Lithium battery degradation for geeks

[booster]

It is probably safe to say none of us, and probably not many, if any, scientists actually know for sure why lithium batteries wear out and how to slow that process down the best ways. Most information is just from life testing under various conditions to see what happens and doesn't apply to real world use or the mechanisms that happen in the battery because of use patterns. It would be nice to be able to concentrate on the things that make the most difference when installing a lithium system in our vans as the costs and complexity go up quickly as you try to address them all.

Whenever I have some extra time, like early morning before the other half of the house is awake, I run various searches to see what the current literature is saying, particular actual studies and testing from academic level sources.

I ran across this one this morning. Note it is not for Lifepo4 particularly but from past stuff I have seen the reactions and very similar in most ways to the lithium ion batteries they were referring to. It is an observational study so exact chemistries would have to be gotten from the referenced studies used, but they refer to cars, laptops, phones so common types.

It is very long and detailed, very scientific in verbage and complexity so reading the whole thing in detail (I didn't get near doing it) would be a big challenge. I think the whole thing boils down to a cause and effect chart they made that shows what parameters cause what kind of damage to lithium batteries.

It came from this study Lithium study link

I find it pretty interesting and not particularly what I expected, assuming it also applies to Lifepo4 batteries. I do wish they had more detail on the actual amounts of charge/discharge rates, temps, and voltages, etc. Those may be able to be found in the referenced studies, but I haven't done that.

 

[@Michael]

It is probably safe to say none of us, and probably not many, if any, scientists actually know for sure why lithium batteries wear out and how to slow that process down the best ways. Most information is just from life testing under various conditions to see what happens and doesn't apply to real world use or the mechanisms that happen in the battery because of use patterns. It would be nice to be able to concentrate on the things that make the most difference when installing a lithium system in our vans as the costs and complexity go up quickly as you try to address them all.

I'm coming around to where minor differences in degradation rates on camper batteries doesn't bother me . They last long enough and are cheap enough that a few years her and there doesn't bother me.

On my EV battery though, at 10-15x the cost to replace, I care a bit more. But it's also harder to fine tune the charge profile - there aren't very many knobs to turn on an EV's battery. The best I can do is keep it between 30-80% with an occasional topping off to 100%.

--Mike

 

[booster]

I'm coming around to where minor differences in degradation rates on camper batteries doesn't bother me . They last long enough and are cheap enough that a few years her and there doesn't bother me.

On my EV battery though, at 10-15x the cost to replace, I care a bit more. But it's also harder to fine tune the charge profile - there aren't very many knobs to turn on an EV's battery. The best I can do is keep it between 30-80% with an occasional topping off to 100%.

--Mike

I think this is likely true to a large degree, especially on the smaller systems. Larger systems may get there soon if prices keep dropping. Probably the highest costs will be on the integrated systems that require, at least on paper, replacement with batteries from the system manufacturer like Victron or Lithionics, and of course the older overpriced Roadtrek stuff. It will be interesting, if we get accurate information, as to what the average life of systems comes out to be. My guess is that the 6-8 year thing is probably pretty good, but we don't know how quick poorly designed systems will lose off of that, or how much being very careful helps the other way. The cellphone companies seem to be on a longer life preservation kick lately. Our Samsung S24s even have a "battery saver" setting that only charges to 80% and allegedly does some other thinks. The also recommend using low rate chargers unless speed is needed.

 

[hbn7hj]

My first two battleborns lasted 7 years. I know they warranty them for 10 years but good luck getting it. I happened to be in Reno, went to their front door, nothing wrong with my install. They sent me two new ones.

 

[booster]

My first two battleborns lasted 7 years. I know they warranty them for 10 years but good luck getting it. I happened to be in Reno, went to their front door, nothing wrong with my install. They sent me two new ones.

Thanks, I hope we hear from more users as the systems age. You are right in the same range as the few others we have heard of (except for Roadtrek systems that seem to go early for many users) and that the article postulated might be the normal, aging related, lifespan for lithium.

 

[Luv2Go-ClassB]

We installed our battery system in the Roadtrek 210 in December 2016. Back then "grade B" batteries were affordable so that's what we used. Calculated initial capacity based on seller battery capacity was 344 A/H (12V nominal system). "Bulk" charge voltage setting is 14.0V, "Float" setting is 13.5V, low battery alarm is 12V.

Capacity in 2017 was 338 A/H to the low battery alarm. In December 2024 we inadvertently did a full discharge at a low current rate and they started alarming low battery at 280A/H. So we lost about 17% in 8 years.

For the first 6 years they were stored at 100% charge level at "Float" voltage from the Victron inverter/charger. For the past two years they have been stored with no constant power available, relying on solar charging and occasional grid charging.