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12V 100Ah LiFePO4 Lithium Iron Phosphate Battery $200 ($195 eBay Plus) Delivered @ Outbax eBay

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12V 100Ah Lithium Iron Phosphate Battery LiFePO4 Rechargeable Camping RV
These have pouch cells and are usually sold as 'Gentrax' brand.

Ebay plus makes it a great price

Original Coupon Deal

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Comments

  • +4

    Wow! These are getting cheap.

    • -2

      do they sell the 16V LI-ION Battery as well?

      • +1

        How the hell would I Know?

        • +5

          hi, is battery this suitable for me?

  • +7

    The ebay images are hilarious!

    • +7

      Haha comparing themselves to a jeep might not be sending the message they were going for

    • +1

      Damn I have an "Other Brands" battery, where can I dispose of it that would charge up the most eels?

  • Can I wire this in to a UPS? The BMS should do all the magic for charging yeah?

    • I couldn't find anything on it. I bought a lifePO4 charger just in case.

    • -4

      To ensure the best compatibility between the charger and the battery, stick with the same chemistry. AGM deep cycle batteries are going to give you great bang for buck and you're charger won't see a difference. Here's an example from Kings https://au.adventurekings.com/solar-batteries/battery-charge…

      PS: You may need 2 of them wired in series as many UPS' contain 24V lead acid batteries.

      • +6

        lithium has all almost all its AH as usuable amp hours where AGM you can only use 50% of capacity IIRC

        • +4

          If you keep your lithium battery charged using one designed for AGM you're going to have a bad time.

        • +2

          You can use theoretically use up all the charge in an AGM, it will just cause sulfation and significantly reduce its lifespan.

        • -2

          That is a fallacy. You can use as much as you want it depends on the volts. The 50% rule was to show a higher cycle rate for sales.

          • @Geoff01: Not fallacy at all. As 42 suggested, it's simply a result of the chemistry of LA batteries. In addition, the longer you leave a discharged LA battery before recharging it the greater chance you have of killing it completely. Add to that the effect of Peukert's Law (and other obvious differences such as weight) and AGM is left in the dust by LFP.

            Nothing wrong with good quality AGMs for particular purposes though.

            • @Igaf: I agree that lithium is the future for now and that it's imperative that deep cycle are recharged as soon as they are depleted but it still goes without saying that they can be depleted below 50% as long as the appliances will use the voltage. It means less cycles but that's counteracted by the longer use and discharge. It's all relative.

              • @Geoff01: The fact is that chemically LA (AGM in this case) sulfation - formation of lead sulfates - is accelerated by deeper discharge. Sulfation eventually also reduces LA battery capacity as some lead sulfate won't be converted back to Pb, PbO2 during charging. A combination of deeper, faster depletion and/or elapsed time between depletion and recharging CAN and HAS resulted in early failure of AGM batteries. So you're not trading off, you're risking failure and/or guaranteeing shorter life and reduced capacity. If you have no choice on rare occasions (eg you're 'off grid" and the sun isn't shining and you need to power your fridge) then not using your battery beyond 50% would be silly.

                People who buy quality AGMS (eg Fullriver…) and who ususally observe the ~50% depletion "rule", quick recharge etc can usually look forward to long battery life.

    • +11

      No. UPS that aren't specifically designed for Lithium will run a 24/7 constant float voltage of around 13.7V. Doing that will ruin a lithium battery.

      • -2

        You're thinking of lithium ion batteries without an internal BMS. These batteries manage charge internally - they will most likely shut off input power when full.

        • +2

          No internal BMS I know of will prevent float charging.

          How could it anyway? It would have to cut 12V power, causing whatever device was floating it to think its suddenly got no battery. The only way this would work is if there was a separate charge-only port on the battery itself. And I've never seen that, and it would also require the floating device to support that functionality.

    • +3

      I've got 2 plugged in series to make 24v and it works fine.

      It's only a problem when you fully discharge the battery as one battery BMS might turn off first. Also make sure you're within limit of the max continuous current. For UPS it'll be bo problems.

