small battery/fishfinder question

[lars56ca]

I'm hoping someone can shed a little light on a few questions I have

I’ve been given a small 12V 7Ah battery. I’d like to try it with my fishfinder ( Eagle Fishmark 480) but am not sure how many hours to expect from it.

On these small batteries, what should be the nominal voltage? Right now it reads 12.6 V DC.
What can I safely let the voltage drop down to before I recharge it?
At what point can this type of battery no longer be charged?

I have a battery charger with a 12V 2A setting that puts out 12.5 V dc. My understanding is that this is what I should use to recharge these smaller 12V batteries. It is also my understanding that I can leave the battery charging this way for a long time without damaging it. Is this true? Is there an easy way to know if the battery is at it’s maximum charge, other than taking a voltage reading.

Thanks in advance

[ady]

7AH means 1 amp for 7 hours - when new and in tip-top shape. Look at the spec for the fish finder and see what current it uses. then a bit of math is involved.

[bass ackwards]

Careful this is a gel cell, these are designed to be constantly trickle charged
it will probably last you all day running the fish finder.
Take it slow charging it, 2 amps the max and take it off after 4 or 5 hours.

[SKEET544]

That is what i use on my flasher and it runs it all day no problem if you let the voltage get too low (11.5) is as low as i would go, you can burn out resistors in your unit, happened to me once, bad connection in the plug. I use a small trickle charger, (the kind that come with radios, flashlights etc.) 12volt, 1000 milliamp. just cut the plug off, crimp on push on terminals that fit the battery, check and mark the positive wire. I let it charge overnite. PM me if you need more info.
Skeet