One for Shake

[boogieblues50]

Hey Shake
Can you tell me if I can hook up a 12 volt accessory to two 12 volt battery's set up for 24 volt if I just hook it up to the plus and minus of one of the battery's....BoogieBlues

[lakebiker]

Hey Shake
Can you tell me if I can hook up a 12 volt accessory to two 12 volt battery's set up for 24 volt if I just hook it up to the plus and minus of one of the battery's....BoogieBlues


Sorry shake, you must be sleeping in today. Yes you can Boogie. That's how I've got my bow mount trolling FF wired. Just make sure you only use one battery, the same battery, for both the pos and neg feeds. Won't hurt to also have an inline fuse in it as well. *thumbsup*

[Shakespeare]

Despite the rumor that I screw around at work, just surf the Internet and eat Hostess Twinkies all day long.... sometimes I gotta pull my own weight around here at the office. ;D ;D ;D

To confirm LB's response. Yep, just go across the + & - terminals on one battery and that'll give you 12 volts.

Mike C.

*009* Oh, a little afterthought here. Try not to seriously deplete the charge on the battery in question. As a battery discharges it loses voltage. In a series configuration the battery with the lesser voltage adds a little more resistance to the circuit which equates to heat and in the long term that battery's life expectancy is affected. You typically want to keep both batteries as balanced as possible with respect to the amount of charge each carries. So, if whatever you have plugged into the accessory really milks that battery then you should come up with a way to swap between sources (batteries) to maintain equilibrium. You can uses a double pole / double throw switch or perhaps some spring clamps to switch between one battery to the next. To determine the status of each battery then two voltmeters would be required or one voltmeter wired across your double pole switch. I'm talking about a good quality meter not a 5 dollar thing that the needle swings into some colored area. If your accessory is light duty (low amps) then don't sweat it.. but you may want to play the swap game every couple of weeks or on each outing.

[bobreeves]

sometimes I gotta pull my own weight around here at the office

Rolling your chair over to the next pack of Twinkies does not count *laughing*

[bobreeves]

I was gonna jump in here, but wanted to give Shake the 1st shot. If you have two instruments that draw similar amounts of current (GPS and fishfinder for example) hooking one up to each would help maintain the load balance. Again, fuse each one appropriately.

[boogieblues50]

hey
Thats exactly what I wanted to here...Duhhhh Me I was looking at24 to 12 volt inverters...I have an old 3d sidefinder hummingbird sonar I want to mount on the front rails that Ray made...a fast release mount and some battery clips should work great...take it off and put it on when I need it...Thanks again...BoogieBlues

[Shakespeare]

Glad you got the answer you were looking for Boogie. *thumbsup*

Man!!!... This is a tough crowd. *nutkick*

[NOTHING ELSE MATTERS]

Glad you got the answer you were looking for Boogie. *thumbsup*

Man!!!... This is a tough crowd. *nutkick*

Twinkies uh? *laughing**laughing**laughing*
I find a very good interest in sun flower seeds, try to cut down the Marlboro's.

[Shakespeare]

If you have two instruments that draw similar amounts of current (GPS and fishfinder for example) hooking one up to each would help maintain the load balance. Again, fuse each one appropriately.

In addition to this idea of load sharing, which is a sound idea BTW, make sure that you identify the wiring with some labels to indicate which battery is being sourced. Later down the road if someone picked the wrong black wire to go with a positive, or visa versa, then you could be applying 24 volts across that shiny new instrument. Probably not a good thing. *clonk*

Mike C.

[NOTHING ELSE MATTERS]

Just to put my 2 pennies, check with your unit, some electronics are rated from 12 to 36 volts. Just a thought.

[lakebiker]

Twinkies uh? *laughing**laughing**laughing*
I find a very good interest in sun flower seeds, try to cut down the Marlboro's.


sun flower seeds are for sissies. switch to Camels. ;D;D;D;D*ROTFLMAO*

[Shakespeare]

Just to put my 2 pennies, check with your unit, some electronics are rated from 12 to 36 volts. Just a thought.

