V8 battery upgrade!!!

[alcatraz]

10 hours ago, palachzzz said:

My 20S4P verison:
80 x LG MJ1
1050 Wh (Inmotion terms, 1008 Wh in reality)
Battery 4 Kg
V8 ~ 15 Kg
~70 km on one charge

  Reveal hidden contents

 

Hey cool. Bit crazy with melting the cover. ?

Is the original bms in the battery pack?

How many cells do you reckon can be jammed in without deforming or doing any but minimal dremeling?

Thanks for posting.

/a

Edited July 20, 2018 by alcatraz

[mezzanine]

11 hours ago, palachzzz said:

My 20S4P verison:
80 x LG MJ1
1050 Wh (Inmotion terms, 1008 Wh in reality)
Battery 4 Kg
V8 ~ 15 Kg
~70 km on one charge

  Reveal hidden contents

 

I was sure I was going to attempt to increase the battery capacity of my V8 when I first bought it.  I'd still like to try, but I'm not technically knowledgeable.  

Someone mentioned a mod to increase the capacity to 740wh using the existing cells and purchasing more batteries.  Can anyone tell me if there is a way to do this?  I think I've asked before, but no one knows.  

[alcatraz]

29 minutes ago, mezzanine said:

I was sure I was going to attempt to increase the battery capacity of my V8 when I first bought it.  I'd still like to try, but I'm not technically knowledgeable.  

Someone mentioned a mod to increase the capacity to 740wh using the existing cells and purchasing more batteries.  Can anyone tell me if there is a way to do this?  I think I've asked before, but no one knows.  

Originally you have 40 cells (two 20 cell chains in parallel). You can add increments of 20 cells but not less. You can replace the cells with higher capacity but you're looking at 10% max (probably not more than 5%).

60 cells is possible to fit inside. The original 40 cells are in a special tray that needs to be removed in order to fit another 20. In order to remove the trays you need to break the spotwelded connections between the cells. (I guess you could break the tray around the connections but it wouldn't do much gooe because the connections are made with nickel strips which hold the batteries in their original configuration). 

So in essence you need to spotweld a new pack together. You can use the old cells but if you want to dummy charge (original charger) you will have a longevity problem.

The only way to reliably be able to use the full capacity of newly added cells (with original charger) is to replace all of them. Tough.

In my opinion since the original balancing is so poor you can increase your battery lomgevity by several tenfolds by using a balance charger. Problem is, you need to create a small wire harness that you can hook up to.

Edited July 20, 2018 by alcatraz

[mezzanine]

8 minutes ago, alcatraz said:

Originally you have 40 cells (two 20 cell chains in parallel). You can add increments of 20 cells but not less. You can replace the cells with higher capacity but you're looking at 10% max (probably not more than 5%).

60 cells is possible to fit inside. The original 40 cells are in a special tray that needs to be removed in order to fit another 20. In order to remove the trays you need to break the spotwelded connections between the cells. (I guess you could break the tray around the connections but it wouldn't do much gooe because the connections are made with nickel strips which hold the batteries in their original configuration). 

So in essence you need to spotweld a new pack together. You can use the old cells but if you want to dummy charge (original charger) you will have a problem.

The only way to reliably be able to use the full capacity of newly added cells (with original charger) is to replace all of them. Tough.

I couldn't be more grateful for your response!  Thank-you for taking the time to make it.  

I've done very little basic welding and never spot-welded.  It sounds like this would be beyond my ability.  I'm not opposed to attempting to spot-weld a new pack, but hadn't realized I'd run into problems with being able to charge it.  

I guess if my battery performance deteriorates significantly over the next year, it might make sense build a new pack.  I'd have to weigh the cost against just purchasing a new V8 battery pack off aliexpress.  

When I first purchased the V8, I didn't think it would be this hard to increase the battery capacity.  

 

 

I'm really hoping someone confirms that the V8 BMS doesn't balance the cells when fully charged.  I've never heard of a wheel that doesn't do that, and was surprised to read it in this thread.  I won't ever charge to 100% again if that's the case.

[alcatraz]

The spotwelding machine is special for lithium batteries and the nickel strips are all you need.

I ordered a used machine here in China for like 40usd. I'm determined to build a new pack. 

If I go through the trouble I'd like for charging be to my liking. 4.215V is over 100% and would mean any new pack is going to lose 20% capacity after under 400 cycles.

I guess a compromise could be to use a charge doctor set at 90% and having a balancing harness ready under the cover that is only used once every ~50 cycles to balance the cells.

Btw I have never built a battery. I'm going to attempt it. Take my advice with some care. ?

[mezzanine]

45 minutes ago, alcatraz said:

The spotwelding machine is special for lithium batteries and the nickel strips are all you need.

I ordered a used machine here in China for like 40usd. I'm determined to build a new pack. 

If I go through the trouble I'd like for charging be to my liking. 4.215V is over 100% and would mean any new pack is going to lose 20% capacity after under 400 cycles.

I guess a compromise could be to use a charge doctor set at 90% and having a balancing harness ready under the cover that is only used once every ~50 cycles to balance the cells.

