Announcement

Collapse
No announcement yet.

LiFePO4 batteries ?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • LiFePO4 batteries ?

    So ... my S13 battery died, again. My fault again for not using the car enough and not charge it ... But i need to remove the intercooler cold pipe to remove the battery, and that really is a pain. I decided to move on and get a very small battery, like an odissey one.

    Then i came across these lithium batteries. They do look appealing; very lightweight, same price as an odissey battery, and seem to fit cars that dont get used so often, amongst other things.

    I wonder if some people here are using them ? Please chime in if you do, or know something about these.


    This is what i have learned so far:

    Pros:
    Weight/price ratio. Fancy a 200$ / 3lbs battery ?
    supposedly 10x more life cycles than lead batteries.
    Voltage does not drop until battery is out (like other. Empty battery is at around 12V, full is around 12.8/13V)

    Safe, environment friendly and dry cells: no need for a battery box.
    Very low internal resistance => very good at starting cars, and very low losses when not used. also, very fast at charging ... 30mins charge. Then you have to wait 30mins for it to cool... Way better than my 24h slow charger.

    Small, and can be installed in any position.

    Cons:
    it needs some electronics, and not a lot of suppliers fit it on the battery.
    Their ratings are fake. divide Ah by 3 to get the real rating.
    PCA rating is a fake CCA too. Shorai started these fake ratings to compare the batteries to a lead one. Nearly everyone followed. If you see a 20AH battery for less than 600$, it means its a faked rating.
    terminals are not car terminals.
    mostly used on bikes, powerboats, skidoos. Not on cars.


    Techs:
    It looks like there are 2 types of cells mainly, cylindrical and prismatic ones. Prismatic is supposed to be better.

    You can get your own cells and electronics from ebay, and build your own. That will still be chinese ebay stuff though ... i would not use that.


    You really need that electronic board, called BMS, IN your battery. Some manufacturers sell their battery without, then put one in the charger. That is a bad idea really, as the battery is unprotected when used in the car. The BMS is not cheap, i think i saw 60$ on ebay. They protect from over and undervoltage, which both kill cells, and they balance cells. Some also limit the max discharge current. If you are getting that kind of battery, get a BMS that do all of that and have it fitted at the battery, not in the charger. Unless you like buying new batteries often.






    Makes:

    Ballistic:
    Someone on sxoc was using an "Evo2" 16cells one. Seems to work. The 12cells are used to power kawasaki vulcan 1500cc custom bike. These dont include the electronics.

    EarthX:
    Seen some comments around, looks legit. Assembled in USA from chinese parts. They do however include the electronics (balancing, under/over voltage protection, current limiter). I may go for that brand. They do a 24AH (read 7.4AH) model which i think would suit my CA18DET. There also are 18 and 36AH versions. I still dont understand what the "C" or "D" at the end of their references means.

    Shorai:
    dont know much.

    XSpower:
    not the one that sells crap i believe. These ones have been the first, but their price range is unbelievably high.



    If you feel i am missing something, please comment.

  • #2
    Ok, some news.

    I am definately going this route ... but i will be building my own battery. All cells are built in China / Taiwan, and i now know a lot more things on these - like which cells i should avoid, and which should be good. Still debating on wether i will use a battery management system or not. these are safe batteries, unlike Lipos; they just die when under/over charged. Fact is, a BMS able to accept the current drawn from starting the car will just double the price, so not sure it is worth it.

    Comment


    • #3
      There are cheaper and easier ways to save 20lb on the car.....
      Originally posted by SoSideways
      I don't care what color they are as long as they are LONG AND HARD.
      '04 G35 Sedan 6MT- The DD
      '96 240SX- The Track Toy

      Comment


      • #4
        http://www.amazon.com/Shuriken-SK-BT...shuriken+SK-BT

        That's all I use. It's cheap, ~11lbs, and turns over the LS1 no problem. My car often sits for several weeks unstarted, no issues after that length of time.

        Comment


        • #5
          Originally posted by croustibat View Post
          Ok, some news.

          I am definately going this route ... but i will be building my own battery. All cells are built in China / Taiwan, and i now know a lot more things on these - like which cells i should avoid, and which should be good. Still debating on wether i will use a battery management system or not. these are safe batteries, unlike Lipos; they just die when under/over charged. Fact is, a BMS able to accept the current drawn from starting the car will just double the price, so not sure it is worth it.

          All said and done, what is your major advantage of making your own vs buying an off the shelf setup? I'm not sure the time is worth the savings IMO, but to some it's a labor of love
          'Slicks on a car show me you care - broken axles show me you're trying'
          [I]Nitrous Rental Cars - Turbo Festivas - Vehicular Lunacy[/I]
          [SIZE="3"][B][url]www.sloppymechanics.com[/url][/B][/SIZE]

          Comment


          • #6
            Originally posted by Matt93SE View Post
            There are cheaper and easier ways to save 20lb on the car.....
            I don't know about that. You can get the cells from eBay for ~$50-70. That's cheap dollar/weight ratio - especially since the LiFePO4 batts will have about the same overall capacity to discharge as a lead acid batt that's about 4-5x heavier.
            '18 Chevrolet Volt - Electric fun hatch for DD duty!


            DefSport Koni Sleeve and Spring Perch Buy!!!
            http://www.nissanroadracing.com/showthread.php?t=5902

            Comment


            • #7
              Originally posted by CodyAce View Post
              All said and done, what is your major advantage of making your own vs buying an off the shelf setup? I'm not sure the time is worth the savings IMO, but to some it's a labor of love
              Cost... you're looking at about $150-200 difference. And I don't think you need a BMS for these cells. The charging voltage from your alternator is a perfect "charge voltage" for these, and a BMS won't stop you from discharging them with steady current draw. A lead acid batt dies from deep discharge as well.
              '18 Chevrolet Volt - Electric fun hatch for DD duty!


