waste of time. don't bother.

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I'd see what cell_man can build you. He has A123 cells for cheap and can weld them up into pack with copper interconnects. Life doesn't get much better than that.
 
ericmann2000 said:
..
can you give me a link to tongxin sale in europe please ?

I know a dealer, who sells tongin in germany http://www.novosport.de/?Produkte:E...atz:Paket_%22_klein%2C_leicht_und_leise%22%3A

ericmann2000 said:
some people told me tongxin have problems, they are not robust and they will break after some time or giving it too much power
what's your experience with them?
That is correct, the mini tongxin or the mini front cute may not be overloaded.

ericmann2000 said:
what controller do you use? what's the max current you send into your littlest motors (cute or tongxin)?

I operate these small motors only with max 10A current. I mostly use the three level controller of e-crazyman with Eb206 board (L1 = 6km/h L2=20 km/h L3=28km/h).

salute!
Nader
 
Okay, in the meantime I've got a pretty good deal with Doctorbass, he's supplied me with some crazy battery packs, so i hope he can support this project with his dewalt pack cells, he is pretty good at packs if i have to cut costs and build it myself

texaspyro said:
I'd see what cell_man can build you. He has A123 cells for cheap and can weld them up into pack with copper interconnects. Life doesn't get much better than that.
 
thank you a lot Nader
do you use your tongxin at 36V ?
do you get the same speed from the cute motor ?
do you find differences between them ?

bye
 
what kind of controller you want to use ? 200amp :D :D am wondering if my 18 fets lyen controller can handle it because i want at least 120 130 amps burst for my daily drive :twisted: :twisted:
 
I've discovered what i'm suffering from is a very common case of chain suck!
"What is chainsuck?
worn_chainring.jpg

Chainsuck is when the chain does not release from the bottom of the chainring. the chainring lifts the chain up to meet the incoming part of the chain. Because it can't carry on around the chainring and that there is a chainstay there, the chain gets jammed between the chainring and the chainstay"

the cure is titanium chainrings. they will still wear, but 4 x less than normal chainrings. They also may come in the right 5 hole bolt pattern, so this should be a simple easy fix after all :D
The etek'll crack before he wears titanium out!!!


"The only way to avoid it is to replace your Aluminium chainrings as soon as they show signs of wear (pointy, narrow teeth, wide gaps). This is an expensive job, with very fast wear rates in the Winter and the dreaded chain suck around the corner, the answer has to lie with harder wearing rings. Steel and Titanium rings wear at about the same rate (Ti has the edge) but Steel is a heavy alternative, especially for a middle and granny combination. Titanium rings will last around four times as long as Aluminium. There are many chainsuck preventing ‘gizmos’ on the market and one or two fairly effective home cures, involving giant zip ties. The trouble is that worn chainrings accelerate wear on your chain and this passes that wear rate to your cassette. The Steel cassette rings should give long wear but a prematurely worn chain will kill your cassette in a far shorter time. Once the cassette is badly worn the chain will slip suddenly and unpredictably during occasional hard efforts (we only put in hard efforts occaisionaly...) This can cause badly banged knees and shins, ouch. In order to ensure a smooth shift under load the Cycle Dynamics Ti Chainrings have four pins and shaped teeth which assist the chain as it climbs from the granny to the middle ring. Without these changing gear would be a clunky affair."

http://www.mtbbritain.co.uk/cycle_dinamics_titanium_chainrings/cycle_cynamics_titanium_chainrings.html
 
About 2 years ago I met dreaded "chain suck" on my trike (homebuilt). It was my fault but it still hurt when I locked the rear wheel and flipped me at about 20 mph. 6 broken ribs! Luckily I was only a block from the hospital and was able to motor over there on my trike (I didn't pedal) with my wife on her bike. Chain suck sucks! Trikes make good electric wheelchairs.
otherDoc
 
I tried finding the biggest Lipo battery out there, this is it.

