V8 battery upgrade!!!

[Heymelon]

4 hours ago, alcatraz said:

Sure.

It's almost like adding 50% more capacity (720Wh) gives you like 65% more range. I know it sounds weird but it makes sense if you think that a small pack has a lot of voltage sag. 

A gentle acceleration can be sustained at a slightly lower voltage on the larger pack, because it can hold its voltage better.

Makes sense! Hmm actually, are you still a V8 rider btw? If so how many miles has it gone? Just curious about it's  potential longevity . I probably won't upgrade the battery on mine though unless I'd stumble on a cheap pre assembled pack somewhere.

[alcatraz]

8 hours ago, Heymelon said:

Makes sense! Hmm actually, are you still a V8 rider btw? If so how many miles has it gone? Just curious about it's  potential longevity . I probably won't upgrade the battery on mine though unless I'd stumble on a cheap pre assembled pack somewhere.

I have two V8. I bought them both 2nd hand. One with 2000km and one with 4000km for my wife.

The first one now has 12000km I believe and the second maybe 6000km.

I stopped riding mine a while back when I got a Gotway Tesla.

I don't spend much on euc's because I noticed lots of people are selling them. (They upgrade faster than me). Got the V8s for 200-300usd each. 500 total. The Tesla was 300usd, and the MSX84 I'm riding on now was 450usd.

The first V8 still runs on its original battery. All the cells are in perfect balance. The motor runs fine and the control board is fine. Had to change tires a few time, fix punctures. I crashed it hard once so it's all cracked but it just keeps on running.

The secone V8 is a completely different story. It came with a damaged battery so that I had to rebuild. Made a 720Wh pack from the remaining good parts and spare LG MH1 cells I had to buy. 

The motor has a flaw in it that I didn't discover until a few weeks later. Now I know how to check for that sort of flaw. Anyway, it's still rideable but climbing isn't perfect. The problem with it is that it has a dead spot. It's like one out of the many magnets inside has come off or something so there is zero torque at a specific point in a revolution. You can feel it if you climb extremely slow. A good motor should pull evenly but with this it jerks once every revolution. As soon as you don't require lots of torque at low rpm, you couldn't tell the flaw was there. I learned to live with it.

It's an amazing wheel but after crashing at 33km/h (I unlocked the speed limit), I became extremely aware how close to the cutout speed I've been riding for 10.000km. It scares the living hell out of me because I've been in heavy traffic A LOT. That's when I decided that I'm not going to do anything stupid like that again. I'm not even talking about raising the speed limit. If you think about it, they don't really have speed limits. It's just a point where there isn't enough torque for the circumstances. Be it a different rider, riding style, speed bump, headwind, tire, whatever. So I got a Tesla that can do 50km/h (even a bit more on a good day) but I limit it at 40km/h (tilt-back).

Riding a V8 at the stock limit of 30km/h is possible but in my opinion extremely unwise. It's too close to the actual limit. (Free spin 44km/h)

The MSX84 I'll probably raise to 45km/h because the free spin is at 76km/h. That's one hell of a margin. 

I'd limit any V8 to 28km/h at most. Mine is at 25 now. I'm a small light dude too. The larger battery made the wheel feel better so I thought I had some headroom. I was sorely mistaken. Less voltage sag doesn't give you more speed/power. Not even 1-10% more.

And oh yeah. Rebuilding a battery isn't a great solutionif the BMS has stopped to balance cells properly. Like with mine. You can't source a replacement bms so you have to balance manually every few months. It's doable but the wheel will forever require special maintenance, so you can't really sell it or give it away.

[Heymelon]

3 hours ago, alcatraz said:

I have two V8. I bought them both 2nd hand. One with 2000km and one with 4000km for my wife.

The first one now has 12000km I believe and the second maybe 6000km.

I stopped riding mine a while back when I got a Gotway Tesla.

I don't spend much on euc's because I noticed lots of people are selling them. (They upgrade faster than me). Got the V8s for 200-300usd each. 500 total. The Tesla was 300usd, and the MSX84 I'm riding on now was 450usd.

