So I’m new to the lithium world, how is this cheaper/better then buying a northstar or limitless? All ears
Totally different animal than AGM or LiFe PO4. To try to condense many many hours of research into a short version:
AGM:
cons: Very slow charge and discharge rate, terrible size and weight.
Pros: Tried and true, somewhat inexpensive, easy to find off-the-shelf with warranty, very tolerant to temperature extremes.
2-5 year life expectency
LiFePO4:
Cons: Sort of expensive for the total energy stored, unknown life expectency 2000-3000 cycles (3 years?), cannot tolerate 100% discharge
Pros: Very high charge and discharge rating, small and lightweight, easy to find pre assembled (JY, XS, etc.), easy to work with voltage rating cells.
LTO (AFAIK a variation of LiFePO4 with some titanium nano-crystals in the cathode):
Cons: Size and weight not nearly as good as LiFePO4, 2.3V nominal cells make useful car audio banks awkward, high charge rate but not nearly as good discharge rate as LiFePO4 (you need 120AH LTO to deliver the same burst current as 40AH LiFePO4), NOBODY is selling consumer ready banks,
Pros: Big amp hour ratings, very fast charging (if you have enough current), big improvement over AGM as far as size/weight, 10X the cycle life of LiFePO4 20,000-30,000 cycles (15-20 years!), much better perormance at low temperature, can tolerate 100% discharge.
Both LTO and LiFePO4 are safe. The flavors of lithium batteries that for example make your note 7 blow your balls off in your pocket are still very popular for consumer electronics because they're the highest energy storage for the smallest size/weight, those are the ones that are unstable. Most of the LiFePO4 cells manufactured are NOT the high current rated ones we use but lower current ones fit mostly for backup power storage where you have a 1000AH bank that would deliver 100A continuous to power your house if the lights go out or overnight when solar isn't collecting or similar. LTO is being used in a lot of EVs. Toshiba makes an excellent cell for a couple hybrid cars and some electric busses but you cannot get them unless you're the guy manufacturing EVs and send a tech to Toshiba for their training.
Will you be running bms on these?
Total hokum for our purposes. Consider I'm using 240AH banks capable of 2400A charge and discharge. Mind you, I'm only charging at 350A max but now picture a smart circuit that can pass 350A/2400A that can quickly open the circuit if it sniffs trouble. To do this properly would cost thousands of dollars and be a box the size of the breaker box in your house. BMS for solar banks is for small cells with limited charge ratings. Get a huge stack of 10AH batteries running .5C charge and discharge and you can simply use transistors to pass current and quickly shut off if trouble is detected (these BMS systems look like an amplifier with a big series of transistors along a heatsink doing the heavy lifting and some ICs doing the smart stuff.
Otherwise cells wired parallel will self regulate. Sadly down to the level of the weakest cell. Catastrophic failure would hose your whole bank quickly and one dying prematurely would also rape your life expectency. Real world you simply can't "smart" charge or manage the type of current we need for big boy car audio, absolute best you could hope to do is remove them periodically and test each individual cell. Consider pretty much every other battery we use above 5V is multiple cells and if one fails they all go down with it quickly (traditional car batteries included).
Ive been running my own DIY LTO lithium batteries most of this year. They are awesome.Different cells though.
Different shape or a different "brand"? YingLong is doing some really cool things with electric busses in China.
I'm curious on the LTO builds as all i thought there was is the lithium iron phosphate. Are these other cells safer? Charge just as fast and everything as the lithiums? I'm gonna research these as I'd rather build one of these then get another agm and a h/o alternator. How much did it cost ya if u don't mind me asking? I know these builds aren't cheap but much cheaper than buying a premade like jy or limitless one. You haven't had any issues with this build? So many questions on building these still.
LTO is as stable or moreso than LiFePO4 (you can find videos of abuse testing on youtube, there are no catastrophic failures). If you can afford the size/weight of AGM I'd say stick to that. Buy "platinum" or other premium series parts store batteries and kill them right before the warranty is up effectively getting 6-8 years out of your purchase.
Cells were low 20$ range each, plus shipping from China (roughly 2.5 pounds per cell). Copper bar we used was roughly 200$ per bank's worth (delivered), and we put out another 200$ into nuts, washers, drill bits, cutting oil, sanding wheel, dielectric grease, and other odds and ends. Figure also the cost of building a small box to house them. Remember for intents and purposes you can't just apples to apples with amp hour sizes. While the total storage is the same how much you can use before voltage drops to unuseable and how quickly you can dump that energy are totally different! 100AH LTO, LiFePO4, and AGM are totally different. The original plan was to buy the A123 LiFePO4 cells and build up 120AH banks which would have been a fair bit smaller and lighter and probably been even better at delivering burst current than the LTO 240AH.
Are you on any of the diy lto groups on facebook? If so, what's your name? If not, you need to be.
I found a lot of good info on electric vehicle forums and DIY "green" energy forums.
