Marine Electronics Forum - Optimax / Fountain electrical / battery / alternator question..

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03-29-2012, 05:20 AM
I have triple 225 optimax mercs on a 38 Fountain. I recently did a lot of rewiring and set it up with one battery per motor all isolated. Each battery is dedicated to starting each motor and each has house loads on it. No separate house battery.

I do a lot of sword fishing with engines idling. The other day I had my two garmin 5212s shut off on me... keep in mind I have all of my sensitive electronics on one bank/engine. (VHF / Radio / Amp / Radar / garmin components. I am running 3 2150 Odessey batteries..brand new. The voltage on the garmin displayed 11.5 when i turned the units back on......This happened 2 times while idling. I paralleled all the switches thru the battery switch problem was resolved..

I checked all alternators..they are fine....boat has all new battery cables / 2/0 and all new console wiring.

Is it possible that the alternator can not keep up with the house load on this bank? The alternator is a 60amp......

I really want to keep all batteries separate

Let me know your thoughts


03-29-2012, 05:30 AM

I have a single 2002 225 Opti on my Whaler. I have a Start and House set up on a BEP 716 system. I have never had any issues with power to all my stuff.

I have a the following connected to my house battery.

Garmin 740
Simrad NSS8 TM260 ducer
WM2 Sirius Weather Module
Fusion Sonic Hub (Stereo)
Garmin GX51 Smart antenna
N2k backbone
Fusion Zone Amp (Stereo)

Do you have both Garmins connected to the same battery?

I would recommend at minumun you install one house battery. Something is putting a load on your batteries. Bilge pumps???????

03-29-2012, 10:57 AM
Alternators at idle dont put out much, maybe 10 to 20amps of charge, if that. You could put VSRs (ACRs) between all the batteries that will automatically balance the charge across the batteries if one particular alternator can't keep up. But I recommend a house battery, moving all those items to the house battery and then getting 3 VSRs, all from the charging engine batteries, all to the house load battery.

cayman donzi
03-29-2012, 12:24 PM
I think on some set ups the center engine has a power steering pump and no alt.

03-29-2012, 03:08 PM
Add 2 more batteries to that bank or split that load up. Ur amp should be on its own bank anyways away from electronics. Add all that up my house bank with everything cranked and pulling max amps is over 200 amps. Meaning even with 2 batteries I'm dead in 45 minutes. My stereo is on a completely separate bank with 3 batteries.

Glen E
03-29-2012, 08:11 PM
did'nt we all recc a house batt a few months ago when you asked before? and all motors don't charge crap when trolling or below 1500....easy to discharge below that rpm...

Mid Shore Electronics
03-30-2012, 12:51 PM
SAlty G gave you a good answer. 1st verify battery is GOOD with a load tester. Battery could be going bad.
consider creating a separate battery bank and use an ACR (automatic coil relay) this will allow you to shut down engines, drift with all electronics running. Then once you have KILLED the house bank your engines will jump to life when you hit the key. The ACR will isolate engine start battery(s)

Glen E
03-30-2012, 12:57 PM
"automatic charging relay"=ACR

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