DAISY CHAINING BATTERIES... and keeping it 12v???

[Gone]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

I'm with Tex, I had the same thought as I read that post. I fail to grasp dual bank chargers charging two batteries in parallel and recognizing one from the other. In series, yes....isolated ,yes.... parallel???? The IR drop in the cables should be too insignificant for the chargers to
A. use any sensing data
B. keep one charger's current out of the other battery.

CD

 

[jtexas]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

zuke1: I been running my trolling motor like this for a year and a half...discharge 'em together, charge 'em together, I use a 15A charger with auto shut-off. If needed you can disconnect 'em from each other and use 2 chargers to charge 'em faster. Actually get more than their combined run time because discharging 'em more slowly makes 'em last longer.

You also asked about using a deepcycle for starting...it's okay long as it meets the CCA requirement of your motor.

Are these two batteries going to be connected to your outboard? Don't count on the alternator being able to keep them charged up.

[note to zmoz, original poster later posted "ok, so i have two identical batteries", presumably a change from his original post]

 

[xtraham]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

hi I have been owner operater of an auto,truck,marine and whatever comes along repair for over 20+ years and I will agree that it is recommend that all batteries be replaced when one fails,........BUT no one ever and I mean ever does, I have replaced one battery in 600 hp cat diesel engines that requires (4) 31-mhd batteries and so on so on if someone rolls up in a diesel pickup with one bad battery and you try to sell them 2 I just lost a customer to wal mart cause he will go buy one and stick it in. I also have a 44' boat myself w/3 8D battreries and when one goes bad I only replace one, just rember that when connected in parallel if battery has a deed cell ect it will drain the other and will have to be isolated to diagnos which is defective, sorry for rambling but in short if you have 2 known good 12v batteries hook em' up does'nt matter about the brand, size, gel, dry cell, starting battery, whatever hope this helps

 

[zuke1]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

exide nautilus NC24

that is brand and type of batteries im going to be connecting...

the guy i bought the boat from said that these were good batteries, and were perfect for either starting or trolling...

since i had by own deep cycle battery , and i do a lot of trolling, i figured i would connect the two like batteries for trolling, and use the deep cycle for starting...

as far as i know, the nautulus batteries were purchased on the same day, one is almost completely drained down, and the other one has been used for starting...

so i think im going to connect the two batteries together...

i bought two 4 guage battery cables from the auto store... it was the smallest guage they had...

i should be going out in the garage to cram myself into battery compartment here in a couple hours...

let me know if there is anything else i should know, (like past experiances, or what not to do's )

thanks
zuke

 

[xtraham]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

are these connected for thr trolling motor or will you be using them for starting batteries?

 

[Silvertip]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

One final bit of info on dual bank chargers. Although typically used in a series (24V) application, the two outputs can be paralleled to essentially create a larger single bank. If you have two 6A outputs, parallel them, and connect to either battery you have a 12A charger. If you connect them separately to both batteries, you still have a 12A charger -- 6A to each battery. And the charger manuals will also tell you that when one battery is topped off, they two outputs will load share -- although not all chargers have that level of sensing. So whether you have a single or dual bank charger, both will work in a parallel system. The dual bank simply gets the job done faster. I've done what I can here.

 

[zuke1]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

quote...

"since i had my own deep cycle battery , and i do a lot of trolling, i figured i would connect the two like batteries for trolling, and use the deep cycle for starting..."


trolling....


and thanks to everyone for your help...

ill let you know if it blows up in my face or not...

zuke
out

 

[Texasmark]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

Hey xtraham, I used to run a 400 hp Cummins with those 4 31's you're talking about. Again, I never took them apart and checked the charge level of each. Like I said, they may have all been up to 100% or 3 at 100 and 1 at 85; who knows; but they were charged sufficiently to roll that big baby over on a cold morning.

Mark

 

[zuke1]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

ok.......

so the batteries looked the same from the top ( the view in the boat) but when i took em out to look at them before i hooked em together. i noticed the little plaques that say the cranking amps and such....

i also noticed that one battery said "marine starting battery" and the other one said " dual purpose marine battery with reserve"

so seeing that the one battery is for starting and the other was for trolling/starting, the cranking amps were about a 100 off.......

so based on that i decided not to connect the batteries... as everyone before stated it was only good to connect like batteries..
thanks for all your help

zuke
out

 

[Silvertip]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

You can still do it. If it really bothers you, put a switch (a big one) in the read lead connecting the POS terminal of the two batteries. Open the switch when stored. Close it when running. And by the way, you are making way too much of this. Connect them and go. Is it an ideal situation -- NO. Will it work ok? YES. Even if both batteries were identical in name, CCA and physical size, chances are they would test slightly different in true CCA so the 100 cca you have is not a big issue. To prove this, take a "D" cell battery and a "AA" battery. Connect them in either series or parallel and connect to a bulb. It will work just fine. Its just that the lesser capacity battery will die quicker than the "D" cell. In your case, neither battery will die in a heartbeat because of the difference in capacity or design.

 

[zuke1]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

what i did in place of connecting the two together was i just bought those little quick release battery cable ends...

so when the one trolling battery dies, i just connect the other trolling battery up, i keep them right next to eachother in the battery compartment...

its no real hardship just to switch out the cables when one dies, and i dont have to connect two batteries.

so it all works out in the end...

zuke
out

 

[Silvertip]

Re: DAISY CHAINING BATTERIES... and keeping it 12v???

Whatever works for you is good.