What batteries are you using?
- Thread starter AlexLTDLX
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MkngStffAwesome
Active member
The temps are there.... 25.5/10c
One thing this has proven is that when stating a batteries IR the temp should also be mentioned .. Also it takes many hours for the temps to equalize.
One thing this has proven is that when stating a batteries IR the temp should also be mentioned .. Also it takes many hours for the temps to equalize.
MkngStffAwesome
Active member
Life = 0.23
LTO = 0.06
Lipo = 3.12
18650 = 5.9
This is the difference between 25.5 - 10c expressed in the difference between them in milli ohms instead of percent like i had previously
Hi!
Can i build a battery pack with these components, that it would work out and give me high discharge output?
Do i need anything else for this BMS or something? Im quite new on this, i have seen some of your battery packs and projects and would like to build my own because you cant get already made anywhere.
Can i build a battery pack with these components, that it would work out and give me high discharge output?
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Do i need anything else for this BMS or something? Im quite new on this, i have seen some of your battery packs and projects and would like to build my own because you cant get already made anywhere.
Hi Armando and welcome! To answer your questions - yes, you can. Those are the exact parts I'm using. In fact, I just modified my packs (took two cells out of each, because the new stuff isn't capable of as high a voltage as the APD ESCs were); now I'm running twin 12 cell packs. I just measured the internal resistance of each pack - .12 milliohms for each entire pack (!) . So for both packs in series, it's still less than a quarter of a milliohm. I'll be testing under load in the very near future, so we'll see if those numbers hold true.
I don't use a BMS btw. I'd rather do a low voltage cutoff in the ESC or with ardiuno control. I use a 500 amp contactor, so all you have to do when battery voltage is too low is just cut power to the contactor. Though VESC will shut itself off at too low a voltage anyway.
I will say, those LTO cells (if they're genuine or at least test well) are unbeatable power output wise. But they're not the cheapest or smallest/lightest option.
I don't use a BMS btw. I'd rather do a low voltage cutoff in the ESC or with ardiuno control. I use a 500 amp contactor, so all you have to do when battery voltage is too low is just cut power to the contactor. Though VESC will shut itself off at too low a voltage anyway.
I will say, those LTO cells (if they're genuine or at least test well) are unbeatable power output wise. But they're not the cheapest or smallest/lightest option.
I've tried a bunch. Blew up two fliers, FWIW. Right now I'm playing with that 75/300 VESC and I have an MGM 800 amp continuous/1,000 amp peak unit on the way. What engine are you putting this on and how much power/boost are you looking for? And unless you step-up the impeller speed, an electric motor won't be able to drive an hx40 fast enough to get on the compressor map. In other words, you'll probably make a little more power, but you won't make any boost to speak of. That P2 blower is really the best starting point for a whole bunch of reasons. I really don't have anything to gain by pushing that supercharger, so take that for what it's worth. The hx40's compressor map STARTS at 50,000 rpm; the P2 is nearly done at 50,000 rpm (and starts at 25,000 rpm).
WB projects
Active member
Hey guys I found this A123 32157. I talk with Alex and he found a good deal on ebay of cheap A123 26650 with good specs and I want to go with it for a good moment now. The specs of the 26650 is about 70A continuous Discharge and 120A in pulse.. I want to have a set up of probably 15s5p so 48v with 350A. The problem is the 75cells that I need to spot weld with copper/nickel strip but im not a big fan of it.. and I found this! Little bit biger in diameter and little bit more then 2x longer BUT a lot more power 210A continuous its going to be pretty much the same battery size but lot less cells and the cells going to be screw and not spot weld !
Wath do you think?
Wath do you think?
I looked at them too, but after some research I declined from buying cylindrical A123 cells! (after the first purchase order actually had to be refunded due to fake shipping)
Their new mother company (who bought A123) stopped producing any cylindrical cells in 2017! (only prismatic pouches are being produced)
So all those cheap A123 cylindrical cells are not brand new. Best case 5 years shelf time, worst case "recycled/refurbished"!!!
