Hidden Power E-bike Conversion—Light-weight Motivation

Hidden Power E-bike Conversion—Light-weight Motivation.

The whole Hidden Power kit comes in a fairly small and light box.

Just over a month before the holidays I got this kit to test, ride and review. The Hidden Power kit has some great benefits and more than a few drawbacks too. I wanted to get this report out sooner, but I have been kind of aggressively following other interests and trying to keep warm and dry at the same time. Plenty of bike riding has been taking place and I will work to get back to my weekly posts on everything bike related. Thanks for staying connected while I was a bit off the grid.

This kit has 5 variations, 4 for different folding bikes, and the one I chose, the standard kit. I expected it to fit on one of my hybrids, yet the distance from the seat tube to the tire was too great for the drive wheel to reach the tire. You may have already noticed two things, one is that this is a friction drive kit where the drive wheel of the kit turns the tire at the tread. Also, to use it, the bike must be rear fenderless or have the fender modified. So some time was used to see if it would fit any of my other or vintage bikes, no luck there.

This is my new bike for doing more E-bike conversion tests. The Hidden Power kit is not all that noticeable.

My new quest was to borrow or buy a suitable candidate bike, with the need considered of fitting the next E-bike conversion I already had in waiting. I was lucky to find a young couple with their first new baby that decided to sell their mostly unused bikes on Craigslist. I always worry about getting a bike this way, not wanting to feed the stolen bike market. So I safely got a great bike at a super deal and the test proceeded. The install was a breeze, yet a few small adjustments were needed. That was the swing of the unit to contact the tire correctly and when needed. I got it close, yet still felt I missed the narrow sweet spot.

One thing that bothered me was on the box is the mention of the fact that the Hidden Power conversion kit won the Eurobike Gold Award in 2010. I am curious if the team has been working on upgrades and just how old the kit they sent me was. It all seemed new and unused in the past, so I am going on that assumption and what I could see and feel. I did have two issues with the way it worked (coming up), yet on the whole it got me where I was going with each ride.

This is the motor and controller mounted and ready to ride.

Two nice things are that it only weights your bike down by about 5 lbs., so if it does have problems, it won’t slow you down much. Plus, the drive wheel retracts from the tire when not in use, so no extra drag either. It pretty much takes very little space on your bike and when idle affects your ride very little. Which was good because several times I turned the throttle I got no assist. It usually would work with the next (or one after that) throttle attempt. If you stop the bike with the assist applied it will sense the overload and turn itself off. I feel like the lack of it coming on sometimes was linked to this safety feature

The other problem I had was being able to charge the battery, which uncovered one more deal too. I got the kit with the battery fully charged so riding quite a bit was no problem. When I went to recharge it, no luck there. It uses the same basic charger set-up as most E-bikes. I tried hooking it up many times, yet the lights on the charger would cycle through the colors and the voltage output fluctuated, but wouldn’t charge the battery. I decided to reach out to the supplier to see what they thought—or to get another battery and charger to complete my testing.

You can see the whole kit (minus the throttle) from this angle.

This was when I realized that customer service was slow or close to non-existence (at least in my part of the big world). Weeks later they contacted me to say that maybe they had supplied the wrong battery and for me to send some pictures. It has been over a month with again no response. I solved my charging problem myself so the test could resume. I used jumpers to charge the battery from the output wires instead of the normal charging inlet jack. That worked, so good deal there. Being a 14 volt, 20 Ah battery, I had no other charger to use, plus a very strong rule with E-bikes is to use only the charger supplied by the bike of conversion kit maker.

Before I talk about the ride, some more on the kit. It came with a  PAS unit for the pedals to activate the motor automatically when pedaling. With a short look I decided it wasn’t going to all line-up on this bike, so I decided to use the handlebar throttle only. This is a small unit that works like an old-school volume knob for a radio. Thing is it didn’t have different speeds, it works as an on-off switch only. This wasn’t really an issue as the motor is not that powerful. It took some time to get to full speed (about 18 mph I found).

Love it or hate it—this is the throttle unit.

