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Changing from SLA to LifePo4 batteries
dochubert:
I think in my other posts I mentioned that my 3 year old SLA batteries were starting to fail. I had two separate banks. My main bank that runs my house was (16) 200ah SLA 12v batteries set up in 4 sets of 4 in series for a 48v bank. They still had lots of umph, but because there were 4 in series (for 48v in each of 4 strings in parallel) as they were discharged they didn't discharge evenly.
So my actual usable capacity was seriously diminished.
I ended up selling them to a guy across town who is going to use them in 12v banks. He should get quite a bit of use out of them that way. I thought about doing something like that with them but decided I didn't want to mess with them.
I made a good deal on some used BYD LifePo4 24v 220ah packs from Batteryhookup.com. After some mishaps with shipping companies I then had to repair 4 of them damaged in shipping. The first pic shows the shattered pallet they arrived on.
I ended up arc welding the terminals back in place using a 12v gel battery and a carbon rod. Kind of a pain but it worked on all but one. Batteryhookup replaced the damaged packs so by repairing the damaged units I got 4 extra packs, so a net gain.
The next challenge was to get these heavy packs (125lbs per pack) into place for use. I had to beef up the shelf where the upper 2 stacks of 2 sit. Then had to build custom ramps and rig a chainfall to get them installed.
That took awhile as I have no help and have to figure out how to safely do it all solo. Got them in. Didn't kill myself or drop anything so its all good.
The second bank is 24v so 6 packs in parallel. I put them on their sides and strapped them together once in place.
These required a different custom ramp but only had to lift one at a time instead of stacks of two.
For both banks I used flattened copper thick-walled pipe for bus bars. I had picked up a coil of used air conditioner copper at a yard sale last summer. Peel off the insulation, cut to length and flatten with a vise and mallet. Beats buying copper bar stock or using/buying welding cable.
Next post I'll talk about hookup.
dochubert:
All the pics are flipped 90 degrees left.
If it ain't one thing its another!
Pete:
Hi Doc well done on getting the batteries in place. They can be pretty hard to move about. I have VRLA batteries and each cell weights about 36 kg. I put them in wooden boxes with lids, Luckily I could pick each cell up individually and put them in the box before connecting them.
Seems that the USA needs a new voting system
When George W Bush beat Al Gore it was claimed that the voting machines were rigged.
When Trump won it was claimed that the Russians influenced the election
Now when Biden wins it is claimed to be a fraud too.
Either people love making spurious claims or your system is broken.
Cheers
Pete
ClockmanFrance:
LifePo4, Nice pics,
I am very interested to see how you get on with these used LifePo4 batteries.
Please keep us informed.
solarnewbee:
Hey Doc,
Nice work! I just recently sold some batteries very similar to those. Inter-connected with aluminum buss bars. Battery hookup ended up refunding quite a few folks for lack of kWh advertised. I got more back than I paid so it was a win. You can see mine were in A server cabinet and my son and I had hell loading them up as they were 168lbs. I like your ramp, I didn’t have the room that. I found that 57v was the sweet spot(max charge) before cell voltages got wacky. David Poz on YouTube, if you’ve seen him, paralleled his and it made a big difference.
I know your going to be very happy with the change.
Best of luck!
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