      It will never over charge unless they are not balanced.

      Been doing it for over a year.

      Note: Mine said not to series it, but I did it anyways. Just check they are relatively balanced and you'll be fine.

      Worse thing that can happen is you lose power in UPS abruptly. That has never happen except when I drained it for testing.

      • Thanks man, appreciate it. What voltage does your UPS hold them at?

        • I have a 12v UPS holding at ~13.67V and the the 24V UPS holding at ~27.4V

          Some people might be thinking, you can't keep your LiFePO4 on charger all the time, it will overcharge it etc.
          The charger is not pushing more current into the battery since my UPS charger voltage max out at 13.67V and 27.4V respectively and the maximum voltage is 14.4V and 28.8V respectively. The resting voltage for LiFePO4 is 13.6V and 27.2V.

          All that is happening is I'm charging my batteries to ~97% and resting there and I don't care about the last 3% so I'm not bothered it's not 100% utilised. I'm already getting 2x the capacity of a similar lead acid battery as you wouldn't want to discharge your lead to 0% anyways.

          Remember this is just a UPS and the current draw when power is out is not crazy.

          Things to consider

          Overheating

          The issue you should be concerned about is the UPS overheating on extended battery use especially now that you have a battery that's about x20 bigger. i.e. if you are replacing a 7-10Ah lead with a 100Ah LiFePo4, your UPS will run 20 times longer on battery power and likely overheat if you don't have good ventilation.

          I've burnt out one UPS because I cycle it every day at 60-70% load for 4-5 hours a day and It died after 18m (this is with no modification to the UPS, just plug and play with LiFePO4). This is excessive and most probably not the normal use case for most people's UPS, but it gives you a good stress test for comparison if you want to protect your UPS.

          VA of your UPS

          One other thing you want to be careful about is the VA of your UPS.
          The one I have is rated for 50A continuous discharge so it can power a 12V UPS rated up to 640VA (12.8V nominal x 50A max continuous discharge)
          This particular one is rated for 100A, so in theory, you can go up to 1280VA. Just make sure your cables are rated properly else cables will start melting. If you plug and play into existing UPS cables and they have fuses too.

          I did stress test mine and checked temperature in the early days when i ran my UPS for 4-5 hours straight, the wires get pretty hot but my cables were rated for it.

          You will quickly tell if the battery is not actually rated for 100A when you put a load of close to 100A on it for 30-60 minutes as the battery's BMS will shut it down.

          • @SeVeN11:

            you are replacing a 7-10Ah lead with a 100Ah LiFePo4,

            How did you fit the 100Ah LifePO4 battery into the UPS?

            • @spasto: I ran the cables outside the case (drilled some holes) to an Anderson plug and the battery sits next to the 12V UPS.
              My 24V UPS already has an Anderson-type plug so I just cabled the battery and plugged it in. Again battery sitting on the side.

              • @SeVeN11: Ah ok. Was hoping there’s a “cleaner” way as I prefer the UPS to be fully rack mounted.

          • @SeVeN11: You are plating the electrodes at anything over 13.4V.

            • @stumo: The main causes of electroplating are overcharging, high currents and low/high temperatures.

              1) I'm definitely not overcharging as the Lead UPS is unable to fully charge a LiFePO4
              2) UPS is a very slow charger as its designed to charge a much lower-capacity lead battery. I'll be lucky to charge it at 0.05C
              3) the battery is sitting at room temperature and definitely between 5-45C (best charging temperature), the only time it gets hot is after a long discharge and it would be sitting near the high range of that temperate range, but being slowly recharged at ~0.05C.

              i.e. I'm pretty sure electroplating is not occurring, but if it did, I haven't noticed from the last full discharge I did, it ran about the same duration so it hasn't lost any noticeable capacity.

              Remember the alternative is an AGM that can only be used up to 50% of this Amp, i.e I have a 50% buffer for electroplating.

