Originally Posted by herk7769
Check out the battery FAQ Sticky in the FAQ section.
I believe there was some issue with GEL batteries in a deep discharge scenario. I will have to re-read it to refresh my memory.
you mean this -
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.
I read the instructions to the converter / charger and it says it will charge gel batteries without an issue besides I get my GEL batteries for free since my brother works for a place that installs and frequently replaces Large Building UPS's that use these batteries