DIY 12v LTO (Lithium Titanate) Battery

so today we're gonna build a lithium titanate battery I order these from China and I've never been able to afford them because they're really expensive but these things are incredible so the charge cycle life of these is twenty thousand charge cycles alright a lead acid is like five hundred to a thousand lithium iron phosphate is like 3,000 to 5,000 but these do twenty thousand charge cycles it's gonna be insane this will last longer than I will be alive on this earth so I don't have a BMS yeah but we can test the voltage right now two point two eight four two point two eight four two point two eight three two oh two point two nine three two point two seven would a two point two eight all right so most of them are pretty darn close that's not that bad actually they're within point zero two we're fine alright guys I was inspecting the batteries and this one has a dent in it but I was relieved because all I need out of this for a 12-volt pack is five cells because the BMS I'm using is five cells and I've got five and so the six one I wasn't gonna use and this is the only one that had damaged I don't know if you can see it in the video can you see that right there it's a very subtle but you can feel like it got whacked and these were packaged really nicely so I don't know you never know what happens during shipping everything else looks perfect so for my project I'm gonna use these five batteries and then put this one to the side and I actually don't know how I'm gonna put this battery together look at this these can short-circuit real easily so I have to protect both sides so I think I'm gonna drop this in a box and have them stacked like this very carefully I'm going to wrap this with electrical tape I know how much my viewers do not like my electrical tape jobs but I think it will be good at the end so just give me a second alright give me a chance so now I have three cells and it's positive negative positive and then we have negative positive on top so main battery terminal positive over here and main battery terminal negative down here it was a big pain in the butt but it does fit it's not super fancy but it does work check it out finally have the lithium titanate 5s BMS so this will be able to take our cells and turn it into a safe 12 volt battery system these terminals are massive I have a size 19 to tighten these things down these are half-inch studs so it requires these huge terminal connectors look at this thing so notice that a lot of these will not fit these large half-inch studs so what I'm doing is cutting these big ones and it check this out it actually fits on there so yeah just clip it with maybe one of these little tools and you'll have something that you can connect balanced leads alright so we have the BMS connected and I'm gonna check the voltage and it's at eleven point four three it looks like a bomb but it's not and now we need to organize these wires somehow there's a lot of wires so we're just gonna strap them down with some zip ties like that but that's pretty much it now we have a negative and a positive and I can connect it to an inverter or a solar charge controller whatever I want really now we're gonna charge this up and see what happens when we give it an over-voltage situation so the max voltage that this pack will reach is 13 volts and I also check the cell voltages and it's balancing the pack correctly doing a capacity test so we're gonna see how much of this battery we can use with standard 12 volt equipment so we have a heat gun we've got a watt meter we're gonna see how much we can pull all right guys we're 175 watt hours and this thing's beeping like crazy so I'm gonna check the voltage it's 10.5 that's not good and going by the chart it looks like a lot of the usable is right around 10 volts and these inverters like to cut out at ten point five so that's gonna be a problem after doing some math and thinking about it I think I would prefer to have a 6 s pack that would charge up to like 15 to 15 point 5 volts but I would have more usable for 12-volt appliances and what's a bummer though is most of the BMS is that they sell online or 5s but I want a 6s so I think I'm gonna look online and I have another cell that I bought and I might make this into a excess and see how well it performs with these kinds of appliances so this morning it did the low voltage disconnect and it was around three hundred and thirty watt hours but these are 40 amp hour or supposedly 40 amp hour cells and I actually did the math and I'm actually guessing that these are advertised falsely these are actually 30 amp hour sells I've actually read about this happening on some message boards for lithium Audio batteries a lot of guys complained that they'll just repackage these and put a sticker on there for 40 amp hours so yeah I might try to return these that's kind of a bummer I mean the battery now has six cells in series and it was a pain in the butt I also had to wire up my own balance cable so I can connect it to my balancer and also cell voltage monitor but what was crazy as this thing beeps at 2.5 volts but these cells have such a low voltage compared to other lithium-ion chemistry's that I can't balance it in the alarm just keeps beeping like crazy even though everything's fine it doesn't have a lithium titanate I'm still monitoring setting on here also finding half-inch terminal connectors for these studs was very difficult I actually lost one of the nuts and so I have this little clamp right here holding it on but right now I am charging it with the Vic Tron up to fourteen point nine volts and going by the discharge curve it seems like 2.5 volts is like the start of