              • +1

                @SeVeN11:

                1) I'm definitely not overcharging as the Lead UPS is unable to fully charge a LiFePO4

                Applying a float voltage after its fully charged is still overcharging. Doesn't really matter what voltage or rate this full charge occurred at, it is still being overcharged at that point if you are applying a 24/7 float voltage. The higher that float voltage is, the faster the plating occurs.

                The only way to stop it plating is to stop overcharging, which isn't a lead UPS's use-case. The only way to limit it is to apply a float voltage that is lower than its true resting voltage (which is 13.4V for LFP, not 13.8V).

                • @stumo: You might be right, I don't know.

                  I just know there's no current going into the battery when it's float charging from my measurements.

                  From a practical point of view I suspect most people where the use case for is a UPS, I don't think they care if they lose some capacity over time.

                  I know after 18m of use, I haven't lost any noticeable capacity.

                  • +1

                    @SeVeN11: Yeah for cheap small LFP batteries like these its not really a big issue.

                    But for large expensive LFP banks, early adopters were sold them as "drop in replacement" to AGM. And they are paying the price now with about 20% permanent decreased capacity after a year of 13.8V floating. These people have since switched to circa 13.4V float and have kept the damage at around 20%. Which is an expensive amount of Ah to have thrown away due to bad advice.

                    The "drop in replacement" BS marketing refuses to die since most cheap batteries are out of warranty by the time people notice.

      • +1

        I run an 80Ah AGM on my UPS. The biggest issue is the charging system isn't designed for such a big battery so recovery takes a long time.

        If I've had a lengthy outage, I need to hook up an external charger to recharge my battery in any reasonable time.

    • +6

      Not sure why I was downvoted above. If you want use aftermarket batteries to replace the small expensive internal UPS batteries with external batteries, keep the same chemistry, that way you don't have to worry about the specifics of the particular lithium battery, BMS's, combinations of battery BMS's with the internal UPS charges, whether it's balanced, whether it can handle the high discharge current or some other extraneous parameter that could lead to your house burning down.

      Deep cycle AGM's are going to handle full discharges for as many times as your UPS is going to running off-of battery anyway, unless you are living in a 3rd world country, or you have some serious power supply problems. They'll also handle the current better when you are in discharge state (they are designed to be engine-starting batteries afterall). And they are forgiving if you accidentally / temporarily short them. Again, considering the limited cycling in this use case and the fact that they are sitting still and not being bumped around (cars / caravans), you'll get years out of them.

      Lithium's are great for many use case, but not as the simplest, "safest", retrofit / upgrade of a typical consumer UPS battery. Don't mess around with this stuff if it's in your home and connected to the grid and if you can't follow this guys process https://www.youtube.com/watch?v=K_S55zITqxI

      AGM's are also highly and easily recyclable, which is great for the environment :)

      • +2

        Not sure why you were downvoted either.

        If your UPS is designed for AGM deep cycle batteries, then best to stick to the same chemistry.

        LiFePO4's charging process is different to AGM, so you'll be depending on the robustness of the built in BMS system to keep it safe.
        It should work in the short term, but in the long term you may get shortened life of your LiFePO4 battery, or worst case scenario a catastrophic failure.

    • AGM/lead acid batteries better suited to UPS, as they like to sit at full charge where as lifepo4 like to sit between 20-80%

      • I thought the same thing but learnt LiFePO4 are a different beast to the LiPo in your phone etc.

        They are quite happy sitting at 100%, even draining to 100% isn't a big problem.

        Temperature change is the biggest issue for them.

        • +1

          I think if you research again, you will find charging LiFePO4 to 100% or discharging to 0% will result in degradation of the cells and reduced charge cycles. I aim to charge and discharge between 20-80%

          • @42: Agree, although good batteries with decent BMS' won't allow complete depletion of the cells so in reality they will (should) never be at "0%". Limited DoD/recharge test reports (eg https://www.researchgate.net/figure/Effect-of-other-SOC-rang…) have shown that 20/80% extends cycle life and appears to be a "sweet spot". Occasional full depeltion shouldn't be a problem under normal conditions.

