EDIT 3/31/21: I wanted to update this review again (changing my three star rating from 3/19 to a four star rating this time) based on the past two years of use (four years total) in my off-grid PV setup. The batteries have continued to deteriorate only slightly over the past two year which fits with their performance once I altered my charging practices (see below for details). At this point I feel certain that the initial drop-off in performance was my fault because I wasn't charging them sufficiently in the first year which reduced their max capacity permanently. They're currently at around 40-50% capacity after four years of consistent off-grid use and I'll probably replace them pretty soon. When I do, despite my sub-optimal experience with customer service (see my initial review), I'll very likely get another set of these since they've held up so well after that initial year of undercharging and because it will make setting up the new battery bank easier.

EDIT 3/10/19: I wanted to update this review (and change my one star rating to a three star rating) because my experiences in the past year make me think my original review was too harsh. The negative that hasn't changed is that I think the seller's warranty is misleading and that the customer service rep was generating reasons not to honor the warranty. That being said, I do think that the company was right that the batteries weren't defective, I wasn't charging them the way they should have been charged. After the return was refused I decided to try charging the batteries much more aggressively (increasing absorption and float voltage and going for three hours of absorb per day rather than one hour) and I also split the battery bank in half and put each half on a desulfator for a month. The combo worked to increase the banks capacity back up to about 60-70% of the original capacity and I haven't seen much more deterioration in capacity since then (I'm also using an onboard desulfator now). So, it's hard for me to say how much of the original deterioration was the battery's fault vs. my own mistakes but I know I was at least part (and likely most of) the problem. If I had it to do again I probably would have gone with a more mainstream off-grid battery brand and with 6V batteries instead of 12V (apparently the plates are typically thicker on 6v batteries which makes the effects of sulfation occur more slowly) but I think proper charging would have prevented the issues I had my first year with the VMAX batteries. Hope the update is helpful, especially for people looking for batteries for off-grid applications.

ORIGINAL REVIEW:
I bought 8 of these batteries to create 24 volt 500 AH off-grid battery bank for my 1200W PV array. When I bought them I thought "Well, they're expensive but they have that 1 year warranty so there really isn't any risk involved if they don't perform well within that first year." I figured that the company must be very confident in their batteries to have the one year warranty (since a lot can happen to batteries in a year) and so I felt comfortable buying them. The first six months all was well but after that their capacity started dropping very quickly. I was using them to about 30-50% depth of discharge overnight and they got to an absorption charge probably 5 days out of the week. By eleven months they were performing at about 35-40% capacity of their original capacity. I expected some drop off but based on the manufacturer's "Depth of Discharge vs. Cycles" charge I expected that at 50% depth of discharge I'd still be about 60% capacity for 1000 cycles (so something like 3 years of use). So, I decided to send them back, thinking "well, as much as it's a pain to disassemble the battery bank and ship them at the cost of several hundred dollars, at least I won't feel so bad about the return on investment. However, when I called Bargainshore to confirm the exchange it became clear very quickly that they were looking for any excuse to refuse the exchange. For example, the rep asked about the max amps of my charge controller and when I said 60 he jumped on that as being too low. I reminded him that he couldn't possibly know if 60 amps was too low since he never asked about the voltage of my battery bank (since watts = amps x volts it makes no sense to just ask about amps). If I hadn't known about Ohms law he would have used that as the reason to refuse the exchange. So then he asked me to keep describing my setup and when I said that the bank wasn't charged to capacity every single night he immediately jumped on that as a reason to refuse the exchange and kept repeating that the batteries had performed as expected (which is crazy since their data sheet says that even at 100% depth of discharge the batteries will have 60% capacity at 300 cycles).

I expected these batteries to last for 3 or 4 years given their usage and they've lasted less than a year. The seller wouldn't honor their warranty. When I replace them I am absolutely going to go with a different company. I hope my experience is helpful to others.

Looked at a lot of different batteries before settling on this one. Installed it as an auxiliary battery in my overlanding vehicle and hooked it to a 30 amp dc/dc charger. It's super heavy but I expected it to be. At 125Ah capacity it has one of the largest capacities of similar sized units. I really liked that the manufacturer clearly stated the charging parameters on their website for this battery so I could set up my charger accordingly. Been using it for a couple of months including a couple of camping trips with my dometic powered cooler running for a few days and other items running of a 2000 watt inverter I have hooked up to it. The battery has not complained once and charges right back up. I love it. I'm sure that charging at the correct voltages for the different phases of charging (bulk, absorption, and float) will help with overall battery health and longevity. I would not recommend charging this battery with a basic battery isolator. Use something with smart circuitry and preferably something that allows you to program the charging parameters.

Very heavy batteries and with free shipping a great deal. I searched for weeks on several web sites and could not beat these batteries for the 125 amp hours and the price. They had several top notch reviews and claim an 8 year life span. Having gone thru several lead acid batteries over the years even with constant solar trickle charge and topping off the water level, I could never get more than a year out of the old style batteries. I like that they are maintenance free, can handle rough roads and bouncing around, since I plan on boon-docking on back-country forest service roads. My last battery could not make it thru the night running the heater, so not only do these have more amperage, but instead of one battery I'm running two and I've set up a 4 panel solar charging system to keep them recharged each day. Yes it was expensive, but I really didn't like waking up to not just a dead coach battery but also the main engine battery drained as well. I accidentally had the engine cutoff switch in the wrong setting and it drained the engine and the coach battery running the heater in the cool desert during spring break. Fortunately my old single panel solar panel recharged the failing coach battery enough in three hours to start the generator and then recharge and start the RV. I camp too far off the beaten path to risk having a cheap battery fail. Expensive, but worth it!!!

I wont buy another one of these until it gets back under $300. I might as well get a lifePO4 for that price.

We have been using 3 of these as the house battery bank for our 4x4 type-2 ambulance conversion. Before we installed them in our battery box, I dropped one out of the ambulance right onto its corner. It chipped off a small piece of plastic, and I wanted to make sure they were still safe to use, as I have very little experience with AGM batteries. I contacted VMax Tanks directly with some photos of my blunder, and they were extremely helpful, reassuring me that the battery was safe to use, while advising that I seal the chip to prevent long term loss of moisture and potentially decreased life. Top notch support.

Our setup:

The 3 battery bank is currently hooked up to a Renogy 40A charge controller on the *sealed acid battery* setting, which best matched the recommended charging rates. It's also connected to the old Xantrex FleetPower 2000 charger/inverter that came with the unit, which we left on its "flooded battery" setting, since it is much closer to the target charging rates than its "gel battery" setting, and never attempts to equalize the batteries without manual intervention (which should NEVER be done to AGM batteries). It is also capable of receiving charge from our dual alternators (through an isolator) which is regulated at a constant 14.3 volts. We can manually disconnect the batteries from the isolator, which is important in the very unlikely scenario that we seriously drain the house batteries (beyond what we ever should) and need to drive before the solar has had time to recharge the house batteries at all. With a low internal resistance, deeply discharged AGM's are subject to charging more rapidly than their ratings if placed on a charger that is only voltage regulated and capable of supplying more current than the bank's max charging current (our banks is charge-rated at 90A total, while our alternators are capable of delivering 220A).