2 batteries
Thread Starter
|
Senior User
Joined: Apr 2005
Posts: 174
Likes: 0
From: south GA
2 batteries
i was thinking of puting a 2nd battery in my 81 ford just to run a couple of accessorys . would i need another alternator. i would like to know everthing that i would have to do. thanks
Moderator
Joined: Jan 2001
Posts: 56,966
Likes: 2,728
From: Virginia
You will only need an isolator. You can buy these at most stores, and a couple of places online. The isolator lets your alt charge the extra battery, but will not let the regular loads on the main battery discharge the aux battery. And any loads tied to the aux battery will not discharge the main battery.
So you could get a deep cycle aux battery, and hook your stereo to the aux battery. You could run the stereo for hours till the aux battery was discharged, and still be able to start the truck from the main battery.
So you could get a deep cycle aux battery, and hook your stereo to the aux battery. You could run the stereo for hours till the aux battery was discharged, and still be able to start the truck from the main battery.
Moderator
Joined: Jan 2001
Posts: 56,966
Likes: 2,728
From: Virginia
Originally Posted by bigrigfixer
I'd parallel them. That way, you got more juice for starting, and no need for an isolator.
That's how it's done in big rigs.
That's how it's done in big rigs.
Do you as a rule replace both batteries on a big rig if one fails? What is your experience with that? I can see an older battery in parallel with a newer battery, and the older battery lessening the performance of the new battery if they are tied together with no isolator.
Fleet Owner
Joined: Aug 2005
Posts: 23,666
Likes: 301
From: Easton,Ks
Originally Posted by bigrigfixer
I'd parallel them. That way, you got more juice for starting, and no need for an isolator.
That's how it's done in big rigs.
That's how it's done in big rigs.
I like the isolated battery way also.
Fleet Mechanic
Joined: Jul 2003
Posts: 1,570
Likes: 20
You need to put the second battery under the hood with the first battery. The voltage regulator on the alternator knows under hood tempertures, not the temperature in the bed, over the frame, or under the floor boards. If you don't do this you will under/over charge the spare battery. For a remote battery you will need two voltage regulators, a real pain to do. The place to get advice on remote batteries is a Marine electronic store.
Trending Topics
Moderator
Joined: Jan 2001
Posts: 56,966
Likes: 2,728
From: Virginia
The voltage regulator operates from the system voltage. I have never seen or heard of one that had a temp sensor in it's circuits specifically for temp measurement. Most of the newer regulators are installed on or inside the alternator, so I don't know how they would get an accurate temp measurement, unless they had a remote sensor. Is this something the new trucks have?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Senior User
Joined: Oct 2005
Posts: 174
Likes: 0
From: brooks a.b.
some newer cars/trucks have a senser in or against the battery tray to sense temp of battery. i have yet to hear a good reason why this is needed, but some say it will help a battery to stop sweating, my 85 f150 had this problem and i had changed battery alt reg, and triple checked the wiring but to no aval.
the big rigs up here run 4 batteries to help with cold weather starts, the series parallel switch is used often up here, you can also run a second alt to the aux, battery, the hardest problem is mounting the alt and belt routing, if have dual alts on my 74 f250 and find it very useful for running winches or other heavy loads when needed, i also had this setup on my 85 f150 4x4.
the big rigs up here run 4 batteries to help with cold weather starts, the series parallel switch is used often up here, you can also run a second alt to the aux, battery, the hardest problem is mounting the alt and belt routing, if have dual alts on my 74 f250 and find it very useful for running winches or other heavy loads when needed, i also had this setup on my 85 f150 4x4.
Last edited by cheez67; Nov 24, 2005 at 11:22 PM. Reason: more info
Moderator
Joined: Jan 2001
Posts: 56,966
Likes: 2,728
From: Virginia
Well, the battery uses a chemical reaction to create electric power, so the temp does affect the chemical goings on inside, but I didn't know some of the vehicles now monitor the temp of the battery.
Fleet Owner
Joined: Aug 2005
Posts: 23,666
Likes: 301
From: Easton,Ks
What he is talking about is a unit put out by one company. They have a battery terminal with a temp sensor in it with two extra wires coming out and going to a regulator that they make. They are selling it to boat owners.
Postmaster
Joined: Nov 2003
Posts: 3,595
Likes: 0
From: Utah County, UT
I have an aux under the bed of the truck, I simply use the trailer charge line to charge the battery. My truck has an iline relay w/30A fuse for the trailer charge. I am thinking about going to a dual alt setup, but for now this works as I don't really but much of a load on the battery and all it needs is a little topping off. I think in your situation I'd go with an isolator. For mine, a good isolator to handle 140A is starting to get into the price range of dual alt setup of which I'd like better anyway.
Tuned
Joined: Aug 2003
Posts: 341
Likes: 3
From: McMinnville
Dual Battery Placement
Does anyone have an idea of where I can mount another battery in my 99 XLT Expedition? I will use it to power an inverter, radar detector and as a general spare. I have read the above of how many different ways there are to use it, but I am curious as to where to put? It will be a gel top battery, don't know what color yet.
Postmaster
Joined: Nov 2003
Posts: 3,595
Likes: 0
From: Utah County, UT
I'm not familiar with the expedition, but there are some kits for battery relocations that come with a box and vent tube to mount it in the cab/or trunk. I don't know if there is enough room under the hood to put the battery on the drivers over the fender well. Also, you might check out what kind of space you have by the spare tire, if there is enough space there you could make a bracket to hold the battery and not lose any compartment space in the vehicle. As far as optimas go, I'd go with either yellow or blue. Blue if it fits the budget. Snap some pictures of various locations, we might be able to help find a location.