If one keeps the battery outside during summer and don't care about hydrogen gas, why doesn't everybody buy those cheaper battery at COSTCO for their solar power installation?
Easy answer,
Because gel will beat the crap out of FLA Costco on every metric, unless you only need it to work for 6 months.
Their idea of "Deep Cycle" and an actual Deep Cycle battery will not stand up to close comparison.
Costco only expects 5% of the people to return their $150 battery. The warranty is for shorts, not capacity loss.
Todays modified answer:
It would take, an absolute minimum, 2 Costco 100ah batteries ($300) to match 1 low to mid range LFE 100ah ($375-$500) over 1 year usage with a 75ah per day drain. Because after that first year there WILL be significant capacity lost. If you manage to forget the water for a week or 2,,,,, now it's less than a year. You would be lucky if you still have 75% FLA capacity after 18 months 50% after 24. Now compare 8 to 15 year expected life span for LFE, and that is to 80% functional capacity.
By the time you add an auto water and high frequency de-sulphate on each battery, you may as well buy LFE even at a 2 to 1 price difference.
Store your LFE at 30% for a few months and comfortably get 10 to 20% more out of it. Let any FLA sit for a week at 30% and you can get a $10 Autozone store card for it.
If you have an enormous FLA battery bank and manage to use 20%, recharging to full with absorb and float every single day, like a starter battery in a car, they will last quite a while like most car batteries. That outfit would still cost way more than a few off the shelf LFE.
Even the high grade gel batteries are fragile in comparison to LFE.
There are a few positive reviewed Amazon LFE in a box, no assembly required, of apparent good quality that you would only have to take into account low temps and modifications to charge profile.100ah $500, 200ah $800.
A DIY build????? 250ish amp hours think a $600ish ballpark. For a DIY If somebody is already off grid or at least supplementing the grid, they most likely have the skills to crimp a few wires.
For those who's time is "too valuable" to waste building a battery, please stop quoting sports statistics.
After 15 years of 100% off grid FLA, hell no, I will never go back. I'm 57 now with 2500ah of 12v DIY LFE, it is entirely possible they will outlive me. For the younger generations, It is not likely you will have anything remaining in your possession after 25 years that you paid $4500 for today.
It's like having twin 2 year olds that seem to never grow up. Then, all at once, in one day, they grow up, get a good job, leave the house and pay back rent.
If Lithium batteries were not significantly or vastly superior to FLA/GEL in all but 2 aspects, much of this forum would not exist.
Sorry die hard lead heads.
