24 replies to this topic

[romano.inc]

Hello all,

basically its time to add another battery to the falcon im sick of the huge voltage drop im getting and i finally wanna finish the install up with fibreglass and all. So basically the plan is, the run of 0 gauge currently going from the battery to the amp will be put onto the alternator and then to the battery in the back with the existing 200amp circuit breaker, is this the correct setup?

Im planning on getting a supercharge amptech either 80 or 100amp hour deep cycle battery, would this be a good choice and would the single run of 0 gauge be sufficient to maintain charge with the stock alternator? From there i will only have runs going to the amp that are like 50cm so in theory this should eliminate voltage drop correct?

Also, my DD s2 amp is a class ab amp and very inneficient compared to others putting a total of 1200w rms per channel at 1 ohm per channel. I was thinking of instead using one of my rockford t4000 amps at 2 ohm which would put out 3000+rms at 2 ohms and is a class BD amp. any suggestions would be great.

Thankyou as always

[D34M0N.inc]

I'd just leave the battery setup in the front and just hook the 0gauge running to the boot directly to the new battery in the back.

[089JAY]

Yeah Im with D34MON... POS Terminal Front to POS Terminal Rear and NEG Terminal on Rear to Ground

[romano.inc]

thanks for the replies, any reason i should do that instead of straight from the alternator?

[089JAY]

Saves about 5mins moving the terminal from the battery to the alternator and acheives the exact same outcome

[romano.inc]

i see well thats good then cos it will look alot neater and i wont have to go buy any ring terminals
cheers

[089JAY]

No worries... Some people will argue that you should probably have a fuse or Circuit Breaker close to the rear battery (aswell as the front battery), but thats all down to personal preferance...

[Lunchbox.inc]

don't forget, you will need a fuse on either end of your charge wire, as the rear battery is obviously also live...

plus i agree with D34MON.inc on this one, just run battery terminal to battery terminal...

Jay_Laser, on 18 December 2011 - 09:04 PM, said:

No worries... Some people will argue that you should probably have a fuse or Circuit Breaker close to the rear battery (aswell as the front battery), but thats all down to personal preferance...

sorry man, that is NOT a personal preference thing, it's an absolute MUST HAVE... as the only protection you would have is if the short happens to occur between the front battery and the circut breaker... anything between the front circut breaker and the rear battery will remain live, and melt your car into a pile of molten jelly like substance...

[romano.inc]

ok just to clarify so i have one 200 amp circuit breaker already close to the front battery, so il need another (or fuse) on the same run of wire just close to the other battery, and then another fuse going from the battery to amp?

Also any opinions on changing the amp and if the battery is a good choice?

[Lunchbox.inc]

depending on the cable length from the rear battery to the amp, you can sometimes do without a fuse on there, as the main rason we fuse is to protect the car from burning down in the case of a short circuit, and depending on the way the cable is run from battery to amp in the rear, you can do away with 99% of the associated risk in shorting out... leaving only amplifier failure as the only risk... that much is up to you, but i believe those rockfords have a fairly beefy onboard fusing...?

other than that you got it right with the fusing...

personally, i would go with the rockford, simply for more power... lol i like power, it's nice to have, and if your running a 2nd battery in the boot, you should have enough electrical to support some big power... i can't really talk for the sound quality/noise issues etc of the rockford compared to the DD, but it's definitely worth chucking it in there and trying it out...

[D34M0N.inc]

That and if you take the wire and directly put it to the alternator then (This is if your keeping the front battery still connected which is best to because more battery power the better) The front battery will be topping up the rear battery in a way through the alt anyway thus not really changing anything. So it's best just to leave it as it is in the front. And it wouldn't hurt (if you haven't already done so, to beef up the alt power cable to the batt and the groudn to 0gauge to help lower volt drop, i had huge volt drop issues and just adding a 0gauge ground in the engine bay changed my volt drop from 10v drops to 11.8v drops.

And i definitely agree with Lunchbox on fusing it at both ends. A $20-30 fuse compared to a $10k+ car i'd want that extra safety.

And best way to know if the batt power is enough is to find out the draw on the amp you want to use.

[Pulse-R]

how much current do you want to draw?

if your 200A breaker doesn't trip, then you really don't need too much big wire or big battery in the back.

If you already have the 0ga in there, fine then... otherwise for a "charge balance" wire - to keep the battery topped up can be only 8ga or 4ga, as you will rarely get more than 60A flowing to the rear.

definitely make sure you have (at least) 0ga grounds and 0ga from the rear battery to the amps.

also the fuse needs to be adjacent to any power source. - to prevent the fire and smoke getting out in case of "accidental" short circuits

[romano.inc]

Yeah i currently have the 0 gauge from front too back connected to the amp so il just use that
No i never trip the circuit breakers the amp just goes into protect.. I have a spare circuit breaker so il have one on each end of the charge wire, and then i might get a fuse and holder from the rear battery to amp, even though the amp is already fused with a ANL fuse i guess it cant hurt!

Well can anyone reccomend a battery size (in amp hours) that would be suitable?

[D34M0N.inc]

Just put the biggest one your willing to fit in the rear, can never have to much battery power

[romano.inc]

yeah i have the whole spare tyre well to work with haha so il just put a big 105 amp hour one in seeing as though i can get it at a good price from work. any ideas of securing the battery box to the car without welding haha?