NERMAK 12V 10Ah Lithium LiFePO4 Deep Cycle Battery, 2000+ Cycles Rechargeable Battery for Solar/Wind Power, Lighting, Power Wheels, Ride-on Toy, Fish Finder and More, Built-in 10A BMS

I picked up this NERMAK 12V 20Ah LiFePO4 Deep Cycle Battery to build out a custom, mobile 12V auxiliary power pack for my outdoor shop tools and high-flow pressure washer supply pumps. To handle outdoor overspray and demanding start-up currents safely, I paired this battery directly with the 12 AWG marine-grade waterproof fuse holders I reviewed previously. This setup has operated flawlessly, proving to be a highly efficient, lightweight power source that works just fine under continuous workshop load. Why this LiFePO4 battery is an exceptional energy upgrade: Shockingly Lightweight Footprint: If you are used to lugging around old-school 12V sealed lead-acid (SLA) batteries, switching to lithium iron phosphate is a total revelation. This 20Ah pack delivers twice the usable energy capacity of a comparable SLA battery at a tiny fraction of the physical weight, making it incredibly easy to integrate into a mobile tool carriage or camping rig. Dependable 20A Built-In BMS Protection: The integrated Battery Management System (BMS) is excellently calibrated. It monitors cell balance and protects against short circuits, over-charging, and deep over-discharging. It handles the continuous high-amperage current draw of my auxiliary water pumps with zero voltage sag, clicking off instantly only during genuine over-current thresholds to protect the internal cells. Flat Voltage Discharge Curve: Unlike lead-acid cells that suffer from constant voltage drops as they deplete, this LiFePO4 battery maintains a rock-solid, steady 12.8V output through nearly 90% of its discharge capacity, keeping connected pumps running at maximum efficiency right until the pack is empty. Workshop Wiring & Charging Tips: Always Pair with Circuit Safety: Because lithium batteries can discharge energy incredibly fast during a dead short, do not wire them raw. Follow my previous build steps and splice a dedicated in-line fuse holder (equipped with a 20A fuse to match the BMS ceiling) directly onto the positive lead wire right at the terminal. Utilize a Dedicated LiFePO4 Charger: Do not attempt to charge this with a legacy automotive lead-acid battery tender. Lithium chemistry requires a specific multi-stage charging algorithm (typically pushing a bulk charge up to 14.4V–14.6V) to properly balance the internal cells and hit that advertised 2000+ cycle lifespan. The big takeaway: NERMAK has delivered a premier, ruggedly housed power cell that offers an unbeatable combination of capacity density and safety features for a very reasonable price. The screw-down terminal posts are clean and provide a rock-solid mechanical connection point, the internal protection circuits are highly responsive, and the weight savings are massive. It is an exceptional value purchase that modernizes any custom low-voltage electrical build.

I needed replacement battery for my Tzora electric scooter, and the 25 AH lead acid battery pack. This barely fit into the enclosure of the lead acid battery, I had to modify it somewhat, so I could not recommend it for that use. In other scooters, it should fit great. If you are handy with tools, then it might work great for you as well. It seems to offer a higher voltage than the 25 AH lead acid battery, the voltage always reads top of the range in the volt meter. It does not sag as much when going up a incline. It feels more powerful than the 25 AH battery it replaced. But it also has the problem of shutting off when the voltage is low, not just slowing to a crawl when the voltage is low like a lead acid battery. It is a safety feature of all lithium battery packs to shut themselves off at a low voltage cut out. Just be sure to recharge it more often. I would expect a longer range than the 25 AH lead acid battery, and many more recharges than lead acid style battery.

So far so good. This is the second battery I buy from this vendor, and after observing good performance over a year or so, I felt compelled to write a review. The first battery was used for a kids ride on jeep running at 12V. This second battery was to upgrade that same ride on toy to 24V by connecting to the older battery in series. It seems the overcharge, overvoltage, and fault protection in the BMS circuit actually works. We have done all of the above and it still works. I didn't do a formal leakage test, but I know for a fact that it holds charge well over decently long periods of time and cold weather. As long as they don't change their process and material, it's totally good value for your money.