            Wrt 100%, as you say the current view :-) is that LFP batteries should NOT be stored/maintained fully charged, NOR as someone commented elsewhere, should you attempt to force more charge into the battery after it has reached its initial cutoff (~14-14.2V) and settled back to ~13.8V. There is valid chemistry to back up this "rule" if anyone wants to search.

  • Interesting. Wondering if i can put this in a battery box connected to a 400watt solar panel to run a aircon

    • +2

      Maybe a small portable 24V AC and two of these sure. You'll need a lot more solar to keep up though.

      A proper 240 Volt AC via inverter - no.

      • -1

        Maybe I wait for the 200Ah which should be able to supply 2Kw of power for a little under 2 hrs

        • +6

          Except its still 100A max current. So depending on your AC and inverter still it may not be enough grunt.

  • +5

    Time to DIY my own power wall…. What could go wrong…

  • +1

    Can we connect them is series/ parallel?

    • parallel only it says at the bottom.

    • +1

      A specific weakness of the BMS, quote from the site:

      As much as possible, only connect batteries in series or parallel during emergency situations.

  • +3

    That is a great deal for someone looking for tinker with an LiFEPO4 battery. Just keep in mind the stresses you’ll put on it (physical, environmental, and electrical) as they are pouch cells. For my project I went 200Ah w/ prismatic cells as my research leads me to believe they’re a little more robust. YMMV

    • +1

      You pay for what you get. A prismatic cell costs almost double of this for 100AH. Depending on storage and use, you could buy 2 and use the 2nd as a backup or double the capacity.

  • I wish they sold all in one solar + battery + mmpt etc for a fridge

    • +2

      the problem being if the goods are crap quality, all it takes is one component to die and it's all landfill. At least if buying them separately, if it craps itself it (hopefully) will only be 1 think you have to replace.

      • I went through 2 cheap lifepo4 batteries before diving deep for a quality one.

        • +1

          What brand? Cheap ones similar to these?

    • -1

      You'd be better off buying a battery generator like what popped up in this deal and just add a solar panel.
      https://www.ozbargain.com.au/node/817805

  • Tempting. Interestingly, the Warranty is listed as 2 years under the Specifications section, but only 1 year under the Guarantees section. Which is it?

    • ebay 10 minutes?

    • Screenshot it and pay with Paypal to hold them to it.

      • -2

        Really? who would take a screenshot seriously? anyone can just edit it or even make their own from scratch.

        • Irrelevant.

        • eBay saves snapshots of revisions at time of purchase.

    • How will you claim your warranty? PayPal has 180 days limit.

  • +7

    I don't know where these batteries are used for the LiFeOfM3

  • a DIY lithium pouch cell setup, what could go wrong?

    I don't doubt there are some good use cases for this, but I imagine many are probably not worth the risk.

    • What is the issue here, for those not particularly familiar with lithium battery technology? I'd be looking at using it to power a camping fridge for a couple of nights.

      • +1

        At least in my opinion, not going to be great in the sun, using while camping specifically is probably fine but I would be more concerned about outside camping, for example having it in a hot car or storage at home.

        I think Lithium is battery is best when you have something actively monitoring/maintaining the battery and particularly if its installed in the right way, for example how house batteries are often installed.

        • Thanks for the reply. I would be putting the battery inside a batterybox in the canopy of my ute to power a fridge. I've used an older 120AH prismatic lithium battery for this purpose for the last few years and that has just given up the ghost. Was looking at batteries a lot more expensive to replace, however at $200 this seems like a steal? Even if it only lasts a couple of years, that's $100 a year, which is nothing.

          • @Tr0jan: This is LiFePO4, not your traditional lipo battery. It does not like heat cycles in comparison to prismatic, yes, but not say it can't and won't perform.

            It's like saying a BMW m4 is not a good track car when you're comparing it to a Porsche GT3RS.

            For the price, it's a steal.

  • +4

    bloody good prices in Victron smart controllers at the moment too… 100/20 was $150 late last year, now sub $100

    • Thanks… Im currently charging my battery with my lab bench power supply and mppt solar charger.

