House Battery

[Riverbug]

I very much like your positive attitude!

Discharging two times (2 cycles) to 60% state of charge (2 x 40%=80% used) produces the same energy as once to 20% SOC (80% used). When cycled like this until not useable, both will have very close to the same battery life but first takes twice as many cycles to produce the same energy as the second. Just counting cycles at different discharges produces a false impression of longer life.

Another way of wording it, if 40% of battery is used every day and in case 1 recharged daily (60% SOC) and in case 2 battery is recharged every other day (60%SOC day one and 20% SOC day two), the energy output is the same for either case and battery longevity, when used either way, is very close either way.

That makes sense. My experience is pretty anecdotal but the key for me is that once I understood the DOD had a direct effect on battery life, instead of replacing lead acid every two or so years as I did for many years, I have now for the past 25 years been getting 6+ years out of them - but 8.5 at the most so far and that pushed it. Between boats and RVs and other toys, that makes a huge difference in investment. I've now transitioned to DIY LFP in the RV and when the boat needs new batteries next, they will be DIY LFP as well. If all goes as planned it will be a long time before I have to think about replacing any of those. Thanks for the cordial debate.

 

[TimtheToolMan]

That makes sense. My experience is pretty anecdotal but the key for me is that once I understood the DOD had a direct effect on battery life, instead of replacing lead acid every two or so years as I did for many years, I have now for the past 25 years been getting 6+ years out of them - but 8.5 at the most so far and that pushed it. Between boats and RVs and other toys, that makes a huge difference in investment. I've now transitioned to DIY LFP in the RV and when the boat needs new batteries next, they will be DIY LFP as well. If all goes as planned it will be a long time before I have to think about replacing any of those. Thanks for the cordial debate.

Well, you use more batteries than I do since I have mostly just had RVs since 1994.

Your typical life for batteries is quite similar to mine. Once I started using a good temperature compensating battery monitor to know SOC and annual capacity testing (DIY, with auto time and voltage shut off) by measuring energy used from 100% to 0% SOC @C20 load 10.5A, the battery life consistency has been good. I boondock about half the time and have never owned a generator--including winter camping for a number of weeks at a time, many hours from places that sell batteries so reliable batteries are very important to me.

At this point, now that I've switched to LFP (not the DIY like you though, wow), things have changed a lot.

Thank you for the cordial debate and I enjoy hearing about your valuable experiences.