The first V8 still runs on its original battery. All the cells are in perfect balance. The motor runs fine and the control board is fine. Had to change tires a few time, fix punctures. I crashed it hard once so it's all cracked but it just keeps on running.

The secone V8 is a completely different story. It came with a damaged battery so that I had to rebuild. Made a 720Wh pack from the remaining good parts and spare LG MH1 cells I had to buy. 

The motor has a flaw in it that I didn't discover until a few weeks later. Now I know how to check for that sort of flaw. Anyway, it's still rideable but climbing isn't perfect. The problem with it is that it has a dead spot. It's like one out of the many magnets inside has come off or something so there is zero torque at a specific point in a revolution. You can feel it if you climb extremely slow. A good motor should pull evenly but with this it jerks once every revolution. As soon as you don't require lots of torque at low rpm, you couldn't tell the flaw was there. I learned to live with it.

It's an amazing wheel but after crashing at 33km/h (I unlocked the speed limit), I became extremely aware how close to the cutout speed I've been riding for 10.000km. It scares the living hell out of me because I've been in heavy traffic A LOT. That's when I decided that I'm not going to do anything stupid like that again. I'm not even talking about raising the speed limit. If you think about it, they don't really have speed limits. It's just a point where there isn't enough torque for the circumstances. Be it a different rider, riding style, speed bump, headwind, tire, whatever. So I got a Tesla that can do 50km/h (even a bit more on a good day) but I limit it at 40km/h (tilt-back).

Riding a V8 at the stock limit of 30km/h is possible but in my opinion extremely unwise. It's too close to the actual limit. (Free spin 44km/h)

The MSX84 I'll probably raise to 45km/h because the free spin is at 76km/h. That's one hell of a margin. 

I'd limit any V8 to 28km/h at most. Mine is at 25 now. I'm a small light dude too. The larger battery made the wheel feel better so I thought I had some headroom. I was sorely mistaken. Less voltage sag doesn't give you more speed/power. Not even 1-10% more.

And oh yeah. Rebuilding a battery isn't a great solutionif the BMS has stopped to balance cells properly. Like with mine. You can't source a replacement bms so you have to balance manually every few months. It's doable but the wheel will forever require special maintenance, so you can't really sell it or give it away.

Talk about above and beyond, thank you for that history! 12000km sure does inspire some confidence in mine. I think I'm on my way to be taking the same path as you potentially. I like buying used and got my V8 at 1300km and for 150$ believe it or not, seemed to be in good shape as well. It was a nice seller with many wheels who wanted to just spread the love seemingly. So maybe I'll continue down this road if I find decent deals in the future and learn some home tinkering when needed. I actually already had to because I blew the fuse doing way to heavy off road hill climbing, and I'm kind of a heavy rider. Still I was surprised that it just died and I wasn't given any warning or pushback to warn me. It might have been because I was coming close to the limits and I hit some mud that started a free spin while climbing, and that was it. So having said that, I definitely won't be doing any 33km/h on it  Sounds like you must have had some close calls or did well to avoid any bumps when you were riding yours that fast for so long! I'm still kinda new so I haven't gone over 25km/h and rarely even hit that so this makes me think I should just keep it like that hearing your experiences. And it's a fun wheel at lower speeds too so why not. 

Have fun on the MSX84, I hear it's a great wheel! I've actually kept my eyes out a little but the used ones I've seen so far have gone for 1400$. Which I'm sure is not a bad deal but better ones might come and I'm in no rush. 450$ sounds really great tho!

[Nelson Cummings]

Wow . I would love that upgrade on my Inmotion V8 . How much and where ? thanks 

[OneLeg]

On 5/27/2022 at 7:59 PM, Nelson Cummings said:

Wow . I would love that upgrade on my Inmotion V8 . How much and where ? thanks 

the easiest way to upgrade is to buy a new V8S  S edition using the 5000Mha 21700 and has 1000W motor.

BTW, inmotion use  the 7 wirecomms talk to the BMS of the pack and identify the battery and ensure it only works on a V8S.... You can't change packs and BMS between all the V5's and V8's... even though they are the same... just different cell capacities.