Last edited:
MkngStffAwesome
Active member
Do not buy those... these are old cells . A123 does not make these anymore and haven't for years..
ALSO their specs are trash... 8m ohms is HORIBLE .. much worse than what you have now with your LTO's
ALSO their specs are trash... 8m ohms is HORIBLE .. much worse than what you have now with your LTO's
MkngStffAwesome
Active member
From a simplicity point of view and having screw terminal the only cells that i have found that are viable are the 6ah LTOs that i bought that has super low IR's and thus practical.
WB projects
Active member
Wow! Glad to know this before buying it haha but I dont want to go with LTO for the space I have. Do you know some good lifepo4 cells that have screw terminals? With this specs?
WB projects
Active member
How the pouches look? Do you recommend it?
MkngStffAwesome
Active member
The LTO i was referring too were smaller than the lifepo4 cells you were suggesting at 32145, though you will need more cos of the lower voltage.
It's kinda hard to to avoid spot welding.. cmoalem bought the pouch 123 cells and they seemed good enough (though if the aim is less sage you might want 2p)
It's kinda hard to to avoid spot welding.. cmoalem bought the pouch 123 cells and they seemed good enough (though if the aim is less sage you might want 2p)
looks and first IR test (single cell! but I am shooting for 16s4p => 16x(0.125mOhm) overall):
Post in thread 'What batteries are you using?' https://www.electrifiedboost.com/threads/what-batteries-are-you-using.8/post-1082
do I recommend them? can't say yet ... battery case and clamping mechnism is "in the make" ... then they need to prove themselves under real load. Are they good? According to my research (see my post here
ost in thread 'What batteries are you using?' https://www.electrifiedboost.com/threads/what-batteries-are-you-using.8/post-1058 ) they should be! In the past some Porsche concept car used them as well 
WB projects
Active member
Yes the LTO you were suggesting was smaller but need a take more space/voltage I want.. yes they are powerfull but like my last battery pack, I was pulling 400A in peak and like 300A continue for arround 4500-5000watts. I need more voltage and I need a lot to bring up the voltage. I dont have enough space. The lifepo4 have little bit more voltage and just enough current for the space and the set up I want. So this is why I don't want LTO anymore.
@cmoalem I saw you set up! But I will take a closer look for sure
@cmoalem I saw you set up! But I will take a closer look for sure
I don't think I would recommend the seller I got them from; and they're out of stock. A bunch I ordered showed up dead and they weren't new as promised (some have different length studs, etc). Most of them have come back after charging and testing them all (literally been doing that for months when my bench power supply is free); but they did give me a bit of discount. Even with the discount, I still paid well over $1,000 for them all. Just buying 24 cells would still set you back about $400-$600 if you can find them. I would use the batteries SQCTS on here found. They're smaller, easier to work with, cheaper and have really low internal resistance.
The company is SMC racing based in Virginia. You can PM him here and ask specifics. He's a very nice guy.
BTW - the a123 cells I bought are certainly not new, but they do test very well, and were frankly dirt cheap. I would have no issues using them. So far all the ones I've tested have an internal resistance between 6.5 and 6.9 milliohms. Put 6 in parallel, and 18 in series, and you'll have a pack that's only 25 milliohms, fairly small and quite safe; and only dropping 7.5 volts at 300 amps. I think I paid around a dollar each, btw. I bought 180 of them. Do 8p18s, and voltage drop goes down even more.
WB projects
Active member
I will go with them too! Look good and I have a nice Idea to clamp them! I will machine some custom copper clamp with some custom insulated holder for them! 15s is about 48v 20ah compare to my last set up of 12s2p LTO of 5.9ah.looks and first IR test (single cell! but I am shooting for 16s4p => 16x(0.125mOhm) overall):
Post in thread 'What batteries are you using?' https://www.electrifiedboost.com/threads/what-batteries-are-you-using.8/post-1082
do I recommend them? can't say yet ... battery case and clamping mechnism is "in the make" ... then they need to prove themselves under real load. Are they good? According to my research (see my post here