Cheap ebay lipo review

Hey guys,
I thought I'd write up a quick review about the cheap ebay lipo battery packs.

I've seen several people asking about them, including those wanting to know about how they hold up long term. While my use with them so far couldn't be regarded as long term, I have put them through about 60 cycles and 1000km and they're not showing any signs of losing capacity yet. I'll update again when I get to 100 cycles (which some believe is about all you'll get from these) or if they start to die in the mean time.

These are the ones I'm talking about, from ebay seller TopRacing2007



I have 4 of the above 6S packs wired as 2S2P (which is actually 12S2P for the actual cells) for a 44.4v 8ah pack.
Most of my riding is to and from work, 4 days a week. It's about 15km with a few big hills, and I use around 5ah for the trip with moderate pedalling on the hills and little or no pedalling on the flats. I recharge at work for the ride home, so they're getting 2 cycles a day.
It's probably worth mentioning that I charge with a home made charger, after blowing up 2 hobby RC chargers I charge the 4 6S packs in parallel through a balancer at 9amps (so each pack is being charged at just over 1/2C)

The obvious attraction to these packs is they're cheap - $37 USD delivered is certainly a bargain for a 15C pack. And that's the first problem, they're not really 15C. They're rated for 15C max, 10C constant, but in my testing the max you can get from them is 8C, and which point they sag from a full charge of 4.2v/cell to the minimum recommended voltage of 3v/cell. Ouch. That's where these little guys fall down, they sag more than yo grandma's titties

In another thread liveforphysics quoted the internal resistance of similar 5ah cells to be around 15-20mOhm, dropping around 0.5v/cell @ around 25amps (so around 6v on a 12S pack, for a voltage of 44v) Based on my tests I've found these cells to be around the same, if not a bit worse. Running 2 of the 4ah packs in series for an 8ah pack they sag from 50.4v hot off the charge to around 42-44v when pulling around 20-25a, and then hover around 40v until you've used around 50% of their capacity. Towards the end the voltage starts to drop lower and lower and will hit 36v (3v/cell) pulling 20 amps after around 7.5ah has been used - so fairly close to their rated capacity.

Crusing along the flat at 30-40km/hr my 500w GM draws around 10-15a, which these batteries quite happily deliver with a lesser amount of sag (although still significant). They're usually warm after a 15km ride, but if you drain them much quicker pulling a constant 20-30amps until flat they get really hot. Not "oh no they're about to go thermonuclear" hot, but similar to holding a hot cup of coffee in a styrofoam cup.

So, would I recommend these to others ?
Yes and no.

If you want to pull 60 amps from them as they're supposedly capable of doing, you're going to be disappointed because they flatly won't do it. If you DO want to pull high current from them, or >5C without significant sag, hobbycity zippy packs or more expensive ones are the way to go. Zippy's come highly recommended, and I'll probably get a couple when this lot wear out , but they are more than twice the price.

Who I DO recommend these batteries to are people with fairly low powered controllers. If your controller is rated at 20-25a, you don't mind a little sag and don't need them to last 20 zillion cycles like LiFePO4, these are a great alternative to the likes of SLAs. I originally had 3 12ah SLAs weighing a metric kilotonne and these lipos are like stolen alien technology in comparison

Individually the 4ah packs wont last long in and ebike application (unless you've only got a 15a controller and dont need to go more than 10km), but run 2 in parallel for 8ah pack and they're fine for up to 30 amps (happier around 20). Better still if you ran them 3P to make a 12ah pack there would be much less sag as they'd only be working around 2-3C and you'll get the extra range.

Hyena said:

It's probably worth mentioning that I charge with a home made charger, after blowing up 2 hobby RC chargers I charge the 4 6S packs in parallel through a balancer at 9amps (so each pack is being charged at just over 1/2C)

Click to expand...

What charger brand were you using ?

My bike for 2009 will use hobbycity 20C LIPO (I was looking at the Lipo you are using and some people said they would last...so I madde the choice to go with Zippy pack) I was going to buy 2 R/C charger (MegaPower 12S) to save time building one again...but if they are not reliable...I will start to figure out my next charger

Robin

The first charger was a mystery B6 from ebay, details of its death here.
The second one was one I got locally, a SJ Swallow EQ. It didnt go up in flames, it just stopped working after half a dozen charges.

I gave up on RC charges after that and built one from a switch mode power supply - details here
If you spend a bit of money on a good RC charger you might be ok, but if you're going to buy 2 you'd be much better off buying a 48v power supply (set at 50.4v) and 2 hyperion 6S balancers that can be networked to charge and balance in 12S.
Don't let methods hear you talking about buying multiple or expensive RC chargers

How many charges does a quality lipo pack typically get? Also, I don't think the seller has any more of these packs. I've been looking all over the US and Australia eBay...

Not sure what people are getting from their brand name packs, have a look at a few of the other threads. I think methods has a few that are a couple of years old and have had heaps of use and are still going strong.

