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Hey guys,

So as of now, my battery is powering a CB Radio, 12,000lb Winch, a police/fire/ems radio, a regular AM/FM radio with a subwoofer, as well as all of its regular duties as a car battery. I am looking to get a bunch of lighting so that I can light up the trails. But I am worried that I will overload the battery and it wont be able to power any of this stuff. Plus, There is no more room on the hook ups to hook anything up. Can anyone give me some pointers?

Thanks so much,
Adam
 

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^^^ I also had to much wired to one Battery and I prematurely killed the oe Panosonic. Ended up doing a Dual battery setup and all is adequately powered now!
 

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Technically, your battery shouldn't be powering ANY of this stuff, except for a very limited time when the engine is not running. Your "starting" battery is for starting the engine; once the engine is running, your alternator is the source of power for all these loads.

But, with a single-battery setup, you'll always be at risk of getting into a "no-start" condition if you are at all careless about monitoring loads and battery voltage when the engine is not running. If you've got to power any significant loads when the engine is not running, a dual-battery setup with load isolation is the only way to go.
 

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Discussion Starter #5
Technically, your battery shouldn't be powering ANY of this stuff, except for a very limited time when the engine is not running. Your "starting" battery is for starting the engine; once the engine is running, your alternator is the source of power for all these loads.

But, with a single-battery setup, you'll always be at risk of getting into a "no-start" condition if you are at all careless about monitoring loads and battery voltage when the engine is not running. If you've got to power any significant loads when the engine is not running, a dual-battery setup with load isolation is the only way to go.
Right yeah thats what I am worried about. I think that if I were to keep a single-battery setup I would have to get a new alternator.
 

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Right yeah thats what I am worried about. I think that if I were to keep a single-battery setup I would have to get a new alternator.
It's really how you manage your available power... If you leave your engine running your OEM alternator is putting out a 100 amps and that's at a certain rpm. That output drops much lower at a idle (unknown) so you need to add up all the current aftermarket lights and gadgets amp hours they draw. I run Four 55 watt PIAA lights up top 220 watts and four bumper LED's on the bumper around 74 watts so if I didn't have much battery capacity I could drain the single battery down fast. Plus I was running a fridge. I ran the battery down in less than 30 minutes because I didn't keep my truck running and I did this as a test and it would not start.

I now run two large deep cycle AGM batteries wired in parallel with a 200 Amp alternator. I can isolate the batteries when needed but I just allow them to charge and drain down equally. No problems no more lol
 

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Technically, your battery shouldn't be powering ANY of this stuff, except for a very limited time when the engine is not running. Your "starting" battery is for starting the engine; once the engine is running, your alternator is the source of power for all these loads.

But, with a single-battery setup, you'll always be at risk of getting into a "no-start" condition if you are at all careless about monitoring loads and battery voltage when the engine is not running. If you've got to power any significant loads when the engine is not running, a dual-battery setup with load isolation is the only way to go.
Youre partially correct. But in practice alternators are not designed to power every imaginable thing you ever could think to add to your truck. You can add too much, then the battery picks up the slack.

Read this ;)

http://www.fjcruiserforums.com/foru...electrical-system-read-before-doing-mods.html

For the OP

Yes you can still drain your battery running too many accessories at the same time. Bu the key words being "at the same time". Read the above thread I linkied to to give you some idea of how much you can do. ;)
 

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Youre partially correct. But in practice alternators are not designed to power every imaginable thing you ever could think to add to your truck. You can add too much, then the battery picks up the slack. (snip)

Partially correct?

Nowhere did I suggest that the STOCK alternator could "power every imaginable thing you ever could think to add to your truck".

As far as the battery "picking up the slack", this is a bit of a risky situation. If you've got a poorly matched alternator-output-to-accessory-load situation, the battery CAN provide some supplementary power for short periods of time (like limited time idling), but this is an indication of a marginal electrical system. This is probably of no concern to a mall cruiser where the AAA man is just a phone call away, but assuming that you occasionally use your FJ as an off-road vehicle driven solo to isolated locations, I wouldn't want an electrical system that was constantly discharging the battery during extended idling, even if I had an isolated secondary battery.

Maybe I'm just old school, but I prefer robust design margins wherever possible.

Think of the charging system on a typical police-special Crown Vic, that can idle for 8 hours with the AC, PC, radios, headlights, and light bar all on simultaneously, with a single battery.



QUOTE]
 

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Youre partially correct. But in practice alternators are not designed to power every imaginable thing you ever could think to add to your truck. You can add too much, then the battery picks up the slack. (snip)

Partially correct?

Nowhere did I suggest that the STOCK alternator could "power every imaginable thing you ever could think to add to your truck".

As far as the battery "picking up the slack", this is a bit of a risky situation. If you've got a poorly matched alternator-output-to-accessory-load situation, the battery CAN provide some supplementary power for short periods of time (like limited time idling), but this is an indication of a marginal electrical system. This is probably of no concern to a mall cruiser where the AAA man is just a phone call away, but assuming that you occasionally use your FJ as an off-road vehicle driven solo to isolated locations, I wouldn't want an electrical system that was constantly discharging the battery during extended idling, even if I had an isolated secondary battery.

Maybe I'm just old school, but I prefer robust design margins wherever possible.

Think of the charging system on a typical police-special Crown Vic, that can idle for 8 hours with the AC, PC, radios, headlights, and light bar all on simultaneously, with a single battery.



QUOTE]

As for the "every imaginable thing", it was an obvious over exaggeration due to your blanket statement:

"Technically, your battery shouldn't be powering ANY of this stuff, except for a very limited time when the engine is not running. Your "starting" battery is for starting the engine; once the engine is running, your alternator is the source of power for all these loads."

Which is only partially true. If the alternator is capable of supporintg, lets say, the truck and all OEM accessories and have capacity for, lets say, 30 additional amps and you have 100 amps of extra (non OEM) accessories youre trying to power, where do you think the extra 70 amps the alternator can't supply is going to come from ?

I see you didn't bother to read the thread did you? :|
 

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From experiance and a little electrical knowledge:

A stock healthy alt/gen will carry everything most wheelers install in the vehicle.

You are never running all added electrical load at one time.

The extra battery is nice for those Oh Crap moments or if you are remote by yourself on the trail.

Chicken and Test, seems like you both are correct just pissing on the details.
 

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From experiance and a little electrical knowledge:

A stock healthy alt/gen will carry everything most wheelers install in the vehicle.

You are never running all added electrical load at one time.

The extra battery is nice for those Oh Crap moments or if you are remote by yourself on the trail.

Chicken and Test, seems like you both are correct just pissing on the details.
Perhaps but you should read that thread too. :D

The OP mentions his 12k winch. That one device with no other accessories has the potential to kill his battery even if used with the engine running. At best the FJ alternator will only have and extra 30-40 amps after supporting the engine. A winch could easily pull a few hundred amps on a pull. Thus severely draining the battery even with the engine running, which the alternator may not be able to make up completely (recharge) before the day is done. In a extreme example, having to use the more than once a day or even the next day could further compound the issue. lather rinse repeat, dead battery.

Just sayin' if you've never read that thread eneryone should, it's really enlightening :cheers:
 
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