the curve so I should be able to get a lot of capacity and still be able to use 12 volt appliances now we're gonna do a capacity test with these cells they are fully charged six cells in series we have this connected to a 1500 watt 12 volt inverter and we're gonna see how long we can pull a big load for and right now we're pulling 633 watts and we'll see how many kilowatt hours this will produce and I'm hoping it will hit point five but point four is acceptable because of inverter losses but we will see so again this is the sweet spot like twelve point two to twelve point eight under load with 12 volt with six cells in series it really likes to state at that throughout the majority of the capacity so we're at 200 watt hours and it's doing really good the voltage is holding I feel a little bit of warmth from the cells now so what we're going for is 552 watt hours so if we see with the efficiency taken into account it will be like a point four five watt hours until this is depleted damn it so with the inverter losses included but not the wire loss we pulled 288 watt hours and this is partly and due to the fact that we cannot use the entire capacity of these batteries for 12 volt appliances but I think these are 30 amp hour cells I've seen other people complain online about that and after doing my first and now second test it seems like these are not 40 amp hour these are 30 amp hour cells which is a big bummer so after reading some data sheets I learned that the discharge efficiency is only 85% on this chemistry so maybe that's where we're getting our loss from after messing with these batteries man lithium iron phosphate stands ahead I think I know why everyone's using those ones instead so what should we think about lithium titanate batteries they are very interesting they are fun but I don't think that they are good for 12 or 24 volt solar power system application if you have a very specific application like a satellite or you have like an off-grid structure with like a wildlife observation where you have like a camera and it has like a satellite communication link and you're never gonna go out there for the next 10 or 20 years and it has to log data or maybe for atmospheric condition thing on top of a mountain then these are the batteries that you want to use but for everyday solar power use there is no way the discharge and efficiency is just crazy high it's practically like a flooded lead-acid battery there's a 15 percent loss lithium iron phosphate is 99 percent efficient okay like huge difference here but what's really cool though and so interesting about titanate is they can charge so fast it's like a 10 C charge right max and the recommended is 5 C with lithium ion phosphate you can do 1 C but they recommend on most studies to do a point 5 or 0.4 C so 5 to 10 see like the stats on these are incredible in the life cycle is crazy and the safety is out of this world but but for everyday use with an inverter in like typical 12 and 24 volt stuff I wouldn't use it but man you could still build with it also because the charge cycle life these cost more than most chemistry's of lithium-ion but in the long run they are way cheaper than even lithium ion phosphate these cells cost for the same capacity but you're not getting the same capacity because : be efficient C is not nearly as good so you have to factor that in is well but it costs pretty much the same as these but these last like four to six times as long as a lithium iron phosphate that's just crazy for me to even wrap my mind around there are capacity studies with lithium iron phosphate and even that blows me away because these last for so long even in MC studies we have some where the capacity of degrading like on the Tesla's they're doing really good so I don't think you really need 20,000 charge cycles but I wanted to build it because it's neat I really think though that for 12 volt appliances when I did my load test with this that was a large load when I did it six cells in series and that's probably why my numbers were not as good is when I had the 5s because with 5s I had some little resistor mat things and I had a meter without the inverter so there was less wire loss because it was less large of a load so that's why I think I got a larger capacity with my first test but overall the capacity on these with all factors considered is just a joke but I still think that 6s is the way to go the usable like when you have it under load it saves it like twelve point eight to like twelve point two volts that is perfect for 12 volt system so if you guys want to build a 12 24-volt system you should use a six cell or a 12 cell configuration the safety is out of this world that you can cut into it like you can do whatever you want to these things and I'm not anything but it's just incredible these will not catch on fire at all ice there are some crazy videos on YouTube testing these things out on besides that I hope you guys like this video I had no idea what to expect I saw the twenty thousand charge cycle on the advertisement sounds like oh my god I gotta try this but yeah I didn't I never knew I should have studied more about the discharging in efficiencies but yeah I'll talk to you guys later let me know if you have any questions in the comment section below I'll have my supplier on there but I'm thinking it's a 30 amp hour maybe I'm wrong I don't know let me know what you guys think and I'll talk to you guys later bye

Channel: DIY Solar Power with Will Prowse

Views: 391,099

Rating: 4.7642751 out of 5

Keywords: will prowse, lithium titanate battery, 12v lto battery, diy lto battery

Id: p1xildSl4Hk

Length: 11min 31sec (691 seconds)

Published: Sun Jun 09 2019