dual batteries in the Sport Trac?

[Don Tomczak]

Can anyone give me some guidence? I would like to run dual batteries in the Sport Trac. I have a new battry now, but it is not strong enough to keep the Trac going whille pulling the 24' camper while running off road lights.



Ideally, I would like to get a bigger, meaning more powerful, alternator and have dual batteries.



Does anyone have any sugestions? How do you wire them up? Pos to Neg? Any help would greatly be appreciated.



Don

 

[Kevin Lang]

If I am not mistaken, you would have to wire the new battery in parallel with the current one (pos to pos, neg to neg), because putting them in series (pos to neg) will put out the amperage of one battery, but raise your voltage to 24V, which would be a bad thing for the Trac.

 

[Sal Adinolfi]

Yes. you would have to put them in Parallel. Pos. to Pos. Neg. to Neg.



Might have to upgrade your Alt. also. or you could just try the Alt. first.



the right setup would be that you are able to run the Vehicle from the Alt. once it is running. and still provide enough power to charge the battery also.



you could also set up a Battery Switch. which would allow you to run from one battery and then switch to another or both. ( know they exist, I had one in my Hearse)



Hope this helps.

 

[Jacob Dryer]

Do you have any idea how many extra amps your goodies are pulling from your batt/alt?



That will give you a better idea of what needs to be done to setup properly. A High-Output Alt might be enough or it might be overkill. Without knowing the extra power draw amount it's just guessing.



If you find a place to put a second battery please let me know as I'd love to add one just for extended battery life while the truck is off.



Kevin is right it would be pos to pos and neg to neg. (but you would actually want to ground it to the frame not to the neg post.

 

[Michael Cacioppo]

You can put two batteries in parallel to effectively make one larger capacity battery. It will work but it is not ideal since the same current for recharging will be delivered to both batteries and not per battery. If one battery is very weak and the other charged, the strong battery will discharge slightly into the weak battery until their voltages match. The alternator will see the common batterry voltage and output accordingly. The strong batterry will slightly be overcharged and reduce its total life. The way around this is to use a battery isolator which which will prevent this problem. Both will be charged based on need. The isolators run about $35 depending on maximum amperage.



Don, with your engine running at speed, your alternator should be sized to be able to supply all the electrical power you need. The battery capacity comes in when your at an idle or have the engine off. I thing that a larger alternator is all you'll need IMO.

 

[Don Tomczak]

I am unsure of the total amprage/voltage draw of the trailer. I know that when I simply run off road lights, and come to a stop the truck wants to die. I figured that this was from the lights draining the battery, and could see the same thing when I pull the trailer. The camper itself has batteries to provide power to the camper, but if I have it pluged into the Trac, it will try to recharge it's batteries and power itself. Is there a way to stop it from doing this unless I want it to? I went hunting for a place to put a second battery, but it was some pretty slim pickin'. I think I am going to look more into the isolator thing and try to run a dual battery with high out put alt. My thinking here is that it would be better to have more than I need and not push the alt to run as hard as posible all of the time. Is my thinking here flawed? I know that sometimes a little extra is a bad thing. I feel a project coming on

 

[Chad Merry]

Don,

Your alternator is shot. You do not need to add another battery. Adding batteries is for parking lot time. When I used to compete in car audio competions I only had 1 battery and was pulling alot more current than any combination or amount offroad lights would ever pull.



My Phoenix Gold amps were bridged down to .5 ohm and I had to keep fans on them 24/7 when the system was on.



If you add another battery to your ST now, you will simply end up with 2 bad baterries and still have a bad alternator.



Chad

 

[Don Tomczak]

Chad, that is going to be something that I will have to look into. I don't have the truck wanting to die with out the off road lights on, so hopefuly it's just begining to fail. I think that Autozone or Checker Auto Parts have a way to test it. I will deffiatly going to stop by there on the way home from work. I still think that I would like to have a high out put Alt and posibly dual batteries, so I don't think I will be telling the wife any of this



Thanks guys. I'll make sure to let you know what I find out. I still think that I feel my first member project coming on. I can see it now. Dual batteries and high out put Alt.

 

[Michael Cacioppo]

Don, First check the dormant voltage of your battery (surface voltage) with a volt meter before using any electrics. It should be about 12.5 to 13.2. Assuming your batteries good, check the output by putting a voltmeter across your battery with the engine running. Your alternator should be putting out about 14.2 volts off of idle. Assuming that the battery voltage was OK, and your alternator is putting out less than say 14.0 Volts, I would replace the alternator. Before buying a new one, pull the old one and have Auto Zone check it out. I think they have the setup, but I'm not sure. Your alternator output capability is about 120-140 Amps. A lot more than I think your off road lights and trailer require. You could opt for a HD alternator which would be in the 160-180 Amp range.

 

[Jacob Dryer]

You can get a HO alt at almost any amps you want, thats part of why I was asking how many amps you are using.



MikeC has it right though about taking readings with a volt meter.

 

[Rodger Tellefson]

Would a larger capacity Optima Yellow Top work?