View Full Version : Dynamo Hub

05-05-2016, 10:35 PM
Is it possible and what would be involved to run my DS500 off of a Dynamo Hub?


05-06-2016, 02:59 PM
Hey Ben,
I think that it would be possible, but not without some conditioning circuitry and a battery between the hub and the light. The basic idea would be to have a "throttling" battery charger that takes the input from the hub and creates a regulated output for "charging the battery," which would simultaneously be used to drive the light and keep the battery topped off.

I believe you could use the B&M eWerk (http://www.peterwhitecycles.com/ewerk.php)to charge a standing battery while using the lights.

The eWerk is a very cool little device. Essentially, you would be continuously charging a 7.4V li-ion (2-cell) battery while simultaneously operating the light. You would want to be a little judicious about the power and mode settings, but I think you could pretty much operate indefinitely with a setup like this. Freezing weather, being the one exception. You wouldn't want to be charging the battery below freezing. I would caveat this with the fact that I think it would be wise to start with a fully charged 7.4V li-ion pack, so that you're never "forcing" too much current into the battery. The battery really would just be acting like a large capacitor. So, in that since, you wouldn't need a pack with a lot of capacity.

You would set the output of the eWerk to 8.4V at 1.5 amps and you would have to use a Y-cable on the battery, with one leg plugged into the eWerk, and the other leg plugged into the light. It would be just a bit of custom cabling, but I think very doable. I haven't had anyone try this yet, so I'd be very interested to see how it works. I can't say with 100% certainty how well it would work, and it would be quite an expensive experiment, but I could certainly support you with the cabling that you'd need.

Just a thought...

06-26-2016, 04:08 PM
Hi Stephen,

Is there a way to charge battery packs with portable solar panels?


06-29-2016, 12:41 PM
Hi Stephen,

Is there a way to charge battery packs with portable solar panels?


Hey Utku,
Yes, I think there are probably a lot of different ways that you could do this.
Probably one of the easiest ways would be if you had a solar array that could output voltage in the 12V to 30V range, then you could just hook up one of these portable BUCK regulators (https://www.amazon.com/Converter-Regulator-Step-down-Transformer-Adjustable/dp/B00GZG7X9Y/ref=pd_cp_23_2?ie=UTF8&refRID=2ZPZSX7GHYCRJZEGGF1M):

OR even better: One of THESE (https://www.amazon.com/DROK-Electric-Regulator-Constant-Precision/dp/B013STFDTC/ref=pd_sim_263_65?ie=UTF8&dpID=51uKvS-FOzL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=249MWDND3KHDAZK0F6DT) (same idea, just a little more refined)
And then set the output voltage to 8.4 and the maximum output current to around 1 amp. The battery would then charge any time the voltage from the solar array was above 10 volts or so.

Obviously you'd need to be a little handy with electronics to do this, but it seems very plausible. You would probably also want to verify the actual output voltage with a Voltmeter to insure that it did not go above 8.4V. There are a lot of portable panels out there that have an 18V DC output, and this would be perfect for use with the BUCK regulator.

07-28-2016, 12:23 PM
Hello Stephen. To piggy back off this thread, I was wondering if it's possible to charge the DesignShine battery packs with a USB battery backup. I own a USB power bank that I trickle charge throughout the day while bike touring. I use a smaller solar pannel (rated at 6.5W with a 5V/1.3A output).

In any case, it would be really handy if after a day of riding (and charging the battery backup) I could connect the DesignShine battery to it at night to recharge. Let me know if you think it can be done.

06-21-2017, 01:56 AM
Hi Stephen,

Is there a way to charge battery packs with portable solar panels?


It's possible but it wont produce a ton of charge.

08-24-2017, 02:17 AM
Hi Stephen,
Does it harm the DS-500 if it is powered by a regular 5v 1 or 2.1 amp cell phone power bank by mean of a step up voltage converter?
Something like this.