i bought three of these 4+ years ago. flawlessly used hard and nonstop in my vanlife solar setup till last summer, then bought lithium and 'retired' these batts to become a friend's offgrid stationary setup with the same 200 watts of solar feeding them. they have taken a beating, been drained at least once, and still perform just fine. i don't know what the poor reviews are about, but i'm here now to get another one for a friend.This arrived and worried me at first due to its small size, but it has proven to have plenty of power to run the dankoff flowlight booster pump that supplies my household with water. (4 people). I have it hooked up through a sunsaver 15 charge controller and 45 watt bp solar panel to charge it. That is it, and I have not even thought about it since. Showers, dishwasher, laundry and all.This replaces a AGM spiral cell automotive battery (not deep cycle) that died in two years time. I gave it five stars because it seems to have a lot of power for such a small battery. We shall see how long it lasts.Small size, stupid heavy but... It ran my CPAP (Respironics series 60) for 3 nights (appox 24 hours) without the humidifier and "trickle charged" back to full in about 16 hours. Will be using it on a camping trip with solar panels to recharge but, I have yet to test it on that set up.Wish it had rubber caps to keep the contacts from accidentally getting a short across it. Handy handle on the top so, we'll see how long that lasts.i used this for my solar during the time when we have electric brown out during winter especially at night,good extension life.I've been looking for a bigger AH battery than the 35AH that xantrex used. They replaced it with 3 batteries that got 42AH in the xpower1500. Well this a direct drop in, no cutting needed replacement battery that uses up every inch of space available and you get 18AH more. They really need to market this battery to the people that are looking for a replacement for either unit.The only downside i wished i would have got a bigger AH, haha. It holds alot of juice and if you fully charge it it stays charged for a long time. this thing is also really small.This battery is for my stand-by generator, and holds a charge like nobody's business. Great replacement for the original, since a dead battery in a stand-by power supply kind of defeats the purpose.