LIPO charging

[eMark]

The Turnigy Graphene lipos seems to be pretty good. I've exchanged one that was off a bit, but the good ones don't really need balancing. I'm coming up on 300 light charge cycles (I run from 4.15V to 3.8V, no lower than 3.7V). When I balanced them last, there were only a couple of cells that were 0.01V to 0.02V off from the rest.

amberwolf:
I guess they're better than they used to be when they were very commonly used around here. (and much better than the ones I had experience with, whihc were before the Graphene era).

Doubt E-HP was using his RC Turnigy Graphene battery for testing it out with plans for using 5 in series powering an e-bike with a 60V powerplant.

Turnigy Graphene Professional 12000mAh 6S15C LiPo Pack w/ XT90 ... $175 ea (still need to buy a charger ... what about a suitable BMS)

Turnigy Graphene Professional 12000mAh 6S 15C LiPo Pack w/ XT90

Professional quality batteries for RC cars, boats, drones and remote control planes. Buy Turnigy Graphene batteries online at HobbyKing for the lowest prices.

hobbyking.com

Should we assume amberwolf is [possibly] in favor of Jenming fabricating 5 of those RC Turnigy Graphene Professional batteries wired in series as a 60A Turnigy RC Lipo powerplant for an e-bike? Don't think so, but i could be wrong - it wouldn't be the first time.

 

[eMark]

This DevTu Turnigy MultiStar High Capacity 6S 20000mAh 12C Multi-Rotor Lipo Pack w/XT90 ... $300 ea ($900 for 3) ...

https://www.amazon.com/Turnigy-High-Capacity-20000mAh-Multi-Rotor/dp/B07DRDG7V8/ref=sr_1_3?gclid=CjwKCAiA3pugBhAwEiwAWFzwdfKPU939RF3gp5yqD8qF4VFCHkDGhEZ0udFS6tr-d86-SE_FF_YlQBoCTV0QAvD_BwE&hvadid=570527620933&hvdev=c&hvlocphy=9019693&hvnetw=g&hvqmt=b&hvrand=4975477994819800640&hvtargid=kwd-303654075588&hydadcr=4995_13189552&keywords=6s+20000mah+lipo&qid=1678206705&sr=8-3

The DevTu Turnigy 12C series batteries were designed specifically for multirotor use (MultiStar brand)... Their high energy density makes them a great choice for eBikes, too! They have a similar size/weight as batteries of lower capacity (w/higher C-rating), making these a direct drop-in upgrade for large multirotor aircraft, increasing flight times up to 20%.

Specs:
Nominal Voltage: 22.2V (6S), Capacity: 20000mAh 444Wh, Maximum Continuous Discharge: 12C (240A) @ 20°C(68°F)
Energy Density: 175Wh/kg
Weight: 2525g
Size: 195 x 93 x 67mm
Balance Plug: JST-XH
Discharge Plug: Amass XT90
Wire Gauge: 10AWG
Recommended Charge Rate: 1C(20A) or lower

I still think the above MCD is actually more of an arbitary MCO brief/peak output NOT an ebike Lion 240A MCD rating. Because the nominal voltage 6S is 22.2V then 3 wired in series would be a 66.6V powerplant.

BOTTOMLINE: If you were to use say a 50A Controller with those 3 DevTu in series (66.6V powerplant)) how would you figure a reasonable MCD rate for an ebike (not RC professional quadcopter) to achieve a cycle life of at least 100-200 discharge cyles?
One way would be to ride your bike up a 15 degree 1 mile incline wo/pedal assist) for as long as possible pulling 48-49 amps until the temperature of your 3 cells in series reaches no more than 140 °F. It's possible after that kind of abusive workout your 66.6V (nominal) powerplant may only register 54V as the cut-off may have already shut-down the battery. 54V is 3.0V per cell (3.7V DevTu nominal).

It's questionable whether or not you could get even 100 usable cycles if you were to frequently abuse that powerplant. As long as you wait until they cool down to at least 75 °F before abusing your RC batteries again with a similar ebike MCOutput and then maybe only once every 10 discharge cycles before repeating such an abusive MCOutpit.