Effectively, you don't need to buy 'minimum order of 5' you can buy two.. for 44.4v 20ah :arrow:
This is the quotation, includes how I paid http://uploading.com/files/1e94cd33/quotation%2BPI-ECY-101013062.xls/

B4 charger x 3
14.8v 20ah x 3
switch mode power supplies 12v 5A x 3
fender aprons (BMS lvc/hvc) x 3

And we get 1 Lipo 44.4v 20ah that doesn't need the cables rewiring to recharge with, otherwise, we can use the 10ah packs (in the quotation) to get parallels for much higher current running through 12ga but the recharging gets complicated.

now with lipo, it's very common to find 10C discharge Lipo in the r/c world, 15C is usually the lowest, and with a good seller like these guys seem to be, they've got gold status, it looks promising.
They're rated a V&R gold seller on alibaba, great reputation as far as i have searched. The charging problem with fewer Lipos is much easier, in fact you could run 4 of these at 88.8v 20ah permanently wired up to switch mode power supplies connected to two 6s chargers... :D no fiddling with wires


This is the battery quotation catalogue http://uploading.com/files/883f47e1/EC%2BENERGY%2BQUOTATION.xls/

These are their chargers catalogue http://uploading.com/files/1f9cmff7/NEW%2BBalance%2BCharger----November.xls/

They mentioned a 'fender apron' which is $15, fender apron means 'BMS', LVC/HVC protects your investment from turning into charred smoke

The pack's 65mm x 55mm x 273mm

http://www.alibaba.com/product-gs/361394222/20000mah_22_2V_20C_RC_Lipo.html



They're $109 a piece.

Claimed 400A peak 300A continuous....


with two of these in series, that's 4kgs, or 40miles worth of range on my ebike, with 4 of these series paralleled 2p2s, that's 60-70miles!

I asked 'Yan' about the fender apron, this is an LVC/HVC cutout function that saves the batteries if one of them goes below lvc or above hvc.
those are $15 each. that's an lvc/hvc
Looks to me like the r/c tech is there, it's just getting the right ammount of lipo paralleled, and at 2.2kg.......... this will be a lightweight long ranger.

I'm going to order 2 samples, to see if they work, if they don't I'll get my money back, I've got a test bed to test their peak power output
I shall ask them what each cell's internal resistance is and paste that in here.

Now I know people generally follow the hobbyking path, because some of the active members on this forum like using them, but I'm trying to keep an open mind on these chinese Lipos if nothing else a lot of them supply 4c discharges, and at that rate, 80A continuous sounds fun. If they supply 10C then that's fantastic! (there is absolutely no way at that price that these supply 20C...i disregard that...).


My suspicions are on the form factor, what kind of flat cells have they used, also, 300A using 12 Guage cables, i'm wondering whether insulated 12 guage could withstand 300A continuous, nevermind 30A, but then, most lipo batteries have those 12 guage, including the turnigy nano 22.2v 5ah rated at 90C mentioned in arlo's electric dragster thread

Any thoughts on this
 
Interesting find.

I very much like the idea of having some bigger capacity cells, just to avoid the rats nest of wires needed to hook up lots of smaller cells. 20Ah seems a nice size to work with, too.

I'm looking forward to seeing how these cells turn out, as I'm going to be looking for a 15S pack of around 40Ah to 60Ah in the Spring, when I resurrect the RD50 project. Six or nine of these packs would make a nice little power package if their performance is OK.

Hobby King are only retailing unknown products from somewhere in China and putting their own brand labels on, so who's to say that these are any worse/different?

Jeremy
 
It's nice to have such a large pack pre-built. I would probably order a couple first and test them throughly to be sure of the quality before dropping tons of cash on it (like anything from china). 20C can mean anything these days... They aught to start using Ri as the spec.... and capacity at rate x.
 
Thanks Jeremy

''rat's nest'' is a good way to describe those cables, I used bits of 'solder reel' when i first connected the a123's up, they would puff up in smoke when i did something wrong, so the solder would melt in an instant acting as an active fuse, that was my method of 'wiring' noob-style any a123's i had. I got to know those a123's and now am looking at the lightweight of lipo.
I've got an ammunition box ready for them.

I found the factory that makes these, so who knows, hobbyking might well get their packs from the same place..as these come from one of the bigger factories.
If this pack is what i think it is, it could really get us going with lipo at last, we could use two safety devices per pack, the stock 'apron' and tppack's bms, and we're all good. This might be something that could make the lipo scene a lot easier to handle for a first-time lipo n00b like me for a 'charge it' and keep an eye on it, but don't risk a plasma ball with it!

Jeremy Harris said:
Interesting find.

I very much like the idea of having some bigger capacity cells, just to avoid the rats nest of wires needed to hook up lots of smaller cells. 20Ah seems a nice size to work with, too.

I'm looking forward to seeing how these cells turn out, as I'm going to be looking for a 15S pack of around 40Ah to 60Ah in the Spring, when I resurrect the RD50 project. Six or nine of these packs would make a nice little power package if their performance is OK.

