Help on 24v DC power supply to test Tongxin!

[larry3t]

I introduced myself on the other page as a newbie who is converting his Next Beach Cruiser with a 24V Tongxin 180 Watt 190r/m 9.9A front hub motor. The motor and spokes are coming in a couple days - wish me luck with my first build - I'm sure I'll be back here with questions and to share. I would like to test the motor when the controller comes from China in a few weeks but need help. I plan to develop my battery/case/wiring over the winter and am studying the posts here studiously.
To test the motor before building it into the wheel I would like to use some kind of DC power supply. Could I adapt a cheap 24v charger, use a switching power supply like you see on eBay for LED lights in 24V DC. I am thinking 1-3Amp as someone suggested using a 2-3 Amp fuse when trying to get connections right on the new motor controller/throttle.
Any and all suggestions or experiences welcome!!!

 

[Deleted member 4366]

If you just want to see the motor turn without load, it'll draw about 0.5amps in the steady state, but a lot more in a surge at the beginning to start uo, That's no problem for a battery, but could very easily blow a low amp fuse and I'm not sure what it would do to a low amp power supply. It would therefore probably be better to use a pair of 12v batteries if you can. You might get away with a power supply if you spin the wheel by hand to get it going before you power it up.

 

[larry3t]

Thanks for the advice! I have read your threads before and know you are very knowledable. I could use a power supply of 5,6 or even 10A. The reason they suggested so low was not being sure of matching the controller wires to not do damage or blow the controller. If I get two 12v Pb batteries it would be just for this test as I definitely would like to go with Lipo or at least NiMH. Thanks again and all thoughts wanted and solicited.

 

[jerrysimon]

When I first got my 36v Tongxin I had a 36v, 1.6amp charger and connected it up to that to test if it worked before I got my batteries. It did but turned very slowly.

As stated probably better to test with a couple of 12v PB batteries though.

Here are my threads showing my Tongxin and DIY battery build.

Regards

Jerry

 

[larry3t]

Wow! Great threads Jerry! I have gotten into several more linked to it, very helpful.

Good news! My Tongxin came from Utah today. They have more on USA eBay here.
Mine came without spacers, washers and nuts which I plan to talk to them about, will let you know I hope I don't have to scour for them and they will supply them. Spokes arriving in a few days, and believe it or not the Chinese controller ordered on November 29 on eBay is in the USA in NYC already.

Now for a couple battery questions. I am thinking of using a couple of Lipo batteries in series. I see these possibilities:

(2) 3S = 11.1x2 = 22.2 volts (seems low)
(3) 3s = 11.1 x 3 = 33.3 volts (seems high but I can get a deal on them)
(2) 4s = 14.8 x 2 = 29.6 volts (seems high) (more expensive and harder to find)
(1) 7S = 25.9 volts (good but very expensive and hard to find)
How much over 24 volts can I go? A little worried about the 10A controller, but could get a higher rated one.
Also of course how many Amp and how low can I get away with.

can unequal voltage batteries ever be connected in series? I assumed not.
Would be great if I could use a 11.1V + 14.8V = 25.9v

Any thoughts on A123 combination for 24 volts appreciated. How much can I go over?

Thanks again for the advice! Here's my new motor from a bike shop in Utah via eBay:


Adding this after speaking with the bike shop on eBay where I bought the Tongxin - they are as good as they're word and sending out the nuts and washers from Utah right away. Thanks Mike!

 

[amigafan2003]

How much over 24 volts can I go? A little worried about the 10A controller, but could get a higher rated one.

I'm running my 190rpm Tongxin @ 44.4v (2s2p 5000mah 6s lipo) with a 13 amp limit on the controller - watts peak at 650w.

It does 20mph unassisted on my 700cc Trex FX 7.5

Very happy with it - 250miles so far.

 

[jerrysimon]

Amigafan yours is no doubt a 36v one though and not 24v like Larry's ?

Larry thanks for your comments and interesting to see a supplier of Tongxin's on ebay. They must be the only one!
Its not clear but looks like they don't sell internationally.

As I state in my threads I use 12s1p A123 batteries which are 39.6v nominal and 43.2v fully charged. I am not sure what the limit would be on a 24v one but would say history on this forum proves that these motors can be fragile and should not be over volted. That may have an impact on the controller which I think need to be limited to 13amps or thereabouts. I purchased the motors with controller so assumed they were correctly specified.

I am not sure about 24v motors as have never used one. Don't they draw more current ?

Regards

Jerry

 

[jerrysimon]

Interesting looking at all their motors. This one is wrong not being a 8-Fun but definately a Tongxin

8-FUN Electric Motor Bicycle Hub 36H 24Volt 180W | eBay

Regards

Jerry

 

[NRG]

If anybody knows where to get a 36v one please PM me! Thanks....