charging 2 batteries in parallel, and other questions

[The Yeti]

Question #1<br /><br />i have 2 equally rated group 27's in parallel (+ to +, - to -).<br />we'll refer to them respectively as battery one, and battery 2.<br />when charging them:<br />------ should i hook up the + and - leads from the charger to battery one (which by now, are connected to the + and - of batter 2 via jumper cables). will this fully charge both, showing no preference to battery 1 to give it more or fuller flow since it's first in line. OR<br />-------should the pos. lead from the charger go to the pos of battery 1 and the neg lead from the charge go to batter 2's neg lead or vice versa. wouldnt this create a more even, round flow of electricity, or does it really not matter?<br /><br />question #2<br />i fully charge my cranking motor (with my 3 bank minn kota mk3 charger) to a full charge overnight or whenever. this battery also receives a charge from the alternator when running. will this extra charge from the alternator "overcharge" or hurt my battery on top of a previous full charge, OR generally, does the alternator trickle it in as needed (mercury v6 inboard jet engine)similiar to how a vehicle alternator never overcharges under normal circumstances.<br /><br />question #3 (thanx for bearing with me by the way)<br /><br />ok, bear with me again.........<br /> My trolling motor is 12volt. im goin to put my 2 rear trolling motor batteries (wired in 12v parallel, each rated at roughly 875 mca, 100 reserve equalling approximately 1550 mca) on a perko dual battery switch (switch will be up front for convenience,their supply will be the primary) Also, im installing a smaller sized battery (as big as i can fit, so it could end up being a 1525mca from cabelas) up front to the trolling motor as a secondary and it will also of course, be on the switch. my question is......IF i inadvertantly hit the switch to ALL, will this 1550 + 1550 total mca burn, hurt, or in anyway F up my TM? that seems like one heck of a lot of mca to one battery. <br /><br />obviously, i wouldnt be running them in "ALL" mode unless sorely needed (low yeild on all 3 batteries or whatever), but if this happened by accident, with all 3 of the TM (trolling motor) batteries fully charged, what kind of electrical ramifications would i be looking at?<br /><br />thanx<br />if you don't wanna post back here, feel free to email me at gt.ivan@comcast.net

 

[swist]

Re: charging 2 batteries in parallel, and other questions

Question #1<br /><br />i have 2 equally rated group 27's in parallel (+ to +, - to -).<br />we'll refer to them respectively as battery one, and battery 2.<br />when charging them:<br />------ should i hook up the + and - leads from the charger to battery one (which by now, are connected to the + and - of batter 2 via jumper cables). will this fully charge both, showing no preference to battery 1 to give it more or fuller flow since it's first in line. OR<br />-------should the pos. lead from the charger go to the pos of battery 1 and the neg lead from the charge go to batter 2's neg lead or vice versa. wouldnt this create a more even, round flow of electricity, or does it really not matter?<br />

If the connections are good, and the wire properly sized, it won't matter.<br /><br />But some other things might... The batteries should be in a more or less equal state of discharge. Also not sure if this will work with gel-cell or other higher tech batteries than need intelligent chargers. I would think the parallel situation could throw off the changing process....

 

[llfish]

Re: charging 2 batteries in parallel, and other questions

To charge you would hook red lead of bat charger to + on bat 1. Black lead to - on bat 2.<br /><br />Here is a good diagram on parallel and series wiring of bat. http://www.otherpower.com/otherpower_battery_wiring.html

 

[Sea Six]

Re: charging 2 batteries in parallel, and other questions

If your batteries are jumpered together, it won't matter which battery you hook your charger up to. As long as red is + and black is -. If the two batteries are different capacities or types, I'm not sure they will both charge properly if they are connected when charged. I do not think you can mix lead acid with gel-cell in this setup.

 

[coby-5]

Re: charging 2 batteries in parallel, and other questions

it doesnt matter if you hookup 30 batteries <br />12 volts is 12 volts.also your alternator wont overcharge unless the regulator goes bad ! ! !<br />and from charger hook cables + bat 1 and - bat 2

 

[The Yeti]

Re: charging 2 batteries in parallel, and other questions

thanx fellas

 

[Silvertip]

Re: charging 2 batteries in parallel, and other questions

People tend to worry far too much about having too many "amps" feeding their electrical systems when in fact its the amount of "stuff" you have hooked to your batteries that determines how much they draw from them. Therefore, you can't have too many batteries nor can than they be too big. Your accessories only draw what they need. In other words the batteries don't push amps into the accessories -- the accessories draw current from the batteries. The only way you can get into electrical trouble is to wire batteries in series (to get 24 or 36 volts) and connect them to devices that operate on only 12v or 24v.