              DefSport Koni Sleeve and Spring Perch Buy!!!
              http://www.nissanroadracing.com/showthread.php?t=5902

              Comment


              • #8
                Originally posted by icantdrift View Post
                http://www.amazon.com/Shuriken-SK-BT...shuriken+SK-BT

                That's all I use. It's cheap, ~11lbs, and turns over the LS1 no problem. My car often sits for several weeks unstarted, no issues after that length of time.
                You sure it's around 11 lbs? I've handled tons of these things, and they're basically PC680 clones. ~15 lbs and ~16 Ah in reality.

                Good lead acid batteries for the price, but they're not as light or as powerful as most people report.

                You don't need much battery capacity to crank over an engine from a battery that's not cold as arse.
                '18 Chevrolet Volt - Electric fun hatch for DD duty!


                DefSport Koni Sleeve and Spring Perch Buy!!!
                http://www.nissanroadracing.com/showthread.php?t=5902

                Comment


                • #9
                  Originally posted by Def View Post
                  Cost... you're looking at about $150-200 difference. And I don't think you need a BMS for these cells. The charging voltage from your alternator is a perfect "charge voltage" for these, and a BMS won't stop you from discharging them with steady current draw. A lead acid batt dies from deep discharge as well.
                  For sure Lithium batteries rock, we use them in the power tools all over the shop (and yes they are pricey) but I dont' see any particular reason for a street car to go out of their way for them. I've had my ETX14 for almost 4 years now, and it's a champ, and was like 65 or 70 bucks. (Not to mention light, small, and works great). Sure every spring i throw it on the Tender, but nothing major.

                  Not trying to be argumentative with the O/P but I just can't (yet at least) wrap my head around the Lithium batteries for a car yet at their cost. They are cool tho
                  'Slicks on a car show me you care - broken axles show me you're trying'
                  [I]Nitrous Rental Cars - Turbo Festivas - Vehicular Lunacy[/I]
                  [SIZE="3"][B][url]www.sloppymechanics.com[/url][/B][/SIZE]

                  Comment


                  • #10
                    Originally posted by Def View Post
                    You sure it's around 11 lbs? I've handled tons of these things, and they're basically PC680 clones. ~15 lbs and ~16 Ah in reality.

                    Good lead acid batteries for the price, but they're not as light or as powerful as most people report.

                    You don't need much battery capacity to crank over an engine from a battery that's not cold as arse.
                    You're right, the advertised weight is 13lbs so it's a little over my estimate. No issues with mine starting at temps in the low 30's having sat out all night at the track. But it's only a track car so that's all I need it to do (other than be cheap, and it does that too). I was just offering it up as a cheap alternative to experimenting with the lithium cells, although I would like to see what he comes up with as well.

                    Comment


                    • #11
                      A real 20AH LiFePO4 battery (not pbeq), made of 4 prismatic A123 cells would weight 4lbs, cost around 150$, can be mounted anywhere and is 3"x3.15"x1" . I could get 8 or 15AH cells too, but that is a 10-20$ difference, so i'd rather go 20AH to avoid killing it again too easily.

                      I am tired of killing SLA batteries every year, too.

                      TBH i want to try these because they are small, and because they are supposed to get 10 to 20 times more life cycles than an SLA battery. Weight saving is an added bonus, if i wanted light i would have bought some FRP elements before

                      Comment


                      • #12
                        Has anybody done the DIY Li battery thing in other, more active car communities?
                        ~1992 240SX, SR20/Koni track day car
                        ~2016 M3, daily driver

                        Comment


                        • #13
                          I did not find that on car forums, but on an e-bike DIY forum. These guys put an electric engine on a bike, and make 48/ 60/ 72V batteries with these. They also work on powering electric cars and electric dirt bike, some even race them.

                          The requirements are a bit different as to start a car you need high discharge cells, but i already have some references that can discharge from 30C to 60C , which is more than most SLA batteries can do (i even found one that has a 2200A max discharge rate, but these are rather expensive). Remember these are lithium iron, although they can be called lithium ions, they are way more safe than lithium polymers (lipos) .

                          Comment


                          • #14
                            First of all, sorry for bumping a 4.5 year old thread. Since there's a lot of good info in here I figured it would be more appropriate than starting a new thread. I'm wanting to go this route, primarily for the weight savings.

                            I'm ok with building a batt, or an off the shelf option. Who has gone this route, what did you go with and why? What cells are the best ones I should be looking at and from where?

                            Comment


                            • #15
                              IMO, buy an off the shelf solution. The biggest problem with just tossing an LiFePO4 battery in your car and cranking it is that the voltage can be low from sitting, then you crank, discharge it further down the charge curve, then the alternator hits it with 14.4 V. This gives it too many charging amps, and it will kill the weakest cell.

                              I think a smaller LiFePO4 battery with a current limiting resistor and an ultra capacitor bank is a better solution. A little bit more complicated, but will last much much longer than just tossing a lithium battery in there and hoping it works. BTW, best to disconnect the battery when storing for any length of time. Any sort of drain will kill a tiny battery in no time.

                              If you want an off the shelf batt, I'd think about something like the 8.4 Ahr Zippy Flightmax LiFePO4 batt. Probably about $90 or so, and way more capacity than you get when you buy an "automotive" lithium batt.
                              '18 Chevrolet Volt - Electric fun hatch for DD duty!


                              DefSport Koni Sleeve and Spring Perch Buy!!!
                              http://www.nissanroadracing.com/showthread.php?t=5902

                              Comment

                              Working...
                              X