Alibaba lithium ions

joeA

10 mW
Joined
Nov 11, 2015
Messages
29
Hey guys
Im looking at these 48 v 20 ah batteries on Ali Express... i was wondering if anyone thinks ali express is a reputable company to buy through and if these particular batteries are well made, safe, have accurate parameters etc.... most of all this battery pack is extremely cheap for its specs... normally it might cost 450 dollars for even a 10 amp 48 volt battery.... so this is essentially the best i could find price wise.... i figured id get some opinions before i go ahead and buy it...

im planning on getting a 48 volt 500 watt motor and im trying to get as long of a range as possible while getting around 23 -25 miles top speed which is more than enough for me... this battery bank seems liek it should give me about 40 miles distance.... give or take.. probably take.... around 34 miles perhaps..... theres a lot of 20 amp battreries that go for between 350 and 380 dollars.....

also my plan is to buy two of thse and keep one 20 ah battery on the bike and another in a backpack to be charged indooors at my workplace... or to be taken out and swapped when the previous battery runs out... essentially giving me a 40 amp hour battery system.... is this feasable.. how easy would it technically be to swap out a battery mounted on my bike and hook it up to the speed controller... it seems liek it should be pretty simple actually to jsut swap out a battery and plug it in to the controller after unplugging the dead one... i could probably use a special bracket or something on the bike that allows for swapping or an easily unscrewed bracket that i can swap the batteries and screw the new battery in on the fly on long trips... or perhaps a rear cargo thing.... either way it doesnt matter my qyestuin is how easy would it be to swap out a 20 amp battery from the controller... for another 20 amp battery...
 
http://www.aliexpress.com/item/FREE-Shpping-High-Capacity-Electric-Bike-Battery-48V-20Ah-Lithium-Battery-1000W-Rear-Rack-Battery-with/32502147608.html

this is example battery im looking at buying
 
Aliexpress is a crapshoot, like pretty much any China direct retail.

If you are going to carry two batteries, charge them simultaneously and hook them both up in parallel on the bike. That way, they discharge at half the amperage and you get better range, performance, and battery lifespan.
 
He's right, it's a crap shoot. And, they do ship it to you illegally. If it comes in a few weeks, they flew it illegally. It won't be labeled battery, they'll call it a power supply, or even toys.

I bought a similar alibaba pack last summer, and it works ok. Never get 20 ah out of it, but for now it's putting out 18 ah.

If you buy a 48v 20 ah, it will be plenty large enough to power a "1000w kit" You'd get between 20 and 40 miles range, 40 miles being riding very slow, and pedaling up almost half the power. So you'd need a very long ride to want to carry two batteries.

I carry two batteries sometimes, 48v 30 ah total. So I can ride up to 30 miles very fast. It's a lot of battery weight, but I ride cargo bikes that can handle a heavy battery. When I carry two, I connect them parallel to get the maximum ah from them. I have to do this, because it's a 2000w bike.

Start with one battery, see how that deal goes. There will be a percentage of bad ones sent out. So see how happy you are with battery one first. You might be able to just charge it, vs carrying two.
 
Don't know where you're located, but if it's the US why get involved in a crap shoot when Luna Cycle is available?
 
well this is basically the cheapest ive seen a 20 amp 48 volt battery....

would you guys recommend doing a 40 amp hour battery instead of buying two 20 amp hour ones.... im worried it might break or something from a bumpy ride and frock me over... id rather get two...


and you say it will ride 1000 watt 48 volt bike around 20 to 40 miles..... going very slow.... i thought 48 volts go fast!! are you saying it wouldnt have the ability to go a top speed of 20 - 25 miles per hour or are you saying that if you did chose go 25 miles per hour or whatever the top speed is... it wouldlnt go as far as the 20 - 40 mile range youd get by just cruising at a lower speed... or perhaps 20 -25 miles per hour is slow in your opinion because for me 25 mph is perfect as a top speed... 17- 20 for cruise speeds... is IDEAL for me...
 
