[twospeed46]

Question, I just had a Dual Battery System installed on my 2002 Cuddy Cabin and I'm not sure how it charges both batteries,it has the following postions; Off,Both,And postion 1 & 2 , I understand the basics you use postion one or two to run the eng and the other while anchored for Accessories ,Do you have to put the selector in the both postion to charge the batteries while the eng is running, Is that correct or am I off in left field ????

[WetWilly]

Hi twospeed46,

Maybe a little to the right but definitely not in left field.....

Having the switch in the both position would seem logical but it really depends on how the person who installed your switch wired it up.

I use this system (Click here) and it incorporates an ARC unit which charges both batteries when the engine is running, regardless of the switch position and it also prevents the weaker battery from draining the charged one by isolating both batteries.

Check with your installer and make sure the charge wiring doesn't allow the weaker battery to drain the stronger one when the motor is off or you could end up with both batteries too low to start the motor.

WetWilly

[ShabahZ250]

Hi twospeed46, I have a dual battery system on mine too. If yours is a "Blue Sea Systems" switch, here's how it works.

When you switch to battery 1 and the engine is running, it will charge battery 1 only. Switch to battery 2, and it will charge battery 2 only. In the manual for the switch, it says to run it on both for emergencies only to get it started, then switch back to a single battery. So technically there's no way to charge both batteries at the same time while underway, without modifying your charging system to incorporate an ACR (automatic charging relay). Some on here have done it, and could probably walk you through it.

Do you have a 3 prong charger outlet on your boat? Mine came with one on the transom. It connected to a ProMariner "Bat Sav'r", which was hooked up to battery 1 only. I replaced it last year with a new dual bank charger, so whenever I plug in the extension cord, it'll charge both batteries. I think I posted all the details on here, if not, let me know and I can answer any questions for you.

Hope this helps.

[indykoch]

I may be wrong, but I always leave mine on "both". It uses both batteries, and charges both all the time... almost like doubling the life of one battery.

One thing I'm sure of - NEVER turn the switch while engine is running!

[twospeed46]

To everyone that replied to my question about dual battery system Thanks,Info will help alot,I hope to have this issue resolved by this coming weekend,I will let you know what I find out

[Provo]

FYI do not turn the switch position to off while the engine is running. It will fry the alternator.