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  #1  
Old 08-22-2017, 08:10 PM
chalinaty's Avatar
chalinaty chalinaty is offline
NAR 85414; NARTREK Silver
 
Join Date: May 2006
Location: Chatham, ON, Canada
Posts: 128
Default Battery Recommendations?

Hey Folks!
My club has a great launch system that we purchased last year. We had been using a car battery with it but it needs to be replaced. The system is a relay-type with 10 Low-Medium Power pads and 10 High Power pads. We only use about 4 Low-Med pads currently but we do launch up to G engines and some clusters. We also have the occasional drag race. My question is: What do I look for in a replacement battery? I can get a cheaper, small lawn and garden battery with 250 cold-cranking amps, a regular car battery with 500 CCA, or a battery with 710 CCA. Any recommendations?
Thanks!
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  #2  
Old 08-23-2017, 06:52 AM
jetlag jetlag is offline
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Join Date: Aug 2006
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Spend the extra $ and get a sealed battery. Then you won't have to worry about acid leakage if it turns over and as it charges. Amperage is your friend, so get a battery with capacity to spare. Keep it trickle charged between launches, and it should last a long time. Interstate and Duracell make great sealed batteries. You can get Duracell sealed batteries at Sam's. You want reliability and safety.
Allen
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  #3  
Old 08-23-2017, 08:34 AM
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tbzep tbzep is offline
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Join Date: Mar 2005
Location: TN
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To give you an idea, a little 7Ah gel cell (sealed lead acid) will fire off a large cluster with solar igniters easily. I've routinely done 4 and 5 engine clusters with solars, and I used to do crappy copperheads and tiger tails with 100% reliability. In other words, you don't need 250 cold cranking amps much less a 710 cca car battery assuming your system uses relays and you aren't running ignition current 500 ft to an away cell and you pay a little bit of attention to igniter installation.
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  #4  
Old 08-23-2017, 10:55 AM
stefanj stefanj is offline
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Join Date: Mar 2005
Location: Hillsboro, OR
Posts: 2,847
Default

Oregon Rocketry uses, for its low-power launch system, an emergency car battery charging system.

I bought a a near-identical model for myself, at Harbor Freight. It cost about $40.

The unit has a handle, a very sturdy plastic case, a meter, an emergency light (for changing tires or other repairs), and two heavy-duty battery clips. It charges overnight with AC.

I've never, ever seen a case where it runs out of "juice" during a launch. There have been cases where I forgot to charge the unit, and it maintains enough charge from the previous month to run a launch. (Say, 50 - 75 launches.)

These units are certainly larger than a small sealed battery, but they have multiple uses and are readilby available.
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  #5  
Old 08-23-2017, 03:06 PM
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BEC BEC is offline
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Location: Auburn, Washington
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...and they contain a small sealed lead-acid battery about the size of the one tbzep mentions.

I fly with a couple of clubs who use these jump starter devices to power their launch systems and their PAs.
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  #6  
Old 08-26-2017, 08:45 AM
PaulK PaulK is offline
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Join Date: Nov 2005
Location: WI
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Quote:
Originally Posted by BEC
I fly with a couple of clubs who use these jump starter devices to power their launch systems and their PAs.
Our club uses the same. Look at the amp-hour capacity, though, they're not all created equal. We had some cheapo ones that would barely last a full day's launch. Our newer ones go the whole weekend.
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  #7  
Old 08-28-2017, 12:34 AM
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ghrocketman ghrocketman is offline
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Join Date: Jul 2005
Location: Nunya Bizznuss, Michigan
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I use a jump-starter box to launch as well. It contains a 7.2Ah 12V Gel Cell.
Same battery for use in my R/C glow-engine flight/starter box as well.
Will fire hundreds of rocket igniters on a single charge.
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