So where are you located ? 20ah is good size for a bike.
If you go 15mph you can get 44miles, 20 mph 32miles, 28mph 23miles. Guesstimations. Speed kills range as you sit on the bike like a parachute.
 
joeA said:
well this is basically the cheapest ive seen a 20 amp 48 volt battery....
which usually says something about it's quality, specs, and/or performance and/or longevity. ;)

would you guys recommend doing a 40 amp hour battery instead of buying two 20 amp hour ones.... im worried it might break or something from a bumpy ride and frock me over... id rather get two...
I presently use two 20Ah packs on my SB Cruiser trike...it leaves the option of using only one if I don't need the range, or if sag of just one pack vs both at same time doesn't matter, etc.

Because I have mulitple vehicles, having more than one pack that can be combined for greater capacity on one vehicle, or can be split between vehicles, gives me options I like to have. If I only had one vehicle, I'd probably wanna have the bigger pack all the time...but two packs still makes sense because you can mount it on either side of the vehicle for better weight distribution.

And also in case something does go wrong with one, you can disconnect it and still use the other to get to a place you can deal with the first one. ;)

and you say it will ride 1000 watt 48 volt bike around 20 to 40 miles..... going very slow....
The faster you go, the more power you use, and the faster you use up the power, so the less range you get. So if you go slower you get more range out of it.

If I go 15MPH rather than 20, I get several miles more range, under flat terrain no-wind conditions, on the bike. It's even bigger difference than that on the trike, cuz it has more drag..
 
yes all very true and very helpful speedy responces.... I am in New York City.... the user feedback on these batteries is near perfect and they apparently allow you to return the battery at zero cost to the buyer if it arrives not working... . which is understandable i mean even for ANY company even a high quality battery could have something bad happen in shipping and not work....

so going 15 mph id get 40 miles.... with NO pedaling??? because thats what i usually go (no pedaling) by when i refer to mile range... and if you were talking about 40 miles with pedal assist.. that means id get around 20 miles so thats cool... 40 miles pure electric no pedaling at 15 mph would be even better lol and probably life changing....

but anyway... im wondering how easy it would be to just swap out batteries like when one runs out you put in the other 20 ah.... im pretty new to this but from what ive heard its easily plugged in and unplugged from the speed controller.....

also im looking at some ebay 500 watt 48 volt conversion kits... any recomendations... for example i hear front wheels are better... and i know nothing about disk brakes.. geared hub motors vs whatever the non geared hub motor is called... obv i want brushless... solid state controllers.... etc... what should i look for
 
http://www.ebay.com/itm/201453686831

this seems like a good option considering i could just ride slow to lower the amp usage to around 500 watts... essentially making it a 500 watt kit....
 
also this lol

http://www.ebay.com/itm/26-48V-1000W-Front-Wheel-Electric-Bicycle-Motor-Speed-Control-Conversion-Kit-/201456854568?hash=item2ee7c3a628:g:9-YAAOSwYHxWMD5q


also i have a hampton cruiser style bike with the rear wheel style brakes that work by moving the pedals backwards if i get a front wheel electric bike. this essentially will function just fine as a break system???? also would i be able to pedal assist by pedaling the back wheel and having the front wheel aid me with the motor?
 
geared looks attractive while direct drive also looks attractive.... if i get a DD motor... and the powerful high voltage battery and 1000w motor i plan to get and my weight of like 117-125 lbs as a skinny teenager... will it be able to climb hills decently...

also


last question and ill shutup....

disk brakes physically stop the bike so if the throttle is still on thats a perfect example of what you dont want to do????? especially if the disks are on the same wheel as the hub??? or am i wrong and it really doesnt matter and you can activate the disk breaks reguardless of the throttle although it will just slow down the quickness of the breaking by fighting the motor....

some goes for pad breaks obv... and i dont even think the rear hub breaks where you pedal backwards is even possible on a rear hub motor i guess.......

also what about regenerative breaking is that a special attribute of certain motors or does it work on any motor as long as your speed controller has the regenerative breaking function!?!?!??! or how does regenerative breaks work in general because i have no idea besides that its magnets stopping the wheel.... which is a very basic understanding id like to improve on

thanks!
 
joeA said:
I am in New York City.... the user feedback on these batteries is near perfect and they apparently allow you to return the battery at zero cost to the buyer if it arrives not working... . which is understandable i mean even for ANY company even a high quality battery could have something bad happen in shipping and not work...
Personally, I'd doubt that they'd actually pay return shipping (with all I've read on ES over the years) but I suppose it could actually be true.


so going 15 mph id get 40 miles.... with NO pedaling???
That entirely depends on teh amount of Ah (capacity) used up for each mile by your system, terrain, how much you stop and start, etc. The more slopes you go up (and steeper they are), the more starts from a complete stop, and the harder your acceleration from those stops (and up those slopes), the more Ah you'll use up.

