12 volt battery??

[bluedevil]

I am making a homemade underwater camera for ice fishing and I am not sure if I have large enough batteries? I have two 12 volt 7amp/hr batteries and one will be used for my fish finder. Will just one battery be enough to run a 9" color TV and camera for at least a half days fishing?

I was thinking of getting another battery of the same size and doubling them up or I came across a 12 volt 12amp/hr battery for $29.95 plus s/h. http://www.batterymart.com/p-12v-12ah-sealed-lead-acid-battery.html

Your thoughts??

[boomerang]

mike (GLF) is the electrician maybe he can offer some advice.....ill try..."Will just one battery be enough to run a 9" color TV and camera for at least a half days fishing?"....that all depends on how much power the electronics draw, how well the batteries are charged and hold a charge....if you have a boat with deep cycle can you use that one???....."I came across a 12 volt 12amp/hr battery for $29.95".....this battery will give you 1 amp for 12hrs OR 12amps for 1 hr....or somewhere in between if i remember correctly, depending on the load on the batteries. maybe someone can add more or correct me if i am wrong.....also Remember, wiring batteries in series increases

voltage and wiring in parallel increases amp/hour

storage capacity.SO....you MUST wire them togther in PARALLEL as if you wire them in series you will get 24V and SMOKE your Electronic stuff TRY here for more info

http://www.solarseller.com/battery_bank_wiring_diagram.htm#12_volt

[1mainiac]

Boomerang got most of it divide the AHR of a battery by the load and you get the time it will run before requiring recharge. 7AHR battery and 500ma load 14 hours, 3.5 ampload 2 hours based on a fully charged good battery. Batteries will continue to work past their ratings but not without damage. I destroyed a set of batteries running in on my trolling motor a few years ago but we did make it all the way to the dock.

[bluedevil]

How can one find out what the load is?

On the back of the TV it just says 9" 12V DC 34.5 watts.

Thanks for in info.

[1mainiac]

Watts divided by voltage is amps yours comes to 2.875a so on the 7ahr batttery about 2.5 hours.

[bluedevil]

Watts divided by voltage is amps yours comes to 2.875a so on the 7ahr batttery about 2.5 hours.

Thanks Jim. Learn something new everyday.

So if I just added another 7ahr battery that would give me about 5hrs of run time then right?? If this is correct then math wise I would get over 30min longer run time with two 7a/hr battery's than just one 12a/hr battery??

[1mainiac]

Pretty much how it goes Matt just remember the rating on the battery is a suggestion of what it should be not actual test results. Most New batteries will out preform the rating on the tag as it is a test standard for the battery.

[GLF]

Thanks Jim. Learn something new everyday.

So if I just added another 7ahr battery that would give me about 5hrs of run time then right?? If this is correct then math wise I would get over 30min longer run time with two 7a/hr battery's than just one 12a/hr battery??

Jim is correct on the math, and you are correct on the battery time. But....in the cold a battery will not last as long as it would if it was not cold.

Also......make sure they are wired in parrell like John said.

[bluedevil]

Thanks for all the help...

I will let you all know how it turns out.

[bluedevil]

Finished the camera a few weeks ago and have tried it out on a few different lakes and it is pretty cool. Had one leak issue on Saginaw Bay but got it home that night dried the camera out and sealed it better and all is well again.. Water clarity is the key. I first tried it on a local lake here that is somewhat murky and I had about 15' of view on a sunny day. Tried it on Higgins Lake last weekend and WOW what a difference. Had 50'+ of clear visibility. I could see farther but could not identify fish/structure very well. Only downfall with it is that it is not lite. 9" TV, 100' cord, 2-12volt batteries, and carrying case is not something to carry around all day... If I ever find my digital camera I will get some pics of it and maybe a underwater video. After all is said and done I have under $200 in it.