Yeah it seems that ebay seller doesnt have any listed at the moment. You could email him and get him to list some, or you can also get them from his website.

They're a few dollars dearer there, but when you buy the ebay ones they come with a 10% discount card for that site, bringing them back to around the same price as ebay. I've thrown the cards out that came with the batteries the few times I've bought them, but from memory the code is PUC'73.
They also sell 8000ma packs, although only 3S. 2 8000mah 3S packs work out a little more expensive than 2 4000ah 6S packs

hello
I'm using my pack as a 6s2p pack, seems too small to be real compared to sla's (a kind of alien technology thats it, a bit like the credit card battery the Jedi gives to young padawan to power his racing pod in ones of the star wars, amazing ! )
better performance at same price range, I don't know how much i am pulling from them but the get hot for sure.
theoretically the motor is rated 400w max, so for my ~200wh pack it's about 2c , but I think I'm getting much higher peak power.

good deal so far, bit messy charging solution, 4hours charging 4s2p and 2hours charging 4s1p work well but...
well just messy!
need to find something better and keep this setup for time to time balanced charge (each 5 charges seems reasonable ? )
my bike is just a joy machine, so range and charge times doesn't matter (get to the pub and return is just 10 km :wink: )


get fun

Hey guys,
Another quick update on these batteries.

I've now got around 80 cycles on them now and they're about 6 months old. I did a bit of a lipo no-no though which seems to have affected them.
I was charging them up last week with my home made charger and got distracted and left them on over night. It charges through a balancer but I suspect it doesn't cut off the power when they're done because the next morning the amp meter was still showing about 150ma (so they'd basically been trickle charged all night) It's also gotten alot colder lately, although not by Canadian terms, cold for this time of year here in Australia is 10 degrees

On the next ride I set off and noticed the voltage sagged straight down to 38-40v on acceleration out of my driveway. Suspecting a dead cell I went back in and tested each cell voltage but they were all fine. I've since ridden 15ks to work a few times and they're still going the distance, but they just sag alot from the get go. My 15k ride this morning used 5.5ah (of the rated 8ah) and although cruising voltage was around 40v from a fresh charge it maintained that most of the way, dropping to 37v minimum when pulling 30a up a hill. Resting voltage is now 45v, so they've still got a bit in them.

When they finally give in I'm not sure whether to replace them with 10ah of zippys or spend a bit extra and go with a 48v 10ah v3 ping.
I'm not sure if I could lug around "heavy" LiFePO4 now after being spoiled with these super light lipos

After a few more rides I've hit it's max capacity, now doing 6.5 ah to LVC.
That said, when I tested the individual voltages one of the packs of 2 (the older one) is reading quite a bit lower and with the cells significantly out of balance. At rest one empty pack (2x 6s lipos in parrallel) was reading between 3.05 and 3.6v while the other pack was reading 3.6v on every cell. The bad pack is only a few weeks older than the good one, but I guess it had a harder life initially - being run as a 12S 4ah pack and running up tp 7C for a few rides (which these cheap lipos DON'T like). Ah well, it was worth the experimenting.

It's still happily getting me my 15km commute to work but when the sick side of the pack finally gives in it'll be time to replace the lot. Hopefully I can keep the 2 better ones to make an 8ah 6S booster.

Hyena, how long have you had them? Sounds like a ping lifepo4 v3 would be better. Do you agree? What do you do with the batteries when you reach your destination? They are so small that you could probably carry them with you. Can you literally put them in your pocket? Maybe a coat pocket.

Morph I got them just before xmas so about 6 months.
They are very small so you could carry them on you if you seperated them, although I've put the 4 6S packs in a hard plastic jiffy box for some protection so that makes them a little larger. After initial ebike testing with SLAs in a backpack and then moving to these super small and light weight lipos, I seriously considered making 'bat utility belt' style lipo pack... :lol:

A ping pack is probably the way to go for my rides to work. I burn about 5ah each way so with this little pack I've been charging at work thus putting 2 cycles on the batteries a day. Ideally I probably should get a 15ah pack so I dont have to recharge at work, but then the size/weight and cost is starting to get a bit high, and I've been spoiled with these cheap light lipos.

Hobbycity has been out of stock of their $75 5ah 6S packs for a while now though, so that helps push things in favour of the ping.

I think I need 2 bikes, a lifepo4 powered commuter and lipo powered fun trails/off road bike thats light, can be thrown around and the weight of the batteries doesnt affect the handling

have you had any funny looks or remarks about how your bike is powered?

I get funny looks from the lycra brigade as I casually cruise past them up hills while they're flogging themselves :lol:

I've had a few people ask about the batteries, I usually carry a backpack when riding to work so most people assume the batteries are in there. When I point them out under my seat they're like "oh, ok cool" but then when I tell them I get 20-30km range from such a tiny pack thats when they're really impressed. People mostly look over the frame then ask where the motor is.

I've seen about half a dozen ICE powered mountain bikes in the last year or so, but only 2 other ebikes, so they're still largely a mystery to the general public.