tplife wrote:
pianotuna wrote:
Hi,
If you want zero maintenance then AGM chemistry needs to be seriously considered. A single 8D would possibly meet your needs.
+2 for AGMS as the way to go. They last longer, take A LOT more abuse, can be mounted inside living areas, upside down or sideways, can be discharged lower without damage, etc. The advantages are too numerous to list. :B
Battery Info
I know this can always lead to the wet vs AGM argument, but many would take issue with the data and opinions in the link provided. The decision on batteries is not as clear cut as the author would indicate IMO.
AGMs are nice batteries, no maintenance, minimal venting, high charge and discharge rates possible. They also cost twice as much, have lower capacity for their size, and contrary to the link info there is a lot of info out that would say AGMs are more prone to abuse damage than wet cells, and have similar or lower cycle life. I don't know where the link got their cycle life, but showing the Trojan wet at 1/2 the cycles at 50% isn't what I have seen in the past. And both wet and AGM recommend staying at no lower than 50% DOD for max life with a max discharge of 80%. The claim that AGMs handle the 80% discharge better has not been shown, that I have seen, and the AGM manufacturers don't want you go that low anyway.
AGM salesman will always say they last longer, are tougher, etc to justify the price. The wet cell folks always tout similar or better performance for lower cost and size. The higher rate charging and discharging of AGMs is only useful if you have a very large charger and a very large inverter to make use of the higher rate. AGMs also are less tolerant of bad chargers and overcharging (as in driving long distances with the alternator charging), especially if they are in a hot area.
I am certainly not saying to buy wet cells over AGMs, as both have their places. If you want trouble free, no maintenance, and/or they will be inside, then AGM is the way to go. Just be certain to get a good charger, have it set to the right charging profile, and monitor your use not to drain them too far, or not get them full when charging. If AGMs start to lose capacity from undercharging or too deep of discharges, they are much harder to bring back than wet cells.
If you want the most capacity for the size, and cost, and are willing and able to do the necessary monitoring and maintenance, then wet cells are probably for you.
Just don't believe all you hear from the folks selling the batteries, they are as reliable as car salesman in most cases.
