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View Full Version : Anyone know about amps? Possible electrician?



Team M&M
05-02-2007, 09:03 AM
O.k. I admit I know nothing about amps or electricity in general. Heres my situation and my question. Im gearing up my boat for nightstalking(fishing at night over a light) and I want to buy 2 Q-Beam Starfire lights to drop in the water. One at the front of the boat and one at the rear. Now I'm going to buy an extra trolling battery and use that when I fish at night to power the 2 lights. Each light says it draws 3.5 amps. The battery Im buying says its a 730 amp deep cycle battery.
Now my question is, on the lights is that 3.5 amps an hour or a minute or what? If its an hour, does that mean a 730 amp battery could potentially run the lights for say 8 hours straight? If I had both lights on the battery that would be a 7 amp draw, but Im just not sure if thats an hour or what?

If you know about this kind of stuff please let me know, as I want to make sure I have plenty of battery power for all night trips. I could also run one of the lights off my already existing trolling battery since I wont be using it when Im anchored down at night.

I chose the Q-Beam Starfire because I've read several articles and most have recommended it. Its easy to change the bulb in it and it supposedly gives off 250,000 candle power. I thought about a green light, but people here are saying they've had better luck with the white.

Barnacle Bill
05-02-2007, 10:20 AM
730 is probably the CCA (cold cranking amps) for the battery. There is another rating written somewhere on the battery giving you the A/H or amp hour rating. It will probably be down around 100. The bigger the battery, the higher this number. This is the rating that you are concerned with. Theoretically, a battery rated at 100 A/H will support a load of 10 amps for 10 hours. But since most batteries are depleted at around 50%, you would get around 5 hours of use. Deep cycle batteries can go much lower than a car battery. Those numbers also determine the length of time required to recharge the battery. Using the example, that battery depleted to 50% would take 5 hours to recharge at 10 amps. So with all that bull, find your A/H rating, divide by 7, subtract a few hours, and that will tell you how long it will last. Approximately.

rangertee
05-02-2007, 10:30 AM
O.k. I admit I know nothing about amps or electricity in general. Heres my situation and my question. Im gearing up my boat for nightstalking(fishing at night over a light) and I want to buy 2 Q-Beam Starfire lights to drop in the water. One at the front of the boat and one at the rear. Now I'm going to buy an extra trolling battery and use that when I fish at night to power the 2 lights. Each light says it draws 3.5 amps. The battery Im buying says its a 730 amp deep cycle battery.
Now my question is, on the lights is that 3.5 amps an hour or a minute or what? If its an hour, does that mean a 730 amp battery could potentially run the lights for say 8 hours straight? If I had both lights on the battery that would be a 7 amp draw, but Im just not sure if thats an hour or what?

If you know about this kind of stuff please let me know, as I want to make sure I have plenty of battery power for all night trips. I could also run one of the lights off my already existing trolling battery since I wont be using it when Im anchored down at night.

I chose the Q-Beam Starfire because I've read several articles and most have recommended it. Its easy to change the bulb in it and it supposedly gives off 250,000 candle power. I thought about a green light, but people here are saying they've had better luck with the white.

The amp rating on the lights should be what they draw continueous. If that is true, then they will draw a bit more at start up. I would make sure you intall in-line fuses (probably 7 amps each, I would not go over 10) on both lights. You might find that you need two deep cycle batts to last you all night. Q-Beam(Brinkman) folks should be able to answer that question. I wouldn't use my troll motor batt as a primary source for the fishing lights, you might need it to get you to the bank some night. If you are set on those lights, what I would do is a test run before you get totally rigged for a night trip. Hook up both lights to your NEW DEEP CYCLE batt one mornin, do yer rat killin around the house and see how long that 1 batt provides full power to both lights. You'll know for sure what you got then. Good luck

joejv4
05-02-2007, 12:08 PM
IBNFSHN is right on the money, you want to find the amp/hour rating. 100AH in theory will handle 10A for 10 Hours, but again IBNFSHN is correct about batteries not working below a certain percentage - go with a deep cycle to maximize the time it will work - a real good one will work down to 20-30% charge, where a cranking battery will last down to probably 50%.

A separate battery for your lights is a good idea too, like rangertee said, you may need your trolling motor to get you home some night.

I'm not positive, but I think the Qbeam's need to be operated under water to avoid heat damage, so if you do the time-test like rangertee suggested, you'll want to stick the bulbs in the tub or a barrel of water. That's probably the best way to go about figuring out how long they'll last you - make a trial run. check the manufacturer's instructions to find out if they need to be run in the water or not. I'd hate to hear you hung them from the clothesline to see how long a full battery would last you, and that the lights burned out.

fishman78
05-03-2007, 01:15 AM
Not sure if it will help you but this website has some good info on runtimes for fishing lights. http://fishinglightsetc.com/RunTime.html

joejv4
05-03-2007, 07:20 AM
Not sure if it will help you but this website has some good info on runtimes for fishing lights. http://fishinglightsetc.com/RunTime.html

The fact that those guys have so much info on their site is the reason that when I eventually have something bigger than a row boat and start night stalking, I'm going to by my lights from them. Reasonably priced and I really like that they have replaceable bulbs - they even tell you what kind of bulb to look for at the auto parts store so you can buy your own replacements locally. I also like that they have the different colored sleeves so you can go with blue, green or plain white. (30 bucks for the combo is a really good price)