installing 2 batteries, what combo??

bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,304
ok so I went to start the boat for the first time this year, It was last run in December of last year. I had no power to tilt the motor. Went to check the battery switch, turned it on #1. still nothing... went to check the charge in the batteries... the charge was zero...because THEY WERE STOLEN!!

some drug crazed kid probably stole my batteries to get his next high. (prevelant in the area all of the sudden).

SO, heres the scenario, the boat was mainly built for late winter seaduck hunting on salt water. But will also be used for fishing when the weather is rougher or I am going further from shore on that fishing trip. The boat is a deep V 22 ft starcraft closed bow boat. I love the security of having two batteries. I run the normal electronics and lights, the biggest draw maybe a golight spot light. I do not have a trolling motor. I have always tried to buy the battery with the most cold cranking amps possible with the most reserve. because I have needed that when trying to start a poorly running motor in 5 degree weather!!

my question is, should I buy two starting batteries?, or two deep cycle long lasting batteries, or ONE OF EACH?

the last few years on my main duck boat which runs 2 group 29 batteries, I have just set the battery switch on both about half the time and one battery #1 the other half... and I have never been let down. which might just be the fact they are constantly charged and that the motor was running very good, who knows.

so help me out and tell me why

thanks

bob
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,417
I've always used a pair of grp. 27 deep cycles, mainly to support my electronics.

A couple of years back, I seperated all circuits to house and start batteries and installed an ACR to eliminate messing with switches.

Now that the electronics are on a dedicated deep cycle, I might try a large cranking battery on the motor when one of the deep cycle dies just to see how it acts
 

Grandad

Lieutenant Commander
Joined
Jun 7, 2011
Messages
1,504
Bob, if you're concerned only with security (reliability of performance), I think what you have been doing is the best way. I have a pair of 27H deep cycle batteries that each have much greater cranking amps than required to start my 2.5L I/O. I periodically cycle my use between them as you've been doing to ensure that both are still reliable. If I find one is getting weak as they age, I'll get home on the other one and then replace them both. - Grandad
 

bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,304
I see a brand new DIEHARD PLATINUM battery in craigslist it is a size 31 with 1150 CCA and 205 min reserve..... they want $270. I am wondering if it is more prudent to try and buy two size 27 batteries at about 3/4 the power, than to only have the ONE battery....if I have two 27 group batteries with 160 minutes of reserve.... and maybe 750 CCA...will I have more reserve and power with them using the BOTH position of my battery switch, than having the one big group 31 battery with its higher specs???

bob
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,417
I've seen too many things go wrong with batteries, charging circuits, etc. to ever put my faith in just one battery.

Under normal conditions, I have no problem starting my motor using a single, grp. 27 deep cycle. When it gets cold, I typically use "both" to give me that little extra RPM first time in the morning. I've never had any issues, but there have been times I was beginning to doubt.

Now that I have my battery management worked out, I'm thinking of swapping out one of the deep cycles for a cranking battery. I'm thinking the 50% added MCA in the morning might be a better way to go.
 
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