Dual Battery System how to charge correctly.

mojokoko · Post by **mojokoko** » April 3rd, 2006, 7:38 pm

Sorry for all the newbie questions about Fishing and or Boating! I have grown leaps and bounds from where I was last year. Anyway, I was wondering if you guys could tell me how I should "properly" use my dual battery system charger. I have a battery switch with 1, 2, and ALL. I run a trolling motor which I tend to replace soon with one I can operator with my foot but thats a few weeks away hopefully. ALso I run a Garmin Fishfinder, GPS, and a onboard livewell. From what I understand I should leave it on ALL while I head out and then switch to Battery 2 which has all my eletronics on it when I get to a spot and turn the motor off. Pretty much I belive you Run it on ALL, then once I find a spot I turn the motor off and change the switch to 2. Maybe I have been doing this wrong or maybe not. Once again sorry for all the questions.

Post by **Dubble Trubble** » April 3rd, 2006, 7:51 pm

Ok, first, you should never charge both at the same time. BEFORE you go out, make sure both battteries are fully charged with a GOOD trickle charger/maintainer. Then use the out on 1 in on 2 rule. Charging 2 batteries at the same time can ruin 1 of them, especially if they are not the same age or amp rating. Also, some smaller motors alternators will not have enough amps to charge 2.

As for the switch be sure you go from 1 then to BOTH then to 2 or vice versa. Never go to OFF while switching on the move. You can blow the alternator.

One other reason to never use both is that if you have a short, you can quickly kill BOTH batteries, then you are dead in the water. The only time you should switch to both is when you do not have enough power in either battery to start by itself.

Now I am sure there will be those who run on both, but it is not advisable for all the above reasons.

Hooked

mojokoko · Post by **mojokoko** » April 3rd, 2006, 8:06 pm

So pretty much go out on 1, then once you find your spot turn off the motor and then turn the switch to off. After all this you then turn it to 2 and run all your eletronics etc etc. That way if you lets say use most of Battery 2 you use 1 to run back in? Also while im running back in on 1 I would assume it charges battery to while im running back?

Post by **wevans** » April 3rd, 2006, 8:47 pm

The way I work mine is, have the trolling motor connected directly to ONE battery, everything else goes through the switch. I run the boat from the trolling battery most of the time "running everything" this leaves a fresh battery for anytime I run down the one battery. I will at times switch it to the other just to get some discharge and recharge on it and put a trickle charge on both from time to time. I NEVER switch the batteries while the motor is running and will run on both only long enough to put some charge in a weak battery, then shut down, switch to the weak one and fire it back up and charge the weak one while running

mojokoko · Post by **mojokoko** » April 3rd, 2006, 9:06 pm

I guess what im getting at is how can I choose which battery to charge. Like lets say ive been running the electronics battery aka 2 for a while and I decided to run to a new area and then switch it to 1 well it then charge 2 while I run?

Post by **Chalk** » April 3rd, 2006, 9:42 pm

I think the altenator will only charge the battery it's connected to, regardless of the switch position....You can buy this switch that will switch to the second battery and provide a charge to it from Bass Pro ShopsÂ® XPSâ„¢ 12V Phase Charger

Post by **Dubble Trubble** » April 4th, 2006, 8:13 am

Chalk wrote:I think the alternator will only charge the battery it's connected to, regardless of the switch position....You can buy this switch that will switch to the second battery and provide a charge to it from

That depends on how it is wired. If the alternator is connected to the common Positive(+) before the switch(as it should be), then it would charge both if switch is on BOTH. It should not be wired direct to either battery, or it would not charge the other when switched...

And NO, I did not say to switch all electronics off before switching over. I said to be sure you go to BOTH as you switch, not through the off position.

IE....if on 1 then from 1 to both to 2..... NOT 1 to OFF to 2... Got it? No need to turn off electronics or shut down motor if you do it that way....

Hooked

Edit: One thing I forgot is to make SURE you have the type switch that has constant contact when going from 1 or 2 to both. Some of the older ones would not do this. You can easily check it with an ohmmeter to be sure.....

mojokoko · Post by **mojokoko** » April 4th, 2006, 11:53 am

Cool one more question and that should be it lol.
How do I tell what the alternator is connected to?

Post by **Dubble Trubble** » April 4th, 2006, 12:12 pm

That is not so simple...

Normally, it is hooked into the positive circuit somewhere. That could be at the battery. or it could be at the fuse or breaker panel. (Sorry but too many boats out there to narrow it down).

IF there is a smaller Red wire connected to the positive terminal on one of the batteries, then this is probably it. However, to work properly with a 2 way switch, the positive feed from the electrical system should be connected to the common line on the switch. (Usually the large red wire going to the motor starter).

Yours may or may not be connected properly already. Just be sure you know what you are doing, if not let the experts do it. may save you money in the long run....

Hooked

chugbug · Post by **chugbug** » April 5th, 2006, 9:50 am

This is how I did mine. I connected my engine to the cranking battery and all of the electronics, pumps, etc... to a deep cycle battery. The draw from a radio, GPS and FF won't kill a deep cycle if they are on all day. At least mine didn't. When you get home put the batteris on a charger. I cut the switch out altogether. If my cranking battery goes dead, I can hook the leads to the deep cycle to start it and get me home. If the deep cycles fails, change the leads for the electronics to it and go home. I didn't have a trolling motor though. I hope I haven't confused you.

Chug

Post by **Dubble Trubble** » April 5th, 2006, 12:21 pm

Chugbug. I sure hope you do not venture far offshore with that setup...

What happens when the main fails at end of day and deep cycle will not turn motor over because electronics have it weak?

Also with that setup, you would have to hook cables up to even charge deep cycle with alternator....

Hooked

Post by **Chalk** » April 5th, 2006, 12:40 pm

HookedUp wrote:Chugbug. I sure hope you do not venture far offshore with that setup...

Its the same setup minus a switch....no different...whether you have a switch or not....even if you have a switch you still have to switch it inorder to charge the other battery.... if you have the switch wired to do that...it still requires human intervention....if you wish to have an automatic 12v system use the phase charger I mentioned earlier, it automaticaly switches once one battery is charged to the other

chugbug · Post by **chugbug** » April 5th, 2006, 2:07 pm

As I mentioned. All the electronics put together won't drain a deep cycle that much. When I get home the battery is at 90% charge and I leave my stuff on the entire time.

mojokoko · Post by **mojokoko** » April 5th, 2006, 2:59 pm

Yeah I pretty much fixed my boats eletrical system now thanks to you guys. Also some things I were doing were a little wrong but not to bad. So next weekend im going to post on the Inshore fishing board with some pictures!

Post by **Dubble Trubble** » April 5th, 2006, 4:30 pm

Ain't it fun doin it yourself....

Way to go. Lookin forward to the pix of fish you catch.

Hooked