Custom 12S8P | project

106 cm with a wheelbase of 83,5 cm

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Took long but i just got the new Hub Motors and the new Vescs

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@Ackmaniac it 's cool seeing your laptop battery job! I was really wondering before where did you place all of these batteries but it looks like there is even space for some more… Have you tried to check how much amps these laptop cells can give?

It looks like you have got quite similar cells (the red ones) do you know what / make model are these and what is their typical capacity?

Anyways… nice seeing a laptop battery build and proving it is possible… especially with the remarkable range these cells might offer :wink:

Let me know what laptop batteries you tore open, looking to do that myself.

These are a mix of half 2600mah (good) and 2200mah (bad) cells. Mainly from lenovo thinkpad packs. I think they are rated to 1C and can stand officially 2C for a bit longer (like 30 seconds). But i drive them far beyond these ratings. In max i draw around 80 amps from the battery. This is 10 amps a cell, so 4C. But then the Voltage sags from 50V to 32V. So i get like 2500 watts in max. They get a bit more than handwarm during a 20km hard ride, so i guess like 40°C or 45°C. The range is between 60 and 70 km. If i would arrange the vescs sideways then it should be possible to go even 14S. And if i would use hub motors i would gain more space and could go for 16S. But that’s not usable for a longboard becasue it is already quite heavy. The board weights in total 12,5kg. Still ok but it should not be heavier. But who knows, maybe the VESC can handle 16S in the future.

Another benefit is that the battery is flexible this way. Now i need some ideas for a flexible enclosure for my next build with 12S4P and propper cells.

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Do u have a pic of 96 (12S 8p) fitted on a longboard? … From the picture it looks like you dont have much other space unless you start to stack them in 2 levels…

2 levels. Exactly.

Just a fyi, Lenovo batteries are jack sh1t. I own a Lenovo laptop, and complained at their customer support so hard that they upgraded my y50-70 to a y-700.

These are from broken laptop batteries. So I take what I can get. And they changed their battery type each year as it seems. Have many different ones. But the 2600 mAh ones seem to be OK.

I just finish soldering all the 18650 holders, i used 18 awg wire to solder the holders together. I hope there is not a lot of voltage drope since its just 2in long every conection.(im planing to change this in the future, also adding a BMS)Props to @Ackmaniac for the idea, check out his build :wink: well i got to go do the other board now :sleepy:

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So each sled (4 batteries) is connected by one 18awg wire. That might be a bit to thin. I recommend to add a second wire at least. Have a look in the Internet for a awg table to see how much amps each wire type can transport. I connected each sled by two 12awg. I saw in a YouTube video that they placed metal stripes behind the battery holders. I will try that for the next build. Maybe this way it will be very easy to build a proper battery pack. And if you would pre-solder wires to the stripes then it would be flexible as well.

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I’ll probably change it to 10awg after, im just goin to try it like this and if it gets hot ill change it. Im not really worried abou that.Im a bit worried about the Vesc tho they dont have the canbus connector.

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Just take male connectors for raspberry or arduino GPIO pins. Or take normal wire and solder it directly.

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just finished mounting everything,Looks Getto AF. i bought new hg2 at the end. Just for the performance. I rode it to class, I was hoping they didn’t stop me and think it was a bomb or something. I have to play with the BLDC tool, because we i was comming to class, my board just got Locked up for aseo and send me flying(sincerely I was just worried about the board been crushed by a car)

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What remote are you using?

@pyttroll

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