problem with canister light battery's...

[ssdiver2003]

hope someone can help me out here with this...
i have a 12volt 7.2amp gell cell bat. which i wanted to use in a homemade canister light...unfortunately this one is a little to big to fit the canister,so i went and bought 2-12v 3.4 amp. which do fit...problem now is,would i be able somehow to connect both batteries and doubble the amp's without doubbeling the voltage and blow the light-bulb...??? i just wanted to increase the amp in order to get doubble the time of usage which is aprox. 3hours and some rather then 1.5 hours...
please help...thank you very much

 

[jonnythan]

The idea is to connect in parallel rather than series. Hook the positive ends together, and the negative ends together (as opposed to hooking one positive end to another negative end). Not sure how charging will work exactly, but you'll get your 12v 7.2 Ah.

 

[Padipro]

I originally made a dual 12V 7AH canister and had the same trouble you did with the 4 inch PVC being just a little to small for the batteries to fit. The fix is to take a section of the tube that you're going to use for the canister, pre heat your oven to 400 degrees and place the tube in the oven for about 5 minutes. PVC get very soft when it's heated and can be molded into all kinds of shapes as well as being streched. Once the tube is heated strech it over another section of 4 inch tube that is about 12 inches longer then the first tube. You need to work fast as it cools quickly. Let everything cool completely and then using a hammer gently start tapping on the outter tube to remove it from the inner tube. The now slightly larger diameter tube will fit the 7 amp battery like a glove.

As far as the charging goes. I leave both batteries connected in parallel and hook the entire thing to the charger with no trouble.

Take a look at the other DIY light threads for a link to the pictures of my light and you'll se how nicely the battery fits after streching the PVC.

Scott

 

[pcscuba]

Padipro's suggestion of stretching the PVC is a good one. I couldn't manage to get the pvc to stretch enough to go over another piece so I found 4-1/2 acrylic tubing and it worked perfect. More expensive but alot easier than stretching the PVC at least for me.

 

[budcris]

where did you get your battery

 

[DudeRasta]

check these out 4 of these would give ya a 8 Ah 12 v pack and fit in a 3" cannister these are what im gonna use

http://www.batteryspace.com/product.asp?0=217&1=227&3=169

 

[Padipro]

Looks like it sould work just fine, parallel two of them together and then put the two parallel packs in series and you should have it.

Just a thought though. For that kind of money you might want to check out a local battery store like Batteries Plus and see what they could build you a custom pack for. $80 is steep and I think they might be able to make you something all in a single unit for about the same price. That is if theres is a store in you're area.

Scott

 

[DudeRasta]

Scott they are 21.99 for two packs that isn't much more than a similar SLA
lol wouldn't even consider it at that price per pack

 

[Padipro]

I thought that was per pack.

Yes that is a good price for two and they will fit into a canister 3 inchs in diameter by maybe 8 inchs long. That would be sweet. Please post some pictures of your light when it's done. You can post them on my MSN page also if you want.

Scott