To do upgrades you need a spot welder, someone to teach you, cells, and if you are going to not use 18650 cells you will have to figure out how you hold the batteries together..... the normally plastic battery holder frame only takes 18650's.... If someone could make a SLT file to print a 20700/21700 it would be ace.

[Xilebo]

On 5/28/2022 at 3:57 PM, OneLeg said:

the easiest way to upgrade is to buy a new V8S  S edition using the 5000Mha 21700 and has 1000W motor.

BTW, inmotion use  the 7 wirecomms talk to the BMS of the pack and identify the battery and ensure it only works on a V8S.... You can't change packs and BMS between all the V5's and V8's... even though they are the same... just different cell capacities.

To do upgrades you need a spot welder, someone to teach you, cells, and if you are going to not use 18650 cells you will have to figure out how you hold the batteries together..... the normally plastic battery holder frame only takes 18650's.... If someone could make a SLT file to print a 20700/21700 it would be ace.

 

On 5/27/2022 at 4:55 AM, alcatraz said:

(...)

And oh yeah. Rebuilding a battery isn't a great solutionif the BMS has stopped to balance cells properly. Like with mine. You can't source a replacement bms so you have to balance manually every few months. It's doable but the wheel will forever require special maintenance, so you can't really sell it or give it away.

Think about fitting an external 20s balancer. It is not expensive. It is quite small there is a chance to hide it in the wheel. And it will keep the balance permanently in the battery. You plug it next to BMS without balancer or with broken one

 

 

I have another question... after how many km/time did you change the tyre on the v8?  Or did you do it after it got damaged? I've done about 2500 km on mine. I'm considering whether to change the tyre or wait. It still looks pretty good. But it costs a fortune to repair the teeth. The tyre is not that expensive

[alcatraz]

8 minutes ago, Xilebo said:

Think about fitting an external 20s balancer. It is not expensive. It is quite small there is a chance to hide it in the wheel. And it will keep the balance permanently in the battery. You plug it next to BMS without balancer or with broken one

I don't think those will work reliably. They might but only if you lower the charger output voltage to like 80V.

The reason being that balancing stops at 0.03V difference to the groups beside it. You could theoretically end up with a pack with 4.5v-4.47v-4.43v-...-3.93v-3.90v = 84.0v (worst case delta 0.6v)

Change the tire when the tread is looking nearly worn down, the compound has hardened and you have cracks etc. There's no distance limit I believe. A heavier rider wears out a tire wayy faster than a lighter rider. Also, the road surface can be differently abraisive. In some countries bike paths are made from concrete. It'll eat up your tires.

[alcatraz]

I'm not saying to throw away the wheel. Like mentioned, I still use mine and I'm not afraid about the broken bms. I just have two groups that are discharging over time. I attached balance leads and got two USB lithium cell chargers and top those two groups up every few months.

Because the overvoltage protection in the broken bms still works, I can leave the wheel on the charger without risk. But I did confirm that it works. And I never deplete the pack if I haven't balanced for a while.

[OneLeg]

On 6/10/2022 at 7:06 PM, Xilebo said:

 

Think about fitting an external 20s balancer. It is not expensive. It is quite small there is a chance to hide it in the wheel. And it will keep the balance permanently in the battery. You plug it next to BMS without balancer or with broken one

 

 

I have another question... after how many km/time did you change the tyre on the v8?  Or did you do it after it got damaged? I've done about 2500 km on mine. I'm considering whether to change the tyre or wait. It still looks pretty good. But it costs a fortune to repair the teeth. The tyre is not that expensive

I think integrating a second BMS or balancer into the V8 is must try, and deserves its own thread...

I think about I changed the original tire after 4000km.  The wear is mostly about tire pressure. Pressure too low the tire wears out quicker and you lose manuoverability, to be able to do a 180 flip on the spot and switch direction. I use to always pump to 40 PSI (I am 88kg), but lately I am enjoying 37-38 PSI.

I personally don't recommend over pumping the V8 tire above 42 PSI as battery/controller will be forced handle a lot more spikes, the wheel may loose forward balance temporarily if your batteries are worn out.