Btw I have never built a battery. I'm going to attempt it. Take my advice with some care. ?

I'm going to be watching your project with great enthusiasm.  I hope you'll document the procedure with photos; I may use your experience as my guide if I can build up the courage to try it myself.  

I'm all about simplicity and preserving the longevity of the batteries.  It may end up making more sense for me to replace my battery using a pre-made V8 battery pack from aliexpress.  I was concerned to read that you're observing a decrease in capacity.  

When I was looking at wheels, everyone mentioned range as the major reason for going with a bigger battery wheel.  No one talked about battery longevity after being charged 500+ times.  It's tough to get quality information with a community this small.  

[palachzzz]

5 hours ago, alcatraz said:

Hey cool. Bit crazy with melting the cover. ?

Is the original bms in the battery pack?

How many cells do you reckon can be jammed in without deforming or doing any but minimal dremeling?

Thanks for posting.

/a

Yes there are original BMS. 
And BMS is the problem due to which it was required to melt the cover (it about 5-7 mm thickness, without BMS everything will fit without melting cover). 
But as we need BMS, you can put 60 cell into tray and about 9-11 atop, it useless as we need 20x cells without changing voltage.

[alcatraz]

1 hour ago, palachzzz said:

Yes there are original BMS. 
And BMS is the problem due to which it was required to melt the cover (it about 5-7 mm thickness, without BMS everything will fit without melting cover). 
But as we need BMS, you can put 60 cell into tray and about 9-11 atop, it useless as we need 20x cells without changing voltage.

Cool! Great info.

I see in your picture you installed an external balance cable harness. Is this only to monitor voltages or are you using it to balance the cells somehow?

[palachzzz]

Yes, you are right, I use it for monitoring cells from time to time, and also for balancing using Turnigy Reactor balance charger.

I had assembling the battery during 5 months (it was a long project , winter is not good time for riding in Russia). But I made a mistake- I didn't check each cell voltage before packing the battery. As a result, I had to balance the battery through thin wires that can carry only about 0.5-0.7A, it's very slow for a battery with a capacity of 14 Ah. I spent about three days on the first balancing after the assembly.

Also I balanced it maybe 2-3 times, after several cycles.

Now I use this battery for 2,5 month in my V8, and pretty happy with it.

Edited July 20, 2018 by palachzzz

[bishops1101]

Does anyone have pictures for cell layout, polarity and connection diagram for in motion V8 BMS, I am trying to add LG HG2 cells to a new inmotion V8 bms?

[US69]

5 minutes ago, bishops1101 said:

Does anyone have pictures for cell layout, polarity and connection diagram for in motion V8 BMS, I am trying to add LG HG2 cells to a new inmotion V8 bms?

Are you upgrading to 60cells? Just curious...cant help with diagrams!

Perhaps it is worth noting that on one of the russian "Powertests" one of the upgraded V8 with higher capable 30Q batterys not only was more powerfull...it also burned the board in one case. So the limiting factor on the V8 are not only the 2P config...it is also the board which is Kind of a bottle neck!

[MaiKi]

How can it burn if you dont change the volt?! Am i wrong thinking you just increase the capaticity with 60 cells?! 

[bishops1101]

4 hours ago, US69 said:

Are you upgrading to 60cells? Just curious...cant help with diagrams!

Perhaps it is worth noting that on one of the russian "Powertests" one of the upgraded V8 with higher capable 30Q batterys not only was more powerfull...it also burned the board in one case. So the limiting factor on the V8 are not only the 2P config...it is also the board which is Kind of a bottle neck!

I am doing 40 cells only, had got my unicycle from Shenzhen without battery pack in a suitcase. Just received the bms from inmotion guys!!

[US69]

2 hours ago, MaiKi said:

How can it burn if you dont change the volt?! Am i wrong thinking you just increase the capaticity with 60 cells?! 

The actual Setup..40 cells =2 times parallel 20cells with cells that are able to deliver 10Amp continuos, means 2 time 10Amp = 20Amp max.

Now using different cells with, lets say able to deliver 20Amps continuos would then upgrade to 2 times 20Amp = 40Amp max!

On a 60cell System even 3times 10Amp(original cells) or 3times 20 Amp = 60Amps.

 

So instead of producing About 20Amps max...with a cell Change you can now perhaps produce and deliver 60Amps...if the board isnt layed out for that, it might burn!

Actual it are amps which stress the board/Mosfets etc...not the voltage alone!

Edited August 29, 2018 by US69

[Chriull]

18 minutes ago, US69 said:

Actual it are amps which stress the board/Mosfets etc...not the voltage alone!

Exactly!

Just your max amperage approach (nominal max ampere) is not the full reality - by more cells in parallel the internal resistance of the battery decreases and by this more current can flow in a given circuit. 

Edited August 29, 2018 by Chriull

[US69]

1 minute ago, Chriull said:

 

Just your max amperage approach (nominal max ampere) is not the full reality - by more cells in parallel the internal resistance of the battery decreases and by this more current can flow in a given circuit.  

Thats what i said, or? More current on more parallel cells…..

