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V8 battery upgrade!!!


iMaster

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16 hours ago, Chriull said:

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?

Not exactly, I said that inmotion board has enough current sensors (one general, and three phase), but it reports only one current, and it seems to be battery current (it does not exceed 30A, even on V10/F )

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Does anyone know what voltage the low battery warning comes on at?

Also, what is the cut-off voltage when battery is empty and tilt back occurs?

I too am upgrading my battery and I currently don't have an Android phone to check my wheel. Any help much appreciated.:cheers:

I plan on upgrading battery to 21s3p (original is 20s2p) so that when fully charged it is at 75% charge ... only thing to take care about is when low battery cut-off occurs as individual cell voltage will be about 5% lower as the 84v will be spread across 21 cells instead of 20. I think cell balancing before assembling the pack will be a little tricky as I need to partially drain the cells so that I don't accidentally over-volt the main board with 88.2v (21 x 4.2v) as that might kill it.:crying:

Edited by Nic
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3 hours ago, Nic said:

Does anyone know what voltage the low battery warning comes on at?

Also, what is the cut-off voltage when battery is empty and tilt back occurs?

What difference between this two questions? 

At 68V occurs Low battery warning and tilt back. It will be OK for 21S.

And I'm sure that 88 volt won't burn the board, because MOSFETs are 100v, capacitors too. +5V provided via DC-DC. In worth case it will trigger to error state.

Edited by palachzzz
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39 minutes ago, palachzzz said:

What difference between this two questions? 

At 68V occurs Low battery warning and tilt back. It will be OK for 21S.

And I'm sure that 88 volt won't burn the board, because MOSFETs are 100v, capacitors too. +5V provided via DC-DC. In worth case it will trigger to error state.

@palachzzz thank you for your reply...:)

Difference is first low battery warning appears you can still ride a little before unit goes to tilt back as battery not completely drained. If you keep riding the unit will eventually tilt back and can no longer be ridden. I think that's what happens, but I've not tried this on my V8 yet and saw this behaviour on youtube videos.

Edited by Nic
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  • 3 months later...

Hello everyone,

It's great to see that you're upgrading batteries. I have some questions about this. In Turkey EUC is not so common, and there's less experience and knowledge about these parts. For example someone told me that he tried to replace 18650 batteries inside his V8, he did everything correctly, but BMS didn't respond after the prosedure. He said there may be a protection or something like that to prevent battery modifications. And the funny thing that I heard this from multiple users, not one person. But as I see here, you're doing exaclty what we want to do and succeed it. So BMS is not shutting down itself, right? Or it shuts itself but there's a trick to block it? This is a real mystery for me and I'd be glad if you enlighten :) 

 

My other question is, how did you include extra 20 battery into the BMS system. BMS is capable of managing 40 batteries, and there is a cable going to the BMS from every single connection. I've added the a photo of what I think BMS is and what I imagine BMS connections should be. So the V8 BMS circuit is built for managing 40 batteries, how do you put 20 more batteries into the system? How should the BMS-Battery connections for 60 (or even 80) batteries? I read 3 pages but couldn't see this detail.

WhatsApp Image 2018-12-21 at 12.54.06.jpeg

Edited by Tayfun Murat Ipek
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27 minutes ago, Tayfun Murat Ipek said:

My other question is, how did you include extra 20 battery into the BMS system. BMS is capable of managing 40 batteries, and there is a cable going to the BMS from every single connection.

These 40 batteries are configured as 20s2p. The BMS manages 20 2-cell pairs with 21 connections...

27 minutes ago, Tayfun Murat Ipek said:

... So the V8 BMS circuit is built for managing 40 batteries, how do you put 20 more batteries into the system?

Just make them a 20s3p configuration. So the BMS then manages 20 3-cell triples...

27 minutes ago, Tayfun Murat Ipek said:

How should the BMS-Battery connections for 60 (or even 80) batteries? I read 3 pages but couldn't see this detail.

You should ask yourself if you really want to and should mess with the battery pack! Beside the imminent dangers of short curcuits/false configurations causing extreme currents (fire/explosion) any "imperfection" can lead to nasty faceplants some time just out of nowhere...

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4 hours ago, Chriull said:

The BMS manages 20 2-cell pairs with 21 connections...

I was thinking that BMS managing every single cell individually, if It's managing with 2-cell pairs, then I understand the logic, it can manage 60 batteries with 3-cell triples. Thank you so much ;) 

 

What about "when the energy cuts off (when batteries are removed) BMS is shutting down and never work again" myth? Anybody experienced something like this?

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5 minutes ago, Tayfun Murat Ipek said:

I was thinking that BMS managing every single cell individually, if It's managing with 2-cell pairs, then I understand the logic, it can manage 60 batteries with 3-cell triples. Thank you so much ;) 

Could be that every cell is managed seperately - then the battery pack has to be configured as 2 times 20s1p.

As soon as two cells are in parallel they cannot be managed one by one anymore....

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  • 1 month later...
On 12/21/2018 at 10:35 PM, Tayfun Murat Ipek said:

What about "when the energy cuts off (when batteries are removed) BMS is shutting down and never work again" myth? Anybody experienced something like this?

This is a myth. Once all the cells are reconnected to the BMS and are above critical voltage (2.5V), the output will be switched on. To be safe, reconnect the cells in sequence (B1, B2, ..., B20) so that you don't prematurely reactivate the BMS and put it into a weird state. Keep in mind that batteries cannot be switched off so you will be working with live voltages. 84V starts to get a little dangerous so try not to complete the circuit with your body.

