Recent content by cord

I had my ~4kw bike setup with no chain AND no freewheel/sprocket on the hub motor. I was pulled over one time after passing a cop at ~40mph, and of course I was "freepedaling" to give the illusion that I was still riding an electric assist bike. The cop took a look at my bike and told me to...

Please excuse my newb-ness if this is a bad idea but would it be possible to wire two of these switching regulators in series on the input, and then parallel on the output? So then let's say your battery pack is at 80V, the regulators will each see 40V at the input, and then you can get 12V 10A...

Yes I'm happy to help! If they are already building something similar then that will help a lot. Does the board they are currently building have internal electronics like this board? It's hard to tell from the CAD file you posted but I'm wondering if you will make the base board carry all the...

Composites Engineer here. I'm not sure how the Chinese company you listed builds their parts but those prices are REALLY low. That doesn't necessarily mean they can't make good parts, but it does mean that you may have to work with them to get what you want, and the prices may go up. For...

I had never built a wheel until I tried it with a hub motor. First one must have taken me 4 hours. But once you get the hang of it and get a system down it's not too bad. I usually clear a spot out in front of the couch and build the wheel while watching football / movie / whatever. It's less...

I've got 800Wh of lipo on the bike plus an extra 1300Wh that I throw in a backpack if I'm going on a long trip, although I hardly ever go far enough to need it. I can easily make 15 miles with the 800 hauling ass around town at ~35mph :D

I'm a water skier so this is very exciting to me! http://nautique.com/videos/index/100-electric-nautique

Have you had problems with any cells puffing after sitting a while without the heat shrink on them? I have had one 5Ah Turnigy pack where a cell puffed after sitting over night with the shrink wrap off, so I've been nervous about removing the shrink on any other packs. Note that this was a brand...

I also spend 30+ hours a week using CAD (Soildworks). The best advice anyone ever gave me and that I can ever give someone who is trying to learn is to get a hold of someone else's files with the build history. Back up the history to where they began and see what they did, why they did it, what...

What about running two DC/DC converters in series on the input side, then in parallel on the output side? With say, 72V, each converter would see 36V input. Would that work?

Order up two of these: http://hobbyrcworld.en.alibaba.com/product/361391030-209613140/20000mah_18_5V_20C_RC_Lipo_Battery_For_Big_Airplane_RC_Battery.html

Ok so I've got some light to shed on the pricing side of these batteries: And when I inquired about next year's prices: So there you have it!

It's difficult to read between the lines sometimes when dealing with Chinese companies. I was curious about these prices being so low so I send an email to the factory asking if these were promotional prices to alleviate inventory or if this is the permanent price on these cells. This is the...

After doing a quick google search, I found a few images of discharge curves for lipo. It seems to me you'd have closer to 90% or more by stopping at 4.1. Hell you could even stop at 4. Set the LVC to 3.4 or 3.5. Why aren't we already doing this with lipo? If the cycle gains are really that...

They said they's sell me one sample. My Megapower charger won't cycle lipo, what's the best charger for cycling 6S lipo? I'd be willing to get one and test the pack.