Amp Hours on Motorcycle Battery 12 Volt

[jbrowning]

Hello everyone. I am trying to find a 12 volt battery that has around 60 amp hours per full charge. I know I can get this in a car battery. But I'm wondering if anyone know how many amp hours a motorcycle battery normally has? I'm was looking at Walmart but none of them say what the amp hours are. This is to temporarily power my digital picture frame for a craft show I do the first weekend of December and I'm wanting to display some of my photographs for people to look at.

Thanks
Jim Browning
Rockymtnphotos.com

[Scored51]

I would suggest going to Batteries Plus. What you're after is a deep cycle battery. Car batteries (or wet cells) are designed to pass current through. In other words, they need a source of electricity pouring into them in order to maintain a given level of output. A car battery will provide several hundred amps at start up, but you know how quickly they drain down at that pace. A deep cycle battery is designed to deliver a steady current flow without the next for a charging input.

HOWEVER, I would take another look at your amperage requirements. There isn't a household appliance that requires 60 amps (stove/ovens being the worst with 220 volts and the circuit is only rated at 50 amps). Additionally the motorcycle batteries I've experienced have all been less than 10 amps and the main fuse somewhere around 30 amps. Meaning, there isn't any way a bike could produce that power even if it wanted to do so. In fact it would only be a heavy duty automotive alternator that could consistently pump out that much flow.

I suspect your digital picture frame will be between 1 to 2 amps. Batteries Plus should be able to set you up with a 12V Werker battery. Some of them actually power surveillance cameras. Hope this helps.

[jbrowning]

Hi Chris thanks for the reply. The output for the amps is 3 amps (per hour I am thinking). I am estimating it will be running at the max 10 hours on Saturday so that would be 30 amps I would be needing. I just rounded it up to 60 to be on the safe side. I didn't want to run out of juice during the show. I will check with Batteries Plus and see what they have.

Thanks
Jim Browning
Rockymtnphotos.com

[rohorn]

This might be too late - but most deep cycle battery producers will show you all sorts of useful info, such as this:



That came from this battery & company (both picked at random - not promoting this battery or this company):
http://www.tempestbatteries.com/html/tg40-12.html

Stuff like that comes in very handy when building electric bikes and trying to predict range and performance (or lack of), etc...

[Scored51]

Interesting stuff. The graphs reminded me of how the auto industry developed it's ratings in the first place. It used to be law (I don't know where or when) that people who parked vehicles on the street overnight were required to have their parking lights on for the duration of the night. Therefore a 40 amp hour battery would be able to sustain a 40 amp load through the night and still have the ability to start the vehicle in the morning. I have a sneaky suspicion that at the time a lot of the vehicle in question were started by crank and ran magnetos instead of alternators. That way the magneto would only need to be "excited" instead of having to run a starter until the ignition system and battery could take over.

I did a search to find some numbers and found out the time frame was supposed to be 20 hours for an overnight stay. Hey, that's a lot of stamina even for a college student to be visiting a girl overnight!

Jim, you may also wish to put a "choke" on the power supply lines if there is nothing else in line other than the wire. This will clean up the power signal to the digital frame. All electronics prefer clean power sources.

[jbrowning]

Hi Chris, all I had planned on putting between the battery and picture frame was going to be some sort of fuse to protect the picture frame. What is this choke you are talking about please?

Thanks
Jim Browning
Rockymtnphotos.com

[Scored51]

They're available at Radio Shack for a few bucks. This is the little cylindrical thingy usually found on laptop power cords just before the end that gets plugged into the computer. However, they don't actually do anything to the power entering the device, but rather filter out interferences. (ed. note: I must have been using the same brain cells when I made my first reference as when I was quoting grid sizes in another post.)

Here's a pic stolen from the Radio Shack site, and another of what it looks like installed. Hope this helps.

[jbrowning]

Thank you Chris, I will check with Radio Shack and pick one of those chokes up this weekend. I am hopefully going to have this finished this weekend so I can do a test run with it.

Thanks
Jim Browning
Rockymtnphotos.com

[jbrowning]

Thanks Scored51 and rohorn for your help. I got this project finished today. I ended up getting a 33 amp hour battery from Batteries Plus and since I'm only drawing 3 amps per hour for the frame I think I should have enough charge for the job. Then next size battery up was over a 100 amp hours. Ha ha that is a little overkill for what I am wanting to do. Oh and Chris I got the choke but haven't installed it yet. One question about it is do I need to remove the plastic off the wire before putting the choke on? The folks at Radio Shack gave me the deer in the headlights look when I asked them. lol

Thanks
Jim Browning
Rockymtnphotos.com

[Scored51]

Nope, just snap it over the wire near the plug end going to the digital frame. Glad things have worked out. Just remember to fully charge your new battery slowly before having to press it into service. Good luck.