Ya know that's a good point NEM. If that's the case with Boogie's Hummingbird then he can straddle both those bats and forget about all this battery balancing stuff. Now a VHF radio on the other hand might not like the higher voltage, at least my Uniden won't. Good stuff to know. *Cheers*

Mike

[NOTHING ELSE MATTERS]

Shake, i haven't see a vhf more than 12-18 volts.

LB, i'm trying to quit smoking,or cut down at least, not get lung cancer.;D

[lakebiker]

Shake, i haven't see a vhf more than 12-18 volts.

LB, i'm trying to quit smoking,or cut down at least, not get lung cancer.;D


NEM, quitting is easy, staying quit is the hard part. I've quit 3-4 times and smoke more now than ever.*clonk**clonk*
Good luck with it. *008**thumbsup*

[Chatham Scott]

Oh, a little afterthought here. Try not to seriously deplete the charge on the battery in question. As a battery discharges it loses voltage. In a series configuration the battery with the lesser voltage adds a little more resistance to the circuit which equates to heat and in the long term that battery's life expectancy is affected. You typically want to keep both batteries as balanced as possible with respect to the amount of charge each carries. So, if whatever you have plugged into the accessory really milks that battery then you should come up with a way to swap between sources (batteries) to maintain equilibrium. .

I have a question about this.. In another thread, you were telling me that I can just hook two batteries together to extend the amount of time before they would run out from the bilge pump running if I were to be away from the boat for a few weeks. I bought two short battery cables and was planning on just hook + to + and - to - to effectively double the life.. Sounds like from this post, however, that if my bilge pump is hooked to one of those batteries, it won't draw from the other one.. What am I missing?

[Shakespeare]

Good question Chatham. In your thread we were talking about wiring the batteries in parallel. In that case you essentially double the amount of current that can be delivered. It's still 12 volts though and the current draw is equalized between both batteries, so there's really nothing to worry about in that respect. In a parallel configuration there's no way one battery can be favored over the other, unless there was a dead cell or two and that's a whole different topic. In Boogie's application his batteries are wired in series and he just wants to tap off one of them for an accessory. If he taps off one battery then he depletes it more than the other one thus offsetting the balance. He has doubled his voltage to 24V by this series configuration but hasn't done anything to increase the amount of current that can be delivered. Two 100 AH (amp hour) batteries wired in series still delivers 100 AH. Two 100 AH batteries wired in parallel essentially delivers 200 AH.

Why have a 24 volt system? Well, when you double the voltage you half the current. In other words a 24 volt motor draws half as much current as a 12 volt motor of the same hp. For his trolling motor to deliver the same amount of torque at 12 volts it would require a massively big battery and the wire size and other installation components increase in size, as well as the cost. It makes economic and electrical sense to use a higher voltage motor to accomplish the task. There's no free ride here however... you either pay your dues with voltage or pay them with current. You're on the right track by wiring your bats in parallel to extend the amount of run time on your pump. You can't series your bats because the pump is rated for 12 volts. Make sense? I hope this explains it.. if not ask more questions.

http://i235.photobucket.com/albums/ee78/CSO_Shakespeare/CSO_Biz/BatSeriesParallelDiagram.png

Mike C.

[Chatham Scott]

Makes sense... very helpful.. One last question I was going to ask in the other thread.. After reading your comments and various product manuals, I concluded that, for my purposes, there was no good reason for me to buy one of those battery switches that let you toggle between batteries or combine them. I could not think of a use for one that wasn't satisfied by the simple combining of the batteries in parallel as you've so eloquently described in your post... Is there some benefit to a switch that I may be missing in my analysis?

Thanks a bunch..

[Shakespeare]

Is there some benefit to a switch that I may be missing in my analysis?

I believe that the most popular usage of the switch is for segregating the starting battery from the house battery. A lot of guys will power their electronics, lights, aerators, etc., off the house battery and when it's time to scoot somewhere else they flip the switch and fire the motor off the starting battery. It's a peace of mind thing knowing that you'll always have plenty of power to start the motor vs taking a chance of running it down with all the accessories coming off a single battery.

There may be other ways to employ a switch and hopefully someone else will chime in and tells us what they do with it.

Mike C.