Marin Muirwoods eBike (3RD BUILD)

[TonyReynolds]

Is something like this what I need to step down 48-52V DC to 12-14V DC?



http://www.powersupplydepot.com/-48V_Input_12V,_17A_DC_to_DC_Converter_Phihing_18093_PS.asp

Looks like it would work, but it's big and needs 35CFM airflow. Any better options?

They have others as well. One has 4 outputs: 3.3V, 5V and 12VDC x 2.

The latter would be ideal for running separate circuits for headlight and taillights/marker lights.

???

[TonyReynolds]

I've been investigating batteries for powering my lighting. While I could easily find a 7 or 8Ah Turnigy or Zippy LiPO in 14V that would power my headlight, I would also have to buy a charger/conditioner, plus mess with a different chemistry than LiFePO4. I could get a power tool battery and modify ot for use on the bike, but that's expensive and limited Wh.

I asked Paul (cell_man) for a quote on a 16s1p A123 battery, thinking I could use it for my lights and as a "reserve" e-tank for my motor if needed for a few more miles on a ride, but at $160 plus shipping, I think I'd still be paying a lot for limited Ah's.

I've pretty much decided to ask him to do a split build on his standard 9.2Ah 52V A123 battery, which is 16s4p and $450. It comes with a charger, and I need a second charger anyway. The first 16s1p option would require me to buy a charger separately.

I'd end up with two 16s2p batteries connected by a harness that would easily have enough Ah's to power my lighting as well as be a nice "reserve" for my 11.5Ah triangle battery. I was going to purchase more capacity at some point anyway, and the 16s4p battery allows it to be split equally. The only thing is finding a DC-DC converter that would give me 12-14VDC, and I'm onto a couple that would work.

The DC-DC converter will go in a mess bag on the handlebars and the battery will be split between two front panniers on the front rack. Between the batteries in the front rack, center triangle and motor in the rear wheel, weight will be low and well-distributed.

Thoughts?

[DCMotorworks]

I'm running 24v for my headlight/taillight/brake light. I just shunted 24v off the 48v battery pack. not ideal but it works.

I recently bought one of these off of E-bay. supposedly can be run off of 24v - 90v.

$(KGrHqVHJBEE7)2UUkWUBP!+qftWkg~~60_12.JPG (35.94 KiB) Viewed 285 times

http://www.ebay.com/itm/12w-led-head-li ... 231ba5077c

but I don't expect delivery for a few more weeks. i intend to use in on a bike I am building which primarily will be run on 48v but occasionally 72v (or vica-versa? not sure how the motor is going to perform that 72v yet).

I'm also currently looking for a switch-mode regulator to supply power to a 36v lighting system from a 48v battery. haven't been able to locate one yet so I was thinking of using an old 48v brushed motor controller and using a potentiometer (or resistor?) to permanently set the throttle at 75% or whatever so the output is around 36v. not sure it will work but i will give it a try.

also, since they are cheap and I have an old bike light housing that will hold 2 of these 24v halogen bulbs

26845-2T.jpg (12.7 KiB) Viewed 285 times

I was toying with the idea of wiring them in series with maybe a capacitor to smooth out the initial voltage spike.

DC

[DCMotorworks]

huh. my led light showed up today. a lot faster than I expected. I touched the leads to a 48v pack and it seems pretty bright. not sure how I will mount it yet.

DC

[TonyReynolds]

That looks like a nice light. I'm using a driving light because I want to shape the beam, especially as regards a horizontal cut-off for oncoming drivers. I tried a LED tower, H-3 eqivalent and it was virtually useless, so I'm stick with using a 25W halogen, at least for now...

[hillzofvalp]

On my bike I just run the DC-DC off half the pack. The difference is usually 5Wh at most with my magic shine. It takes one pack about 1-2 seconds longer to charge (two halves).

Looking good. I've been looking for alternatives to the big apple because I want something with more protection. SChwalbe makes a 622 bike tire, but it's only like 1.75" wide or something like that--BUT with a ton of protection.I may ride a large 2.35" rear big apple with a smaller one of these bombproof tires in the front to make me feel safer.

I was thinking of coating my controller in black as well, what did you use? I was looking into this:
http://www.brownells.com/.aspx/pid=1119 ... -HYDE-reg-

[TonyReynolds]

On my bike I just run the DC-DC off half the pack. The difference is usually 5Wh at most with my magic shine. It takes one pack about 1-2 seconds longer to charge (two halves).

Looking good. I've been looking for alternatives to the big apple because I want something with more protection. SChwalbe makes a 622 bike tire, but it's only like 1.75" wide or something like that--BUT with a ton of protection.I may ride a large 2.35" rear big apple with a smaller one of these bombproof tires in the front to make me feel safer.

I was thinking of coating my controller in black as well, what did you use? I was looking into this:
http://www.brownells.com/.aspx/pid=1119 ... -HYDE-reg-

I simply used Krylon primer and paint. I wanted it to be more stealth. Thin coats work best.

Best, Tony