What batteries are you using?

AlexLTDLX

AlexLTDLX

Administrator
Staff member
To get this forum rolling, I'd like to pose a question - what type of batteries, how many cells and what current rating are you using or thinking of using?

I started out with a mishmash of lipos - one 9 amp hour bank (16s) paralleled with a 6 amp hour bank (also 16s). I'm now going to a single bank of 18 amp hour Lishen LTO cells - 50c max continuous discharge (900 amps CONTINUOUS!); 15c continuous charge and 28 cells in series.
 
So far none :) I was leeching your ideas so far, haha!

Now on a serious note: I can very well live with a larger/heavier pack placed safely and securely in the trunk! What is more important to me is operating temps, capacity and recharging behavior. I want fast rechargeability even if it means I need to plug the block to the wall socket. I want capacity to be able to spend a full day flooring it in the dunes and all this needs to be SAFE and stable. I want to be able to CONTROL electric motor revs preferring a constant boost over a wide engine RPM band (instead of simply ON, full boost on switch click, and then dropping when engine RPMS go beyond 3.5k). I prefer to have battery saving 3-4 psi with a slower spinning eDrive on lower RPMS ... and then spooling up maintaining the 4psi or even maybe increasing to 6psi up to 5.5-6k RPMs.

I want to develop a small piggy back controller which plugs into a OBDII port, takes TPS (better even pedal pos on DBW vehicles!) and RPM, maybe even load request, and to close the loop: MAP and smartly spools up the electric blower. Positive side effects: fuel economy, battery saving, constant boost, tunability, drivability, engine protection (not throwing the full load abruptly on the conrods) ...!
 
Last edited:
In other words ... the first step in "hybridizing" a modern EFI combustion engine by introducing eBoost as a piggy back kit, even if it means I have to scavenge half a Tesla for it ... hehe!
 
And the ideas keep coming ... the controller needs to have the possibility to choose between "eBlower off", "eBlower overcoming restriction mode" (battery saving stock engine behavior) and "eBlower (constant) boost mode" maybe with a "at option". :giggle:
 
cmoalem said:
would this work? (I mean to recall the LTO cells are going to cost you nearly as much ...)

www.ebay.com

Tesla Model S Battery Pack Module 444 Panasonic 18650 Cell | eBay

Find many great new & used options and get the best deals for Tesla Model S Battery Pack Module 444 Panasonic 18650 Cell at the best online prices at eBay! Free shipping for many products!
www.ebay.com
as far as I can see there is a controller board included ...
Click to expand...
After I watched Alex's video about the LTO cells I started looking at the hybrid/electric vehicle cells and many of those were LTO and priced very well if I wanted a used one but I'm still unsure about what option to take as far as batteries go.
 
Hi guys - so here's my two cents on the matter. We basically have 3 chemistries to choose from - LiPo, LiFePo4 (lithium iron phosphate) and Lithium Titanate Oxide (LTO). They all have pros and cons; at least in my (limited) experience. And pack structures are also important. Let's look at them one by one:

Lipo - Very high power density; fairly high discharge rate; dangerous - prone to fire and explosion. Highest cell voltage of the three. The also aren't as temperature stable as the other two chemistries - in other words, they have a fairly narrow optimal output temperature range - which is why Teslas in ludicrous mode need time to adjust pack temperature before you can make a hit. Fairly inexpensive, too.

LiFePo4 - Middle of the pack power density; fairly low discharge rate, but much more tolerant of over/undercharging and safer. Middle cell votage of the 3. They're a bit better as far as operating temps, but don't like to be too cold. these are also fairly inexpensive. Cells tend to have high capacity (I dunno if you saw my LiFePo4 car battery video, but I'm using 100 Ah cells). You need high capacity cells in order to get sufficient output current. Though these are still some mean cells - I accidentally shorted one cell and immediately melted 2 M6 stainless studs into puddles. Cost is middle of the road.

