Prepared Society Forum banner

Hand Crank Radio/Flashlights

9513 Views 15 Replies 13 Participants Last post by  insidethebunker
We have a hand crank radio that has some short wave stations. Does anyone know if these have parts that will need to be replaced like a battery? We have some flashlights too with the same technology. We've had them for years but wondered how long they last.
1 - 16 of 16 Posts
Without knowing the specific radio, I don't know that anyone will be able to say for sure which parts will need replaced. I know that the ones that have rechargeable batteries in them will need to have these replaced at some point. The manuals will say that they have to be replaced by an authorized service center because they are usually soldered in. I've also heard of some of the cheap China radios having regular batteries in them instead of rechargeables. This means that once they are dead, the radio will only be useful while cranking.

I'm still shopping for one of these radios. I haven't decided on a specific brand or model, but I'm leaning towards one of Kaito radios. Anyone have any good or bad experiences with them?
Roto Glo hand crank flashlight

I've got a Roto Glo hand crank flashlight that I was messing with the other day. It's a pretty neat little gadget. You can use the on-off switch to select one or three led power. It's no searchlight, but it beats fumbling around in the dark. There's something about a renewable power source, even a dinky one, that is just very cool.

I've always wondered about the voltage and current capabilities of the little generator mechanism in it. I was checking it out yesterday and mulling over idea of taking the thing apart and seeing if I could tap the output of the generator and do some measurements.

While surveying how many screws hold the thing together, I noticed a little electrical connector jack that was hidden by the crank handle. Oooooh, that really piqued my interest. I rummaged around in my goodies and located a connector to fit it and was able to hook up a VOM to the output. I checked the voltage on it before cranking the generator and measured about 3.5 volts or so. Ok, so I could measure the battery voltage. That was a start. I left the VOM hooked up and started cranking the generator handle a little. The voltage rose to 3.8... crank a little faster.. 4.2... a little faster... 5.0. So started giving it a good cranking and got the voltage up to 6 volts. I was fairly impressed.

I dug out an old rechargeable 4.8 volt, 4 cell AA battery pack (Ni-cad cells) that had been sitting uncharged for a few years. The pack measured about 3 volts, so I put a 12V bulb across it, to drain it down, until the bulb barely glowed. I wanted the pack basically 'flat' to start. I got it down to just over 2 volts.

I hooked it up to the output of the little generator and did 100 moderate 'medium speed' cranks of the handle. I stopped and disconnected the battery (didn't want the internal flashlight battery to be part of my measurement) and measured 4 volts on the battery pack. I did another 100 moderate cranks and re-measured, 4.4 volts, another 100 cranks, and I was up to about 4.6 volts. I did another 100 and the pack was reading 4.8 volts. I was impressed again.

Now my disclaimer. Various rechargeable batteries all have their preferred charging parameters (voltages and rates), for both battery health and more importantly, safety reasons. Ni-cad cells are fairly tolerant and the pack I used for the experiment was just wasting away on the shelf. It was my 'lab rat'. NiMh cells are a little pickier about their charging. Lithiums even more so, to the point they can be dangerous. I've charged a lot of R/C packs (Ni-cad & NiMh) over the years and packs for my ham radio hobby. I have and use the right chargers for those jobs.

I just wanted to satisfy a curiosity, and see if this little hand crank generator possibly had the potential to get me out of a 'dead (rechargeable) battery pinch' if I really needed it to. The results were promising, (and fun) and I'm going to experiment with it a little further. I want to see if I can get some output current measurements while charging my 'lab rat' battery pack.

By the way, I haven't cranked up my little flashlight since my experiment almost 2 days ago. I turned it on (all 3 leds) and left it on the desk when I started typing this novel. I'm a terrible, two fingered typist and I've been pecking away on and off (and doing some other stuff) for over an hour and a half. The little Roto Glo light is just now reaching 'dead' status. Not too bad.

I'd like to do some real life testing on this small scale, generating experiment. Maybe charge up 4 NiMh cells for my 2 meter HT (the correct way) and drain it down with normal usage, and see if I can pack enough electrons back in the cells with the flashlight generator to make a few more transmissions. It's worth a try. Might be a useful trick that comes in handy some day. I'll post the results if anyone's interested. (We all have a little McGuyver in us, don't we?) ;-)

See less See more
Roto Glo follow up

I measured the output current of the Roto Glo flashlight generator. It was a bit discouraging. It put out 40 ma or so, at a leisurely-moderate pace, while charging my little 4 cell pack. At a semi brisk pace it was 60 - 70 ma. At a crazy hamster on it's treadmill pace (which I wouldn't want to keep up for more than a few minutes) it was up to 110 - 120 ma.

