Originally Posted by billt460
Originally Posted by Char Baby
I have maintainers on two seperate vehicles/items and I use a third for when I am letting my DD sit for several days. Such as this long weekend where we had so much snow(I've been in the house for 84 hrs), we were asked to stay off the roads. I did go out to snowblow/shovel 3X just in case of emergencies. We cooked up a storm...lots to eat.
I swear by Tenders/maintainers. One battey(Firebird) is 14 yrs old. And as long as I keep the acid level up, who know how long it'll last. The other is(backup sump pump) 5 yrs old and same goes for it. I've never used a maintainer on a DD for any super length of time(only as mentioned above) so, I only get the normal 5-7 yrs out of them.
I think by having them even slightly discharge from sitting, then get recharged by the vehicles charging system, will sulfate the plates over time, and decrease the life of a battery substantially.
Agreed. Lead acid batteries self-discharge at some rate as high as 1% per day. Add a quiescent draw on an installed battery, and it can drop faster.
At 0% state of charge, in reality, there is some ability to do work, which is why people have slowly cranked their cars over, and had power door locks work at 11.x V.
It's not a terribly exact science, and tenders tend to get it about right. Some on here talk about many otc chargers not charging batteries fully. I also talk about alternators not charging batteries fully/optimally. All the case, but how much it matters is the bigger question.
The degrading side reactions are based upon Arrhenius (temperature affects the rate of reaction) and Tafel (voltage affects the rate of reaction), as well as actual use (materials effects). So yes, being below true 100% SOC induces some sulfation, but existing at all does, and existing at lower SOC does as well. How much really matters? These aren't mission critical applications. Vendors usually design the batteries with somewhat more capacity than nameplate to allow for some capacity loss and impedance growth.
In well kept *charge and climate" conditions, like data centers, batteries can last 15 years. Batteries kept well in automotive use have been known to last 10. A tender or good enough unit like that, which for safety sake can not drive too much currrent in at float, is a good thing if you trust the electronics and controls..float voltage is tempersture dependent, so temperature compensation is important, especially if in a harder climate. Some chargers have a manual setting, but I like the battery minder 2012 series due to the thermistor that can be remotely attached. I understand that the battery tender metal box units also have compensation, but it's in the box (near electronics heat sources), and not actively identified the way the LED is set up on the 2012. I have and use both brands.