LTO - Lowest power density (only about a quarter of lipos) & lowest cell voltage. 10x higher cycle life (the other two are good for ~3,000 cycles; LTOs can do 30,000 cycles). The highest discharge rates (or at least comparable to lipos - the jury's still out on that, but I do think these have a higher discharge rate, simply by watching some youtube vids on LTO discharge tests vs voltage drop; we'll find out soon enough - if my new LTO pack drops to 54 volts under load then they'd be comparable, but if it drops to 58-62 volts, which is the ballpark I'm expecting, then they will be the "discharge kings") by FAR the highest recharge rates (15c in the case of my current cells). Most tolerant of over/under charging. Not prone to fire or explosion. Most temp stable. Most expensive.

But then there's the design of the packs. Having cells in series along with parallel is the best idea. That way if a cell goes bad or you have a weak cell, it gets "taken up" in the average. My lipo pack was 16s2p - meaning, 16 cells in series; 2 packs in parallel. I'm not doing that with my LTO packs. Instead I've tested all 60 cells I bought and am only choosing the 28 strongest, most closely matched cells for my pack.

Since we're not trying to power the cars from these packs, the weight penalty from LTO cells are offset by their benefits. Plus I should never wear out a pack...
 
I am curious about those:

2 in series would be nice, yes?


EDIT: NO!!! ... to make a 48V (or higher!) system which could deliver a few hundred amps continuously it would need a massive parallel setup which reallly gets expensive!
(found some testing of some guys who got some quirky used ones here: https://secondlifestorage.com/index...cells-out-of-an-lg-chem-resu-10h-system.9532/ ... and this turned me down big time!)
 
Last edited:
he highest discharge rates (or at least comparable to lipos - the jury's s
Click to expand...

LIPO spank LTO in IR and Current draw.. The ONLY reason why in your case your LTO's are good is because each one of your LTO cells is MANY times larger than the LIPO cell you were using before.. IF you find a LIPO cell the same size as the LTO then it's a fair test.


the other two are good for ~3,000 cycles
Click to expand...

Err Lipos have worse cycles then LIFEpo4, OR at least with the ones you get from ALIexpress.


Also LIPOS should not be stored charged otherwise they will puff up.... Which is a bit of a problem cos i would think in most implementations most people would want to leave them charged.
 
Last edited:
i mean the Lishen LTO Battery have a discharge of "Max. Continuous Charge/Discharge Current 15C/50C"

This is worse than most Lipos, so LTO is worse based on C rating and Size.. not sure about weight though.
 
Last edited:
or 2 beasties of those :

batteryhookup.com

BEAST MODULE WITH 32 HEADWAY 38120 HP 3.2V 8AH 24V

Under $9.50 per cell with busbars, spacers, and metal enclosure. The Headway battery game has just officially gotten better. These modules have 32 headway cells inside and they are configured in 8s4p (24v). All you have to do to convert these into 12v is cut the busbar in the center of the one...
batteryhookup.com

8s4p ... the weight is on 4p here ... IR and discharge rate 👹 (shoot ... and a suitable BMS :unsure: per beast module)

EDIT: after looking up the specs of Headway 38120HP cells ... the Batteryhookup picture saying 200A (per cell?!) seems a bit exaggerated!
headway_77f368fc-5c90-4bfe-85c4-b716fc871fa0_1024x1024@2x.png
 
Last edited:
Those modules even come with the exact same (by appearances, anyway) contactor I bought. The contactor alone is $30-$50 depending on where you find it. Seems like a pretty good deal.
 
