View Full Version : Second battery size (AH and RC)

13-11-2001, 06:49 AM
What are the recommendations regarding AH and RC for a second battery (deep cycle) size?

It would be used on a 5.2m with 85hp. The battery would be used for general array of periperals [radio, sounder, instrument lights (5), anchor & running lights, cabin and cockpit light, bait tank pump/areator, and small spotty].

I t also will be needed to assist the primary (starting battery) if it fails.

Century Marine or Excide Marine also seem reasonable options rather than some of the more expensive or exotic options.

Thanks for you advice in advance.

15-11-2001, 04:33 AM
I have a 5.25 m noat with a 75 Merc on the back. We have two century marine pro 500 hundred batteries onborad and i can't give them enough praise. We do all of the usual running around that you do as well as run a 100 watt floodlight for about 3 or four hours when ever we chase jew and trag. We doo all of this off one battery and there is still heaps of power left to start the motor. Go with the century but i reccomend that you go for the 600 series. You won't be disappointed.

15-11-2001, 04:01 PM
have 18ft with 130 on back and i run two century 600 series
with isolater , use both to kick her over, and during normal
running leave isolater on 1+2 , have been out allweekend
for 2nights, with fluros running and sounder/radios on plus
anchor lites, plus in no action time have the am radio going,
as long as u switch to 1 and run all access on next morn
just switch to both to kick her over have had no trubs yet
with good run back to ramp both get charge up again.

16-11-2001, 07:21 AM
I have just done a major job on my boat ,installing a duel system ,with isolation switch. The switch is the important thing here. If you dont have one installed, and one battery gets lower than the other,the lower one will draw from the higher,and this defeats the purpose.I tested this with a battery with only 8 volts left,and measured the voltage after 5 minutes, after both had been connected in parallel, and was surprised at how quickly the batteries levelled out.

A starting, or high crank battery does not like being run down, then recharged. This shortens the life of the battery.

The correct way is to start your motor on the crank battery only,and let it recharge when running. Then switch to the alternate battery to run all your gear,switching back to your crank to restart.
Make sure that you dont buy a sealed type battery,unless the charging system on your motor is regulated.( A lot of charge systems are not regulated) See my posting on this topic .I also have a small solar panel,$25 Super Cheap,and run that during the day to trickle charge the accessories battery.Add up all the amps your accessories draw,the get a battery to suit that need in a deep charge type.
Hope this helps

24-05-2006, 09:36 PM
If you live in or around wollongong, give key battery service a go, i just replaced a battery and when i pulled it out it was a key battery and it was 9 years old.

i told the guy about it it and he said yeah we quite often get them between 5 and 9 years old "doin ourselves out of business, but you keep comin back"