Jonnytub

Another 24 cells from the same date inbound...... my kid just text and obviously i said yes

Hi all, I’ve managed to procure some panasonic 3400 mah genuine cells, 80 in total, brand new and i’m at a loss as to what to use them for. My previous battery which is now on my wifes bike was replaced with a newly built 12ah samsung 30q pack, (thanks D8veh). I would love to have a backup battery for my commute bike so willing to build another but seeing as the samsung pack is performing so strongly i think having such good cells lying in storage is a complete waste and wondered if you guys had any other ideas for using them? I actually wouldn’t mind building a new stealth type power ebike and getting a few more batteries but would need guidance with regards to battery config and motor choice, my preference being range not top speed but any other clever ideas for the use of these cells would be appreciated. I’ve so far ordered 2 anker type powerbank circuits so once they arrive i will be down 12 cells but i’ve already asked for another 80 so ideas for these awesome batteries would be welcome. 1. Yes, i have a family member who imports the 18650’s from the large manufacturers. 2. No, I can’t get you discount. 3. I get around an 80% discount, this is a fickle sum which i take advantage of when it’s good. 4. My discount is essentially my bro’s free box. 5. My bro’s free box is noyb. please don’t ask. 6. I have a limited time (literally a 1 hour period each month) to ask for these. So, as jammy as it sounds, i have this box of 80 cells and no idea what to do with it?

Just to clear a few things here up guys: This is a new build so wiring is current regs. A picture of the faceplate is meaningless given that this is a chinese box. This box is notorius for tripping breakers due to inrush current. 9 times out of ten it will switch on fine using the first socket from the cb on the kitchen circuit, otherwise a quick trip to the fuse box is required. I’ve watched every single english speaking youtube video on this welder and I can say that build quality is much better than the original ones, this particular box is 20 weeks old, soldering points are now mostly machine performed with hand soldering jobs on the_ pcb not being bad but they are chinese. It’s still a crap chinese box but it’s welds are good and I haven’t blown a fuse in it yet despite being supplied with 3. Most of the parts in this thing are recycled or repurposed from other machines, I’m sure I’d have a different opinion had I not gotten this to work but all in all, inrush current with UK typical circuits is the downfall of this particular box.

That was my thinking too so whilst I won’t outright claim ebc ltd are lying about their ah claim I will be dismantling this pack to change it out for 30q’s sometime in the next year or so now that I’ve got the spot welder running. I’ll report back here when the time comes. Speaking of which, I’ve also managed to fix two dead makita 3ah batteries as well so it’s a win for the cheapo chinese unit so far, I’m sure it will flunk out on me in the future but so far it’s done a grand job, just gotta remember to let it cool down after so many welds....

All welded up. Just waiting on the BMS which should have been here yesterday.

Obviously further up the pack it expands but I can't get to that bit without dismantling and this is where I stumble on calculating it.

Hi D8veh, Quick question if your around as I think I'm confusing myself here. The current (old) pack has the same number of cells (FST 2400mah) but is rated 15Ah, how does that work with cell configuration as I can only see 4 rows tabbed if I take a peek under the cardboard?

Sorry, the actual welding isn't what causes the trip, it's the initial inrush current to the transformer as far as I can tell.

Yes, as tested when I tried to make a cuppa with the kettle and tried to turn it on using the same circuit, it tripped, turned the kettle off and fine. Happy days. It's a greedy box so I'm going to make sure for initial switch on it's the only running device, after that, no problem.

Hi guys, Sorry for not replying sooner, took too much on lately. Anyhow, i did a little socket hopping this morning whilst all the appliances were either in standby or not being used and voila, what i believe to be the first socket in the run from the consumer powered it up no problem so project battery is back on! Thanks for the ideas and advice!

Hi guys, New here and after getting some excellent advice here recently I wanted to ask the boffins a theoretical technical question. I recently borrowed a spot welder from a mate who bought it on ebay for the same reason, making our own batteries. He could only get it to run at work as the current draw is too much for normal house circuits, he failed (or forgot) to mention this when he dropped it off. It’s a cheapo Sunko 788h which I had a little dig around being curious. I have limited experience with electronics but do have good soldering skills having worked in a factory as a youngster tinning and soldering capacitors and transistors on a production line and I had a thought. I’ve already given up on the idea of putting my own pack together and have been talking to Jimmy at Insat to arrange for him to make the battery using my own sammy 30q cells and then I got wondering whether the transformer in this machine which I presume is what’s causing the huge initial current pull and subsequent breaker trip to happen could be replaced with a car battery, i.e. keep the main circuits powered from mains but the actual weld current supplied from the battery, my battery will still be going to Jimmy but was wondering whether this is even possible, maybe even to use on future projects. I’m only asking as really butthurt over not being able to make my own pack so once that’s sorted maybe a future project. Thanks Jonny

Thanks d8veh, just bought that one you linked to and thanks for all the advice. Cheers Jonny

I vaguely remeber 30amp but would have to check for certain, the current battery is supposedly rated at 15ah but i think it uses the same number of cells (fst 2400mah)? Think I’ll pull this battery out again and recount lol

Thanks, just bought a 200 pc set for future use as well, awesome I have some sticky back 3mm foam and kapton tape as well, used to tinker with electronics years ago but never really got into batteries so this is a first. Thanks for the great advice!

Yeah going for 48v, what ah would this config run with the sammy cells? Got my nickel strip ready, just waiting for the spot welder to get dropped off. Thanks for the photo and advice it really helps. I guess the next step will be adding the bms, not sure which one I need to get? (I just chucked the cells in there temporary to keep them from rolling around).