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-   -   Dual Battery Setup (http://www.wranglerforum.com/f218/dual-battery-setup-143559.html)

year1camaro 03-02-2012 08:41 AM

Dual Battery Setup
 
Hi everyone. I installed new winch, some lights and other power hungry things in my YJ and now I'm thinking it's time to upgrade the charging system. But I don't wanna spend 500.00 to do it. I hear tell of the 98 Grand Cherokee 136amp alternator works on my 4.0. So that works for that. I just wanna add a battery now. I'd like to have a switch under the hood or in the cockpit to switch from one battery to the other. Just a simple switch....nothing fancy that costs 200.00. I'm already in over my head with this upgrade. 150.00 for the alternator, 80.00 for a second battery, and unless I can figure out how to get another battery under the hood on my own, it's gonna be another 120.00 for a dual battery tray. So any ideas or help would be appreciated, maybe a picture. But please keep in mind I'm on a tight budget.

ballistx 03-02-2012 09:41 AM

Why?
 
That is a multi-faceted question.
1. Why do you need dual batteries? The dual batteries give longer to drain but won't help on long term. The alternator has to be able to handle both battery loads so both will discharge.

2. Why do you need dual alternators? (that is how I was running). Only to have two totally separate systems, such as a winch, where you can deplete it enough, quickly, to kill the engine and can't restart. I had the solenoids weld together and stall in a blizzard. NOT GOOD.

3. Why is it necessary to upgrade beyond a 136A alternator? If you aren't running very heavy loads at very slow rpm, why isn't 136A enough? It isn't enough to stay ahead of a heavy winch load, but that is true with dual batteries also.

You typically don't need to run any heavy electrical loads when you are winching. You aren't winching when you are running the other heavy loads. So they are really independent loads.

What I am saying is that you probably don't even need to upgrade your alternator beyond a 90A that is standard. Run it awhile and see if there is an issue.

After you find all of the parameters, THEN decide what you really need.

year1camaro 03-02-2012 10:47 AM

Quote:
That is a multi-faceted question.
1. Why do you need dual batteries? The dual batteries give longer to drain but won't help on long term. The alternator has to be able to handle both battery loads so both will discharge.

I don't want to be charging them at once. Independently the batteries I will choose with a switch which one is being used.
I'd like dual batteries so I can have a back up battery. So i can leave a light on to set up camp, maybe the jeep is stalled and I need to pull it free before I can see why it wont start. Radio. Charging GPS and other things like phone while the jeep is off. If i kill it by accident I can just switch over to the one that was not being used while the jeep was off, restart the vehicle hit the switch back to the dead battery and charge it. And vise versa.

2. Why do you need dual alternators? (that is how I was running). Only to have two totally separate systems, such as a winch, where you can deplete it enough, quickly, to kill the engine and can't restart. I had the solenoids weld together and stall in a blizzard. NOT GOOD.

Not using dual alternators, just the higher output grand cherokee one. Would like to replace the stock one with a little better one?

3. Why is it necessary to upgrade beyond a 136A alternator? If you aren't running very heavy loads at very slow rpm, why isn't 136A enough? It isn't enough to stay ahead of a heavy winch load, but that is true with dual batteries also.

I do run heavy loads at idle while winching out of trouble. Sometimes getting back behind the wheel to give it gas is not an option while winching.
Yes the 136amp one is enough and what I plan on using.

Quote:
You typically don't need to run any heavy electrical loads when you are winching. You aren't winching when you are running the other heavy loads. So they are really independent loads.

What I am saying is that you probably don't even need to upgrade your alternator beyond a 90A that is standard. Run it awhile and see if there is an issue.

When I tested the winch while sitting in it the voltage dropped pretty low so the 136amp alternator is just for insurance also.

The advice I'm looking for is to be able to change which battery the engine is using in the event of a dead battery. I'm driving across counrty and don't want a dead battery to have me in the middle of nowhere. It's mostly for insurance reasons.

Quote:
After you find all of the parameters, THEN decide what you really need.

Unfortunatly I'll be on the road for about a month exploring very desolate places in this great country of ours and will not be able to test out every situation or know that a battery can just fail. This project is about insurance mostly. I wanna flip a switch to go to a charged battery in the event of the primary one failing for whatever reason and flip the switch again to charge the dead battery.

daddyjeep 03-02-2012 10:49 AM

Instead of dual batteries, upgrade the battery you have. Get yourself an Optima battery. They are designed to handle the kind of abuse we throw at them.

year1camaro 03-02-2012 10:53 AM

Quote:

Originally Posted by daddyjeep (Post 2094604)
Instead of dual batteries, upgrade the battery you have. Get yourself an Optima battery. They are designed to handle the kind of abuse we throw at them.

