LiFePO4 bank upgrade - 280Ah from SunFunKits SFK-275SE
a reframing
I’ve been below budget enough on this reduced circuit to have enough to (mostly) pay for an LFP bank upgrade. I spent about a week wrestling with the idea, mainly because I thought I’d be squandering the remaining cycles on the 100Ah I already have.
“Oh”, I thought at 3am when I couldn’t sleep, “I can parallel in the existing 100Ah instead of replacing it”. In practice this might be problematic, as the projected draw for 380Ah of LFP (~76A) is right at the limits of my VSR and fusing (80A). In the data there is a tendency for larger banks to accept lower C-rates from the alternator. More current, but less in proportion to their capacity.
If the current is too high I can either remove the 100Ah or upgrade the alternator charging setup. I suspect the 280Ah will be perfect and I will do something with the 100AH.
the competition
In the kit market the main competitor is probably 18650 Battery Store. The site is not as organized and does not have “configurator”-style ordering.
If we compare pre-builts the closest analog might be the SOK 280Ah. Both are well-regarded and are maintainable. I went with SFK because of the active balancing option, JBD-ish BMS, and known cells. The owners/spokesmen for both companies are somewhat prickly.
the process, with much room for improvement
July 7th - ordering and “capture”
It was a late night. I placed my order around 2am. At 5am I got an email that said
We have captured your Order #INV-[redacted]-US
That sounds alarming (especially when one is groggy at 5am). It seems to be a term of art in credit card transactions meaning we have the money, not just an authorization.
July 12th - followup with a ticket
The listing said:
Shipping Availability: 2 to 3 Days
Stock Status: In Stock
On the 5th business day after “capture” I made a ticket:
Will SFK be able to ship this order? If not, would it ship if I ordered the kit equivalent1 instead? I checked the blog/twitter/YT to see if y’all were affected by Beryl but no updates there.
The ticket was not (and has not been as of this writing on the 13th) answered, but coincidentally (?) I received a flurry of automated emails about the order.
progress
The order was now marked SHIPPED. The notes said:
Sending customer free battery disconnect2 because of the delay. Testing on battery completed July 11th 2024 shipping out today.
Delivery date 7/19/2024
Narrator voice: “Sadly, it did not ship”.3
Later that night and the next day I checked the tracking number:
UPS doesn’t have possession of the package yet
July 13th - follow-up
At 1430 I got an email update from SFK that said current status “Drop-Off”. UPS appears to have the package since it now says “on the way” and “The delivery date will be provided as soon as possible. “.
July 14th
The delivery date will be provided as soon as possible.
I suspect this means it was physically taken to a UPS store or similar and was scanned in.
July 15th
The delivery date will be provided as soon as possible.
CS ticket still not updated. I am not brimming with optimism.
later that day
We Have Your Package … Estimated delivery Thursday, July 18
I needed a win…
July 16th
6:50 A.M. Departed from Facility Jackson, MS, United States
Jackson -> Dallas -> Amarillo -> Santa Fe -> Los Alamos ?
ETA unchanged (Thursday)
Update: now in OKC. Woot!
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I didn’t particular want the kit version or I would have ordered that in the first place. I don’t have a large space to lay it all out, and dust is everpresent in my semi-arid location. ↩
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I don’t need or want a disconnect. Putting that amount toward a shipping upgrade would have been welcomed. ↩
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I use ship to mean left the premises. SFK seems to mean “printed a UPS label”. ↩