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Posted

Comparing a 2nd life cells LifePo4 batteries vs new cells.

If both are rated 100AH should you spend extra to buy the new cells?

 

Example:

https://lithiumbatteriessa.co.za/collections/cells

https://www.bidorbuy.co.za/item/549688242/Hubble_S_120_1_5kWh_12V_120Ah_Lithium_Ion_Battery.html  2nd Life

https://www.bidorbuy.co.za/item/550576764/Freedom_Won_LiFePO4_12V_100Ah_Auxiliary_Range_Battery.html  Think this is new.

Posted
5 hours ago, Pietpower said:

Comparing a 2nd life cells LifePo4 batteries vs new cells.

If both are rated 100AH should you spend extra to buy the new cells?

 

Example:

https://lithiumbatteriessa.co.za/collections/cells

https://www.bidorbuy.co.za/item/549688242/Hubble_S_120_1_5kWh_12V_120Ah_Lithium_Ion_Battery.html  2nd Life

https://www.bidorbuy.co.za/item/550576764/Freedom_Won_LiFePO4_12V_100Ah_Auxiliary_Range_Battery.html  Think this is new.

If you buy a 2nd hand car would you pay more or less even though both can do 120Km/h

Posted
17 hours ago, I84RiS said:

If you buy a 2nd hand car would you pay more or less even though both can do 120Km/h

This is like saying a 2nd hand car at half the price of a new one is not value if it is in great condition.

Right now people are paying more for 2nd hand double cabs than what they cost new.

I know of at least 9 S-100/S-120 that are performing at their spec. Time will tell how long they will last but they are at half the price of new ones.

I get more than 100Ah from my S-100 and that is not charging to 100% or discharging below 12.4V each.

Posted
On 2022/04/09 at 2:45 PM, Scorp007 said:

I know of at least 9 S-100/S-120 that are performing at their spec. Time will tell how long they will last but they are at half the price of new ones.

That is the question:  If both give 100Ah. Will the 2nd life fail sooner than the new battery?

Posted (edited)
1 hour ago, Pietpower said:

That is the question:  If both give 100Ah. Will the 2nd life fail sooner than the new battery?

It need not. The reason as I understand it the 2nd life are say 120Ah that have lost 20Ah and 100Ah is the current capacity. With a linear loss of capacity over time and discharge cycles I still think a 2nd life of 100Ah can loose this capacity at the same rate as a new battery. 

I use some ex laptop batteries for camping LED lights. They might only have 300mAh left but some are 12 years old. 18650 cells. Some are used everyday and built into a torch with magnetic strip and always stored on a door steel frame.

I stand to be corrected.

PS The S-120 is R1200 cheaper on the powerforum store than the bidorbuy link you posted earlier :)

Edited by Scorp007
Posted (edited)
22 hours ago, Scorp007 said:

PS The S-120 is R1200 cheaper on the powerforum store than the bidorbuy link you posted earlier :)

How do I order via the store?  I placed a "Request for Quote" yesterday but still awaiting a quote with shipping fees included.

Edited by Pietpower
Posted (edited)

Like a second hand car, you just dont know how the previous owner used it or cared for it.

2nd life batteries sound well and good and the rationale behind them sounds fine - except how hard were these batteries used?

I've got AGM's that are now 2 months away from 7 years old. My system is only used as a big UPS - keeps everything going while we have a cut to supply or a load shedding event (which thankfully seem few these days). So my AGM's dont get that much of a work out - and as soon as power is restored the Victron inverter charges them right back up so they never sit in a partial state of charge.  The treatment my AGM's get is about as good as it gets for AGM batteries in terms of getting a long life out of them.

At 7 years there cant be many years ahead for them so I wouldnt sell them second hand but if I did, these AGM's have lived a charmed life - compared to AGM's out there that get cycled daily to 30%-40% DOD and sit for a week before being charged back up.

If both sets of batteries from the description above were sat side by side to each other and offered for sale, which would you prefer to buy?

So the thing is, with 2nd life batteries how do we know how the batteries were treated/cycled ? Seems like a roll of the dice at best.

Edited by Delta9
typo's
Posted
On 2022/04/17 at 10:32 AM, Delta9 said:

Like a second hand car, you just dont know how the previous owner used it or cared for it.

2nd life batteries sound well and good and the rationale behind them sounds fine - except how hard were these batteries used?

So the thing is, with 2nd life batteries how do we know how the batteries were treated/cycled ? Seems like a roll of the dice at best.

With a car you know the age and how far it has driven but you don't know how worn out parts might be.

With a battery you don't know the age but you do know how worn out it is or how much is left in it.  Say a 120ah battery now has 100ah left.

Can something in the treatment history make a 100ah 2nd life battery degrade faster than a new 100ah battery?  Or will they have a similar life if both are treated equally?

Posted

So when I designed my solar system, I was really considering going with the revov batteries for the price. I did a bit of research regarding the second life batteries and eventually decided against it for the simple reason that you dont know how those batteries were used... Investing in solar for 10 - 15 years, it does not make sense to skimp on the most important part....

Posted

I bought second life cells (from lithium batteries SA), planning to build a 10KWh 48V battery in the next month or 2. My reasoning. In 7-10 years when I need to replace them there will hopefully be stacks available as some EVs replace their battery packs and you will be able to buy them for slightly more than the scrap value. The cells I bought will not all be perfectly matched so I might need to do some top balancing from time to time, but I love building electronics and automation and I plan to automate this. 

Posted
2 hours ago, Pietpower said:

With a battery you don't know the age but you do know how worn out it is or how much is left in it.  Say a 120ah battery now has 100ah left.

How do you know?

Posted
3 hours ago, Beat said:

How do you know?

As for the Hubble 12V in the links above I presume they take the cells and test them and then build it into a box with bms etc.

With a few tools you can test the battery capacity.

Posted
4 hours ago, Pietpower said:

As for the Hubble 12V in the links above I presume they take the cells and test them and then build it into a box with bms etc.

With a few tools you can test the battery capacity.

One would hope that is how Hubble select the cells used per battery. I can just say with mycucling -  not daily of the 2 x S100 in series they both are still in balance after 5 months of use. I see the voltmeter reading on each one about 10 times a day to act when needed.

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