Conclusion: That generator is right where it belongs. On the side of a very low current consuming led flashlight or receive only radio. In a dire pinch, you might be able to recharge 4 AAA or 4 AA cells to a semi usable state, but it's going to take some cranking.

A fun experiment nonetheless, and knowledge gained is always a good thing!
I just found the same flashlight but different label in the LL Bean catalog. It uses lithium batteries and lasts 10 years. Hopefully the batteries are replacable. The light isn't very strong but it would be handy.
I have an Eton radio and flashlight set that has a Dynamo hand powered crank. Ninety seconds of turning charges the Dynamo batteries. The radio is also operable off of standard alkaline batteries. It's an AM/FM/TV/Weather Receiver with a little light on it, and a siren-type alarm that you can activate for whatever reason. It will also sound if you have it set for weather alerts. Additionally, the set comes with a card so that you can send off for a free adaptor to attach to your cellular phone. I sent away for mine, and used it to power my Motorola Razr during a power outage. It worked too. The flashlight that came with the set has three LEDs that charge only by cranking and the Dynamo battery. It works well enough for getting around your house in the dark, but it's not adequate for field usage. I'm pleased with the set.
In my opinion, the best setup for emergency radios would be a radio with built in solar panel, short wave, weather channel, am/fm and a new digital tv tuner
Does anyone make one? 10101?
Does anyone make one? 10101?
KA - 500 Voyager sold by 21st Century Products. I am not familiar with the product or the company. This was sent to me by a friend.

Here is the link:
Does anyone make one? 10101?
KA - 500 Voyager made by Kaito. Sold by 21st Century Products. I am not familiar with the product or the retailer. This was sent to me by a friend.

Here is the link:
We have three emergency radios, a Grundug AM/FM/Shortwave with a led light, sixty turns of the crank charges a Ni-cad battery which will run the radio for one hour, (same as cordless phone battery, replacement can be purchased at Radio Shack) it also can run on four AA batteries, a Baygen AM/FM/Shortwave that has a clockworks windup that powers a little generator that can run the radio or charge a built in Ni-cad battery (just like the cordless phone battery) it also has a solar panel for running the radio or charging the battery. It has a bright flashlight that is corded to the battery in the radio and the least expensive radio I bought from a rescue mission second hand store for $4.00 is a Baygen radio that had the crank missing. It's only AM/FM, has solar panel and I made a crank adapter to wind the clock spring. Both Baygens have an external power supply plug in so they can be run on 120 VAC battery eliminator.
I bought a Grundig FR-200 about 5 years ago. It too has AM/FM/Shortwave bands and a built-in flashlight. It was worth the $39 I paid, but I just use 3 alkaline AA's instead of the NiCad. Got tired of cranking...I've had the same batteries in it for almost a year and it works great - it stays in my unoccupied hunting cabin year round and despite the temps. the batteries haven't died yet!
how about building one of those WWII hand crank generators. Convert it to foot power or mount it on an old treadle sewing machine. Use your feet, keep your hands free for other thing (multitasking).
Recharge the deep cycle marine batteries to run the inverter to run the recharging units for the rechargeable units in your equipment.
I KNOW there has got to be an easier way, but this just popped into my head !
One drawback to these, and believe me I've look into them a lot, is that they run on bastard voltages, 45, 400vdc and the like. Granted you could with a little ingenuity convert them to other voltages, but, and you are right there must be a different or easier way to get human powered gen sets to work. I plan on using solar and wind to supply my needs, I will also keep a solar panel down in the 'pit' with me just in case the system upstairs get damaged.
I'm planning on getting one of those Grundig Hand Crank Radios also, just another item to pick up whei I have a little extra cash.
KA - 500 Voyager made by Kaito. Sold by 21st Century Products. I am not familiar with the product or the retailer. This was sent to me by a friend.

Here is the link:

Solar Power Products- solar radios, solar lanterns, solar chargers, flashlights: 21st Century Goods
I've owned a Voyager for a year now. Works great. This Christmas I gave two of them as presents. It seems to be the most complete and it runs under $50 from
1 - 16 of 16 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.