TheChamp

Honorary Master
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Feb 26, 2011
Messages
34,959
so when people say they have bought an inverter, are they generally not aware that they have bought an inverter plus battery?

or you can have inverter without a battery? i ask as some friends seem never to mention battery.

or is it likely that they are talking about inverters that are not off-grid?

all probably stupid questions
It's most likely they are using the term in a generic way, inverter meaning a backup system, like someone would say they are installing solar, we usually get the idea even when they don't mention explicitly that they are installing solar panels, an inverter and a battery.
 

TheChamp

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Joined
Feb 26, 2011
Messages
34,959
100Ah is 12V x 100Ah = 1200Wh, but you can only use half so 600Wh then there's conversion inefficiencies so times 0.8 = 480Wh. Assuming you're using 250W, it will last 1.92 hours. So you will need another 100Ah battery.
Or that TV must go.
 

jezzad

Senior Member
Joined
Jan 2, 2013
Messages
815
@jezzad , you didn't respond to my question, and I am curious (if I may) to know your reasons for considering a 2nd life battery over a cheaper new one? Or did you perhaps miss it in all of the updates?
Hey, sorry missed it with all the comments. Where did you see 2nd life? Happy to send you the full breakdown if your want.
 

RonSwanson

Executive Member
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May 21, 2018
Messages
5,149
Hey, sorry missed it with all the comments. Where did you see 2nd life? Happy to send you the full breakdown if your want.
The listing contained a "10.2 KW Revarve" (sic) battery, which, in all probability, is a Revov battery. According to the Revov site, they supply both "LiFe" (new) and "2ndLiFe" (repurposed) batteries. The only 10.2kW battery that they supply is a 2nd life battery, so the assumption is fair that this is a second life battery. "Second life" means that the battery has reached less than 70% of its original capacity, and thus fulfilled its useful life in its primary application (such as in automotive use), and still has some capacity left, so it is sold to manufacturers who recycle and repurpose it for the price-sensitive domestic market and in that way it is literally given a "second life".

This is not to say that 2nd-life batteries are bad in any way, it ostensibly appears to be a good thing, instead of (costly) disposal or "metallurgical recovery", it can be turned into a useful product through "upcycling", and providing a useful product at a far lower cost to the consumer. The problems with this is that:
1. You never know where the original battery came from. Was it perhaps a Leoch stolen from an MTN tower or did it serve its "first life" in a Tesla Roadster?
2. The batteries are still subject to "metallurgical recovery", but the onus now falls on the new owner . In environmentalist terms, this is simply "kicking the can further down the road", and the new owner may or may not be in a good position to oversee its correct disposal.
3. A 2nd life battery would naturally have less useful capacity (and thus performance) than a new one.
4. In a situation where the battery is not clearly labelled as a second life battery, or where there is poor consumer education as to what a 2nd life battery actually is, then it could be seen as duping an uninformed consumer into comparing and buying a product that is not what it appears to be.

I am personally neutral regarding 2nd life batteries. I think that they could be good, providing that:
  • The consumer is aware of the difference between the two, and does not make direct price and performance comparisons with new ones.
  • There is a substantial financial advantage to the consumer, which does not seem to be the case with your quote.

 

itareanlnotani

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Joined
Sep 14, 2008
Messages
3,767
The listing contained a "10.2 KW Revarve" (sic) battery, which, in all probability, is a Revov battery. According to the Revov site, they supply both "LiFe" (new) and "2ndLiFe" (repurposed) batteries. The only 10.2kW battery that they supply is a 2nd life battery, so the assumption is fair that this is a second life battery. "Second life" means that the battery has reached less than 70% of its original capacity, and thus fulfilled its useful life in its primary application (such as in automotive use), and still has some capacity left, so it is sold to manufacturers who recycle and repurpose it for the price-sensitive domestic market and in that way it is literally given a "second life".

This is not to say that 2nd-life batteries are bad in any way, it ostensibly appears to be a good thing, instead of (costly) disposal or "metallurgical recovery", it can be turned into a useful product through "upcycling", and providing a useful product at a far lower cost to the consumer. The problems with this is that:
1. You never know where the original battery came from. Was it perhaps a Leoch stolen from an MTN tower or did it serve its "first life" in a Tesla Roadster?
2. The batteries are still subject to "metallurgical recovery", but the onus now falls on the new owner . In environmentalist terms, this is simply "kicking the can further down the road", and the new owner may or may not be in a good position to oversee its correct disposal.
3. A 2nd life battery would naturally have less useful capacity (and thus performance) than a new one.
4. In a situation where the battery is not clearly labelled as a second life battery, or where there is poor consumer education as to what a 2nd life battery actually is, then it could be seen as duping an uninformed consumer into comparing and buying a product that is not what it appears to be.

I am personally neutral regarding 2nd life batteries. I think that they could be good, providing that:
  • The consumer is aware of the difference between the two, and does not make direct price and performance comparisons with new ones.
  • There is a substantial financial advantage to the consumer, which does not seem to be the case with your quote.

Their battery sourcing is from China, so ex Bus batteries mainly given thats the usual source for those.

I actually own one, haven't taken a look inside, but I have had 1 battery in the pack fail which they replaced under warranty without any issues (in December 2020).
 

crysis

Expert Member
Joined
Dec 22, 2006
Messages
3,224
The listing contained a "10.2 KW Revarve" (sic) battery, which, in all probability, is a Revov battery. According to the Revov site, they supply both "LiFe" (new) and "2ndLiFe" (repurposed) batteries. The only 10.2kW battery that they supply is a 2nd life battery, so the assumption is fair that this is a second life battery. "Second life" means that the battery has reached less than 70% of its original capacity, and thus fulfilled its useful life in its primary application (such as in automotive use), and still has some capacity left, so it is sold to manufacturers who recycle and repurpose it for the price-sensitive domestic market and in that way it is literally given a "second life".

