SOS 74v 30Ah Lithium-Ion battery repair

#1

Hello everyone!
I bought the above battery a few weeks ago and today I had an accident. While putting on the charger a very big spark fried the contacts and made reduced my motorbike a useless junk as it wouldn’t power on anymore.

I’m using this bike to commute to work and would like to make it work as soon as possible.

After I disconnected the battery I started to dissect it an I found that one of the positive strips has been ruptured, thus completely cutting power to the bike and the charger… after I measured the other output I found that the battery is in tact and luckily survived.

I would like to make some upgrade on how the batter is constructed to make it more secure for future use.

something like in the video:

Also if you could help me with information about how I can get the parts needed… like the copper plates and block needed for this I would be grateful.

Thank a lot in advance!

Zoltan

#2

I think it would be worth talking to @electrotechs for the help you need, but also on safety grounds, as there are restrictions on high voltage projects for safety.

#3

I agree with @unknowndomain, as you’ve already found, these things are like hand grenadines if you are not careful, Huge amount of energy that’s easily released.
I would be happy to help you fix it but it will have to be closer to the end of the month as I’m not near the space for a few weeks now

Courty

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#4

I can help you to inspect the damage tommorow at the space and see if we can make it run at reduced capacity while you are waiting for the parts

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#5

yes… I agree… I welcome any help end of the months is good for me… in the meantime I’ll put back the old batteries. They should be still good for a while.

but I would like to order the parts so it can arrive in time

#6

Can I suggest the @directors make a call on this regarding fire safety too.

Apologies if this seems like over-kill but this is extremely dangerous in my view from a fire safety and electrical safety stand point.

#7

Totally agree , I was telling someone off for leaving unprotected cells around the space , that’s why I prefer if a trusted person put his hands on it…at lease while inside the space

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#8

IMG_20170805_194247.jpg2610×4640 2.74 MB

I already found the problem… That’s why I decided to remake it better in telsa style

You can see the charger and one of the output cables broke off

The other red cable is giving normal voltage

But having seen that ‘beautiful’ tear on the cable I would like to make it as safe as possible for future use!
I would let a job like this out of my hand ever!

Just as extra detail these are 26650 5000mAh cells

#9

With all seriousness, the deconstruction and making safe should happen outside unless your 100% sure it’s safely decommissioned

Courty

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#10

Hello Courty!

Yes I’m sure :slight_smile:
of course I can put on some extra protection. and cut the cables and isolate them properly
even if we do it outside we would need a proper “work station” to work on it

#11

Would be good to have some clarity about these issues – based on evidence where possible, and solid experience otherwise. Lithium batteries are prevalent, yet there’s a bunch of myths around: making it hard to know what’s actually safe. Especially when it comes to fire hazard.

Don’t wan’t to get into the ‘which is more dangerous AC or DC?’ thing, but guidance on what we consider safe voltages to work with under what circumstances would be very useful.

As always a risk assessment can be a useful tool for clarifying situations like this.

Thursday nights electronics feels like a safe environment for such work, but some guidelines would help members know what’s what.

#12

High current and discharge are just a different set of risks to high voltage.

#13

Yes, we mostly thing of voltage sources, because that’s what we mostly are used to…but we should be aware of all the likely risks.

Presumably our bench power supplies act as current sources also, are they a risk for example? And caps…

Do we need an electronics induction/orientation? I sort of hope not…but if it’s necessary…

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#14

Our bench psus don’t pose a risk batteries and big caps do .

Yes I think that a little electronics induction would be a good idea, switch mode psus , valves , big RF stuff and mains wiring poss the biggest risks in my opinion. In 2017 batteries may also make the list.

And let’s not forget the free energy nutters whos progects should be banned in my opinion.( high voltage and not understanding of the laws of physics is a horrible combo )

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#15

I managed to patch up the battery and replace all the cables needed… Also ordered parts once they will arrive I will reconstruct the whole thing. until then I hope the fix will do

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#16

I have just seen this, just out of curiosity, what motorbike do you have? :slight_smile:

#17

https://www.evoscooters.co.uk/electric-mopeds/evomotion-e-3000-rx-evo-electric-moped-scooter.html
The 3000w motor it not really true… it’s closer to 1500w.
I already replaced the battery and the controller but still does not go any faster :slight_smile:
Next step is to increase the voltage.

#18

Makes me wonder what kind of secondary transmission is there… maybe is possible to fiddle around with it

#19

It’s a hub motor… Should not be any
But I didn’t disassemble it yet but I’m open to any suggestions at this point :slight_smile:

#20

It’s probably the controller that needs a bit of attention.

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