with few other ones until the voltage got up to over 3.5 then the BMS would accept it.

Since then my battery pack has been working great, I have some photos here - 

Not sure this would work for you as your battery cells could have been in low voltage for long time.

 

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1 hour ago, Esper said:

With some time, a little reading, some youtube videos, and help from some people on this forum, you may just be able to replace the battery on your own. This may even ultimately grant you a larger battery than you had before.
If you don't want to go this route, I remember seeing someplace online that makes custom 18650 battery packs with connectors and everything. I can take a look online and see if I can find it if you want to pursue this method. It would be more expensive than making your own.

Thanks Esper... you've given me some ideas.

The luffy version I have is the 200wh one. According to specs from speedy feet uk, it should be

I noticed in Ian's tear down video the battery pack had the familiar blue wrapping.

This battery pack here might fit the bill?

https://www.aliexpress.com/item/60V-3000mAh-16S-60V-li-ion-battery-lithium-batteries-used-in-electric-wheelbarrow-or-the-balance/32842811870.html

Of course I'm not sure if it's using the NCR18650GA in that pack and if it would be compatible with Luffy's BMS.

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I'm not sure @jaytee as I am no expert. @esaj would have much more knowledge in this than I would.
The blue wrap is just a think shrink wrap I believe, so that the battery cells do not come apart.
If your current battery (the one that is dead) has a chip inside it, then it could become more problematic. 
I personally would take out the battery, and then unwrap the blue plastic to view the inside, determine how many cells (18650 battery) it contains, reuse the cables and wire, then order the best 18650 cells I can find and orient them the same way as was inside the old battery. I think the minimum tools you would need is a soldering iron and some circuit board type solder so the electricity isn't inhibited. I'm sure there are videos online, I have not looked though. Then you need to get your hands on that blue plastic shrink wrap stuff.

I hope someone else here may be able to help you more than I can. But don't let a simple battery stop you from enjoying your wheel.

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6 minutes ago, Esper said:

I'm not sure @jaytee as I am no expert. @esaj would have much more knowledge in this than I would.
The blue wrap is just a think shrink wrap I believe, so that the battery cells do not come apart.
If your current battery (the one that is dead) has a chip inside it, then it could become more problematic. 
I personally would take out the battery, and then unwrap the blue plastic to view the inside, determine how many cells (18650 battery) it contains, reuse the cables and wire, then order the best 18650 cells I can find and orient them the same way as was inside the old battery. I think the minimum tools you would need is a soldering iron and some circuit board type solder so the electricity isn't inhibited. I'm sure there are videos online, I have not looked though. Then you need to get your hands on that blue plastic shrink wrap stuff.

I hope someone else here may be able to help you more than I can. But don't let a simple battery stop you from enjoying your wheel.

Thanks.. maybe I will give it a go. 

It seems like the battery pack is 16S 18650. So 16 individual 18650's in Series. This makes sense as 16 * 3.7v is about 60V.

You coul prob even make the pack for about $50. Seems like you'd need the 16S BMS which is about $20 and then 16 18650's and some connectors. Then a bit of soldering and shrinkwrap like you say.

If one wants to spend a bit more seems like a 16S pack and BMS in one is the way to go

https://www.aliexpress.com/store/product/Brand-cell-60v-3Ah-li-ion-lithium-16s-60v-18650-3000mah-15A-BMS-600w-800w-for/1453301_32686348373.html

That's about $100 bucks. The only thing is, I think maybe the Luffy packs two rows side by side, as opposed to two rows stacked vertically judging by the pic below.

I guess I would need to open her up as you suggest to check the exact dimensions.

Here is a snapshot from Ian's video

image.thumb.png.050486ac40688d11a957c6e89fb004a6.png

 

Edited by jaytee
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22 minutes ago, jaytee said:

Of course I'm not sure if it's using the NCR18650GA in that pack and if it would be compatible with Luffy's BMS.

The BMS is in the battery and what cells it contains will be of little concern as long as the packs spec for max current etc or OK.

What will be of concern is that the aliexpress battery has (in its Integral BMS) over current and under voltage protection I.e. it will switch off the output from the battery if you draw too much current or let the battery voltage drop below some (unknown?) value. Not s big problem on an electric bike, but instant faceplant on an EUC.

Replacing it’s BMS with the Luffy one would mean surgery on both packs to remove the BMS from the existing pack and the new one and swap them over. Possible but not trivial as 17 wires will have to be soldered to the ends of every cell in the pack.

 

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Just now, Keith said:

The BMS is in the battery and what cells it contains will be of little concern as long as the packs spec for max current etc or OK.

What will be of concern is that the aliexpress battery has (in its Integral BMS) over current and under voltage protection I.e. it will switch off the output from the battery if you draw too much current or let the battery voltage drop below some (unknown?) value. Not s big problem on an electric bike, but instant faceplant on an EUC.

Replacing it’s BMS with the Luffy one would mean surgery on both packs to remove the BMS from the existing pack and the new one and swap them over. Possible but not trivial as 17 wires will have to be soldered to the ends of every cell in the pack.

 

Thanks, Keith. That is my concern too. The safest might be keep the original BMS and replace the individual 18650's. But thats also a lot of work like you say. And I a b it of a noob with a soldering iron ;)

The second aliexpress link I just posted a few minutes ago says "Max.Continuous Discharge Currents: 15A" and that it's rated for eletric skateboards and unicycles. 

One concern now that you raised a 3rd party BMS is do you think the BMS interacts with the control circuitry and app in a special (proprietary)  way?

 

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8 minutes ago, jaytee said:

Here is a snapshot from Ian's video

image.thumb.png.050486ac40688d11a957c6e89fb004a6.png

 

You know, it appears from that video picture that there is more space in that battery compartment for another row or even two. You could most likely extend the range if it is something you may be interested in.

Edited by Esper
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13 minutes ago, jaytee said:

You coul prob even make the pack for about $50. Seems like you'd need the 16S BMS which is about $20 and then 16 18650's and some connectors. Then a bit of soldering and shrinkwrap like you say.

And picking up on this bit too - you cannot solder 18650 cells (well you can but the odds you will do series damage to the cells internals are rather on the high side!) unless you can buy cells with tabs on them (possible but not too common) then the only safe way of joining them is to purchase Nickel strips and spot weld them together, you can solder the BMS wires to the nickel strips as long as you are careful not to create too much heat: http://www.ebikeschool.com/how-to-build-a-diy-electric-bicycle-lithium-battery-from-18650-cells/

6 minutes ago, jaytee said:

One concern now that you raised a 3rd party BMS is do you think the BMS interacts with the control circuitry and app in a special (proprietary)  way?

Unless I’m much mistaken (I don’t know the Luffy) you have just two, 2-wire leads coming out of the battery into the wheel: one for charging and one for power. The only interaction possible, if that is the case, is for the wheels electronics to monitor the output voltage of the battery - nothing more. 

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9 minutes ago, Keith said:

And picking up on this bit too - you cannot solder 18650 cells (well you can but the odds you will do series damage to the cells internals are rather on the high side!) unless you can buy cells with tabs on them (possible but not too common) then the only safe way of joining them is to purchase Nickel strips and spot weld them together, you can solder the BMS wires to the nickel strips as long as you are careful not to create too much heat: http://www.ebikeschool.com/how-to-build-a-diy-electric-bicycle-lithium-battery-from-18650-cells/

I did see a battery with a tab on it for sale online. I thought they were soldered on. Is there a difference between the spot weld and the solder? other than one is bad and one is better.

Edit:
Here are tabs I found online. Pretty cheap too.
Edit Edit: These are the wrong metal.

Edited by Esper
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