Battery life

[frankz66]

hello everyone, being a beginner I made a mistake in not buying my batteries at the same time. the first bought at the end of August 2022, the other 2 in January and February 2023. in short, 5 months of difference. At the moment it's 4 kw of storage and it's holding up well. I would like to buy another battery and I was wondering if by now 6 months of difference from the first is a lot or not. the batteries are agm 1 c100 12 v 110 amps. Thank you

 

[SamDeleted]

hello everyone, being a beginner I made a mistake in not buying my batteries at the same time. the first bought at the end of August 2022, the other 2 in January and February 2023. in short, 5 months of difference. At the moment it's 4 kw of storage and it's holding up well. I would like to buy another battery and I was wondering if by now 6 months of difference from the first is a lot or not. the batteries are agm 1 c100 12 v 110 amps. Thank you

Yea it's not perfect, but it'll still work OK

From my understanding, say the oldest battery is now down to 90% health , if you wire them all together you'll only get 90% out of all of them , lowest common denominator

Make sure to fully charge all batteries before linking , stick them individually on a charger for 24hrs so they are completely full

 

[SamDeleted]

Make sure to fully charge all batteries before linking , stick them individually on a charger for 24hrs so they are completely full

Your charger will probably tell you they are full after a couple hours , but it's wrong it takes a good while on float charge to finish that last little bit

 

[frankz66]

Your charger will probably tell you they are full after a couple hours , but it's wrong it takes a good while on float charge to finish that last little bit

Thank you for answering . On the other hand, there are those who suggest buying a new one anyway, taking the first leave it in charge and after 5 months to reconnect it ... thus allowing the adjustment of the cycles ...

 

[SamDeleted]

Thank you for answering . On the other hand, there are those who suggest buying a new one anyway, taking the first leave it in charge and after 5 months to reconnect it ... thus allowing the adjustment of the cycles ...

Haha they are obviously more patient that I am!

There's not much I'm willing to wait 5 months for lol !

 

[Jordi]

Thank you for answering . On the other hand, there are those who suggest buying a new one anyway, taking the first leave it in charge and after 5 months to reconnect it ... thus allowing the adjustment of the cycles ...

I would do that because 5 months compared to the life of an AGM battery seems a significant amount of time, the old battery will cap the capacity use of the 2 other newer batteries and If you are to replace the system one day, you also aged them all similarly and can start from zero again without wasting useful capacity.

For LifePo4 I think it would matter less thanks to an expected 3.000-5.000 cycles.

 

[Bbbbrass]

another option, look for a place that sells reconditioned or used batteries! There is a store local to me (other cost I'm afraid) that sell the Armasafe Hawker AGM batteries that the military cycles out. They have them in different stages of life, and are amazing deals!

 

[SamDeleted]

another option, look for a place that sells reconditioned or used batteries! There is a store local to me (other cost I'm afraid) that sell the Armasafe Hawker AGM batteries that the military cycles out. They have them in different stages of life, and are amazing deals!

Is that UK ? Couldn't get the details could I pls ?

 

[Bbbbrass]

Is that UK ? Couldn't get the details could I pls ?

South Carolina I'm afraid. Not idea what the UK situation would be, but they are NATO standard so there is probably a supply of them somewhere!

 

[frankz66]

I would do that because 5 months compared to the life of an AGM battery seems a significant amount of time, the old battery will cap the capacity use of the 2 other newer batteries and If you are to replace the system one day, you also aged them all similarly and can start from zero again without wasting useful capacity.

For LifePoC4 I think it would matter less thanks to an expected 3.000-5.000 cycles.

Ok thank you . Considering that an AGM battery should have a life of a minimum of 4 years if treated well and considering that the first battery when it produced on its own, I discharged it to 20% (even if not recommended). I could buy a fourth and leave this one for 3 months in disuse and then reconnect it. Or ?

 

[frankz66]

I would do that because 5 months compared to the life of an AGM battery seems a significant amount of time, the old battery will cap the capacity use of the 2 other newer batteries and If you are to replace the system one day, you also aged them all similarly and can start from zero again without wasting useful capacity.

For LifePo4 I think it would matter less thanks to an expected 3.000-5.000 cycles.

Hello and thank you . If I take away the oldest one bought in August 2022, I would end up with 2 other batteries bought one at the end of January and the other after 15 days, so we can say almost the same age. Considering that an AGM depp cycle battery if maintained well should last even several years / up to 6 years), as you advise, if I take a new one the first one I would put it to rest for at least 4 months. I also ask you how the ampere absorption works. This, at the moment with the panels (4 of 180 watts in 2p2s configuration), sometimes my epever 4210AN manages to send 620 watts into the battery for an absorption of the 3 batteries of 42 amps. Should this value prove the positive state of health of my accumulation or not? If the batteries take a maximum of 42 amps, how are the amps distributed? Do I have to divide 42 amps to 14.45 volts by three? Thank you

 

[HRTKD]

If the batteries take a maximum of 42 amps, how are the amps distributed?

It depends on how you have them wired up. See the link below for a guide on how to connect two or more batteries.

Wiring Unlimited

Wiring Unlimited is a great resource that covers many many common topics and questions relevant to DIYers. It is a free E-book from Victron Written by Margreet Leeftink. Check it out! Download

diysolarforum.com

 

[Jordi]

Hello and thank you . If I take away the oldest one bought in August 2022, I would end up with 2 other batteries bought one at the end of January and the other after 15 days, so we can say almost the same age. Considering that an AGM depp cycle battery if maintained well should last even several years / up to 6 years), as you advise, if I take a new one the first one I would put it to rest for at least 4 months. I also ask you how the ampere absorption works. This, at the moment with the panels (4 of 180 watts in 2p2s configuration), sometimes my epever 4210AN manages to send 620 watts into the battery for an absorption of the 3 batteries of 42 amps. Should this value prove the positive state of health of my accumulation or not? If the batteries take a maximum of 42 amps, how are the amps distributed? Do I have to divide 42 amps to 14.45 volts by three? Thank you

I am not wise enough to provide you a reliable answer here. Please experienced users provide more feedback.
My idea would be that when a battery is in absorption phase it can absorb the same amount of current (A) regardless of age. The difference would appear on for how long that happens, thus on capacity (Ah). The battery, when fully charged, should also preserve its design specs, just that because of lower capacity, for a shorter time.

See here an example:

This battery is not just getting a lower capacity with more cycles but the amount of time it can sustain a voltage above the 3V is getting shorter, thus its capacity to provide a continuous power (eg. 300W) over time.

 

[frankz66]

I am not wise enough to provide you a reliable answer here. Please experienced users provide more feedback.
My idea would be that when a battery is in absorption phase it can absorb the same amount of current (A) regardless of age. The difference would appear on for how long that happens, thus on capacity (Ah). The battery, when fully charged, should also preserve its design specs, just that because of lower capacity, for a shorter time.

See here an example:

This battery is not just getting a lower capacity with more cycles but the amount of time it can sustain a voltage above the 3V is getting shorter, thus its capacity to provide a continuous power (eg. 300W) over time.

Thank you so much for your technical intervention. I add with your indications more information to the degree of my competence. Very kind