AlexLTDLX said:
Those modules even come with the exact same (by appearances, anyway) contactor I bought. The contactor alone is $30-$50 depending on where you find it. Seems like a pretty good deal.
Click to expand...

shux ... they cannot ship to me directly.
Need to find a freight forwarder who can ship to UAE 🙄.
 
cmoalem said:
or 2 beasties of those :

batteryhookup.com

BEAST MODULE WITH 32 HEADWAY 38120 HP 3.2V 8AH 24V

Under $9.50 per cell with busbars, spacers, and metal enclosure. The Headway battery game has just officially gotten better. These modules have 32 headway cells inside and they are configured in 8s4p (24v). All you have to do to convert these into 12v is cut the busbar in the center of the one...
batteryhookup.com

8s4p ... the weight is on 4p here ... IR and discharge rate 👹 (shoot ... and a suitable BMS :unsure: per beast module)

EDIT: after looking up the specs of Headway 38120HP cells ... the Batteryhookup picture saying 200A (per cell?!) seems a bit exaggerated!
Click to expand...

Just hold off on those 38120hp.. if you look on the internet these don't appear to be as good as the manufactures spec which is <3mohms ... a guy on the internet tested them at 5.5mohms.

i have ordered some A123 AHR32113 because they have been review very well on the internet at 1ohms which is less than their manufactures spec

This coming month i will also order some 38120hp and some A123 26650's

Assuming that the A123 26650 achieve their manufactures spec of 5.25m ohms then these are probably the go (within cylinder LifePo4 chemistry)
That's because they are obviously about 1/2 the length of the others.. But also they can be packed more densely so in my space i can fit 14s4p of 26650 V 14s1p of headway 38120hp's ... the 26650 will give me more capacity and lower resistance.(in therory)

NOW i know this is all based on theory because these none of these cells have been tested by the same person and in the same way.. Im ordering some more test equipment to test the 3 in the same fashion so it's a fair test... After this i'd love to see people buy the same test equipment and test other batteries in the same fashion to build up a DB of appropriate batteries.

EDIT updated 30/08/21 (updated LTO resistance to what Alex tested. I had the capacity wrong for the 26650,s recalculated everything )

A note on LTO's (in theory) (So could be total BS without testing both cells)
32 LTO's in series @ 2.8v = 89.6v
32 LTO's in series with a IR of 0.77 = 24.64m ohms capacity of 18ah
Manufactures Spec that i found said <1mohms so they could be much worse than this example. (update i have since found a few places saying 0.57 and 0.49) ALEX tested them a 0.77 mohms

25 A123 26650 in series @ 3.65= 91.25v
25 in series @ 5.25m ohms = 131.25 capacity of 2.5h
2p 65.625m ohms C = 5ah
4p 32.8125m ohms C =10ah
6p 21.88m ohms C =15ah


Total cells 84 @ 0.076 kg
Total weight 6.384kg (not including fixings)
Volume based on a square 26mm x65mm X 84 = 56,784 square mm


32 LTO @ .8kg= 25.6kg (not including fixings)
Volume based on a square 60mm X 130 X 32 = 249,600 square mm BUT this excludes the terminals on each end which will make them a good deal bigger.
 
Last edited:
MkngStffAwesome said:
Just hold off on those 38120hp.. if you look on the internet these don't appear to be as good as the manufactures spec which is <3mohms ... a guy on the internet tested them at 5.5mohms.

i have ordered some A123 AHR32113 because they have been review very well on the internet at 1ohms which is less than their manufactures spec

This coming month i will also order some 38120hp and some A123 26650's

Assuming that the A123 26650 achieve their manufactures spec of 5.25m ohms then these are probably the go (within cylinder LifePo4 chemistry)
That's because they are obviously about 1/2 the length of the others.. But also they can be packed more densely so in my space i can fit 14s4p of 26650 V 14s1p of headway 38120hp's ... the 26650 will give me more capacity and lower resistance.(in therory)

NOW i know this is all based on theory because these none of these cells have been tested by the same person and in the same way.. Im ordering some more test equipment to test the 3 in the same fashion so it's a fair test... After this i'd love to see people buy the same test equipment and test other batteries in the same fashion to build up a DB of appropriate batteries.


