Need some help on electrical

[Ron36]

I have 6 batteries on a 250amp alt with total RMS with mids about 4K u need a bigger or another alt and way more batteries , why buy a great sub and amp and not feed them

[Karkov]

I'm assuming your alternator options are limited. For electrical, start with what you have, get a good volt meter, and watch voltage, I am sure you will dip lower than you want, and at that point add batteries to the rear for extra reserve. Truly you would actually need more alternator output (which should come first and is more important IMO) but you are prolly limited to what you got. The batteries in the rear (once you get enough) will allow you to not drop so far or so fast and will protect your amp from going into protect or being playing with too low of voltage and frying. If weight is an issue go Lithium or super caps. Split that 500 amp fuse rating between your two wires.

^^Ron36 he might be limited for what alts go with his car.

OP what car do you have?

My setup is in my signature (if you are on a desktop) and I can drop to the 11's due to lack of alt output (full tilt a couple songs of steady bass). I use a large bank because weight wasn't an issue and it helps protect the amp boards. I could have and should have went with more alts. since there are larger kits available to me but since mine is daily ground pounder and NEVER gets metered I went with what I have and call it good, and generally 99.9% of the time it's just fine.

I like overkill so I will say this, if your amp has dual inputs just run dual positive from front alt/batt to back batt bank then to amp. Your alt in theory won't put out what one run of 1/0 OFC can handle though as others have said. I have 3 runs of 2/0 OFC for 10k+ RMS (substage only).

FYI I ALWAYS watch my voltage, both charging systems, front, back, you name it, I want to know what everything is at at all times.

[sTp]

First of i am from the UK so i am limited to getting certain thing due to having to pay load for shipping and customs so i try to order most of the stuff from the UK but if i have to get stuff from the states or wherever it's no real problem.

Car is a Citroen Saxo 1.6 its a small hatchback so weight is also a problem.

if i went Lithium how many batts would i need?

Also i got a good meter got the SMD-VM1.

and final question if i ran the cable straight from the alternator to the batt bank do i need to fuse the cables coming of the alt to the rear and if so what size and also where would i ground the rear batts would i need to do a single run back to the chassis or can you ground it in the trunk.

Many thanks for the help guys in much appreciated.

[RainStryke]

Lithium's are really expensive, like $1000+ each battery.

Keep your grounds local and short, don't run one from the battery in the front to the back. Make sure to pick the best places to ground with lots of thick metal, like where the seats bolt the chassis or a rear strut tower bolt.

[DLHgn]

Depending on what lithium's you get, you can sometimes use less batteries than AGM's for the same power but like Rain said, they are pretty pricey. If you're trying to justify it with yourself, think of the weight you will be saving and compare the required number of lithiums to the number of AGM's. A lot of times it will come out to around the same price.