Li-FE for bicycle alternatives

Thats a lot of money. 20AH is a lot of range, perhaps a good deal if you need that much. Here's a couple of good deals on ninh/nicd if your willing to give them another look. 36v 8AH 5C nicd $250. 36v 18ah 3C nimh $690.
www.ebikes.ca/store

In Li-POLY they have High Power Polymer Li-Ion Module: 37V 20 Ah (740 Wh) 50 Amp Rate for $959, and Hi-Power Polymer Li-Ion Battery Module: 37V 10Ah ( 370 Wh) 40A Drain Rate for $450. Of course LiPOLY has the capability to explode...

I guess that is why they put them in a "Water-proof / Fire Retardant Enclosure"

You don't want to be sitting on those if they explode.

I'm thinking about options before I plunk down for this. Batteryspace? LifeBATT? DeWalt? Milwaukee V18? PingPing? Others?

I'd consider the Ping battery. You could get 36V 20AH for about $500 with BMS and charger. The BMS while not that elaborate, is effective. The high Amperage disconnect of the BMS is set to just over 30 amps. If that isn't enough amperage for your application, it's pretty easy to change by adjusting the shunt resistence with a couple of copper threads. The cells used are rated for 2C continous and 3C peaks. For a 20ah pack that's 40amps and 60amps respectively. I'm testing one as a range extender on my Viento. With the High current cut off set to ~60amps the battery is performing real well after just a couple of test rides. Max amperage peaks have been 58 and the full speed on the flat amperage from it is about 22amps (just to give you an idea of how hard I'm pushing it).

Time is the only thing that will tell if these batts are a good value, or too cheap to be any good. So far except for the duct tape I'm pleasantly surprised by the build and performance of the pack itself.

Aerowhatt

I have the 36v13ah from batteryspace with 3 chargers. I think the pack is good, safe and solid, and can recommend it for the smaller size motors say constant 400w. The Chargers need fan cooling. But over 16amp draw it noticably sags, my max amp was often about 22amp for 31v. So if you need a regular 30amp to 40amp discharge I think this pack is too weak, you'd want to double up.

Anyways to fix this for my bike I have added 8 more cells to another 9.6v which is perfect for my motor, and voltage sag is not an issue as I rarely go over 15amp with 46V.

A 20Ah pack means you want to go 25 miles
If not, try a 12Ah pack
falconev

Hey dude! I just got done commute on 20a 80v ebike for 30+ mph, no problem. I bought 3 ping battery, 36v10ah...(a little thicker than 7ah sla battery, weigh 8lbs each, assembled with flat foil cells, rigid inside, bms included, charger included...I cut the 4950mah, 3.2v cells apart to single cell series, same size as 36v10ahlifepo4 11.8"x 4.5"x2.8"...I remove bms, and ride 5mile to work and charge till green light with supplied charger, I checked amps, read 1.33, so it 1.5ah 40v charger, and then I ride home today after 4hr charge (1/2 in parallel). The battery perform flawless ubder 20a load, no bms, and measure 39.6v per1/2, same as 10mile trip with 72v ping batteries, I'd guess at 2/3 capacity, So these batteries perform super with the smallest size and weight, the cells are perfect size for bike, cells flat take up less space...but of course the best part is the price! About $250 ea delivered quickly...the chargers have 3prong (not xlr, but chinese) but there is no chrger receptacls, but complete system, high power, my guess is the 2c current cutout could be bypassed easily, by running the negative power wire from the battery, instead of up through the amp cut out, then the charging bms, still there, and switch back negative through bms...I have been running the single cells at 20a ea, 4c, ping said they could do 5c, they can...but, after my riding today, the cells got a little warm, nothing hot, just warm, I see that these cell can run 20a with no detectable peukert thingy...I had been thinking about the drill batteries, and all the hassle , and expense, and these ping cells are flat and square, not cylinders, and bms and charger,,,plug and play! And then I found out because the battery is so much less dense than lead, I made easily a clip on battery, and put one in the basket, as won't bounce around like lead chunk...so I say get ping for either correct amp bms, or try a bypass switch for neg for 4c max, won't hurt the battery, but one could use 2 of these 36v 10ah and bypass the cut off, and I would see no reason for battery malfunction, but its cutting close ...Anyhow, I have no bms for charging or discharge, all the cells are maintaining perfect balance so far, a $250 battery or %500 for 36v 20ah, and he made mine configured to my size...They work great! No more invisible power fade from weak sla battery, these things are so much fun! My bike goes so fast, there is no way I could hold the throttle on ...so I just gas and coast, the bike is so light now, I cannot whelie like before with sla battery, but man can I take off...all the way to 33mph...I wouldn't recommend remove bms...it was just too many wires for me, but now that I've seen the insides of the battery, looks like an easy bypass...I connected my battery to 250w scooter, It was hard to go , as bms continually cut on and off from way over 20a draw, so didn.t hurt anything, so this great price for an excellent performing battery...now I've got a bunch of extra batteries...Ok, now finally, everything is available to make a nice ebike... The battery rocks! 80v, 2hp, good for 7-8 miles?

How much do the cells cost & where can I get a BMS for
my 36 volt battery pack??