hooking up batts....

[wrong way]

how can i hook up 2 d8 batteries to my alternator and run my setup without draining the main battery? would an isolator work? where would i get one?

['Doc]

FWIW... just for information.

Try this;

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I just 'googled' "battery isolator" and got several hits. The one above is a pretty good explanation of how they work.
Have fun.
- 'Doc

[p71vic]

Most larger boats are set-up this way with an A/B/AB switch.

Find a local and ask for recommendations.

[MECHMAN]

Be carefull running an isolator, they are very hard on alternators. They switch charging from the hot starting battery to the depleated rear batteries on startup, which can cause the alternator to overheat trying to bring them back from the dead.


Also, you will have about a 1/2 volt drop going through the isolator, which means your charging voltage will only be around 13 volts; not really high enough to properly charge a battery for optimum performance.

[Jb1rd]

So what would be the best way to do it then, I was thinking along the same lines about getting an isolator thinking it would be the best route to take? Mike

[wrong way]

Be carefull running an isolator, they are very hard on alternators. They switch charging from the hot starting battery to the depleated rear batteries on startup, which can cause the alternator to overheat trying to bring them back from the dead.


Also, you will have about a 1/2 volt drop going through the isolator, which means your charging voltage will only be around 13 volts; not really high enough to properly charge a battery for optimum performance.

alright prishiate the reply but I got to do somthing. Did you get my pm about the high output alt for my nissan pathfinder I dont want to slap the gm 1 wire 120amp on where the A/C compressor is the air works in this one but I have to do somthing fast I'm going to georgia (through Knoxville) in 2 weeks and I'm in the mud with no cb at all and I want to raise some hell on the way down there ya know. Wrong Way

[wrong way]

Does anyone have a small alt and extra batteries that is hooked up that seems to work for them that could let me know how to do it? I have a red top main battery and will be getting two D-8 1475cca 150lb batteries and I would like to know the best way to do this I plan to put the batts on the back floor boards amp in between them and am thinking I would just run them parralel back there then run a hot and ground to the red top up front??? BUT what about the weaker stronger short life draining problem Im hearing about I would hate to ruin $550 worth of batteries ya know? Maybe Mechman has the alt I need and I can stop worrying But I dont know. Thanks Wrong Way

['Doc]

FWIW
I've run one of those isolators with no problems (that weren't my own fault). Not the same as what you plan, but sort of close. The problem I had was a result of not checking that 'back' battery often enough, so my fault, not the isolator or alternator's. That's been quite a while ago so I have no idea what brand, etc.
Good luck.
- 'Doc

[wrong way]

I think I'm gonna scratch the BIG D-8 batts and just get two more red tops shouldnt run into too many problems just hook them up and roll with it somthin bad happens I'll worry bout that later Thanks for the replies.

['Doc]

And just for grins, if I could afford them, had a place to put them, and wouldn't need a forklift to move them, I'd like to have a few of them 'D-8' batteries too! They hold a whole lot more of them 'amps' than other sizes of batteries. 'Course, a 'red top' battery case full of 'lipo' batteries would be nice too. Unfortunately, I can't afford them either! (Not to mention the specialized recharger needed for them. ) Oh well, soon as I get my 'Bama Check' everything will be just fine! Right?
- 'Doc


did they really name him after them pies in the candy section??

[the_junkie]

Does anyone have a small alt and extra batteries that is hooked up that seems to work for them that could let me know how to do it? I have a red top main battery and will be getting two D-8 1475cca 150lb batteries and I would like to know the best way to do this I plan to put the batts on the back floor boards amp in between them and am thinking I would just run them parralel back there then run a hot and ground to the red top up front??? BUT what about the weaker stronger short life draining problem Im hearing about I would hate to ruin $550 worth of batteries ya know? Maybe Mechman has the alt I need and I can stop worrying But I dont know. Thanks Wrong Way

i have 2 group 31 batteries and 2-6v batteries in the back of my truck, charging off of the positive of the battery under my hood. (105 amp alternator)

no voltage drop, i can talk on my 1x4 all i want without losing watts

put the group 31's in paralell, the 6v in series(to create a 12v battery), run the ground from the first 12v to the body of the vehicle, and then a common ground is all you need...run the amp off the final battery

i should have pics somewhere...lemme look around

[wrong way]

I guess I'm gonna stop worrying about this and that and just get the D-8 batts tomorrow and pos to pos neg to neg then take a pos and a neg to the pos and neg of the red top under the hood run 1 ground from the neg of the farthest D8 to the frame, hook up the kicker and and puck mount the 55 1 foot from rear of the roof of my pathfinder and wait on the money to be right for the motor maul get an 8 pill and a maul and have 300lbs of battery for plenty of talk time. wow I was thinking out loud there. Anyone see any problems with my plans???? THANKS junkie for the explanation do you think I'm on the right track here??? Wrong Way

[MECHMAN]

Just Parralel all the batteries together. With a properly sized and regulated alternator(s) a motor maul is totally unessesary. All a Motor Maul does is regulate the voltage from the batteries, you still have to charge the batteries back up somehow. If you have enough alternator current, the system voltage will remain constant without a motor maul, and can even be boosted on our adjustble voltage units.

