Suggest a noobie parts for 2nd build please

[phaseshift]

Ok so this will be my first real build. I bought a 450w Izip conversion off CL a few months ago and got hooked. I first bought it as a toy to walk my insanely hyper dog and ended up putting 14 miles on it the first day . Now I plan on making a better bike... Something I can take out on the trails here in Florida. Not many hills but a bunch of sand and a lot of heat. I am also kinda on a budget. I have about 500 to spend initially, then approx 100 or so a month depending on the mood of the gf. I have decided to go with a GNG 450w brushless motor and use the stock controller with it at least for a month or two. Frame will be something I can steal off CL for 50-100, but I have not decided on a full suspension or just front. A full suspension would be nice but would leave me little room in the triangle for batteries/controller. I am open to suggestions here. Batteries are where I really need the advice. I was thinking of using a battery from elifebike.com (48v 10ah + charger and bms for about 315) but the 4s1p Turnigy 5ah batteries look like a pretty good option as well. I am not too experienced with electrical but am willing to learn, so I might go with the RC batteries to save some money. Opinions are welcome on that one too.

 

[parajared]

GNG is a fun kit. Buy an extra belt, the kit likes to nom on the edges of the belts and eat them completely when it gets really hungry.

Lifepo4 is a neat way to go, but it's pretty expensive for what you get. I think that battery tech is going to make a jump in the near future so the extra money you spent for extended lifetime lifepo4 may never pay off. I felt like I rode the heck out of my bike last season and only put a little over 100 cycles on the battery. Since hobby batteries last a good 500 cycles or so, they seem like the ticket for e-bikes at the moment.

Beware of the mighty hobby lipo fire however! Lifepo4 and lithium ion users pay the extra cash often because the risk of fire lowers significantly. I charge my hobby lipos in a full fledge bunker made of cinder blocks (about $10 in bricks).

a few more tricks of the trade to pass down:
You can avoid some grief if you go to Radio Shack (or any local computer store) and ask for a 2k resistor (about 10 cents). Make a second wire coming off the positive lead of your battery and a second plug with the resistor to the positive plug on your controller. Plug the resistored wire in first every time you plug your batteries in, otherwise the electricity will arc and make little divots in your connectors and hammer your capacitors on your controller.

also BVM 8s is a nice little voltage gauge for hobby lipo. It's $10 and its really light so you can just sticky velcro it on instead of having to devise some kind of elaborate mount.

 

[phaseshift]

Man after I add up all the RC lipo stuff it gets pretty expensive for only 500 or so cycles. I found a 48v 10ah tube battery at BMSbattery.com for 230+76 shipping. I may get a little less out of it, but the ease of use and mount options are gonna make me go with it for now. I figure I can mount this on the top bar if I get a FS bike with no triangle. Now on to a display.... I was thinking a Turnigy 130A watt meter from HobbyKing for $24. Any suggestions there? I know CA is the best but $150 is a bit out of my range atm. Well, I think that is it for now... Feel free to correct me on that one.

Motor/Controller: GNG 450w Brushless
Battery: 48v10ah (15a continuous, 30 peak) with bms/charger
Display: Turnigy 130a watt meter
Frame: ?

 

[parajared]

I have a turnigy watt meter. The part that tells the wattage broke so I only have voltage, but I think it hasn't been too bad for the price. There's probably a better way to do this, but I mounted my watt meter by grinding slots in the plastic and zip tying it to the handlebars.

About BMSbattery: BMS is notorious for having pretty bad service. The standard way to deal with BMS is to buy your stuff with paypal and 3 months later you start a claim against them. This usually gets them to finally decide to send your order over, and most of the time you even get what you ordered. They can be a total PITA to deal with, but there prices sure are cheap.

I think Li-ion is a great way to go for the GNG. Hobby lipo would be 168 plus shipping for 12s/48v 10ah (usually around $50) so for just $90 more you are getting 2000 plus cycles and less risk of fire. Sounds pretty good but 15 amps continuous sounds like a big problem. I run mine at 1500 watts which is great because you can pop the front wheel up and hop up on rocks and things. You can climb up stairs and straight up the side of a mountain like a billygoat. 15 amps only gives you 750 watts, and low discharge rates leads to pretty saggy energy levels, potentially sagging you into the 500 watt limp dick range which is fine if you are just trying to get around, but will leave you feeling like a ninny little girl for more aggressive purposes.

High discharge rate lifepo4 may be a better answer, but it sure isn't cheap.

Hope this helps,
Jared

 

[parajared]

for a better description of batteries you need to see Hyena's Guide to Ebike Batteries

SLA

This is the fat girl at school. She ate all the pies and if you have to put her on the back of your bike you'll know all about the extra weight. She may break your frame if you're rough with her. That said she'll put out because she doesn't know when someone will show interest in her again. Expect some nasty sagging, and while she might be able to travel 20 miles at walking pace, don't expect her to go that far if you make her run. Expect her heart to give out after a year.

2-3C LiFePO4

This is common plain Jane from accounts. She'll cost you a bit more than SLA the Hutt but you won't break your back lugging her around and she won't drop dead after a year of you exercising her. She does have asthma though so while she'll whip along the flat OK don't expect her sprint off the line or blaze up steep hills.

6-10C LiFePO4

If wheezy Jane from accounts isn't performing well enough for you meet Helga. Part Barvarian, part Viking she can run just as fast as Jane but has bigger muscles to flex. Wanna get off the line quick or up that steep hill ? She'll throw you over her shoulder and carry you up. The trade off is she isn't exactly slight... mmmm, chunky

20-50C Lipo

Meet Kara Kent. She's hot with a fit athletic body but for her small size and weight her power is out of this world. She can easily lift 20x her weight, be super fast and in the RC world she can fly. Be warned, if you get on the wrong side of her she'll melt your skin off with her heat vision. She's a little higher maintenance than Helga but isn't she worth it ?

 

[ions82]

I went with Kara Kent for my first e-bike build. As noted, she is definitely a high-maintenance kind of girl. However, she gets my gears going (on my MAC 1000W 8T, that is) like you wouldn't believe. Her measurements are 12s3p.

Part of the reason I went that route is because the LiPo packs are modular. I can use a meter and see what the health of all the individual cells are. I had read accounts of people that lost a $500 LiFePo pack because one or two cells went bad. If one of my six LiPo packs goes bad, I can just chuck it and get a new one. I could even run 12s2p while I'm waiting for the new pack to come in. Plus, I would MUCH rather replace a $50 LiPo pack (and wait a few days to get it) than a $500 LiFePo that has to come on a slow boat from China.

Even as a noob myself, I think LiPo is great. I just make sure to take precautions when charging. I use a Cell Log to check the votage of each pack before I parallel balance charge. It takes a little time getting everything connected, but it's worth when it comes time to twist the throttle!