Contraption to Measure Current Pulled from Bike Light Battery Packs - REVISED - See Post #13

Note: 12/5/2014 - My New Revised Setup is in Post#13.

I wanted a way to measure the current pulled from a battery pack of bike lights, did some ebay searching for power connectors, stumbled on these for CCTV use, and came up with this idea:

That photo above is showing the current pulled when the light is off. I then just simply use the switch to toggle modes:

Levels are approx. 25%, 60%, & 100%. The above light is my SolarStorm X3. Here is a typical MagicShine 808E (XM-L) Clone:

Above is "off".

High.

Low.

As you can see, this one isn't driven very hard!

A few pics of the connectors:

I used my DMM to verify the connections ran "+" and "-" the same way the bike battery pack did (which is center pin "+").

I'm a bit concerned about the runtime I'd get on the SSX3. I will have to take a ride with it and see if low is enough light to ride comfortably (rails-to-trails type trails). My buddy and I are planning what we call a "suicide run" which is to ride the 184.5 mile C&O Canal Towpath bike trail from Cumberland, MD to Washington D.C. in less than 24 hours (it's been done before by others, but few have posts on the web about their trips). You only have to average about 11MPH in order to complete the trip in 18 hours (few very quick stops though). This trip is now one on my bucketlist. The ride will of course require good lighting as even during the summer we will have quite a bit of riding in the dark. Most of the trail is wooded too and full of ruts, roots, branches here and there, etc. . . We were supposed to do the ride this summer, but life got too busy. I wasn't even prepared with my lighting yet. Another area I am working on is mounts. I am trying out some of the Chinese GoPro clone stuff. I've accumulated a bunch of parts, but haven't tested any yet.

I love finding real world uses for lights and not just keeping them all as "shelf queens". I enjoy finding a light for a purpose rather than a purpose for a light.

-Garry

That's a pretty nifty set up you created there. Interested in selling me one of your extras? I hate purchasing 5 when I only need 1 set

That trip sounds awesome except that it sounds like a real bum bruiser. Keep us posted when you take it. Can a tweet feed be channeled to a thread?

I see you accidentally unveiled your next high powered bike light build. The red and black should look pretty cool, but it doesn't look very aerodynamic.

I got 10 pairs from BIC to use with led strips, they sell those separately too.

http://www.buyincoins.com/item/37871.html

http://www.buyincoins.com/item/37790.html

The Rayovac lantern? Thats the one I built and posted about awhile ago, old news.

Sure I can send you a pair, PM me your address.

-Garry

I’ve got tens of these connector pairs from BIC too. Really cheap yet pretty good quality. Also can setup quick way to make serial connections.

You may want to consider these quick connector as well, really really helpful when connecting in a pinch:
http://www.buyincoins.com/item/38990.html

I think to the OPUS BT-C1000 takes a 2.1 x 5.5. Can anybody confirm?

Yep. I use my own 12v PS for both litokala and opus, same 5.5mm connector.

Good, I just ordered 10 plugs from buyincoins for $2.05, and thanks Garry for showing me these in a roundabout way!

Thanks for the BIC links guys. Thanks for the offer Garry. Looks like I can get purchase them cheaper than you could mail them to me.

I totally forgot about that build. So you keep the cardboard display label on it still?

Lol! Yeah, I guess it adds to the "sleeper" effect!

-Garry

Vancbiker on mtbr sells GoPro adapters for the chinese lights, so you can use GoPro mounts easily. He’s a really cool guy and I don’t think they’re that expensive. Really neat to see the CNC mill they’re made on too :slight_smile:

That ride sounds pretty awesome btw, hope you end up doing it.

Yeah, I've thought of ordering his mount/adapters. I have some others coming in which I think will work well to mount to the bottom of the light (someone at MTBR also used them).

-Garry

Thanks to ledoman, I now have a much simpler setup to test bike lights! I've bought one of these voltmeter/Ammeter contraptions (link a trusted US Seller I've used) and wired it up like so, powering with an old cell phone charger:

And then test charging a typical 2S2P bike light battery pack:

Especially important to use to monitor charging from a "Traver Charger"!

Now switch the male and female DC Power connectors and you can measure current & voltage from the pack to the light while doing runtime tests, etc. . .

I've found my sample to be remarkably accurate too! Voltage is within 0.01v of my good DMM, and current is spot on!

-Garry

I got some of those Voltmeter/Ammeter thingies from the above post., but I have no idea how to wire them. It appears in your pics, the thin wires are to power the meter, the thick Black is Source Neg, Red is Source Pos, and Yellow Output Neg. Is that correct?

Also, I don't have the copper bar that would measure voltage drop to calculate current. Do yours have that copper bar (Left side from product page pic below)?

There is a wiring diagram at that ebay link, see under "Rules of Safety". Yes the thin leads are just to power the meter (I used an old cell phone charger wall wart.) Mine looks exactly like the pic you posted complete with copper bar.

If you still need more help I can post pics of my wiring tomorrow.

-Garry

Darn, Mine don't seem complete. I received them a long time ago, but I'll contact the vendor. I guess I can do a dchomak external shunt resister mod to them to get them working.

Thanks for info Garry. :)

Vendor (different one than the one Garry linked to above) doesn't seem interested in helping me out. If any of you buy these, make sure to check out the back of them as soon as you receive them. Here is what I got:

Photo clarification on how to switch this device from measuring battery charging current to measuring current pulled by a lighthead from a battery pack (image clickable):

-Garry

The ammeter is neat. For the connectors, this is why I have a bunch of xt-60's and I'm not afraid to cut other connectors off in order to solder them on. But these are great if a) you just don't want to modify the equipment, b) you don't want to solder, both being understandable.