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Re: LiFePO4 Lithium House Batteries.

PostPosted:Fri Jun 21, 2019 3:36 pm
by NeilV
Here’s a great deal!

https://www.trademe.co.nz/motors/used-c ... 077740.htm

63% of 24KW is 15.12 KW of lithium batteries, currently going for 7,000 (and spare car parts could be sold separately too :-T )

15.12Kw is 1,260Ah (at12V) of lithium... and includes an AC 3.3Kw charger too...

Just imagine having that in your MH and pulling up to an EV charge station to fill up the whole thing to 80% in half an hour for around $5 :lol:

Or we could get 6interested parties and split it into 6x+/-200AH packs? 🤔

Re: LiFePO4 Lithium House Batteries.

PostPosted:Fri Jun 21, 2019 5:00 pm
by Nut17
I think you may have a job on your hands re configuring the battery into 12 - 13 volt banks. A reasonably complicated construction encompassing a LOT of energy.

https://qnovo.com/inside-the-battery-of-a-nissan-leaf/

Re: LiFePO4 Lithium House Batteries.

PostPosted:Fri Jun 21, 2019 5:25 pm
by Nut17
Update on my purchase of the 100 AH Hi Power LiFePO4 cells on trademe. I have spent the last couple of days charging the cells in groups of four and doing a top end balance using resistors to suppress the cells getting too high. I now have achieved a top end balance at 3.8v per cell and assembled them into two 8 cell packs comprising 200 AH each. There was minimal bulging of the cells which has been easily corrected with the compression assembly.

The final test will comprise a capacity test of each pack over the weekend. The response to charging and balancing has been identical to the 300 Ah Hi Power cells in our recently sold van. I intend to use my recently purchased Votronic Battery Monitor in conjunction with a constant 10 Amp load to measure the capacity.

Re: LiFePO4 Lithium House Batteries.

PostPosted:Fri Jun 21, 2019 6:00 pm
by NeilV
Sounds awesome!

What sort of price are you looking at for these?

Re: LiFePO4 Lithium House Batteries.

PostPosted:Fri Jun 21, 2019 6:15 pm
by Nut17
$800.00 There is only one set left - However the capacity test will determine the worth. I am quietly confident. :-T

Re: LiFePO4 Lithium House Batteries.

PostPosted:Mon Jun 24, 2019 7:36 am
by DarrenM
NeilV wrote:
Fri Jun 21, 2019 3:36 pm
Here’s a great deal!
Does look like a good deal, though they don't often end up selling much under 10.
If we find a suitable one I could be keen to go halvsies, there is also one at Turners damaged cars, last one there I stopped bidding just over 3k and it sold for 3500 (probably a good thing, would have been an unauthorised purchase and that is never a good idea)

Gotta wonder how he gets 100kms out of 8 bars though

Re: LiFePO4 Lithium House Batteries.

PostPosted:Mon Jun 24, 2019 5:19 pm
by pve
Jaycar are now selling a line of 12.8V 100Ah Lithium Deep Cycle Battery for $1050. What caught my eye was the low permissible current draw "Discharge current 50A, Max current for 5 seconds 100A"
50A is not much, my inverter pulls up to 150A from my 240Ah of AGM's when I turn the microwave on. A 120Ah AGM on the jaycar site has "max discharge current for 5 sec = 1800A"
I don't know if these litium batteries are typical or not but I would not be able to replace my AGM's with them if that is the permissible current draw.
What sort of max current do you lithium users draw from your batteries?
Cheers
Peter

https://www.jaycar.co.nz/12-8v-100ah-li ... y/p/SB2203

Re: LiFePO4 Lithium House Batteries.

PostPosted:Mon Jun 24, 2019 6:39 pm
by scubadoo
Peter
Most of these "drop in replacement" type lithium battery packs contain cells of unknown style, make and quality. The same applies to the inbuilt and never to be seen BMS circuitry, cutouts and wiring.
There are a couple of expensive exceptions.
I would ask a few questions to the supplier prior to purchase but would not really expect many straight answers to be forthcoming. They may genuinely have no idea of what is inside the black boxes they sell.
pve wrote:
Mon Jun 24, 2019 5:19 pm
What sort of max current do you lithium users draw from your batteries?
I can't answer that with accuracy but guestimates on my part.
Our Sinopoly 4 cell 300Ah LiFePO4 battery pack has started our 3.9l turbo diesel motor often multiple times daily during our 4 years of fulltime travel. Perhaps 600A for a second or two each time.
"BMS" circuitry is external.
When occasionally tested it does not flinch delivering 200A for 5 minutes powering our kettle via a 3kW inverter.
Our typical loads average 5 or 6A varying from 0.8A idling to c80A for the rare coincidental toaster operation, fridge defrost cycle and "everything" else running mode. Solar and or alternator (driving) usually handle that easily during daylight hours with the battery cruising at other times.