I have 0 gauge wire connecting the 2 batterys. 100 amp fuses on both ends. Is that enough? Did the alternator to batt with 4 gauge. And batt grounds are 4 gauge.

 

4 gauge is way overkill for the alternator to battery lead.

Grounds need to be equal to the positive leads. They carry the same current.

What are you building?

 

Plans Are to get a high amp alt made or bought. In the 250amp range. I have 2 15s subs rockford amps, p300s planing a a third 15.
but want a power inverter to run a flat screen 40 to 55 inch. With digital antenna. And play station.

 

Plans Are to get a high amp alt made or bought. In the 250amp range. I have 2 15s subs rockford amps, p300s planing a a third 15.
but want a power inverter to run a flat screen 40 to 55 inch. With digital antenna. And play station.

 

You're doing it wrong.

Amplifiers are rated in watts, not amps. If the people you are hanging around with are talking about amplifiers in terms of amps, you are hanging around with ignorant people who are feeding off each other's ignorance. You need to find better people to hang around with if you want a decent system. This kind of nonsense is why a sound engineer can go into a stereo contest and walk away with the prizes with a system that is running a quarter of the power of the kiddies. (It's been done more than once.)

A 250 watt amplifier will draw about 20 amps. That would be ridiculously small for the speakers you have listed. An amp that draws 250 amps would be in the 3000 watt range. (12v * 250 amps = 3000 watts) Stupidly big unless you are entering contests, but a lot of people do it. That's probably in the neighborhood of what you have in mind.

To that you want to add an inverter. How big an inverter? Do you know? What kind of power does the TV require? What else might you want to run on that inverter? How long do you want the inverter to last? (It won't last if you constantly run it at the rated power.)

Now that you know the power requirements, what are the losses for that current for the distance you are running the cables?


The point is, you start with planning the equipment you are going to power, then the layout so you know cable length, then you calculate the size cables you need. You are doing this completely backwards.

It's like having a custom driveshaft made for a 'built-from-scratch' 4WD before you even decide what engine, transmission, and transfer case you are going to use.

 

Wizzy214,,, Where did you acquire those battery terminals?

 

Those are available on , among other places. They're not hard to find. Unless you need all those ports, I prefer the , myself, with properly crimped cable ends.

 

Thanks for the links

My Mark III conversion 1988 has a very simple wiring. They just ran 2, 12 gauge wires from the battery to inside the van to power the TV and lights. They used a inline fuse at the battery. Using standard battery terminals the copper wires keep corroding off even with crimped terminals them.
I have a brand new spare battery I was thinking to use for a house battery when I go camping. I plan to change all the interior lighting to led and use a laptop for a TV. From what I have read a laptop pulls less power then a TV.
I know a deep cycle battery is best but I have the spare battery just sitting around hooked to a solar maintainer. I haven't figured out how I am going to hook it up yet.

 

When connecting a second battery, you've got to ask yourself one question. Do I feel lucky? Well, do ya, punk?

Oh, wait, wrong story! Sorry!

The question you need to ask is, "Do I want my second battery to be available to help start the vehicle's engine?"

If the answer is yes, then you need to use cables that are hefty enough for the current drawn by a starter. Big stuff.


If the answer is no, then all you need from the alt to the second battery is enough cable to carry the charging current, which is a lot less.

Let's go with option 2 for a second. If you just hook that up to the existing battery (with a fuse, of course), it will work fine, but..... if you go on a Netflix binge you could wind up drawing down both batteries, so in the morning, you can't crank the engine over. That ain't good!

Since we don't like dead batteries, we need to find a way to isolate the auxiliary battery from the primary battery, so one does not kill the other.

One way to do that is with a . Basically it's a pair of diodes mounted in a housing. You take the charging lead from the alternator, re-route it to the center terminal of the isolator, and then go from each of the other terminals to the respective batteries. Again, you don't need massive cables - just enough for the charging current.

The other way do do that (which Ford uses in some vehicles) is to run the auxiliary battery through a which is designed for that.

I'll try to come back later and whip up a diagram for you using both options, and show what you need to consider for cable sizing.

 

The new tvs use a 12 volt supply. You'd still need an inverter for your game system but the tv will draw less going straight 12v then through the inverter. The tvs will draw less than a laptop just because of the loss from converting from ac to dc unless your using a 40inch+tv.

I've had cub scouts charging their phones and devices over a weekend about kill my van battery but I've still stayed away from a second battery. Those new phones can definitely draw some power. Couple of phones on a fast charger can pull like leaving your interior lights on.

I ran 1/0 from my alt to the battery but never upgraded my alternator...yet. Still need to upgrade my body to motor ground. Be sure to post your progress and finished product please.