UrGrlGveMeDkBrn

I have a 94 f150 which I turned into a cooler truck and I'm having a problem running my inverter box which is 2500 continuous watts and 5000 peak. Its fine when the truck is running along but you can watch the gauge drop if you at at idle and it will will kill the inverter after 10 min or so because its not enough power to run it. Well my question is... can I run 2 batteries ? Honestly I know I can but I really don't think that would help anyway because the alternator is the main power source right? Would a new aftermarket bad ass alternator do the trick? I'm in the dark here ... anyone want to share a helping hand to try to get this problem sorted out? Also the truck has a brand new alternator and battery Upgrading

boredom

im not sure how you would wire 2 batteries to run off of 1 alternator, but im sure its possible. i would consider a generator of some sort vs putting your motor at jeopardy.

UrGrlGveMeDkBrn

I had one but it just didn't work. I'm pretty sure you can put the batteries in parallels. Also it wont hurt the motor but fry my alternator..........maybe

burnoutboy

Just get a HD alternator. Thats what guys with 10,000 watt stereos do.

UrGrlGveMeDkBrn

Like a high output one? Where do I find one of these? Anywhere local?

burnoutboy

Yeah, high output is exactly what I mean. I'm in Baltimore so I have no clue where might be local to you.

UrGrlGveMeDkBrn

obx-va beach

Fabrik8

If you have a lot of continuous power draw, an extra battery won't help. If your power draw is more than the alternator can output continuously, you'll just have two batteries to drain instead of one. You need a bigger alternator.

And having two batteries in parallel is fine, it's done all the time.

Let's get to the root of the problem though: It sounds like you need more power at idle, so a bigger alternator will only help if it can output enough power when you need it. So if you're spending lots of time idling, you obviously need an alternator with enough power output at idle. It may be possible to use a bigger alternator and use a second battery to give you some additional storage if the alternator is slightly below what you need while idling, and then the batteries would just be depleting slowly. It's hard to say without knowing more about how you're actually using the setup and what your needs actually are.

I guess I should give a word of caution here too.. A lot of high output alternators don't have very much output at low RPM, so you'll really need to get your hands on an output curve for the alternator and select the right size pulley to get the alternator speed into the output range that you need at idle. There's obviously a top end there also, because the alternator can only spin but so fast so you can't select some pulley ratio that will overspeed the alternator at high engine RPM.

So this is a case of sizing the alternator to do what you need, when you need.

bZeRk187

If you have the 5.0L V8, the best alternator upgrade is to the internally regulated, large case 3G. There is a 250A unit available.

http://www.alternatorparts.com/Ford_3G.htm

Fabrik8

That's a bad assumption unless you can back it up with an output curve. It might not put out anywhere near that amount of power at engine idle, so if the power output at engine idle is important then it must be verified with an output curve for that exact alternator. Don't forget to take the pulley ratio into account. I don't think we know enough about what the OP needs to say that anything is the "best alternator upgrade" for him though.

If I've misinterpreted what the OP said and it doesn't need to idle for long periods of time, then the alternator curve doesn't really matter and you can pick pretty much any alternator that you want.