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Dual Battery System how to charge correctly.
Posted: April 3rd, 2006, 7:38 pm
by mojokoko
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.
Posted: April 3rd, 2006, 7:51 pm
by Dubble Trubble
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

Posted: April 3rd, 2006, 8:06 pm
by mojokoko
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?
Posted: April 3rd, 2006, 8:47 pm
by wevans
Posted: April 3rd, 2006, 9:06 pm
by mojokoko
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?
Posted: April 3rd, 2006, 9:42 pm
by Chalk
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 Shops® XPS™ 12V Phase Charger
Posted: April 4th, 2006, 8:13 am
by Dubble Trubble
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.....
Posted: April 4th, 2006, 11:53 am
by mojokoko
Cool one more question and that should be it lol.
How do I tell what the alternator is connected to?
Posted: April 4th, 2006, 12:12 pm
by Dubble Trubble
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

Posted: April 5th, 2006, 9:50 am
by chugbug
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
Posted: April 5th, 2006, 12:21 pm
by Dubble Trubble
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

Posted: April 5th, 2006, 12:40 pm
by Chalk
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
Posted: April 5th, 2006, 2:07 pm
by chugbug
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.
Posted: April 5th, 2006, 2:59 pm
by mojokoko
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!
Posted: April 5th, 2006, 4:30 pm
by Dubble Trubble
Ain't it fun doin it yourself....
Way to go. Lookin forward to the pix of fish you catch.
Hooked