Some USB power banks I've worked with have had their BMSes go into "sleep" mode when the cells are disconnected, and they don't immediately come back online when the fresh cells are connected. Plugging them into the charger will reactivate them though, so if your BMS doesn't seem to want to come back online, try charging it through the standard charge connector (small black JST SM connector).

 

On 8/30/2018 at 4:09 AM, palachzzz said:

It was me, and I can repeat - yes, V8 haven't balancing feature.

I have observed the V8 battery charging through the stock connector, and can confirm that the BMS does balance, but only near the full voltage, and very slowly. Same as the 16S generic BMS I've worked with in the past.

Basically, when a cell hits about ~4.15V (or whatever the full voltage on that BMS is), it starts to draw current from that cell, venting out the energy as heat in the BMS PCB. You can feel this if you touch the BMS while it is in balancing mode, and it can hit around 40-50°C. The cells remain cool though. The heat dissipation of the PCB is fantastic -- if you disconnect the charger, it returns to room temperature in about 5 minutes. This suggests that the dissipated energy while balancing is of quite significant wattage as well in order to sustain that temperature.

I did notice that if the cells were significantly out of balance (B18 was at 4.18V while the others were at 3.7-3.9V) , the BMS appears to continue grinding (feels warm to the touch), but also throttles the charging current (charger LED turns green, while battery indicator continues blinking), presumably to control the heat generation on the BMS so that it does not overheat and kill itself.

 

Here are some photos I took while repairing my V8 pack. I left some details in the photo descriptions where relevant. It's not an upgrade, but the photos may help those who are planning an upgrade or repair of a V8 battery pack. https://www.facebook.com/media/set/?set=a.10161197629015104&type=1&l=230ec7d981

Edited by hyperair
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  • 2 months later...

Pardon my ignorance.

Is it possible to just open the battery pack and swap the cells for newer ones? I saw LG HG2 for $4 each. If the pack contains 40 cells, for $160 you could “upgrade” or “renew” the V8. 

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On 4/25/2019 at 2:15 PM, Uniafi said:

Pardon my ignorance.

Is it possible to just open the battery pack and swap the cells for newer ones? I saw LG HG2 for $4 each. If the pack contains 40 cells, for $160 you could “upgrade” or “renew” the V8. 

Yes, that should be possible. But the stock battery pack uses LG MH1 cells which are 3200mAh, while LG HG2s are 3000mAh, so it's not necessarily an upgrade. Maybe the LG MJ1, which are 3500mAh, instead.

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^^

I thought the V8 used cheap cells. Now I see why OP showed a mod with 60 cells instead of the original 40.

For what I see, a 60 pack it’s too tight (difficult to make a stock pack) and if the company charges $385 for the original (40 cells), they would charge around $500 for an upgraded with 60 cells. 

You can buy 60 LG MH1 online for $4. X60 = $240.

I imagine people would prefer a 60 mod battery pack if the price were the same or even a little lower than the stock $385 here in US. 

 

Maybe there’s a market for that?

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  • 3 months later...
13 hours ago, Nils Reichert said:

Hi, would it be possible to mod battery to multiple packs of max 100Wh each and therefore be allowed to transport all batteries on an airplane?

I'm pretty sure the total amount is not allowed to exceed 100Wh which is a mere 1/5 of the total capacity of an already small v8 battery.

Furhermore, the battery needs to be in your carry-on and originally stamped with it's capacity. DIY batteries will not make it is my guess.

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The V8 is 84V, which comes out to 20*3200mAh*3.7V = 236Wh for the smallest battery pack size (assuming using the same 3200mAh battery cells as used in the V8 battery). You can't subdivide it further, a pack must always be at least 20 cells (the V8 has 2 of them for 480Wh).

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When I search for rules about batteries on airplanes I find this info: https://www.faa.gov/hazmat/packsafe/more_info/?hazmat=7

Yeah the v8 battery consists of 2x 20 Cells.

the question would be if it is possible to split it to packs of 5 cells, so around 50 Wh each pack, since this *should* allow to take them with you in hand luggage. Isn‘t it possible to replace a connecting wire/metal with a cable+plug and so still split it?

If I am wrong, can you please post a screenshot/link to that rule about max 2 batteries with less than 100Wh? I cannot find that info

5DB1E34C-7CD3-4B4A-9C4A-467D8D829303.png

Edited by Nils Reichert
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The problem is that should you have an argument at the security check (regardless of who's right) you risk having to leave your batteries behind or miss your flight.

Expect different countries to have different guidelines. It would be a gamble each time you pass through the security check.

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12 hours ago, meepmeepmayer said:

First result when googling "iata lithium battery rules":

https://www.iata.org/whatwedo/cargo/dgr/Documents/passenger-lithium-battery.pdf

Max 2 packs <160Wh each in carry-on luggage only.

Document says max 2 batteries 100-160, and max 20 batteries <= 100.

thanks for the link, so there is an actual limit for such batteries. But with 20x 90.. 1800Wh would be much more than needed for a long driving EUC.

yeah, I am a bit worried about discussions at the airport, but until now they knew very well about their own rules and just called Lufthansa and for them it would be okay with 10x 90Wh batteries (could get an approval).

DE88CF96-5402-4BCA-8296-6168863104F5.png

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  • 2 months later...

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