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[DingusMcGee]

Jenming,

As mentioned in your OP, you ask 3 - 6s LiPo or 4 - 4s LiPo. I run both of these setups and use respectively either 3 or 4 HOTA H-6 Pro Smart Chargers simultaneously to charge or balance charge a depleted set of bricks while they are on the bike. It seems there is less availability of the 6S 20Ah packs when trying to purchasing them. For some packs i cut a 6s pack in half to get 2 - 3s packs , which when a 3s pack is added to the 18s group the setup will give the max voltage my controller will accept.


BTW. Crap talk aside, these packs as measured with a CycleAnalyst, can put out some 6C amps = 6 x 20 = 120amps for bursts of power while hill climbing on my edirtbikes — endlessly. Turnigy says Discharge 12-24C, could I hang-on at 24C?

Or at about 125 amps you may break 70 mph with them.

 

[MorbidlyObeseKoala]

I guess they're better than they used to be when they were very commonly used around here. (and much better than the ones I had experience with, whihc were before the Graphene era).

I have 4 of those Turnigy Graphene 6s 8AH I got on clear out for $36 a pop, I can't even believe the discounts hobbyking puts on stuff when they want to get rid of inventory. They were advertised as the same specs as the current ones on the site, namely 15C constant, 30C burst.

I run the packs 2S1P in my 48V 1000w scooter and they do alright with power delivery (if I were to raise the deck of the scooter, i could fit the other 2 and make it 2S2P with the packs). My controllers cut off voltage is 42V and when I run them down to the cut off voltage I see some higher voltage differences across the cells. Something like 0.8V on the highest end, ususally 0.4-0.6V. When I don't run them much below the storage voltage, they stay within 0.1V of each other.

Seems a tad underwhelming for what should be under 3C discharge, I'd expect to see them perfectly balanced since that would not be running them hard. They barely even get warm for a full discharge run, the controller gets hotter and that isn't even that hot so that is good. But I had a higher acceleration build planned which would have a harder initial draw on them, I'm not terribly confident they are up to the task. I also found a deal on a balance charger on ebay so I balance charge every time at 0.5C which is the max the small power supply can handle, it'd be nice to have a faster bulk charge option for longer rides with less preplanning.

TLDR: your mileage will vary greatly with LiPo on the cheaper end of the spectrum, IMO it is probably worth it for tight space constraints so long as you monitor them regularly and don't expect the fullest delivery on the specs. We do weigh more and presumably have a much different power delivery curve than RC drones/helicopters

 

[DingusMcGee]

The BS flies,


“PS: you are using LiPo packs at a high power ebike. soo make sure to protect those LiPo packs against any fisical damage. Imagine a rock hits a lipo pack, it could be a very danger situation. a 20Ah LiPo would start a massive fire and spread to other packs!! convert LiPo packs into hard case elements for safety!!
a 20Ah LiPo pack could easy put out +50C out, this means +1000Amps continuous draw..”

IMAGINE what contrivances it took to generate the above paragraph about what could happen? 50C discharge? The. Op of the above paragraph pulled this number out of his Ass…..

I have 4 edirtbike which all run Lipo 20 Ah battery packs covered minimally with canvas/nylon. Over the course of several years bike wrecks & crashes have managed to puncture at least one cell pouch on some 5 bricks. The punctures went unnoticed until when balance charging the battery setup, one pouch cell never makes shut off voltage 4.2 volts. Upon inspection: I found punctures . Yikes, i have a bomb in my hands and pin has been pulled, this ain’t no disco, this ain’t no foolin’ around …..

I go to nite school repairing/regrouping LiPo cell pouches so the bricks individual cells charge at similar rates. But alas, my coordination sometimes fails and i have punctured cells with the exacto knife. This ain’t no disco…. Get it? I simply cover the puncture with HS hot glue and regroup the cell by soldering the tabs.

Another post with some Bull Shit to diffuse Please? It is Wartime on the supposes. Bullshit rules Fools — we have seen it on TV.