A note on LTO's (in theory) (So could be total BS without testing both cells)
32 LTO's in series @ 2.8v = 89.6v
32 LTO's in series with a IR of 0.45 = 14.4m ohms capacity of 18ah Manufactures Spec that i found said <1mohms so they could be much worse than this example.

25 A123 26650 in series @ 3.65= 91.25v
25 in series @ 5.25m ohms = 131.25 capacity of 4.5ah
2p 65.625m ohms C = 9.5ah
4p 32.8125m ohms C =19ah
8p 16.40625m ohms C =38ah
9p =14.58m ohms C = 42.5ah

Total cells 225 @ 0.076 kg
Total weight 17.1kg (not including fixings)

32 LTO @ .8kg= 25.6kg (not including fixings)
Click to expand...

Yes, thanks! I am holding off! (first reason: shipping any battery/module from the US to me is going to get reeally complicated / expensive. second reason: what you said ... Headway's 38120HP LifePO4s are not "undisputed" ... (just this package seemed so attractive!)

Interestingly shipping Lithium batteries/cells from China to the UAE seems less complicated. Obviously they have very well established sea freight logistics to the middle east ... so ... all the dealers like EVwest and batteryhookup who sell some interesting high power ("shortcut") modules from time to time for DIY projects are off the table for me personally.

Btw ... I like those A123 AHR32113 a LOT as well ... seems like the smallest package with proper posts (besides their impressive specs).
Only down side: not cheap, but since they have a small formfactor a 14s5p with 22.5Ah is quite sexy (for a 48V setup ... for more: add more s)
And ... the Lishen LTOs are certainly NOT 2.8V nominal ... more like 2.2 ...
 
Last edited:
cmoalem said:
shux ... they cannot ship to me directly.
Need to find a freight forwarder who can ship to UAE 🙄.
Click to expand...
if you want, send them to me and i'll forward them to you
in general, batteries are a real bitch to ship. i remember having loads of problems when i was selling E-cigs
 
InitialAuto said:
if you want, send them to me and i'll forward them to you
in general, batteries are a real bitch to ship. i remember having loads of problems when i was selling E-cigs
Click to expand...
Thanks! But where are you located (Cyprus, right?)? Anything not continental US is going to be a pain!

It is not importing them into the UAE ... it is the packaging and declaration/labelling paperwork which is a paper djungle before actually using any means of transportation.

Batteries are considered "dangerous goods" and the couriers don't like to touch them. Any even just formal mistake by them can lead to very severe fines ... a real modern tragedy which is putting some economies in serious trouble. I am pretty sure shipping gun parts or a gun is less complicated nowadays ...
Batteries are treated more like ammunition ... 🤣
 
Last edited:
cmoalem said:
Thanks! But where are you located (Cyprus, right?)? Anything not continental US is going to be a pain!

It is not importing them into the UAE ... it is the packaging and declaration/labelling paperwork which is a paper djungle before actually using any means of transportation.

Batteries are considered "dangerous goods" and the couriers don't like to touch them. Any even just formal mistake by them can lead to very severe fines ... a real modern tragedy which is putting some economies in serious trouble. I am pretty sure shipping gun parts or a gun is less complicated nowadays ...
Batteries are treated more like ammunition ... 🤣
Click to expand...
yes Cyprus... Wish i could be of more help!
 
Im in New Zealand so battery hock up is also useless to me.. The only realistic place is from china.. But i think thats cause they don't care about the law and post them to me anyway...

But you have to be VERY careful with China with them sending you fake batteries so you need to always test them...but at the same time you need to use your common sense... like these ones... lol

18650s.. with 19,800 mah .... yeah right

Obviously fake


Pricing will also vary depending on where everyone is in the world ... the 38120.. due to their expensive freight to NZ is way more than the other A123 cells i'm intending on testing.
 
You must log in or register to reply here.
Top