I would like to run two batteries

[ad4par1]

So how do I do it? I currently have a second batt that I just charge at home and take with me for the troll. I would like to hook this batt up to the other so I can always have a charged batt. Can I do it or is it too much for my engine?<br /><br />Whatcha think?

 

[Solittle]

Re: I would like to run two batteries

My two cents says that it is a great idea to carry a second battery. It is a lousey idea to hook them together. Best to hook them up with a master switch (about $20.00 or less - wiring instructions should come with the switch - they are usually about 3" in diameter and are bright red) and run one or the other. The reason for this is that if hooked together in parallel they the strongest battery will always charge the weakest until the charge is equal. So if you start out with one fully charged and one pretty much discharged you may not have enough juice at the end of the day to start your motor from either.<br /><br />I carry two and use one on the way out and switch to the other for the way back.

 

[petryshyn]

Re: I would like to run two batteries

Your engine will take forever to charge the troller battery after a deep discharge. You'll have to charge it up on shore......<br /><br />

 

[bean]

Re: I would like to run two batteries

if you still want to run them together connect red to red (pos) and black to black (neg) and then to the motor to keep 12 v total. if you connect piostive to neg you bump the voltage to 24 total and will burn out you motor

 

[Fair Boater]

Re: I would like to run two batteries

What of the possibility of using a battery isolator for charging? I run two batteries in my automobile (one for engine, one for car stereo), and I know that many vacation vehicles have additional batteries for electrical accessories. The isolator allows both batteries to be charged by the system, but for use electrically, they are separated.

 

[alounsbury]

Re: I would like to run two batteries

isolator will work and not a bad idea for your plans. However - to schematic's point - if you deep discharge the trolling battery - depending on the charging output of the motor (3 amps to 20 amps motor HP dependant) - it will take a ton of running time to charge that battery back up. (10A charger, takes approx 4 hours to recharge 180 AH battery). You may want to consider an inboard waterproof charger (http://www.guestco.com/Chargepro/waterproof.html) - that is what I use in my boat for charging my trolling batteries and no longer carry the batteries back up to the cottage.

 

[petryshyn]

Re: I would like to run two batteries

Fair Boater <br /> Isolators are OK for some applications. The problem here is that he doesn't have enough available current to charge both batteries in a reasonable amount of time....What will end up happening, is the battery will never reach a high state of charge, and sulphation will set in. Then he's left with a bad battery.....Unless you are running a REAL alternator (as in an inboard), charge your trollers on shore.....

 

[Fair Boater]

Re: I would like to run two batteries

schematic,<br />Thanks for the note on the deep cycling recharge. I'll keep that in mind if I decide on a similar boat set up for myself in the future!