12v 7AH battery

[little fish]

Hi,
      Can anyone tell me how long a fully charged 12v 7Ah battery will last, my fishfinder draws 400 Ma. I have heard that if you divide the 400Ma into the 7 Ah it will give an approximation how long it will last in hours?

Many thx 

[bpiatt]

Hi,
      Can anyone tell me how long a fully charged 12v 7Ah battery will last, my fishfinder draws 400 Ma. I have heard that if you divide the 400Ma into the 7 Ah it will give an approximation how long it will last in hours?

Many thx 

1ah = 1000mah , so your battery is 7000mah, just divide 7000 by 400 and it will give you an approximate run time in hours.

[CamoHunter]

What he said ^
7000/400= 17.5 hours in a perfect world.  You will not be able to get max charge out of the battery after a while and will go downhill over time.  What fishfinder is it?  Fishfinders will use different draws depending on different factors also.  My humminbird for example will use more or less depending on how bright my backlight is set.

[little fish]

Hi,
      Many thx for the info.............I am using the humminbird 586c-HD c/w the ice transducer.

[delta9]

Someone knows their math. It is correct, and run time will have many factors, beside battery condition, and age, you can throw in temp and connection condition.

[Kevin23]

With a "fully charged" battery, I'd say anything around 15hrs is doing darn good. Batteries usually are not what they say, they all come from china and they are known to cheat on the amp ratings. You might pay $40 for a 9ah SLA and in reality its a 7ah SLA with a 9AH sticker on it... they do that all the time, and you probably wouldnt even notice because 99% of us dont draw them dead every trip.

I'd say hope for 15, be happy with 12.

[gearheart]

The 7000 divided by 400 is the answer to how long to kill the battery dead.  However the fish finder will quit working much earlier than that when the voltage drops to around 8-9 volts.  so realistically if you get a day on the ice you're doing good.  Also batteries don't work as well in the cold as at room temperature.

[dfauverii]

  Always have a spare on hand.  That was my lesson last year anyway. 

[$ignmoney]

The last two years now I have been using my lawn mower battery. Some say I will ruin it, so far it still works great and still started the mower the other day. Even If I do big deal, $40.00 at tractor supply and I'm up and running again. I plug in my camera (aqua-vu) and run my lights, radio and so far I only dropped it to 80% charge after 8 hours on the ice. If you are worried about power step up to a bigger battery and worry about fishing not how much power you have

[MT-Ed]

I've been using a lawn mower battery.....the same one......for more years than I can remember, and have never had a problem. I run depth finder, aqua vue, led lights, even a dc/ac converter so I can hook up my video cam to the aqua vue, TV, all kinds of stuff. Not as heavy as a deep cycle, but far longer lasting than the 7ha ones. my .02

[BIGJim223]

I have been using an 18a/h motorcycle battery that I bought in 2001. Retired it from my motorcycle in 2008 as I thought it was a good idea to get a new battery for the bike before I got stranded somewhere on a 7 year old battery. Put it in the flasher box and been using it ever since. Last year the 2008 battery crapped out in the bike, put the 2001 battery in and it worked fine until I could get a new bike battery ($90!!), then it went back to the flasher box. It runs my 'Bird for weeks without recharging! Still charges to 100% on my battery tender.

BIGJim223

[SDFlagChaser]

I run a H-bird Ice 55 and I can usually get two full days out of a charge.