LF experienced battery builder in the UK

Hi all,

I have a 12s5p 30Q battery pack from eskating.eu that needs repairing. The vendor is ignoring my emails -and sending it back to Italy would probably not be very easy anyway, so I thought to see if there’s anyone here, located in the UK, willing to take the job.

I believe the cells are OK and the problem lies with the BMS or the switch. The problem started in that the button wouldn’t always turn the board off -and even when it did, the button LED would remain on for a while. I foolishly ignored the problem and eventually one day it just turned off for good mid-way. The switch’s LED would still lit but no power on the LCD screen and no power output. I’ve left it aside for the last 4-5 months, but lately I decided to put together a belt-drive, since I already have the parts sitting.

I have no experience with batteries/BMS so I am looking for someone with experience in building 18650 battery packs that can open the shrink wrap, have a look at the BMS/Switch and replace what’s necessary.

Thanks
Nik

1 Like

Where are you located? 4-5 months may be a problem… what was the charge status of the pack when you left it?

1 Like

Northeast, Teesside.

Battery was half empty, I tried to measure it just now and got… 3.3V, though I’m not sure if I can trust that. Could a faulty BMS or a blown fuse result in such ridiculously low for a 12s measurement?

You measured 3.3V for the whole pack? Is the BMS a discharge BMS?

yes, without opening the shrink (which I’m hesitant to), I can only measure the output XT90 connector -that gives 3.3V.

From what I can find from my order details, pack has an antispark switch and uses a “BESTECH BMS 80A Continous”, I’m guessing that’s a discharge BMS?

1 Like

Yeah. Get the shrink opened and measure the battery, you have to know if it’s worth pursuing the pack

1 Like

Thanks, managed to do it without blowing up anything :smiley:
It’s 48.5V so looks fine!

Now I only hope I can find a builder to rewire a new bms/switch for me. If they also build custom enclosures that’d be a bonus as I’ve messed up the old enclosure.

He has a history of doing this.

3 Likes

For anyone willing to undertake this take note that you will very likely have to completely rebuild the battery.

1 Like

I could do this but judging by what @taz has said I’m not sure I want to take it on. I am also down south and not sure on the status or even morals of shipping this battery

1 Like

something happened around 3 months ago. I used him before that without any problems but my last 2 orders were PITA. eventually got them but was frustrating as hell especially considering he charges premium for all his products.

That’s a shame but good to know. Alberto was very helpful at first, I’ve bought about €1300 worth of things from him and chances are I would buy more in the future otherwise.

Here’s a photo, if it’s any useful.

I’m clueless but I assumed the battery pack (spot welded as it is, with all wires) could remain intact and just wire a new BMS/switch in the place of the old one.

But if it’s true that the pack would need to be taken apart, then how about I cut the stripes to release the individual cells and ship them like that, which would be safer? Or removing the spot welded strip bits afterwards would be too much of a pain?

Take some pics of the spot welds mate, lets have a look at it

I already see some gnarly stuff in there

The side strips are covered by something like cardboard and tape -there was only one place I could easily lift it to expose them (not sure if that’s enough)




If you think it’s best I can take it completely apart -I think that might be necessary if you want to see more details.

The welding looks alright actually. Antispark usually fail closed so they are always on but, humour me

Put your meter across this black and red wire, measure the voltage

20190907_155902

This is where I measured the 48.5V

1 Like

Ah ok it’s the Antispark then. Desolder those two wires, one at a time and insulate them so you cant short anything then resolder a new antispark in and you should be good to go

2 Likes

Thank you very much, you are awesome! :smiley:

I am looking around at the various anti-spark switches -FlipSky 2.0 seems common. Hopefully I can wire it properly with the fuse and everything.

1 Like

No worries mate. They sometimes come like you see there with the fuse across the positive side and the negative side is switched on and off. In reality you can put the fuse anywhere, put it after the Antispark on the positive side and you will be ok

2 Likes