Second battery

[jrwalte 10+ year member]

as well as in line to the amp(s)

A fuse here isn't required, but it's recommended if you're extra cautious.

 

[delvryboy 5,000+ posts]

It depends how long the run is. If it's a few inches, then it's not really needed. A few feet and I would fuse it.

 

[audioholic 5,000+ posts]

Fuse both ends of the wire connecting the front and rear batts. Again, there is a power source at each end of this wire, so a short would draw the current from either end. Hence the need to place a fuse at each end of the wire, as close to each batt as possible.

Fuse the distro'd wire(s) to the amp(s), just to be safe.

 

[twisztdauthorit 10+ year member]

so technically you need 4 fuses when upgradeing electrical with a 2nd battery

1.) alt to battery

2.) 10" from main battery

3.) 10" from second battery between main battery

4.) 10" from second battery to amps

is this correct? in that case i need to find me another **** fuse box =/

 

[audioholic 5,000+ posts]

so technically you need 4 fuses when upgradeing electrical with a 2nd battery
1.) alt to battery

2.) 10" from main battery

3.) 10" from second battery between main battery

4.) 10" from second battery to amps

is this correct? in that case i need to find me another **** fuse box =/

Number 1, if you wish to fuse your alt to batt wire, that should be done regardless of adding a rear batt or not. So that's not really a necessity of adding a second batt.
Number 2, fuse close to front batt, should be there already too...

Number 4 is usually in the form of a fused distro block, which again is probably a good idea whether you have a rear batt or not (assuming you are running more than one amp).

So really that just leaves the one extra fuse that needs to be purchased/added when adding the rear batt... number 3.

 

[jrwalte 10+ year member]

1.) alt to battery

I've never bothered with that one - unless it was already fused by the factory (some cars do). If you do, I'd do it on the bat side as well.

 

[audioholic 5,000+ posts]

I've never bothered with that one - unless it was already fused by the factory (some cars do). If you do, I'd do it on the bat side as well.

If anything, fusing the batt side of that wire is most important. You can turn off the alt. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[jrwalte 10+ year member]

If anything, fusing the batt side of that wire is most important. You can turn off the alt. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

More like the impact would //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif It would take a lot of force to damage that wire.

 

[twisztdauthorit 10+ year member]

on the topic of fusing the alt.

My 137 amp alt has some 8awg positive looking wire. Is it safe to upgrade it to 4awg positive and fuse it with 150 amp fuse, Or is that to risky. I think 150 is the closest fuse size to 137 right?

 

[audioholic 5,000+ posts]

on the topic of fusing the alt.My 137 amp alt has some 8awg positive looking wire. Is it safe to upgrade it to 4awg positive and fuse it with 150 amp fuse, Or is that to risky. I think 150 is the closest fuse size to 137 right?

The fuse size should be rated less than the capacity of the wire, but greater than the output of the alternator.

 

[dman4486 5,000+ posts]

i dont have a fuse on my 200a alt. never a problem for me

No fuse on my alt either

 

[twisztdauthorit 10+ year member]

id rather not risk setting my alt on fire drawing 3k watts of power untill i can afford a HO

 

[jrwalte 10+ year member]

id rather not risk setting my alt on fire drawing 3k watts of power untill i can afford a HO

Your Alt will just say FU and your amp will shut off or it'll be the one to pop //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[jrwalte 10+ year member]

then don't run 3kw on a small alt. thats not good anyways, and you probably won't see 3kw with a stock alt. i could be wrong

You can't fight ohms law. You just can't get 3000 real watts at less than 214 amps @ 14 volts. That's not even taking into consideration amp efficiency when it converts to AC power (so it would take even more amps).

 

[twisztdauthorit 10+ year member]

thats constant power.. I figure ill be able to get close to the 3kwatt mark with the 3 batteries ill have.

I know i wont be churning out 3kwatts for 1 min straight butt thats not what im looknig for anyway.

Depending on voltage drop, ill see how much i need to save up for an alt. The highest i can get for my car is 200 without and serious modification so im not ready to blow 400$ on an extra 63 amps of alternator juice just yet.

Thats why im going to fuse my **** alt