      30v * 10 amps. Just make sure voltages match and lower amps to solar chargers maximum just incase.

      A little slow but couldn't afford a battery charger at the time 🤣

    • You need a shunt too, correct?

      • Panels -> Victron -> LiFePo

        Bluetooth to the Victron for statistics.

  • +6

    everyone is saying its a good price, so i bought one. now to figure out what to use it for.

  • +1

    need 12v 50-60ah one

    • Totally - I want to extend the range of my kayak trolling motor, using a 35ah lifepo4 which almost gets me through a session but cuts it very close. A bigger battery, double not triple, would give me the peace of mind/range without being too heavy.

  • I was gonna ask , if this can replace 12v Lead acid battery in car

    Looking at below info, maybe a no, even for a EV or Hybrid

    https://www.quora.com/Can-you-replace-a-cars-starting-batter…

    • +2

      I was looking at using one for my leaf. Couldn't find any JIS posts that I could screw in and didn't want to mess with adapters and that. I don't think it'd work for an ICE but a pure EV it might be ok.

    • +2

      No, doesn't make enough amps to start your car

      • -2

        not even an EV? ahem

        • Different use case, should be ok for electronics like stereo, lights etc, but to supply power to the powertrain its not designed for it, plus would be wrong voltage

    • No it wont. Have a look at deep cycle vs starter batteries if you feeling like having a read.

    • No. Not enough Amps and not designed to survive the constant heat of an engine bay, or the correct charge voltage

  • My caravan's current charger supplies a constant 13.8V to the old AGM battery… I can change this to supply a constant 14.4V which I believe the LiFePO4 needs. Is that it, or should I look at replacing that charger too?

    I think I'll need a Victron SmartSolar MPPT 100/20 as well to replace the existing generic 20A PWM solar charger?

    • +2

      14.4V is the charge voltage, you only run that voltage until the current drops to below maybe 0.05C.

      At that point you need to switch to a float voltage of no more than 13.4V for caravan use-case. (AGM chargers float around 13.8V which is way too high for LFP)

      Lower is better (I float mine at 13.2V), floating at anything above 13.3V is slowly plating the electrodes and causing permanent capacity drop in LFP cells.

    • -1

      You can use your current charger, just change the voltage. The internal electronics in these batteries do the heavy lifting of charging, so you'll be fine

  • Wow, that's an amazing price

  • +1

    Has anyone torn one of these apart (recently)?

    • Please let me know if you find someone who has! I'm interested as well.

      • +2

        Well nobody seems to have any specifics so I cracked mine open.

        For future reference purposes:

        Gentrax 12V 100Ah
        Received 06/2024
        BMS: JBD-ZP04S014-T V1.1

        Discharge Testing: ~105Ah @ 10V, BMS Cutoff at 9V/107Ah

        Interestingly the connector for the external NTC is missing (maybe thats why it has a "-T"?).

        I have yet to pull the cells out as it is glued down tight.
        But it does look likely to be pouch as it is missing the bus bars you'd normally see across the top of prismatics.

        Also if you plan to open it, you will not be able to just pop the top off without damaging it.
        Easier to save yourself the effort and dremel the top (there's a fair amount of free space).
        Also good idea to do it in a ventilated area as it stinks.

        May post images another day if I remember.

        • Please do post images if you get a chance!

          Thanks mate, great info otherwise.

          • +2

            @Freaksta: Images here:

            https://imgur.com/a/8lnWTqM

            Those have got to be the largest pouch cells I've seen in my life.
            Looks like a 4S2P configuration.

            I'm not going to go any further dismantling it as I'll have to rip off the tape etc. and I don't want to potentially short something.
            Also I plan to use it.
            If someone else is willing to, could they follow up with a picture of the writing/brand/etc. on the cells?
            From what I could see, theres no writing on the exposed side of the cells, so you'll have to dismantle the pack.

  • Got 1 to get started. Tempted to get 2 but not sure how I will go.

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