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Where to find Li-ion battery?


Joe Frickin' Friday

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Joe Frickin' Friday

I have a point-and-shoot camera that can record HD video. Am adapting it to record on-board video on the bike. The included battery is 3.7 volts, only 1000-mAhr capacity, and I want to be able to leave the camera turned on for extended periods, to capture snapsnots (and video) on a moment's notice. I bought a 120-volt plug-in power supply for the camera, thinking I could power it with a 12-to-120 inverter from the bike, but after some thought, the whole package - power supply plus inverter - would take up way too much real estate.

 

Alternate solution is to power the camera with an external battery that's considerably larger than the one that came with the camera. Ideal would be a standard size battery (C or D cell), which I could put into a battery holder from Radio Shack. Alternative would be an RC device battery pack with a build-in connector and an accompanying charger.

 

Original battery is lithion-ion, 3.7 volts, 1000 mAhr. Visited a Batteries Plus store today, and he said all they have is proprietary battery packs for various electronic devices - no generic "D"-sized batteries in lithium ion. He said I could probably find what I want on line, but I'm not sure where to look. Tried Amazon, got the same selection of proprietary battery packs; tried Tower Hobby, couldn't find any single-cell batteries; they're all series packs, 7.4 volts or higher.

 

Any ideas where to find a single-cell lithion-ion battery, 3.7 volts, 4000+ mAhrs?

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Joe Frickin' Friday
Mitch, why don't you buy a battery pack and re-wire it to parallel which should be the 3.7V.

 

Interesting idea, but I don't know much about lithium-ion batteries. I understand they're more complicated than ordinary disposables because each cell/pack contains charging and protection circuitry.

 

I suppose I could install a switch to configure them in parallel for service, and in series for charging.

 

Can I configure two or more separate Li-ion cells in parallel safely, or will weird things happen? If this works, then yeah, I could get something from Tower Hobby a battery+charger set.

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Why not go with lithium-polymer (LIPO) ... widely used in electric rc. A single cell is 3.7 volts. The example below is a bity pricey, but only shown for example that single cell high capacity is available.

 

Link to high capacity example

 

Comes in lots of other mAh options and is easly be wired in parallel for additonal capacity which may be cheaper but bulkier, although lipos are pretty small and light in general. Does require a lipo specific charger.

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Danny caddyshack Noonan

Mitch

Is a 12V to 3.7V DC transformer an option, hardwire? That said, I'm not sure which to go go about it. You can go with a voltage divider circuit. Found this while typing. thread

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Joe Frickin' Friday
Mitch

Is a 12V to 3.7V DC transformer an option, hardwire?

 

I'm guessing that the camera wants extremely clean DC power, thus explaining the plug-in power supply's bulky transformer and rather large ferrite bead. I don't know whether any given off the shelf DC-DC converter would provide clean enough power. A battery wired into the original cord (retaining the ferrite bead) would seem to be the best of all worlds: compact, clean, yet with enough capacity to run the camera for several hours.

 

Thanks, folks, for the recommendations and links. LiPo is not out of the question as long as the voltage is correct, and it sounds like it is so that opens up a lot of possibilities.

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There is a possibility that the AC adaptor has a circuit for regulating the voltage from a transformer or diode bridge. In other words, it may have a DC to DC converter built in. There is a possibility it can be made to convert 12V to the required voltage.

 

It would take some tinkering. :Cool:

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Any ideas where to find a single-cell lithion-ion battery, 3.7 volts, 4000+ mAhrs?

 

No but if 2500 will do, look here.

And here's a charger.

 

Note: Free but VERRRRY slooooow shipping.

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Mitch, why don't you buy a battery pack and re-wire it to parallel which should be the 3.7V.

 

Interesting idea, but I don't know much about lithium-ion batteries. I understand they're more complicated than ordinary disposables because each cell/pack contains charging and protection circuitry.

 

I suppose I could install a switch to configure them in parallel for service, and in series for charging.

 

Can I configure two or more separate Li-ion cells in parallel safely, or will weird things happen? If this works, then yeah, I could get something from Tower Hobby a battery+charger set.

 

They are commonly configured in parallel, but ONLY if identical capacity and brand, no mix and match

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another option...with the display screen OFF, you might be pleasantly surprised at the battery life, maybe enough to last between fuel stops?

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Mitch

 

Will the camera run and/or recharge the battery when plugged in to a USB jack? I know mine does. If so, it would be easy to adapt a 12V to USB plug into your bike somewhere. Then just run a generic USB cable from the adapter up to the camera and plug it in. Not only would you have power to the camera all the time, but you would have a fully charged battery any time you pull it off.

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Joe Frickin' Friday
Will the camera run and/or recharge the battery when plugged in to a USB jack?

 

There's a USB port for offloading pics, but unfortunately the camera (Canon SD4500) is not designed to draw power (or charge the battery) from this port.

 

 

Now that I've been turned on to LiPo's, I've found a suitable 3.7V LiPo RC-car battery pack, 6000 mA-hr, and a charger to work with it. The battery is physically small - about 4" x 2" x 0.75" - so it can easily be stuck somewhere on the dashboard with Duolock. The charger is likewise compact enough that it will travel well with the rest of my luggage.

 

All's well. :thumbsup:

 

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