I hear what your sayin. Please read my response to the first dude...for my reasoning.

blazerone22 03-02-2012 11:36 AM

Could you use a battery switch that they use on boats to seperate the batteries.... Bep 701 Mini Battery Switch 275 Amp Continuous#



http://bluewatermarinesvc.com/html/bat_switch.html

year1camaro 03-02-2012 11:42 AM

Quote:

Originally Posted by blazerone22 (Post 2094773)
Could you use a battery switch that they use on boats to seperate the batteries.... Bep 701 Mini Battery Switch 275 Amp Continuous#



Marine Battery Switch

Something like that might work,,,,but the amp rating on that switch you linked to is to low I think. I did find battery disconnects on summit. This might be a good way... PICO WIRING 5575PT - Pico Battery Disconnect Switches - Overview - SummitRacing.com

blazerone22 03-02-2012 11:50 AM

I think you need something more like this... Blue Water Marine Service-DC HIGH PERFORMANCE BATTERY SWITCHES By BLUE SEA SYSTEMS

ballistx 03-02-2012 03:30 PM

add a continuous duty solenoid
 
You can add a continuous duty solenoid between the batteries. Power it through a single pole double throw switch. Center pole to the solenoid. One side goes directly to the second battery through a fuse. Other side goes to the run position of the ignition. Have a center off position on the switch.

Leave the switch in position 2 so whenever you have the ignition on (running) the solenoid is closed and the batteries are paralleled and both charging. When you turn off the ignition the batteries are separated. The load on either will not discharge the other.

If you put it to the center position the batteries are isolated while driving and the 2nd battery will not be charged.

If the main battery is totally dead you can flip the switch to position 1 and the 2nd battery will power the solenoid and parallel the batteries. You can get a switch with momentary on that side so you don't inadvertently leave it in that position and drain both batteries if left long term.

I think that will do what you want. You can put a light on either side of the switch to let you know the condition of the circuit. :wavey:

If you don't have A/C you can rig a bracket on the A/C mount and mount a salvage yard alternator with internal regulator. Connect it to the 2nd battery and do the same with the continuous duty solenoid. Now you have a totally redundant charging system as well. That is how I have/had mine rigged.

year1camaro 03-03-2012 12:42 PM

I'd rather stay away from solenoids and those smart battery tenders. As you stated the solenoid welded itself on your rig. I think I'm leaning towards high amp shut offs. Quadratec has 1000amp battery cutoffs from "Hella" and I'm thinking they should hold up and not weld under extreme loads. I can run one to each battery and cut off whichever I decide. Switch between batteries every other day to keep them charged.
Hella Lighting 002843011 - Hella Battery Master Switch with Key - Quadratec

ballistx 03-03-2012 02:57 PM

Solenoids welding are extremely rare
 
The only time that a solenoid arcs is when energized, or de-energized, under extreme load. Typically you would be energizing, or de-enerizing, under virtually no load. The trouble with a master (manual) switch is you have to be continuously, manually turning it. You shouldn't leave the batteries tied together when static because they will drain across. Not critical but not a good idea.

If you do leave them tied together and something drains one, both will drain. If you leave it disconnected the 2nd battery will not be fully charged when you need it. Work through the process of using it to see how it fits to your needs.

I would have absolutely no concern about the solenoid welding from my 40 years of experience with Jeeps and being an master electrician/licensed electrical engineer.

Besides, if they did weld together, all you would have to do is to disconnect the cable to the solenoid.

brent in az 03-03-2012 03:41 PM

I have nothing to add to this fascinating informative thread except comment on the original poster's sentiment: " I'll be on the road for about a month exploring very desolate places in this great country of ours.."

That's what it's all about baby! That's what makes jeep headaches worth it. If I got paid "for exploring desolate places" in my jeep then I'd have two jeeps by now...

ballistx 03-03-2012 05:02 PM

really into the rough
 
I guess if I were going into the really rough stuff where there wasn't any support, I would put in the solenoid and then install the master switch between both the batteries and also in the main battery cable.

