Idiot's guide to a self build battery

[Andy]

Has anyone on here built using the small 18650 batteries? I always wondered how that went. A fair bit more complicated than a 15 stack of LF's? Cool nonetheless.

I wonder how mobile and controllable such a pack would be in comparison to the commercial smaller form storage units? Just a passing thought...

I was looking at that yesterday when trying to find batteries. It passed through very quickly

I am having issues finding the prices you talk about. I presume you have been on Alibaba. The prices are no where near what you guys are getting. Do you have to talk to them to get decent prices? I also read that it's almost how you approach which determines the good/bad batteries you might get sent. ie are you a pushover. Do you have specific questions you ask?

[Joeboy]

Has anyone on here built using the small 18650 batteries? I always wondered how that went. A fair bit more complicated than a 15 stack of LF's? Cool nonetheless.

I wonder how mobile and controllable such a pack would be in comparison to the commercial smaller form storage units? Just a passing thought...

I was looking at that yesterday when trying to find batteries. It passed through very quickly

I am having issues finding the prices you talk about. I presume you have been on Alibaba. The prices are no where near what you guys are getting. Do you have to talk to them to get decent prices? I also read that it's almost how you approach which determines the good/bad batteries you might get sent. ie are you a pushover. Do you have specific questions you ask?

Andy, PM'd.

[openspaceman]

Has anyone on here built using the small 18650 batteries? I always wondered how that went. A fair bit more complicated than a 15 stack of LF's? Cool nonetheless.

You would have the problem of having to spot weld nickel strips to make up the battery unless you bought more expensive ones with solder tags already fitted.

I have a couple of dozen 18650 recovered from an old (2015 about half were defunct) mower 80V battery and from various abandoned USB power packs plus two very recent ones from a USB blender which I repaired with new ones, They don't add up to enough current for a car starter pack as a 4s, to replace a lead acid one that has expired. Also while a BMS is cheap enough I would still need a 16V charger.

[Joeboy]

Has anyone on here built using the small 18650 batteries? I always wondered how that went. A fair bit more complicated than a 15 stack of LF's? Cool nonetheless.

You would have the problem of having to spot weld nickel strips to make up the battery unless you bought more expensive ones with solder tags already fitted.

I have a couple of dozen 18650 recovered from an old (2015 about half were defunct) mower 80V battery and from various abandoned USB power packs plus two very recent ones from a USB blender which I repaired with new ones, They don't add up to enough current for a car starter pack as a 4s, to replace a lead acid one that has expired. Also while a BMS is cheap enough I would still need a 16V charger.

Thanks OSM, just a fantasy then for me.

[Andy]

I just got a quote from Deriy. Trying to decipher it seems that the items shipped from Poland don't included customs but those from China do.

I initially got a quote for $55 per 280K grade A. Once I said I was happy to buy 32, I asked for photos of the QR codes then it became $65 per EVE 280K grade A. I haven't asked what the difference is yet. Anyone else had this experience? Oh and I get a free gift, no idea what that is.

That's about £2037 with postage and hopefully no customs for about 28.6kWh of storage + busbars. BMS/cables etc extra. £72 per kWh

I am planning on adding two extra 15S to my 8 xPylontech initially and then maybe moving on the pylontech to pay for more storage and maybe more panels.

[AlBargey]

I just got a quote from Deriy. Trying to decipher it seems that the items shipped from Poland don't included customs but those from China do.

They can do DDP from China, but you will legally have to pay extra UK import and customs from Poland to UK

Oh and I get a free gift, no idea what that is.

Probably busbars

I initially got a quote for $55 per 280K grade A. Once I said I was happy to buy 32, I asked for photos of the QR codes then it became $65 per EVE 280K grade A. I haven't asked what the difference is yet. Anyone else had this experience?

That's because no one is selling true grade A LF280K cells for only $55, lucky you asked for QR codes, but red flag for me!

[Joeboy]

Andy,
PM'd you.

[Andy]

Here is an interesting video with seemingly a lot of problems with the new double pole style v280k.
Is the following just marketing BS to push people to their own lasered terminals? Have any of you had experience with them?

Problems raised:

The terminals don't seem to be lasered on using a jig so they don't align with each other.
The grub screw can easily pierce the casing if not paying attention.
The grub screw can work loose. If lock glue used, this can come to the top which means the flat mating surface is contaminated.
If the bolts are not torqued equally then the mating surface won't actually have even mating.
Over tightening can start pulling the grub screw out.

[AlBargey]

Here is an interesting video with seemingly a lot of problems with the new double pole style v280k.
Is the following just marketing BS to push people to their own lasered terminals? Have any of you had experience with them?

Problems raised:

The terminals don't seem to be lasered on using a jig so they don't align with each other.
The grub screw can easily pierce the casing if not paying attention.
The grub screw can work loose. If lock glue used, this can come to the top which means the flat mating surface is contaminated.
If the bolts are not torqued equally then the mating surface won't actually have even mating.
Over tightening can start pulling the grub screw out.

Why use grub screws, nuts and loctite when you can just use a bolt of the correct length.. then most of those issues are gone.

Many sellers are laser welding their own dual post terminals rather than buying the cells from EVE with them, I think also the 280K V3 without factory dual terminals had a different initial capacity, maybe SFK did a video on that if I remember correctly?

I haven't read on the other forums about poor contact complaints with the dual post, but have read many from the single post.

[Joeboy]

If there are any regional clusters of members who are looking to buy LF280K's for diy stacks I would suggest contacting Colin Deng for a combined buy quote.

His professionalism is outstanding.

More details from ourselves to follow later. Although not the price as that fluctuates and the man is due a profit.