Batteries for canister light

Hi all,

I am thinking about building a canister light and now trying to decide what battery should be used. I have 2 options: Lead acid or Li-ion 16850. Lead acid is a straight forward option. Li-ions on the other hand would give me greater power density. If I'm going with Li-ion, I would make 3 x 4 stack to give me roughly 12 V. Any comments? What works and what not?

Thanks,
J

jpou said:

Hi all,

I am thinking about building a canister light and now trying to decide what battery should be used. I have 2 options: Lead acid or Li-ion 16850. Lead acid is a straight forward option. Li-ions on the other hand would give me greater power density. If I'm going with Li-ion, I would make 3 x 4 stack to give me roughly 12 V. Any comments? What works and what not?

Thanks,
J

Click to expand...

Batteries- use 3 LiIon in series by however many parallel. Stay away from the ultra cheap Ebay ones and get the proven batteries.
Lead acid are not bad except you are carrying a huge battery vs. LiIon.
What canister will you be using?

So far I'm leaning towards DIY acetal tube canister with Amphenol Barracuda connector.

Forget lead acid, unless you are short a couple of weights on your dive belt and want to pretend you are Jacques Cousteau trying out his Aqualung for the first time.

You may know this already but the difference between full (4.15V) and 'empty' (3V) on a Lithium type battery is fairly large. Mutiply that by however many cells you want in series and the difference becomes several volts. You may find this difference is too many volts when full, or not enough towards empty. This could damage your emitters, or not give enough light for the second half of your dive... But all this can be fixed by using a driver circuit to manage power to your emitters.

Nowadays there are plenty of drivers for LED choices which are designed to accept a range of voltages and keep the output from frying your emitters. HID ballasts also operate between a range of volts suitable for the Lithium gap so it's just a matter of choosing a battery pack or building your own to suit.

I will be building my own driver, so I am sure that Li-ion voltage drop will not affect me that much. I'll post my progress here anyway.

Have you considered Lipo? Plenty of options in ready built packs.

Norm

I haven't. Main reason is that I use Premier Farnell (Element14) as a supplier of all my electronic needs (company has a corporate acct there) and they have quite limited stock of Lipo batteries. Any links to other distributors with reasonable shipping prices to Europe would be highly appreciated.

Direct links to dealers aren't allowed here.

Search for HobbyKing and you'll find a large range of Lipo batteries. A quick Google search should turn up many others.

Norm