I know that it is a pretty sobering feeling when there just isn't any support. About scared my BIL pantless in Canada. We were about 60 miles past the end of the road moose hunting. I had my 66 Wagoneer with the 327 and a 17 foot trailer. Him and his BIL went out of camp for awhile. I had been having trouble with the acclerator pump ball in the bottom of the bowl of the carb. So, tore the carb all apart to fix and when they came back they found it all apart beside the Jeep. Made me make a run with it aftwards to be sure it ran. :whistling:

If I were going that far and that alone, I would seriously look at throwing in a 2nd alternator if there isn't A/C. It is a real easy mod, just a salvage alternator with internal regulator and new serpentine belt. Couple of pieces of angle iron will fab the mount. Just be sure to get the mounting bolts coordinated so the pulley lines up. That is the most critical aspect of the mod.

year1camaro 03-03-2012 07:19 PM

ok. so switching the batteries periodally is not a problem for me.....so that's the route i think ill go. very solid. duel aternators i might look into cause I'm definetly buying the 136amp alternator so i could use the stock 90 amp for a back up i guess.

year1camaro 03-03-2012 07:24 PM

Quote:

Originally Posted by brent in az (Post 2098812)
I have nothing to add to this fascinating informative thread except comment on the original poster's sentiment: " I'll be on the road for about a month exploring very desolate places in this great country of ours.."

That's what it's all about baby! That's what makes jeep headaches worth it. If I got paid "for exploring desolate places" in my jeep then I'd have two jeeps by now...

I can't wait dude. I'm bringing lots of cash for the ride. But I wanna be overprepared. i'VE REPLACED ALMOST EVERY PART THAT CAN FAIL....but you know something may go wrong,.....But i don't want a dead battery to be one. Once we get to the mid west we are zig zagging up and down the counrtry.....to many things to see in this old jeep

ballistx 03-03-2012 09:14 PM

take as spare
 
You can take the old one as a spare, but it has the regulator in the ECM. That is why I specified to get one with the internal regulator. You can get an old one with external regulator. That is what I did but only so I could switch it and get 120VDC to run any brush type equipment, such as such as electric drills, etc.

brent in az 03-03-2012 10:09 PM

HIJACK:
"I had my 66 Wagoneer with the 327...."

As an FSJ addict and J10 owner I have to comment that a Kaiser 66 Waggy was the last year of the Buick 327's before Kaiser stopped buying from Buick when upstart AMC (just an engine builder at the time; not a car company) entered the market with 302's and 360's and later the 401. The Buick slant-6's (and 327s) are legendary for toughness. I have the 360 and it's a workhorse. Congrats on your piece of history when engineering was king---and yes I have to manually lock my hubs, too!

bc3_Jeep 03-03-2012 10:39 PM

From a TRULY "backup" kind of mindset, I would place the "spare" battery elsewhere in the vehicle and hook it up to a SOLAR charger. This would allow you to charge the battery EVEN IN THE EVENT of a complete engine failure.

If you are really looking for a "failsafe".... that is the answer and WAY cheaper than what you are looking into.

Frenz 03-03-2012 11:02 PM

Battery Specialists Hickory PA. 724 356 2200 ask John.

These guys know everything battery related and handle the steel, coal, gas, power generation, heavy equipment, transportation, and golf cart industries in the tri-state area for like 20 years.

I like the way BC thinks.

year1camaro 03-04-2012 06:24 AM

Quote:

Originally Posted by bc3_Jeep (Post 2100243)
From a TRULY "backup" kind of mindset, I would place the "spare" battery elsewhere in the vehicle and hook it up to a SOLAR charger. This would allow you to charge the battery EVEN IN THE EVENT of a complete engine failure.

If you are really looking for a "failsafe".... that is the answer and WAY cheaper than what you are looking into.

Solar panels are cheaper than switches? Where have I been? I think your confused over what I'm using It's just two batteries and two 16.00 switches. I already have one battery. And if the engine fails well....I'm not gonna need a battery. I'll need a taxi and a tow truck.

year1camaro 03-04-2012 06:26 AM

Quote:

Originally Posted by ballistx (Post 2099906)
You can take the old one as a spare, but it has the regulator in the ECM. That is why I specified to get one with the internal regulator. You can get an old one with external regulator. That is what I did but only so I could switch it and get 120VDC to run any brush type equipment, such as such as electric drills, etc.

I see.....that's a pretty cool idea.

ballistx 03-04-2012 07:15 AM

120vdc
 
To do it you need an externally regulated alternator. You just apply full 12vdc to the field and the generator will put out "about" 120VDC. Anything that plugs into 120VAC and has a brush type motor should run OK.

brent in az: I believe the 327 was an AMC motor and the 350 was the Buick. I also had a 69 Super Wagoneer (NEVER should have sold that :banghead::banghead:) that had the 350 Buick in it. Also had a 64 with the 6cyl.:rolleyes:

I am working towards setting up another hunting rig. My plan is that it will be a 1986-87 J10 pickup. Just have to scrape together the money and then find a good one.

bc3_Jeep 03-04-2012 09:17 AM

I stand behind what I said.....
 
Quote:

Originally Posted by year1camaro (Post 2100690)
Solar panels are cheaper than switches? Where have I been? I think your confused over what I'm using It's just two batteries and two 16.00 switches. I already have one battery. And if the engine fails well....I'm not gonna need a battery. I'll need a taxi and a tow truck.


