Personally, I would never waste the money on multi-star batteries. They have a pretty bad reputation for quality, and although they claim high capacity for a low price, you’d be better off with a higher-rated lower capacity pack for the same cost
Time to save up my pennies for the Gens Ace Tattus then. Damn this sweet, sweet hobby.
Also, to forewarn you, I’m looking at your build, really digging it and also looking to it for inspiration for my board’s upgrade. Thanks for sharing!
2 Likes
Compliment accepted!! If you have questions about it, I’m always glad to help
As far as the gens go, there are alternative options. Plenty of reputable manufacturers out there, and to be honest, 22 amp hour pack is overkill for almost anybody. Check out @Namasaki 's Hi Power 10s lipo with BMS thread
Granted they’re overkill, but I do admire the options it provides. I’ve sunk about 900 miles into my board since building it in May and one of my first world problems is capacity. I see about 10 miles worth of road per charge.
I’ll explore other reputable brands and see how much capacity I can get for small-ish form factor (read fits under 40" board).
I can’t seem to find Namasaki’s post, do you have a link handy? Otherwise I’ll hone my search skills lol.
1 Like
Here it is!
1 Like
Aaahahah looks like this ammo can enclosure idea is gonna work out!
3s 5000mah in there for scale 
A bit tight for the 29" spud lol
@PatRocks are your packs all nice and flat? Mine have some varying degrees of curvature. Gonna check IR and capacity. I can charge them at 40A, but I’m limited to 100w discharge, 3 hours and change.
3 Likes
Ya, mine all look brand new. I hope everything works out great! On 12s those will be unreal.
Cheers, and good luck!!
What are the dimensions of the packs if I pay ask
According to Gens Ace:
195x91x43mm for the 4S 22Ah pack.
Link: http://www.gensace.de/tattu-22000mah-14-8v-25c-6s1p-lipo-battery-pack.html
1 Like
Holy shit, that dog is the cutest!!
1 Like
Update on the packs.
Didn’t have time for a full cycle test, but one swollen pack has IRs not so close together and 1 cell that seems weak. Other swollen pack looks okay so far.
Seller’s super cool and sending out 2 more packs. Not sure what to do with the swollen ones, don’t wanna burn the house down trying to use free old packs! Can’t imagine how big a fire these guys would make.
I know, right? Full scale nuclear meltdown. I’m glad to hear they’re making it right! As I mentioned in some other thread (can’t remember where), buying used lipo’s is a risk, but if you check things like seller-rating, etc. you might do okay!!
What were the IR’s, btw? I’ve been trying to figure out an accurate way to measure mine, but my cells balance out pretty well, so I gave up
Pat you sent me down a rabbit hole
Teh internets says Revolectrix Powerlab IR measurements are not as accurate/consistent as iCharger. iCharger is surprisingly accurate.
The only accurate way to measure is to do an equivalent series resistance (ESR) measurement, using “4 wire Kelvin method”, at some standard temperature and standard state of charge, as IR fluctuates greatly.
The best way to measure is using Wayne Giles ESR meter. Wayne is apparently a retired EE and RC hobbiest. I think he used to sell them in small batches, but now they’re widely available via hobbyking even. The device also calculates what a realistic max C rate is for the measured IR, but that’s just plugging numbers into some formula.
https://www.rcgroups.com/forums/showthread.php?2809470-Wayne-Giles-ESR-Meter-is-back-in-production
http://www.progressiverc.com/universal-esr-analysis-meter.html
Revolectrix put the circuit into a device that can measure 6s simultaneous. A bit cheaper, and circuit’s probably not quite as good.
Gonna try to get my hands on the Revo unit, as it looks like a nice cell voltage checker as well. Revolectrix products are usually very high precision and very well calibrated.
Oh almost forgot, the Powerlab chargers measure IR only when charging, and it varies quite a bit during charge. I charged 2 packs to full, and noted the IR at the end.
pack#1 (bulging, weak cell#4) 3.1 mohm 2.2 mohm 2.5 mohm 2.2 mohm
pack#2 1.3 mohm 1.3 mohm 1.6 mohm 1.3 mohm
These seem very low to me, but the absolute numbers coming off my charger don’t really mean anything, except to establish a reference for comparisons. Will update when I get the honesty meter in.
1 Like
Middle one is the keeper, I’d say. I am sorry to see such puffy pillows:(
My concern with the esr-meter is that it says “up to 12Ah packs” do you think that is an actual limit? I almost bought one a while ago, but couldn’t find any information about the capacity max of the device.
On a side note, I really love the direction this thread is going!! @deucesdown - thank you for your participation in the discussion. I want to expand the degree of scientific substance in this thread so as to allign with the title.
CHEERS Friend!!
nice spot! I should have t he Revo unit in a few days. Too lazy to do one cell at a time lol. I hope I don’t end up getting both…
1 Like
So what are people’s thoughts on these? Didn’t find anything on the forum. 12S setup will cost £700 and these guys are from the UK!
https://www.overlander.co.uk/22000mah-4s-14-8v-20c-lipo-battery-overlander-supersportxl.html
1 Like
specs look nice, especially the low IR and the discharge graph at (18c, that’s 396 amps wow can’t believe the wires and contacts held up). But most spec sheets look nice. For a high power dual vesc4 setup, theoretical continuous from batteries would be 2 x 60a, not even 5C.
If I were you I’d look for expected cycle life and owner testimonials.
TBH if there wasn’t such a good deal for the used ones, I’d not have pulled the trigger.
2 Likes