Deep cycle battery question

(t_brown) · (t_brown) **Join Date: Feb 2006** 03-14-2006, 9:29 PM

I was just given a Trojan Deep Cycle battery and I was wondering if I could use this as a starting battery as well. It has 850 MCA and 225 hour run time @ 15amps. I will have another battery (the original battery) as a back up.

(mhayes) · (mhayes) **Join Date: Jul 2004** 03-15-2006, 5:11 AM

Yes, you can use it as the starting battery as well. When you say "I will have another battery (the original battery) as a back up", are you saying that you are going to have them both hooked up? When hooking up multiple batteries, you should really be running the same type, size and age batteries.

Give us more details of what you are trying to do?

(t_brown) · (t_brown) **Join Date: Feb 2006** 03-15-2006, 8:35 AM

Yes, basically I am going to use a Perko switch and use the other battery (not the same kind or size or newness) as a backup. I would never charge them both at the same time or use them both at the same time. I would either use battery 1 or battery 2.

(acurtis_ttu) · (acurtis_ttu) **Join Date: May 2004** 03-15-2006, 9:41 AM

Todd, that's what I do, just make sure that you keep the backup on a trickle charger every once in a while, when it's in storage.

(3205lpv) · (3205lpv) **Join Date: Nov 2005** 03-15-2006, 3:49 PM

Why don't you just get an isolator. Hook your stereo and electronics to the deep cycle and the starter to the old battery. Then the stereo will draw from only the deep cycle and you starter will only start the boat. They both stay fully charged and you still have two.

(t_brown) · (t_brown) **Join Date: Feb 2006** 03-15-2006, 3:53 PM

that is an option, but is more costly.

(cyclonecj) · (cyclonecj) **Join Date: Jul 2001** 03-16-2006, 9:18 AM

Cheapest, easiest, best isolation for the money is a high current solenoid.

(brucemac) · (brucemac) **Join Date: Dec 2005** 03-16-2006, 10:03 AM

match your batteries up and buy a yandina c100 combiner for $65. you can use it with your switch and it will keep your 2nd battery isolated whenver battery 1 drops below a certain level. when your charging system kicks in, it charges both batteries.

http://www.yandina.com/c100Info.htm

(brucemac) · (brucemac) **Join Date: Dec 2005** 03-16-2006, 10:35 AM

actually, you don't even have to match your batteries up with the c100, you could keep your lead acid starting battery and have a 2nd optima blue top. there's a regulator in the c100 that prevents overcharging

bamer001 03-17-2006, 12:03 PM

If you use the perko switch to run/charge two identical batteries, will that cause any problems? What will happen to the batteries while the boat is not in use? If the batteries were different, what would happen while in and out of use?

(brucemac) · (brucemac) **Join Date: Dec 2005** 03-17-2006, 12:26 PM

i'm no expert, but it's my understanding you don't ever want to charge both batteries at the same time, identical or not, without the use of a combiner/isolator. when using a make-before-break switch by itself you should only ever have it on both if you're trying to start your engine when battery 1 will not do it by itself. leaving it in "both" while charging is hard on your alternator and i believe bad on the batteries as well. people on this board who use only a switch have to manually swith it between 1 and 2 postion to make sure both batteries are charged. another thing to note is, don't EVER switch past "off" while the motor is running as it can really mess up your alternator.