Also, the throttle unit tie-strapped to the handgrip where it is a bit of in the way, so it was kind of uncomfortable with the ride and using the throttle. Not the best design, yet I became used to the action very quickly, so I decided it was ok. Like I said before the install was quick, with very few wires and things to deal with. One thing I thought needed an upgrade was the fact that the battery wires need to be disconnected when not in use. Most would add a main power switch for this purpose, not sure why the Hidden Power kit doesn’t have one.

Riding was easy with enough assist for all but the medium and steep hills. I was surprised at the quiet noise level when it was powered up. It did make a bit of a clatter when it swung into engagement with the tire, yet not that bad. The drive wheel is very smooth aluminum, so that is why the motor was not a big noise maker, although when it’s wet outside I think some major slippage could occur. The last one like this I tested the wheel was sandpaper covered, which caused a lot of noise and tire wear. I am not sure which approach is really best. The deal is that friction drive is kind of outdated, yet basically works ok on low power E-bike kits.

Here is the Hidden Power kit viewed from the other side of the bike.

One thing I wasn’t able to check as good as I liked was the heat factor at the motor and drive. The last one I tested with this kind of arrangement made some excessive heat. The Hidden Power conversion uses less voltage and less power so the heat generated is probably acceptable. It is easy to check with the modern heat guns, so if you get one of these kits, keep an eye on that. Over 200 degrees F is not good.

So on the whole it worked ok—not too fast or powerful. Yet with a 5 lbs, conversion that is to be expected. Customer service is questionable. This is something I rarely have problems with, as most the folks that supply me demo units are normally very interested in the progress of the testing. I do hope they reply when I ask them for a pre-paid return shipping label. It came from a USA source, yet is made in Korea. Hard to say if I recommend this conversion, but it was fun, easy and light. It is always your choice on what works best for you.

Power your ride, Turbo Bob.

“Bicycle means simplicity and simplicity means happiness”—Mehmet Murat ildan.

Check out the videos I did for a better look and more info.


About Turbo Bob's Bicycle Blog

E-bike Enthusiast Vintage Bike Enthusiast
This entry was posted in Bike accessories, E-bike test reviews. Bookmark the permalink.

6 Responses to Hidden Power E-bike Conversion—Light-weight Motivation

  1. azelones says:

    Bob, So if someone wanted to add a conversion kit to their bike, are there shops that would install one for a reasonable price?


    Andrea Z

    On Mon, Feb 20, 2017 at 1:48 PM, Turbo Bob’s Bicycle Blog wrote:

    > Turbo Bob’s Bicycle Blog posted: “Hidden Power E-bike > Conversion—Light-weight Motivation. Just over a month before the holidays > I got this kit to test, ride and review. The Hidden Power kit has some > great benefits and more than a few drawbacks too. I wanted to get this > report out” >

    • Sure—most all E-bike shops and many regular bike shops can do it. Yet you want to make sure they have done many and fully understand the task. From what I understand it usually is about $80 to 100 for a good job (plus the kit and parts of course).
      Locally, I would go to San Diego Electric Bikes—they have been doing them for many a year.

  2. Walter says:

    I’ve been searching some reviews regarding e-bikes conversions. I really appreciate info from this blog. your converted e-bike, do you find it durable? Does it affect bike warranty if you convert it to e-bike?

  3. Thanks—-of course, any mods—especially ones like this , will void the warrantee.
    Nice thing about this one, it is easily removed.

  4. Rinat says:

    Hi! Bob, I have been using this kit with my Brompton bike for more than 2 years. the first problem I faced was the same as yours – charger did not work, only blinked with different colors. I asked the Korean shop for this problem, they suggested to replace the battery too, but as soon I said about the different colors, they replied that all is okay. so that charger starts working you need push the button on battery.
    the kit doesn’t help in wet condition – after rain, or after every time your rear wheel is wet. the solution is another drive wheel provided by the manufacturer. I have no that and cant say anything about how special drive wheel works.

  5. Adrian Hallam says:

    Hi there
    I’m in the UK and would like to try this kit, but I’m struggling to find where to purchase one, can you help at all ???
    Regards Adrian

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