[Nut17]

An update on the 16 x 100 AH cells I purchased about a month ago. All cells have now been subjected to individual discharge and charge cycles which have provided individual cell accurate capacity details and internal resistance. So far the capacity varies from 82AH to 90 AH. These cells are 9 years old, but have hardly been used, so are in pretty good shape for their age.
The individual data has enabled us to reassemble the packs using balanced pairs of cells. Ben (Gadget) is going to install one 8 cell (200 Ah) pack in his caravan. The other will be available ready to install with automated cell balancing circuitry attached. $800.00

[NeilV]

I’m very keen!
As it’s 8 cells (4pairs)
Can it be configured as 100AH @24v for my setup?

[Nut17]

Absolutely ! It will be a very simple task to assemble it in that fashion. Will need to add a second four cell balancer which would add $60.00 to my cost.

[NeilV]

Absolutely ! It will be a very simple task to assemble it in that fashion. Will need to add a second four cell balancer which would add $60.00 to my cost.

Thanks again.
Keen to buy these, so I have PM’d you some questions about integrating this into my setup,
cheers Neil

[Nut17]

Nut17 after a few charge/discharge cycles what % of the 150A where you seeing

I can now confidently reply to this question. Ben has a Lithium charger that has enabled
us to charge each cell individually to 3.8 volts, then discharge to 2.8 volts, then charge to 3.8 volts again. This has effectively achieved a bottom and top end balance. All eight cells have a measured capacity of 155 - 158 Ah. The batteries are now ready for installation and will be fitted with the now well proven HA02 cell balancers. I am more than happy that these cells are as good as new even at 2 1/2 years old and not having an accurate history of their use. I must have truck it lucky.

[Nut17]

A few shots of the tricky battery charger in action. In these shots it is about four hours into discharge mode on cell numbers four and eight. There is a constant 15 amp load on each of the two cells and will take a linear 10 hours or so to deplete the 150 AH capacity. Ben has it hooked up so he can keep an eye on it with his phone or computer
These two batteries had been connected in series in a 24 volt system for a couple of years prior to me getting hold of them. There has been one cell in each 4 cell unit that took a lot more charge than the other three, and yet the static voltage prior to this testing showed them almost identical. Another good indicator that voltage is not an option for establishing an accurate state of charge with LiFePO4 chemistry.

[NeilV]

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

My Lifepo4 cells are rated at 3C continuous and 5C for 60 seconds, so for me in 100A series (24v) that’s 300A continuous (20mins to flat) and 500A for 60 secs.

In 12v config as Gadget will use them that’s 200AH and 600A continuous or 1000A for 60s!

They will happily do your 150A draw (until eventually ‘flat’!)
http://www.litrade.de/pub/Hipowerdifferent.pdf

[Nut17]

The picture below shows the data recently collated from the discharge / charge cycle all the individual cells have recently been subjected to. I is good to see that the internal resistance on each cell is in a range from 1.2 to 1.7. The reasonably similar capacities of all eight cells is also quite reassuring.