This is not to say that 2nd-life batteries are bad in any way, it ostensibly appears to be a good thing, instead of (costly) disposal or "metallurgical recovery", it can be turned into a useful product through "upcycling", and providing a useful product at a far lower cost to the consumer. The problems with this is that:
1. You never know where the original battery came from. Was it perhaps a Leoch stolen from an MTN tower or did it serve its "first life" in a Tesla Roadster?
2. The batteries are still subject to "metallurgical recovery", but the onus now falls on the new owner . In environmentalist terms, this is simply "kicking the can further down the road", and the new owner may or may not be in a good position to oversee its correct disposal.
3. A 2nd life battery would naturally have less useful capacity (and thus performance) than a new one.
4. In a situation where the battery is not clearly labelled as a second life battery, or where there is poor consumer education as to what a 2nd life battery actually is, then it could be seen as duping an uninformed consumer into comparing and buying a product that is not what it appears to be.

I am personally neutral regarding 2nd life batteries. I think that they could be good, providing that:
  • The consumer is aware of the difference between the two, and does not make direct price and performance comparisons with new ones.
  • There is a substantial financial advantage to the consumer, which does not seem to be the case with your quote.

So whats the real negative of using a second life battery (in terms of life expecancy, or is the bigger difference power density)? Do the manufacturers repair them in any way, or is it just straight out of a car and into a domestic application?
 

RonSwanson

Executive Member
Joined
May 21, 2018
Messages
5,149
So whats the real negative of using a second life battery (in terms of life expecancy, or is the bigger difference power density)? Do the manufacturers repair them in any way, or is it just straight out of a car and into a domestic application?
The obvious negative in terms of life expectancy (for lithium-type batteries) would be that it has served in some application previously and no longer deemed fit for that application any more. It is at (approximately) 70% or less of its capacity, and will therefore have a reduced life expectancy.

I am not sure what you mean by "power density", are you referring to gravimetric energy density, volumetric energy density or something else?

It would be best to consult the specific manufacturer on their upcycling process, I am not familiar with it at all, other than the techniques that are described here.
 

wingnut771

Honorary Master
Joined
Feb 15, 2011
Messages
11,806
So whats the real negative of using a second life battery (in terms of life expecancy, or is the bigger difference power density)? Do the manufacturers repair them in any way, or is it just straight out of a car and into a domestic application?
I think what they do is take a used 150Ah cell and market it as a 120Ah cell for example. I don't see any negative in using 2nd life cells. AFAIK, the life of a LFP cell curve flattens out after 80% so could have a good many years left in them.
 

Speedster

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Joined
May 2, 2006
Messages
12,374
I think what they do is take a used 150Ah cell and market it as a 120Ah cell for example. I don't see any negative in using 2nd life cells. AFAIK, the life of a LFP cell curve flattens out after 80% so could have a good many years left in them.
This. Pretty much the biggest drawback is that it is bigger. Also, you don't know how or for what it was used previously but with lithium this isn't a big issue.
 
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wingnut771

Honorary Master
Joined
Feb 15, 2011
Messages
11,806
So my DIY kit (8 cells, 4s2p) arrived, nice and quick (it was only ordered on Monday). I just want to check the inverter (Axpert KS 1kVa) settings I intend to change based on what I have picked up while watching 50+ hours of the YouTubes. Inverter manual

Setting NumberCurrent ValueNew ValueDescription
025040Maximum charging current
05AGMUSEBattery type
2614.114.2Bulk charging voltage (C.V voltage)
2713.513.5Floating charging voltage
2910.513.0Low DC cut-off voltage
32Aut40Bulk charging time (C.V stage)
33EdSEdSBattery equalization

I have menu item 29 as 13.0v because of it being 20% with LiFePO4 chemistry. I'd prefer not to go below 20%.


I also just want to get input on the building of the battery. I've ordered a multimeter which I'm waiting on, but from my understanding the BMS should handle the cell balancing, so should I go ahead and build it without checking each cell, or rather wait for the multimeter to arrive?
How goes it? Any updates for us?
 

jezzad

Senior Member
Joined
Jan 2, 2013
Messages
815
Thanks for all the adivce and comment ut really has been great.

If I decided to buy the components over a couple of months (inverter, panels, batteries) my assumption is that I can find an installer and he will do the install. Is that fair or are there guys who will refuse and will only supply a full solution.

On a second point, any recommended installers in Cape Town? I have a slate roof and I believe they are a mission to install on (no spare tiles)
 

Slinetpixel

Well-Known Member
Joined
May 10, 2016
Messages
122
How goes it? Any updates for us?
Multimeter arrived so I could check and all cells arrived charged to about 3.26-3.27.

Did some DIYing last night to get everything including the inverter stuffed into a crate. Got 2 PC fans moving 37-39CFM through the crate so there is more than enough airflow. The fans are connected with positive on the battery and negative between the BMS and inverter. I might just add an inline switch to the fans so I can switch them off when necessary.

Other than the DIY of chopping up the crate, building the battery and connecting everything up only took 20 minutes.

My main concern is that when I went to bed last night the battery was charging, but this morning it seems the inverter is sitting on float charge without having bulk charged to 14.1v as per the settings. I have a feeling I may need to do a load test to DC cutoff and then let the inverter try charge again.

After re-checking the manual, the bulk charge timer option is only for the larger inverters. Based on running the battery flat (down to 12v) and then recharging, if it doesn't recharge to 14.1v then I'll need to look at another in line charger.

Edit: For now I've just set the floating charge to 14.1 to get it there, once it hits 14.1 I'll drop it down to 13.5 again
 
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