My 4 year old daughter had the wisdom to get me a new fish finder for Christmas. I intend to take it ice fishing but I needed a battery first so I took the advice from some of you here and went to NPS to get one cheap. The battery I got is one of the 12v 7.5amp/hr types. I already have two ways I can charge it. I have a 1.75 amp 12v power supply and a 500ma 12v power supply. How would you charge it, and how do you know when it is fully charged? Do I watch the voltage (with my volt meter) as it charges? And if so, at what voltage should I call it quits?
Thanks in advance for the help. I am hoping to be able to post a report in a few days after successfully trying this one out.
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I don't know if you can over charge the battery with the 500ma charger. Put it on for 12 hours and check it with the meter.
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Use the 500 milliamp 12 V. power supply to charge the gel cell battery. If it's a lead acid type you could use either charger. If you do have a volt meter, check to see that you're getting at at least 13.0 volts D.C. from the charger before you hook it up to the battery. Leave it on the battery for a day and then check you battery voltage ( with the charger disconnected). Verify you have at least 12.6 volts. Hook up you finder to the battery and verify with finder turned on you still have a voltage reading of at least 12 volts or higher. If you do, you're good to go.
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Hey Matador,
I agree with Slade. 12.6 volts is a good number for a fully charged 12v battery. Some chargers have a light or quit charging at 13.5 or even up to 14.4vdc. If you don`t have a volt meter, I suggest getting one because it is by for the best way of knowing what your charger is doing and the status of your batteries. It is the same in your boat, vehicles, RV, four wheelers. Get a volt meter. It is a good investment. Good Luck and Fish On.
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Thank you very much you guys. I do have a good digital volt meter. I just put together a wire harness to go on the battery, with convenient connectors to easily connect the FF and the charger. I am impressed that off the shelf and without charging beforehand, the battery had a voltage of 12.59v. I hooked up the fish finder and in simulator mode with the light on the voltage only dropped to 12.47v. I ran it for an hour or so like that and did not notice a voltage drop. So far so good (I think).
Please allow me a few more questions to those who have used these kinds of batteries. BTW, is it the gel cell kind.
My 500ma charger has a voltage of 17.7v without a load. When I connected it to the battery for charging, the voltage dropped to 12.8v but in only 10 minutes of charging it has climbed to 13.2v. I assume that means that I am already close to a full charge. Am I correct? I ask this because I am already well above the 12.6v recommended above for stopping. Should I be concerned about this? Also, what about the battery heating up during charging? What should I expect?
This is all about what I expected, but I would appreciate any further advice you may have based on your experience.
Thanks again. I am getting stoked to try this rig out!
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I found out this is a sealed lead battery, not a gel cell like I thought(shows how much I know). A little research on the internet gave me the added info, but it was real technical so it was a little fuzzy for me. Does being a sealed lead battery change anything? How is it going to work in the cold that comes with ice fishing?
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[black][size 3]Hey Matador,[/size][/black]
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[black][size 3]Your SLA will hold up just fine for ice fishing. Everyone I know uses the same batteries for their fishfinders and they work just fine. I keep mine in a small lunch cooler that kind of protects it from the elements and insulates it from the ice. [/size][/black]
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[black][size 3]If you keep it charged up by plugging it in right after you get home from fishing, you should get quite a few years of life from your battery. I use mine all year - winter and summer and have had it for 3 years now and it will still give me 2 or so days of fish finder use on one charge.[/size][/black]
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I am with Fishhound on always charging up when I get in from fishing so it sits fully charged. Any time you charge a battery it will get warm but with 500ma it should not get hot. I charge my batteries to inbetween 13.5 and 14.4vdc. After they sit the voltage will drop to 12.6 or a little more like 12.8. One thing I always do is unplug one or both of the battery leads to my flasher or graph. There is ALWAYS some load coming from a unit when it is turned off so while it is sitting your battery is being discharged. If you are going out the next day it wouldn`t matter but if it is a couple weeks it will. My advice from, been there done that, Fish On.
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Man, you guys have this stuff down! After charging it to about 13.7v last night it has been sitting for about 12 hours. It now reads 12.83v without a load. It looks like I am right on track.
Thank you all!
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