[palachzzz]

8 hours ago, US69 said:

it also burned the board in one case. So the limiting factor on the V8 are not only the 2P config...it is also the board which is Kind of a bottle neck!

 It burnt only 30A fuse at 48A current, board is pretty durable, moreover - V10F has the same main board (marked as V8 ver 1.2, the same in my V8), I have 20s4p config on V8 it works great, much better than 20s2p

Edited August 29, 2018 by palachzzz

[MaiKi]

Oh ok thanks, i thought the board "takes" only amps which are needed so is it better to use cells with less.amp? Wirh 3packs ~15amp? Or does sthis config cause problems too?

[palachzzz]

6 hours ago, bishops1101 said:

Does anyone have pictures for cell layout, polarity and connection diagram for in motion V8 BMS, I am trying to add LG HG2 cells to a new inmotion V8 bms?

BMS side:
https://drive.google.com/open?id=1N3ROEPQD6x-LHz0oEgrDWBmfyqjlmb7-
back side:
https://drive.google.com/open?id=1aAZ6gXSbCKwXrkofSXz1d0hMsEij9CEl

 

Edited August 29, 2018 by palachzzz

[palachzzz]

4 minutes ago, MaiKi said:

i thought the board "takes" only amps which are needed

board takes as many amperes as takes the motor, it doesn't control current somehow. 
In my opinion if you make 20s2p battery it is better to use high-current cells (30Q, HG2), if 20s3p or 20s4p - it is better to use high-capacity batteries (MJ1 or GA)

[MaiKi]

But if i make 20s3p with mj1 im at max 30amp, and the normal is 40amp right? So isnt it possible to get a cut off if the motor needs more than 30amp? 

Sorry for stupid questions but i want to upgrade my v8 too

Edited August 29, 2018 by MaiKi

[mezzanine]

Someone said that there is no cell balancing after achieving max charge, is this true?  EUC manufacturers state that we should allow our wheels to fully charge every 10 times we charge to allow the cells to balance, which is why I was surprised when someone said the V8 doesn't have this feature.  

I am no longer convinced a battery upgrade requires a spot welder, which is what I had previously been led to believe.  The prospect of doing a DIY battery upgrade for the V8 is a lot easier if one doesn't need a specialized expensive welder.

I'm not at all surprised to learn that the V10 uses the same control board as the V8.  I've been saying for a while that the V10 isn't really an upgrade on the V8 in the way I define the term "upgrade".  

[palachzzz]

1 hour ago, MaiKi said:

But if i make 20s3p with mj1 im at max 30amp, and the normal is 40amp right? So isnt it possible to get a cut off if the motor needs more than 30amp? 

V8 battery consist of two parallel of LG MH1 which max current is 10A, so normal is 20A for V8, but actually battery can provide more current for a short period of time (it is not good for battery, but still possible if needed), I saw max 30A in logs during my V8 riding experience (I collect logs all the time). So using 30A (or more) rated battery - is good choise for a safety reasons (I mean riding safety), more power battery has less internal resistanse as it was said previously, so it can provide more current with less voltage sag, so EUC will have more reserve power, and there is no bad side effects. Also if you want you can use 60A or 80A battery, no problem, but V8 motor can't use such power, so in this case it is better to choose more capacity and more mileage.

1 hour ago, mezzanine said:

Someone said that there is no cell balancing after achieving max charge, is this true?  EUC manufacturers state that we should allow our wheels to fully charge every 10 times we charge to allow the cells to balance, which is why I was surprised when someone said the V8 doesn't have this feature.  

I am no longer convinced a battery upgrade requires a spot welder, which is what I had previously been led to believe.  The prospect of doing a DIY battery upgrade for the V8 is a lot easier if one doesn't need a specialized expensive welder.

It was me, and I can repeat - yes, V8 haven't balancing feature. Spot welder just make it easier and faster, also you need to know that you need to use powerfull soldering machine (~100W) to make it possible to solder in tenths of a second, otherwise you may overheat cell, and it may lead to lose capacity and increase internal resistance of new battery

[MaiKi]

Oh ok, i thought the cells in the v8 are rated with 20amp, ok so its logical to use mj1. In Winter i have the time to work on my wheel, now i better enjoy rising the last few warm days and order everything for the upgrade in qinter thanks a lot, maybe i have few neq question when starting the project

[Chriull]

2 hours ago, MaiKi said:

But if i make 20s3p with mj1 im at max 30amp, and the normal is 40amp right? So isnt it possible to get a cut off if the motor needs more than 30amp? 

The motor current is different from.the battery current. As far as i remeber @palachzzz mentioned that already the v8 reports motor and battery current (or was it just the v10?) - don't know if whellog logs both values?

But roughly at max no load speed both currents are equal (zero) and motor current gets higher than battery current with lower speed. Almost proportional if there were not the ohmic motor coil resistance and the internal battery resistance.

Quote

Sorry for stupid questions but i want to upgrade my v8 too

Should be no real problem - the blown fuse was in an extremely high burden situation. In such a case also an overlean, some motherboard/connector/wiring problem could occur too (or some instances later). So more or less if this fuse blows one is already riding at the edge of disaster. Imo.