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Dave's Build Thread
#51
I know its been a long time since an update, but progress has been ultra slow recently. 
I still haven't repaired the spot welder, but I did buy a 100w soldering iron as a temporary solution. It works great, and plenty of heat to solder the 2.5mm2 copper to the nickel strip.

I've only finished 4x 20 cell blocks for my third row, but hey, its progress.

Here's some pics




Korishan likes this post
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#52
longmon cables remove the clean appearance lol a necessary evil tho
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#53
They sure do. I did try cable tying them up out of the way, but as soon as I started, the longmons all went dead and hours of problem solving later I discovered one longmon had totally died. I bought a spare, so was ok, but no more cable management for me.
hbpowerwall likes this post
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#54
Xmas gift from my in-laws ???
Maybe I talk about batteries too much ??

Oh. I can't upload the pic. It's a mug saying: I may look like I'm listening but my mind is on batteries
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#55
Images have to be clicked on after uploading them to the image section.
Proceed with caution. Knowledge is Power! Literally! Cool 
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#56
Quite some time later and quite a lot has happened in that time so a little update here guys:

When my spot welder died and I soldered the packs, all seemed good at first but then I had a strange anomaly. I had one string go from perfectly healthy to 0v within one day. the 1.5A cell level fuses didn't blow either. So I took that string out and examined. Every cell was totally dead. I split the packs down (60 cells) and all were non recoverable. None would take any charge at all. I was flummoxed, but discarded the packs and made 3 more of my 20 cells packs.
Then a few weeks later it happened again on another string. Exactly the same way too. No I was worried. I took all the cells apart and looked at each cell. I found two cells that showed strong continuity in both directions. I concluded that somehow those cells had shorted out. Upon closer visual inception, I could see that those cells had a lot of flux around the positive cap bridging the gap to the negative side. I thought flux wasn't conductive though. Appears that it can be. And for some reason it is time dependent?! dust settling on the flux perhaps? I don't know.
Do the killer is that when one of these soldered cells started shorting, it was somehow doing it slowly and dragging the voltages to zero but not fast enough to blow the fuses and it took out all the cells in parallel, included the nice welded ones.
So I rearranged the entire battery to put all the soldered packs in the same strings and all welded in the same strings.
The SHTF after that and over just a few weeks every single soldered pack failed. Every single one. i was mortified. All that time invested  Sad
Now back to welded only packs my wall was down to just 5kwh capacity and barely doing its job. I invested in a new control board for the welder, got that working again and carried on making packs. Took ages as you all know, but eventually I got it back to 10kWh. All welded. No failures since.

What a ballache all that was though.

Anyway, onwards and upwards.

Other than the battery, since I could not find an electrician willing to install me some transfer switches, I did it the expensive way. I had a company come fit panels on my house got all the MCS certs etc and then bought myself a grid tie inverter that can limit current so I can run it off battery. I have it on a timer and it just pushes the set power to my house at set times. I have it set to discharge at 4pm-7pm which is the peak time for my electricity bought from the grid, so it helps keep that usage low.

and, touch wood, everything has been working great since.

Next phase will be to expand to 12kWh by adding another 280 cells at a time. I want to simplify the task too as it is getting tedious now, so when BatteryHookup has stock of the nickel cell level fuse strips, i'll be ordering some of that. I'll also get into 3d printing to make my own wall brackets. It was expensive subbing that out in comparison.

Latest photo:
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#57
(05-23-2020, 11:16 AM)Daveyboy Wrote: .....I could see that those cells had a lot of flux around the positive cap bridging the gap to the negative side. I thought flux wasn't conductive though. Appears that it can be. And for some reason it is time dependent?! dust settling on the flux perhaps? I don't know.
Do the killer is that when one of these soldered cells started shorting, it was somehow doing it slowly and dragging the voltages to zero but not fast enough to blow the fuses and it took out all the cells in parallel, included the nice welded ones.
So I rearranged the entire battery to put all the soldered packs in the same strings and all welded in the same strings.
The SHTF after that and over just a few weeks every single soldered pack failed. Every single one. i was mortified. All that time invested  Sad
Sorry to hear about this - I agree its a LOT of work!    I have nearly 10,000 soldered cells, some over 2 yrs old, with no problem.   I'm picturing a typical cell with donut insulator ring and shrink-wrap holding it in place.  The solder(flux) is usually in the center....   


How did flux get in to the edges of the cells?  
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