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

Although slightly shorter in height than original batteries, work like a charm. I have replaced the batteries in a 90's fold n go power scooter with these amazing little gems. Can and does still use its original charger, battery pack is now half the weight of what it used to be, and packs quite the punch. Installed very easily by swapping everything over to the new batteries, fully charged in very little time and scooter that had been sitting for years was back on the road.

Update 4 days later, 10/11/2024 Well...this did not work out. The battery arrived and was installed on Monday, just before Hurricane Milton struck Wednesday night. After a1/2 second test crank (which was fine), the battery was connected to a new LiFePo4 battery charger designed for this battery chemistry. The charger itself may be suspect, as the battery would not accept a charge. The charger displayed a fault mode after a few hours. I then connected it to a known good charger. After a charge of several hours at 2amps, the charger had to be disconnected as we prepped for the storm. A quick check on Tuesday (the next day) found that the generator would not start. Did not have time to do diagnostics with the storm coming. Had to pull-start the generator after we lost power Wednesday evening. Did diagnostics today, Friday 10/11. No problem with the starter motor, as it started immediately with my portable jumper pack. The Nermark battery showed less than 10V on my DVM. Both chargers displayed a battery fault, and were unable to charge the battery above 10.3V. It's possible there was an issue with the built-in BMS (Battery Management System), but I don't know. It's getting returned once Whole Foods is open again. Original Review 10/7/2024 Very simple installation to remove the old sealed lead acid 12-18 battery and replace it with this one. I have been using LiFePo4 batteries in my RC aircraft for over 20 years and I'm glad that this battery is available to replace the typical unreliable lead acid battery that is used as a starter in portable equipment. I took the opportunity to install the terminal rings and cable for the appropriate 3 amp charger and even without completing the charge, did a quick test start on my generator. I hope it will last several years, as this generator is only used for hurricane emergencies. However, I have batteries of this chemistry that are over 20 years old and still hold 80% or more of their charge. I will report back and update this review in the event that there are any failures, or possibly great news to continue to report years from now.

This small lithium battery has performed very well through six fishing outings supplying Power to my Humminbird Helix 5 fish finder. It holds the charge through 6 hours on the water. I highly recommend this light weight battery.

So ive been using these for about 3 years in some UPS units. Been working fine for the most part but it seems like the non-digital UPS units like the ones that sit on the floor will overload these batteries and cause damage to the BMS or something. I had 2 batteries die, one the voltage just dipped down to 2.3v and another the BMS got so hit it was melting the plastic on top and triggering a cut off. I brought up my issues to nermak on amazon and they shipped out 2 replacements immediately, got them a few days later. Very quick response and zero hassle, which is what all manufacturers/sellers should do. Using these in digitally controlled UPS units like 1000va+ (basically the towers) seem to have no issues over long periods, but APC doesnt recognize the chemistry difference at all and wont fully use the whole capacity of the battery. So im just gonna put all these into a batbox with a inverter and put the lead acids back in. Over all good battery, and good support. Im sure with everything working correctly these will last many years. I think i just got a couple duds lol.

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 a few days into owning this battery, and so far, so good! It’s a perfect match for my UPS 550 (model B0019804U8—the same trusty unit I purchased years ago). Compatibility Check: The UPS recognizes and charges the battery without a hiccup. System Integration: The data cable accurately reads the battery's charge capacity—no issues there. Performance Under Load: The UPS does its thing like a champ, seamlessly drawing power from the battery without errors. Now, onto the one thing I can’t tell you yet: whether this 10Ah battery offers longer run times compared to the 7Ah OEM version. Honestly, I’ve never paid much attention to runtime—I just configure the system to keep my home server running until it gracefully shuts down. (It’s tucked away in a basement closet, doing its thing.) For comparison, I have another UPS 550 with a 6+ year-old OEM battery, but let’s be real—it’s way past its prime and totally untrustworthy for runtime comparisons. The Bottom Line: If you’re looking to save some cash on a battery replacement, this one is a solid option. It’s significantly cheaper than the APC-branded OEM battery and only slightly pricier than the absolute bargain options. That said, I’d think twice about going for the cheapest of the cheap—after all, this is a battery we’re talking about. You don’t want something leaking, exploding, or catching fire! Even if it’s not a “true” 10Ah battery (who really knows?), it’s doing a great job in my book so far.

Due to frequent pwr outage in S.Cal I was looking for replacement batteries for two UPS units. These APC-brand units are over 10 yrs old but are working like champs. The lead acid batteries have been replaced twice and each last roughly 4-5yrs. Initially I was not sure about the charging compatibility b/w Lead Acid and LiFePO, but after reading other ppl's reviews and internet posts, I ordered two battries and surely enough these two units were put to work and test in realtime. Happy to see at one long outage they lasted twice longer (from 3 hrs to 6 hrs) on a relatively low load of 110-130Watts. The battery is fully charged within 1hrs when power is back. It costed a little more than lead one but for the extra $ it's worth. Beside it's half the weight of lead acid ones, when you get older you will appreciate the weight difference. I used LiFePO in RC-controlled airplanes so I love these powerful but lighter one. Seller is very responsive to my concern and timely addressed my inquiry. Highly recommended.

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.