1.5 Watt Solar Battery Charger

How you gonna call if your cell phone AND single battery are dead????

year1camaro 03-04-2012 11:09 AM

Quote:

Originally Posted by bc3_Jeep (Post 2101028)
1.5 Watt Solar Battery Charger

How you gonna call if your cell phone AND single battery are dead????

oooo, that is cheap. Dual battery not single thou. I'm definetly gonna have a spare. it just gonna be hooked up under the hood on 1000amp switches. The alternator will charge both on alternating days is all. So they stay charged. Jeep will only run on one at a time. One will be on reserve and charged from being used the previous day. That was joke btw. I'm fairly certain most of the areas i might be will have no cell service to begin with. I was just sayin what is a charged battery gonna do for me if the engine blows. It's gonna be a hike out no matter what. I'll just have to pray to the jeep gods that does not happen.
I bought the dual battery tray and two 1000amp switches. I'll be able to run acc. on one battery and if I kill it by accident just flip the switches and start it on the other. Flip em back to charge the dead one. Simple. Cheap. I also bought the 98 grand cherokee 136 amp alternator and will be keep the 90 amp as a spare in the bed. Just in case.
The 4.0 sounds amazing, trans feels good. all new u joints, ball joints. new radiator and hoses. What can go wrong?,,,,,,,,lol......famous last words.

ballistx 03-05-2012 06:34 AM

little CRAP
 
Check all the LITTLE CRAP. That is what Murphy relies on. Hose clamps, hoses, frayed wires, cracked vaccuum lines. Make sure you have duct tape and electricians tape, a few extra hose clamps, spray lube, typical tools, flashlights, etc.

You aren't going to recharge a battery enough to start with the 1.5W solar. That is just enough to replace the natural leakage of the battery. If worried about restarting with a manual, just park where you can get a short run at it.

Probably want to take along a can of tire goop in case you get a leak. If you don't have an on board air compressor the old bicycle pumps do actually work. Better than walking 10 miles.

BIGGEST thing is to be observant and don't get into the situations that yield those problems. Avoidance is the absolute best fix. It is far different going out trying to find challenges than taking any unneccessary risks then in a situation where there isn't any help. BTDT.

year1camaro 03-05-2012 06:41 AM

Quote:

Originally Posted by ballistx (Post 2104594)
Check all the LITTLE CRAP. That is what Murphy relies on. Hose clamps, hoses, frayed wires, cracked vaccuum lines. Make sure you have duct tape and electricians tape, a few extra hose clamps, spray lube, typical tools, flashlights, etc.

You aren't going to recharge a battery enough to start with the 1.5W solar. That is just enough to replace the natural leakage of the battery. If worried about restarting with a manual, just park where you can get a short run at it.

Probably want to take along a can of tire goop in case you get a leak. If you don't have an on board air compressor the old bicycle pumps do actually work. Better than walking 10 miles.

BIGGEST thing is to be observant and don't get into the situations that yield those problems. Avoidance is the absolute best fix. It is far different going out trying to find challenges than taking any unneccessary risks then in a situation where there isn't any help. BTDT.

Very true on all points. I won't be taking unnessary risks. To scary. I hear ya on the solar. I wouldnt buy something like that from harbor freight anyhow. I did think of a few things you mention except the vacum lines. I'll need to go over them. My 4wd light stay on for days sometimes but it's not in 4x4, and I know thats vacum. I'm running 6 ply tires but the goop couldnt hurt. Thanks for your advice and tips thou.

denisbaldwin 03-05-2012 09:30 AM

I'm going through this same mess right now. I ended up going with a nice dual battery tray, dual DieHard Platinums and a Mean Green 200Amp Alternator. Should be awesome when it's done.

year1camaro 03-05-2012 05:15 PM

Quote:

Originally Posted by denisbaldwin (Post 2104915)
I'm going through this same mess right now. I ended up going with a nice dual battery tray, dual DieHard Platinums and a Mean Green 200Amp Alternator. Should be awesome when it's done.

daaaam, you got the mean green....I wish
How many amps & $?
I got the 136 amp grand cherokee for 150.00

denisbaldwin 03-05-2012 05:27 PM

I got the 200 amp mean green and paid about $280 for it shipped (from eBay). It was some hot rod source in Cali that got a bunch in.

ballistx 03-05-2012 07:27 PM

Goop
 
The goop is just after you have a flat. Tire people do not like it when you just use it.

The duct/electricians tape and spray lube are the critical. Can fix ANYTHING.. If it moves, and shouldn't, use the tape. If it don't move, and should, use the spray lube. :punk:


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