D Cell Rechargeable pack?

[tomadom]

I have a large Maglite torch which takes 4 D cell batteries. I want to make a rechargeable battery pack for it that can be charged via USB. Something that goes into the back of the torch and replaces those D cell batteries. I was hoping to find something where I didn't have to carry a full-scale battery charger with me to charge the torch every time I want to use it.

Does anyone know where to start looking for something like this? Is there instructions on how to make something like this on the web? I'm considering making something but I just don't know what is currently the best way to do that.

Thanks

 

[Delta Prime]

I would research conversion kits. Good place to start see what you're in for. The kits convert everything type of battery used light bulb etc
Do you wish to keep the original Xenon




Or replace it with as they say upgrade!




every time the cops whack me over the head with their mag lights the first thing that pop's is the Xenon light bulb. Then they call for back up.

 

[tomadom]

I would research conversion kits. Good place to start see what you're in for. The kits convert everything type of battery used light bulb etc
Do you wish to keep the original Xenon


View attachment 59256

Or replace it with as they say upgrade!




View attachment 59255every time the cops whack me over the head with their mag lights the first thing that pop's is the Xenon light bulb. Then they call for back up.

I bought the new LED version recently. Thanks for that tip I will look that up. Hoping to find something inexpensive and usable. I'm happy to build it if I have to.

 

[kellys_eye]

You can get an 18650 (lithium) cell to d-cell converter here:

18650 Li-Ion to 2x D-Cell Flashlight ADAPTER - Conversion - Nerf Blaster | eBay

Find many great new & used options and get the best deals for 18650 Li-Ion to 2x D-Cell Flashlight ADAPTER - Conversion - Nerf Blaster at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Get a pack of 18650's and a fast charger and you're away...

 

[JWHassler]

These folks make cell-replacements with built-in charging.
Not cheap, though.

 

[crutschow]

I bought the new LED version recently.

The LED version should last a very long time with 4 D-cells.
If you want rechargeable, why not just use 4 NiMh D-cells, and take them out for the infrequent recharge using a standard NiMh recharger.

 

[tomadom]

What I was considering doing is buying the nickel metal hydride rechargeable batteries, and having them in the torch permanently. I would then make a cap for the bottom of the maglite with a USB plug in the bottom of it. I would need to build a small charging circuit for 4 D cell batteries that would fit under the cap between the USB plug and the batteries inside the torch.

What voltage and amperage would I need to consider for making something like this and does anyone know if there are kits available for this kind of thing?

 

[crutschow]

What voltage and amperage would I need to consider for making something like this

Since 4 D-cells require about 6V for charging, you would need to have a boost converter to charge them from a standard 5V USB source.
You also would need a charge controller to stop the charge when the battery is full.
I doubt you will find a kit for that.

It likely would be much easier to use a dedicated charger, such as this, which would require no circuitry in the maglight, just a socket for the charger plug.
The 1A charge current should be able to charge the D-Cells (which can have a capacity of up to 10Ah) in about 15 hours.

 

[Bluejets]

What voltage and amperage would I need to consider for making something like this

One can build a simple charger for Ni-cad or Nimh cells from a 317 adjustable voltage regulator ( standard charge rate up to around 1A assumed)
Circuit on the web........... power supply can be anything with voltage and current above largest number of cells voltage and largest current you expect to charge at (usually 1/10 cell capacity)....add a variable wire wound pot and an ammeter for adjustment and monitoring....done.

I've used one I made here for over 20 years...works great, no problems.
Mine uses a 12v dc 1A supply for maximum charging of 9.6v r/c transmitter battery.
Has a max current selector for 100, 200 and 500 mA and a wire wound pot to adjust max charge rate.

 

[crutschow]

One can build a simple charger for Ni-cad or Nimh cells from a 317 adjustable voltage regulator

That can overcharge the batteries, with possible battery overheating and damage, if the charging is not closely monitored.
Better to have a charging circuit that monitors the charging and reduces the charge current when the battery is fully charged.

 

[Bluejets]

So stick a timer on it and discharge before use....OMG...knockers everywhere.

 

[crutschow]

Deleted

 

[tomadom]

That can overcharge the batteries, with possible battery overheating and damage, if the charging is not closely monitored.
Better to have a charging circuit that monitors the charging and reduces the charge current when the battery is fully charged.

Thanks very much for this. I will likely have to go with the external charger option. If I'm out in the bush I can at least plug it into an inverter running off a car battery and charge it that way.

I think I've found some nickel metal hydride batteries to use as well.

 

[crutschow]

I think I've found some nickel metal hydride batteries to use as well.

There are NiMh D-cells available from several different suppliers on Amazon.