Lithium facts in practice

[Izabarack]

Do you reckon all lifepo4 cells swell during their life,....................

............charged to 14.4v (3.6v per cell) and discharged to 11.8v (2.95V per cell) in a 12v pack.

I did not wait to find out about the swelling bit. I am using discrete cells to put together a battery. Decided against strapping and went with an Al channel frame held in place with SS threaded rod. 50 Ah batteries fit nicely under the passenger seat in the VW T5.

My supplier mostly does EV conversions. For EV purposes, he is happy with 14.4 per cell and attention to top balance. The caveat is that the EV comes off charge every morning and gets used through the day. Supplier and I agree that 14.1 to 11.8 is Ok for my house battery set up.

Having a relationship with a supplier has paid off. A supply hiccup to an order has resulted in him being able to supply 220 Ah cells at a 180 AH price. One pallet only, but I did lash out and now have yet another project pending. Going to have to find somewhere to use them, too.

Iza

[native pepper]

Maybe the aluminium cased cells are better as far as bulging, but the stray voltage and capacitance between the cell aluminium cases causes problems all of its own. Some come with a plastic cradle around them to hold them apart, this causes issues of its own due to size restrictions. I've seen them in EV's with that plastic BBQ cooking sheet between them to act as an insulator and that seems to work to get around the stray capacitance test an EV is subject to when being engineered.

T1 Terry

Have yet to notice any problems in my 3 packs, they also sit in aluminium boxes with nothing between them but air, what other problems should I look for just in case I've missed something.

[native pepper]

Do you reckon all lifepo4 cells swell during their life,....................

............charged to 14.4v (3.6v per cell) and discharged to 11.8v (2.95V per cell) in a 12v pack.

I did not wait to find out about the swelling bit. I am using discrete cells to put together a battery. Decided against strapping and went with an Al channel frame held in place with SS threaded rod. 50 Ah batteries fit nicely under the passenger seat in the VW T5.

My supplier mostly does EV conversions. For EV purposes, he is happy with 14.4 per cell and attention to top balance. The caveat is that the EV comes off charge every morning and gets used through the day. Supplier and I agree that 14.1 to 11.8 is Ok for my house battery set up.

Having a relationship with a supplier has paid off. A supply hiccup to an order has resulted in him being able to supply 220 Ah cells at a 180 AH price. One pallet only, but I did lash out and now have yet another project pending. Going to have to find somewhere to use them, too.

Iza

It will be interesting to see how people cells are after 10 years old as mine have passed that age by not using what I was taught as to high and to low parameters and they have lost nothing, they actually seem to be lasting longer which is probably a myth, and my house only uses between 8-10kw a day, close to 10 now days as have more things and just bought a 65inch samsung. In my understanding the amount of energy available above 13.8v is minimal and the same below 12v, but happy to be corrected.

[T1 Terry]

That's about right NP, the only reason to go above or below the cell voltages is to clear the memory effect. That requires a great deal of control and watching them like a hawk so they do not get damaged due to run away voltages at cell level either end.
Could you measure the voltage between the cell negative and the outer case and the cell positive and outer case of each cell?

T1 Terry

[Izabarack]

In my understanding the amount of energy available above 13.8v is minimal and the same below 12v, ......

Still doing capacity testing/checking on my first set of cells. 14.1 and 11.8 in my nominal 50 AH cells apparently yields about 2.5 AH, top to bottom. Still getting my head around this using a method the DIY Li Ion recycling guys are using.

Iza

[T1 Terry]

In my understanding the amount of energy available above 13.8v is minimal and the same below 12v, ......

Still doing capacity testing/checking on my first set of cells. 14.1 and 11.8 in my nominal 50 AH cells apparently yields about 2.5 AH, top to bottom. Still getting my head around this using a method the DIY Li Ion recycling guys are using.

Iza

The gentle charge followed by the gentle discharge? Or the cycling method between a safe upper limit and a safe lower limit? The DIY people have come up with an interesting method of recovering the NMh cells as used in the earlier Prius traction battery.
There is another mob in Adelaide who are recovering used EV proprietary battery packs for recycling as house battery packs, a combination of cycling and active balancing the pack at the top and bottom of each cycle. They are have great success with the IMiev battery packs but I haven't heard anything about the Chev Volt battery yet.
The whole house battery industry and even grid feed in might be in for a rude wake up call soon, maybe even the grid itself with people opting out of the grid and going to stand alone off grid to avoid the savage connection charges.

T1 Terry

[native pepper]

In my understanding the amount of energy available above 13.8v is minimal and the same below 12v, ......

Still doing capacity testing/checking on my first set of cells. 14.1 and 11.8 in my nominal 50 AH cells apparently yields about 2.5 AH, top to bottom. Still getting my head around this using a method the DIY Li Ion recycling guys are using.

