What's the longest warranty you can get with gel batteries?

Juram Solar Expert Posts: 36
Just wondering, I've noticed a couple companies that simply charge you double and basically offer to replace the batteries after x amount of time. Are there any warrantied for more than 5 years?


  • BB.
    BB. Super Moderators, Administrators Posts: 33,479 admin
    Re: What's the longest warranty you can get with gel batteries?

    Why do you want Gel Cell batteries?

    From our hosts Battery FAQ:
    Gelled electrolyte

    Gelled batteries, or "Gel Cells" contain acid that has been "gelled" by the addition of Silica Gel, turning the acid into a solid mass that looks like gooey Jell-O. The advantage of these batteries is that it is impossible to spill acid even if they are broken. However, there are several disadvantages. One is that they must be charged at a slower rate (C/20) to prevent excess gas from damaging the cells. They cannot be fast charged on a conventional automotive charger or they may be permanently damaged. This is not usually a problem with solar electric systems, but if an auxiliary generator or inverter bulk charger is used, current must be limited to the manufacturers specifications. Most better inverters commonly used in solar electric systems can be set to limit charging current to the batteries.

    Some other disadvantages of gel cells is that they must be charged at a lower voltage (2/10th's less) than flooded or AGM batteries. If overcharged, voids can develop in the gel which will never heal, causing a loss in battery capacity. In hot climates, water loss can be enough over 2-4 years to cause premature battery death. It is for this and other reasons that we no longer sell any of the gelled cells except for replacement use. The newer AGM (absorbed glass mat) batteries have all the advantages (and then some) of gelled, with none of the disadvantages.
    AGM's should be a better bet if you don't want the extra costs or to deal with Flooded Cell Battery maintenance...

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: What's the longest warranty you can get with gel batteries?

    as far as warranties go, you won't usually find gel or agm batteries with long warranties to them. it is not that the batteries won't or can't last over 5yrs as they can, but it is difficult to determine if one properly has charged or discharged the battery over that time period. my concorde sunxtender has turned 7yrs old this year. it is true that fla types can be abused more and recover better, but they have their downsides too like sulfation, hydrogen gas discharge, and water replacement.