If you don't have a wattmeter, you won't be able to know for sure until the BMS of the battery (if it has one) cuts out to protect it from overdischarge.

If you do have a wattmeter, many of them display Wh used, which is a better way to track power usage than just Ah, and if it has a speedometer/odometer as part of it, it might even display Wh/mile, which is a good indicator of efficiency you can use to compare to other people's builds and bikes and systems.

For instance, my bike uses around 30Wh/mile, but my trike uses almost double that for the same route, conditions, and speeds, even though both of them have two motors and the bike's controllers actually allow more power usage on starts from a stop/etc., vs the trike--the trike is just so much bigger and heavier and less aero that it uses way more power.

In general, that means around 1Ah/mile for the trike, and around 1/2Ah/mile for the bike.

Probably yours would be more efficient than mine, (being lighter), but you probably would have more complete stops and starts, so you'd probably still use around 1/2Ah/mile, meaning 20Ah might get you 30-40 miles, depending on whether you really get 20Ah out of it or not (and for how many charge/discharge cycles you get the full capacity, cuz batteries lose capacity over time/usage).





because thats what i usually go (no pedaling) by when i refer to mile range... and if you were talking about 40 miles with pedal assist.. that means id get around 20 miles so thats cool... 40 miles pure electric no pedaling at 15 mph would be even better lol and probably life changing....

The catch is if you live in NYC, and you don't pedal, the police may have something to say about that, as i hear from various things posted here on ES that they don't like ebikes very much and seem to want them gone. :/
 
Sorry if that range comment was confusing. But first back to another issue.

They ship you the battery illegally. It IS possible you could get fined for knowingly ordering a battery you know will be shipped illegally. But in fact, I know of nobody ever charged for receiving one. There have been cases of them destroyed by customs. Have a happy time getting your refund if that should happen. IF you get a defective battery, like damage from shipping, YOU CANNOT ship it back. Over in china they ship illegal because they are over there saying come get me. Here, hell yeah they can come get you.

That's the crapshoot I refer to. If there is a problem, they may send you parts, but you better be a battery tech to handle the repair.

I don't mean to spread endless fear, I'm sure a high percentage of even the cheap batteries work. Mine did. The forum has a few bad battery threads, but it's not jammed with them. But it is, a crapshoot buying direct from china.

I can only say what I get for range. I pedal, but not very hard. Personally, If I was to sit in the bike saddle for 40 miles with no pedaling, my ass would be numb as hell. So for me, 40 miles from 48v 20 ah requires at least some pedaling, and going about 15 mph. At 18-20 mph, still pedaling, about 30 miles, perhaps more. Perhaps more because weather also has an effect. At 25 mph, maybe 25 miles, and at 30 mph closer to 20 miles range. 1 ah per mile, hauling ass. BTW, few bikes can be pedaled much past 25 mph. Oh, you can flap your legs, but not usually pedal hard. So the ranges from 25 mph on up are no pedal ranges.

So your target of 18 mph, should get you close to 30 miles no pedaling. But lots of other shit affects range. City riding has lots of stops, which can cut range 25% easy. But most motor setups do better, losing maybe 10% for stop and go riding.

Again, I'd say get a 20ah, see how far it takes you. This will depend on how good it is. My cheapo battery gets 18 ah max, though it's supposed to be 20 ah. Then decide what size you need to go your longest distances. In my case, I find 30 ah of actually usable battery is all I really need. I carry a 20 ah, and a 13 ah. I can ride fast (30 mph) to the farthest side of my town and back on that easy. 30 miles trip, including a huge hill to get home.
 
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