Hobby King are only retailing unknown products from somewhere in China and putting their own brand labels on, so who's to say that these are any worse/different?

Jeremy
 
Hi
really good customer support.
They emailed back (saturday 8pm) stating they'll check all the cells before dispatch so make sure we don't get any dead on arrivals. This is good from a gold seller.

grindz145 said:
It's nice to have such a large pack pre-built. I would probably order a couple first and test them throughly to be sure of the quality before dropping tons of cash on it (like anything from china). 20C can mean anything these days... They aught to start using Ri as the spec.... and capacity at rate x.
 
There must be something wrong with the numbers. :?
I compared the volume of 4x 5000mAH 6s 20C turnigy cells and got 1421x 10³ qmm.
These wonder cells have a volume of 975 x 10³ qmm, which is 40 % less.
Also the weight is 1kg less, again a 40% advantage...

Even when we concider a huge packaging advantage, these cells would be a major breaktrough in technology and couldn't be that cheap.
-Olaf
 

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I will wait patiently on your test results. I hope they will have a good C-rate they claimed it to be and if it's really 20Ah... even if it is 15Ah ...then i'm ok with it. This will give E-Scooters with less storage room for batteries a new perspective !
 
I E-MAILED asking for a price for 5pcs. shipped to zip 33617. After DOGMAN moved over to LIPO he's getting everyone hooked. BTW 5 pcs. was a min. order thay will ship. GOOD DAY :mrgreen: :mrgreen:
 
Ask about cycle life. I found some 10C and 15C lipo for that kind of price last year, though not big capacity packs, and the guy shot straight with me and admitted to a 100-150 cycle life. Granted that was in more demanding RC use, but... Push for getting the IR first, which will be a good indicator of quality. You could also inquire of their procedures for cell matching.

The 12ga wire offers a clue, so forget 300A continuous unless you want to see fireworks. The price is great, so hopefully these are a diamond in the rough and the company has high quality cells and is trying to lead the market in high capacity RC packs that no one else offers. I took 3 Alibaba shots for hub motors, and while one was a total loss, another made up for that loss. This company you found looks legit, so a rip off isn't a worry, just product quality. We all have our fingers and toes crossed for you. :mrgreen:

John
 
They said they'll ship 1 or 2 samples.

Good day :)

BLUESTREAK said:
I E-MAILED asking for a price for 5pcs. shipped to zip 33617. After DOGMAN moved over to LIPO he's getting everyone hooked. BTW 5 pcs. was a min. order thay will ship. GOOD DAY :mrgreen: :mrgreen:
 
I've asked them to post on the forum (on this here thread)
These should be 4ga..to handle 200Amperes for a few minutes...so I don't know, seems to me like these cables aren't going to do the job, but at least there's the capacity to use from these lipos if we disassemble them and rewire them with 2ga or something

nope :oops:
samples, like, I need to pay them $218 for two of these and cost of shipping. Even if they don't supply 300A, it's pretty good for a 40AH pack that probably WILL supply closer to 150A continous with two 12guage, at around 700USD shipped. that's a lot better than an expensive load worth of lifepo4........and the range for me is 70miles at full speed with an etek, nevermind a 9c or x5 :shock:

fizzit said:
novembersierra28 said:
They said they'll ship 1 or 2 samples.

Samples? Like the free samples they give you when you walk around costco? Do you have to pay shipping? :mrgreen:
 
Dear Jeremy

I know knoxie tried disassembling some lipo packs, and it was a nightmare, have you found a way to upgrade the cables?
Best

Nad

Jeremy Harris said:
Interesting find.

I very much like the idea of having some bigger capacity cells, just to avoid the rats nest of wires needed to hook up lots of smaller cells. 20Ah seems a nice size to work with, too.


Jeremy
 
novembersierra28 said:
Dear Jeremy

I know knoxie tried disassembling some lipo packs, and it was a nightmare, have you found a way to upgrade the cables?
Best

Nad

I've not tried to change the pack cables, but as they are pretty short I wouldn't worry. A 12g cable 6ins long is only going to drop about 0.08V at 100amps, and although that's a fairly big voltage drop, it only creates about 8 watts of power loss and is probably a fair bit less than the voltage drop from the pack internal resistance.

Jeremy
 
Good work finding something like this! 20aH LiPo packs would be bitchin'. Subscribed to this thread now.
 
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