BTW, a single one of the the XS power D3100 will stomp a mud-hole in two of those industro batteries and it's half the size/weight. They are only $349 each shipped to the lower 48 states, and you would only need one of them.

[626]

I guess I'm gonna stop worrying about this and that and just get the D-8 batts tomorrow and pos to pos neg to neg then take a pos and a neg to the pos and neg of the red top under the hood run 1 ground from the neg of the farthest D8 to the frame, hook up the kicker and and puck mount the 55 1 foot from rear of the roof of my pathfinder and wait on the money to be right for the motor maul get an 8 pill and a maul and have 300lbs of battery for plenty of talk time. wow I was thinking out loud there. Anyone see any problems with my plans???? THANKS junkie for the explanation do you think I'm on the right track here??? Wrong Way

Yeah fuse your wires to the back of your vehicle. A long run like that and you could have a fire. Figure out what your amp draw is gonna be then add about 30%. That should do it.

[wrong way]

Just Parralel all the batteries together. With a properly sized and regulated alternator(s) a motor maul is totally unessesary. All a Motor Maul does is regulate the voltage from the batteries, you still have to charge the batteries back up somehow. If you have enough alternator current, the system voltage will remain constant without a motor maul, and can even be boosted on our adjustble voltage units.

BTW, a single one of the the XS power D3100 will stomp a mud-hole in two of those industro batteries and it's half the size/weight. They are only $349 each shipped to the lower 48 states, and you would only need one of them.

YOU without a doubt know more than me about charging systems and batteries so I am really interested in how a SINGLE xs power D3100 battery with a reserve capacity of 200 and 1200cca is gonna stomp a mud hole in TWO 8D 1475cca with a reserve capacity of 430? THATS a total of 2,950CCA and a reserve of 860 maybe you misunderstood me I was calling them D8 (like the dozers) because I work for a construction company just got them today and realized they are actually 8D batts. Wrong Way

[the_junkie]

if you run a big battery stack and upgrade your alt, you shouldn't need a maul...

the motormauls don't give you a "ton" of keydown time...mainly because the batts have to recharge...

just run a big stack...high output alternator...and you are good 2 go!

i'd add an analog volt meter in line to watch where you sit and drop to...get the bird-like ones from charger or from ebay...they read up to 30v

[Twink]

without the maul, how do you crank up voltage?

[wrong way]

without the maul, how do you crank up voltage?

I believe you can run a seperate charging system (which we know already I will probably end up doing) remove internal regulator in alt get an external regulator run that back to some 12v series with some 6 volt batteries prolly charge round 18.5 to 19v drop to 17.5 to 18v and blow some smoke! THAT IS ALL A BULL SH#T GUESS BUT I BET IT IS IN THE BALPARK ANYWAY

[MECHMAN]

without the maul, how do you crank up voltage?

I believe you can run a seperate charging system (which we know already I will probably end up doing) remove internal regulator in alt get an external regulator run that back to some 12v series with some 6 volt batteries prolly charge round 18.5 to 19v drop to 17.5 to 18v and blow some smoke! THAT IS ALL A BULL SH#T GUESS BUT I BET IT IS IN THE BALPARK ANYWAY

Yes, you are very close. You could easily run a dual voltage system if you added a seccondary alternator. We offer pre-wired in-dash voltage control knobs for our alternators as an option, adjustable from 13.0 to 21 volts. If you didn't want to bother with the seccondary charging system, you could just run an adjustable voltage unit in the stock location, and safely run at 15.5volts on the vehicles stock electrical. I have run at 16.0V on my Silverado for several months with no problems. The only reason I don't anymore is beacuse I run 3 alternators now.

[127]

how can i hook up 2 d8 batteries to my alternator and run my setup without draining the main battery? would an isolator work? where would i get one?

Why complicate something that is quite simple? The rule of thumb is: In a multiple battery setup, all the batteries should be identical.