VMAXTANKS SLR125 Solar Battery 12 Volt 125Ah Group 31 Battery for Solar Wind Sump Pump Emergency Backup Generators and PV panels

This is a long-term review. I use these batteries along with a 1500W pure sine wave inverter as a back up for the occasional power failures that happen here in the Northeast US. I purchased one in November 2012, yes, 2012, and another in 2019. They normally run in parallel and provide 12 V @ 250AH nominal to the inverter. However, about once a year I separate them and load test them separately due to the large difference in their age. At a 20 hour rate, they both met or were close to spec when new, 120-128ah each. Because the power failures here are very intermittent this is largely a float application. They only get cycled about 10-15 times per year so I can’t speak to cycle life. But the float life has been great. in my most recent test in May 2022, the older battery comes in at around 101 amp hours and the newer one at 122AH. Getting 80% of new capacity out of a 10 year battery is more than I expected. I have other UPS units in the house that use 9AH AGM batteries, and I have to replace those every three or four years.While the newer LiFePO4 batteries have many advantages over lead acid, they are still significantly more expensive than AGM. and lead acid batteries can be easily recycled whereas lithium can’t. While I would not recommend cycling lead acid to 100% DOD if you’re cycling them frequently, I have cycled mine to 100% DOD at least 150 cycles over 10 years and they’re holding up fine. I think lead acid can still be competitive in a float application like mine. Lithium is more cost effective for frequently cycled applications.Vmaxtanks batteries are more expensive than some of the other AGM brands, but I believe the long-term performance demonstrates that they are worth the money. If you’ve decided to go lead acid rather than lithium, in my opinion this is a great choice.

I bought this as an alternative to a marine battery. It fits in a standard series 31 marine battery box. I installed it and hooked it up to an AGM charger and too it out the next day for an overnight meteor watching trip. I ran the anchor, cabin, and nav lights for several hours. We also ran the GPS overnight with an anchor alarm on. After a 12 hour trip it started the 15 HP motor vigorously and provided power all the way back to the dock. When it was hooked back on the charger I found it still had %20 capacity left. I am impressed with this and its ability to deliver a full 12V high amp current even at a low charge. I plan on purchasing another one soon to be able to do multi day trips without hitting shore. We had taken a spare old deep cycle hooked to the solar panels but did not need it at all. Did I mention its a local product? Arrived to Toledo, Oh. From Midland Mi, in less than 24 hours from the time I ordered. I didn't expect to have it for the trip and was much relieved when it got to me in time to be charged up overnight. It is a heavy sucker so be ready, I have the old deep cycle in the opposite side of the boat to balance her out.Update 1 year later:I just bought battery#2 to make into a dual battery system on my sailboat. We were out sailing with a 30w solar panel and an auto pilot for 7 days and had no issues and 50% battery on day 7 60% batt1 40% batt2. We did no conservation and rarely hit shore, preferring mooring buoys and privacy. I bought my second battery direct from the sellers warehouse, with a cash discount no less. If you are in the downriver detroit area give him a call or an email. He also threw in a few freebies for driving 60 miles that were much appreicated, I will be replacing these in a few years with the new 155AH version or more, but there are great for solar storage and I have no issues in a year of use. ALSO this battery retained 90% charge in storage over winter on my garage floor. Super tough battery, I will be adding in a new dual battery meter next week then maybe post pictures of the setup.

I have been using this battery at an off grid cabin with solar for 4 years. I am using a 265 watt poly panel with a morningstar charger and a 1600W Peak Inverter. The cabin gets below freezing regularly in the winter but the battery performed really well. I ran lots of power tools with the battery and had great success. I did drain it down once after two years and it never got it's capacity back but that's probably my fault. So I am shopping for a replacement and I will probably buy again though there are some cheaper options out there that I would like to see.

Like another customer, I did my own extensive research. This is an amazing battery for the price, and free shipping to boot. I currently have primarily wet cell batteries which are extremely dangerous and a pain to transport with that given danger of spillage of sulfuric acid. I purchased an Optima battery, which is a great product itself, however its capacity seems to max out at 66AH. That, and they seem to be a little bit overpriced. These batteries solve both problems with being AGM batteries, and 125AH. I bought two and run them in parallel and they lasted a good few days powering my entire multi-media center (Power guzzling TV, 7.1 700W surround sound receiver and speakers with separately plugged in 12" sub, PS3, Modem, router, various fans, etc.). Only down side is that they are EXTREMELY heavy (about 75lbs. each). But having worked with batteries and power for a living, I understand that that is just a fact of DC life. There is no way around it! The bigger the capacity, the heavier the battery. Plus, these are dry cell (NO MAINTENANCE).These batteries are perfect for the applications they describe (solar). Like another customer mentioned, it even has its own torque recommendations. Given that I don't leave it with a float voltage or anything and move it back and forth from the solar panel system I built to the house to be hooked up to an inverter, I don't really pay much mind...but if you plan on leaving these in a stagnant location, I would definitely follow the torque recommendations to get maximum potential and efficiency from these batteries.I still can't get over the free shipping! Anyway, coming from the point of view of someone who worked with batteries and DC power for a living, these are awesome batteries.