I’d recommend against usage for “legacy” UPS lead acid battery replacement, specifically the common case of quantity 4 or 2 battery systems. These usually are setup with the batteries in series (4x12v = 48v, 2x12v=24v). You are likely better off throwing the legacy lead acid battery UPS away, and buying a lifepo4 based UPS. Even the Lifepo4 portable batteries like the power 1000 have UPS capability. The ups devices that start with a lifepo4 energy source usually have passive and active cooling for the battery array, in addition to the inverter components. There are a few problems with using these in a legacy lead acid battery UPS: 1. The continuous output current is far lower than lead acid batteries. The typical Lifepo4 compatible battery option is rated at 10amp continuous. So, in a 4 battery series system, you’ll get at most about 135w continuous output per battery - so about 500watt max. You won’t get anything near the potential needed in common 1000w, 1500w, and 2000w ups. 2. The BMS present in the lifepo4 batteries generally needs at least exposed passive cooling, or even active cooling. These are enclosed package batteries, so cooling is limited at best. 3. With 4 12v lifepo4 batteries in series, you’d basically need another BMS to manage the 4 batteries, or the discharge and charge levels between batteries becomes imbalanced. 4. The charging circuit will not fully charge lifepo4 batteries, in most cases. Lead acid vs. lifepo4 have different max voltage levels. 5. The legacy ups doesn’t know the proper estimated runtime or charge level of lifepo4 batteries. This is a relatively minor issue compared to above. Technically, a 48v lifepo4 pack that fits most UPS battery compartments could be built to handle several of the issues above. As an experiment, I fully charged up 4 of these individually outside a UPS, then installed them in the ups. Verified the output of the pack was approx 55.8v. The charge/discharge circuit ”popped” with the telltale electronics burning smell, with smoke, when a 200w load AC power fail test was triggered. These batteries may be ok for some cases, like the single battery backup common to home alarm system panels.

Just ordered this for my daughters offbrand Power Wheels Jeep and man, this thing is so light and holds a charge for a lot longer than her other 12v battery. (16Ah is to thank for that I’m sure). I haven’t tested it to see how long exactly it works, but we made it to the store and grandmas and back the long way which was our destinations so that’s all I needed. Thanks!

I bought these for my Cyberpower UPS. They don't fit with the plate that goes between the batteries. I used wooden blocks to make the space between the cells to fit my UPS, but these Nermak batteries are a couple of mm taller than the SLA batteries that they are replacing. This was enough that I had to remove the plate in my unit. The USP is operating normally and isn't getter hotter than before. I'm confident that these cells will last much longer than the 3 years that I got from the last cells that I had in there. Also, the cells were within a few hundredths voltage from each other when they arrived, so I didn't have to balance them before installation. I may inspect them in a few months to verify that all continues to be well.

Update 1/20/2026 I am raising my product review to 5 Stars because of excellent Customer Service. The seller reached out to me and offered a replacement or full refund. I purchased an Eco-Worthy battery right before I returned this one, except a 30Ah instead of a 20Ah. I assembled a whole Brand New system around it and the Eco-worthy lasted exactly Three Days and did the exact same thing. These batteries are leaving the factory with unbalanced cells, the lowest voltage cell is going to pull the others down and instant BMS chip failure. Now I have to return the Eco-Worthy battery. All my old SLA batteries are old and need replacing so this is about the only way to go. You NEVER want to buy used or Bin store or reseller batteries ever, This is a great seller and I am going to continue to order from this seller simply because of the excellent customer service. Which for these batteries is something you are going to need or find out the Hard Way. My other NERMAK 20Ah battery is hanging in so far, fingers crossed! Great seller, Highly recommend. I bought one and my wife ordered one on her account. They charged up just fine, I put one in my solar power system with a 150 watt inverter, high end charge controller and 200 watts of solar panels. It ran fine for a few days and we went to the store, came back and the inverter was beeping and the charge controller said zero volts. There was NO reason that battery should have died like that, under full sunlight. I returned it with no issues and I got a full refund very quickly and ordered a different brand of battery. Have not received it yet. I did attempt to recharge the battery on my smart LiFePO4 charger but the charger would not even turn on. This battery definitely has a faulty BMS chip or something. The 2nd battery did the same thing the other day, but I was able to make it come back to life and is holding in there, but now I always turn the inverter off when I leave. If it lasts 6 months I will come back and update this review and give it the proper star rating. But great seller, fast ship, and no problems with the return. Very happy and confident buying off Amazon.

3 of the 4 batteries I received still work and charge. One battery seems to have died and will not take a charge. Apparently the return window is up and I can't get support. Would not recommend simply because one of the batteries have already died. I purchased in February 2026. Nermak reached out and refunded me the amount for the battery. Customer service team stepped up where the battery failed and made things right. This shows they stand behind their products and understand sometimes things happen. I appreciate the assistance and have adjusted my review rating due to exceptional communication and customer service.

después de meses usándolas, diversos cortes de energía al en estos meses, puedo decir que respaldan mucho mejor que las que traía mi UPS de ácido, sin duda compraré más este tipo de productos por su relación precio/calidad