Iza

The gentle charge followed by the gentle discharge? Or the cycling method between a safe upper limit and a safe lower limit? The DIY people have come up with an interesting method of recovering the NMh cells as used in the earlier Prius traction battery.
There is another mob in Adelaide who are recovering used EV proprietary battery packs for recycling as house battery packs, a combination of cycling and active balancing the pack at the top and bottom of each cycle. They are have great success with the IMiev battery packs but I haven't heard anything about the Chev Volt battery yet.
The whole house battery industry and even grid feed in might be in for a rude wake up call soon, maybe even the grid itself with people opting out of the grid and going to stand alone off grid to avoid the savage connection charges.

T1 Terry

Last year overheard a conversation in our post office, a bloke was complaining about the cost of connecting the grid to their new house they were going to build, it was going to cost them well over $60000 including a transformer and 3 poles. He was also told that if someone connected across the road they could hook up to his transformer and hew would bet nothing, as the hydro would own the transformer even though he paid for it. Was also told he had to maintain the 3 poles to his house, he was pretty pissed off.

As I knew the person he was talking to, said hello and commented that he should go for off grid and got a spray about how stupid that was as it would cost a fortune and he needed to run so many things and it didn't work anyway. The person he was talking to, said for him to check out my house as he would be surprised at how it worked, I told him he was welcome to come have a look. A few days later he turned up with his lady and asked if I could show him my system and when he saw it and what I was running he was shocked at the size of my lifpo4 pack and what it was running. When I told him it was 10 years old and still retained 100% capacity he wanted me to install a system for him, which I declined and gave him the Ph of an off grid lifpeo4 installer I knew. They went ahead and did it, haven't heard from him since, but have noticed what looks like a 10kw array on their roof and no poles.

Will do that test tomorrow for you Terry, pissing rain and has been for the last week except for one day to cut wood, my multies are all in the workshop which is 100m away and the ground is so muddy, plus pretty lazy and it's so warm inside.

[bagmaker]

Last year overheard a conversation in our post office, a bloke was complaining about the cost of connecting the grid to their new house they were going to build, it was going to cost them well over $60000 including a transformer and 3 poles. He was also told that if someone connected across the road they could hook up to his transformer and hew would bet nothing, as the hydro would own the transformer even though he paid for it. Was also told he had to maintain the 3 poles to his house, he was pretty pissed off.

As I knew the person he was talking to, said hello and commented that he should go for off grid and got a spray about how stupid that was as it would cost a fortune and he needed to run so many things and it didn't work anyway. The person he was talking to, said for him to check out my house as he would be surprised at how it worked, I told him he was welcome to come have a look. A few days later he turned up with his lady and asked if I could show him my system and when he saw it and what I was running he was shocked at the size of my lifpo4 pack and what it was running. When I told him it was 10 years old and still retained 100% capacity he wanted me to install a system for him, which I declined and gave him the Ph of an off grid lifpeo4 installer I knew. They went ahead and did it, haven't heard from him since, but have noticed what looks like a 10kw array on their roof and no poles.

Will do that test tomorrow for you Terry, pissing rain and has been for the last week except for one day to cut wood, my multies are all in the workshop which is 100m away and the ground is so muddy, plus pretty lazy and it's so warm inside.

not even a beer???
Society is falling down

[Izabarack]

The gentle charge followed by the gentle discharge?

Charge at 5 Amp and discharge at 3 Amp. Nominal 50 Ah cells. Factory capacity test data supplied for each cell varies between 52.345 to 52.425 AH. My aim is to get 44 Ah at nominal 12 Volts out of each battery, in use. I need multi use batteries. The conversion EV quad needs 48Volts.

Iza

[native pepper]

Last year overheard a conversation in our post office, a bloke was complaining about the cost of connecting the grid to their new house they were going to build, it was going to cost them well over $60000 including a transformer and 3 poles. He was also told that if someone connected across the road they could hook up to his transformer and hew would bet nothing, as the hydro would own the transformer even though he paid for it. Was also told he had to maintain the 3 poles to his house, he was pretty pissed off.

As I knew the person he was talking to, said hello and commented that he should go for off grid and got a spray about how stupid that was as it would cost a fortune and he needed to run so many things and it didn't work anyway. The person he was talking to, said for him to check out my house as he would be surprised at how it worked, I told him he was welcome to come have a look. A few days later he turned up with his lady and asked if I could show him my system and when he saw it and what I was running he was shocked at the size of my lifpo4 pack and what it was running. When I told him it was 10 years old and still retained 100% capacity he wanted me to install a system for him, which I declined and gave him the Ph of an off grid lifpeo4 installer I knew. They went ahead and did it, haven't heard from him since, but have noticed what looks like a 10kw array on their roof and no poles.

Will do that test tomorrow for you Terry, pissing rain and has been for the last week except for one day to cut wood, my multies are all in the workshop which is 100m away and the ground is so muddy, plus pretty lazy and it's so warm inside.

not even a beer???
Society is falling down

They moved here from Sydney and like a lot of city folk from Aus, think they know everything and we are backward and know nothing. So happy to not hear from him, city people seem to be living some where in space these days.