how much more electrical do I need?

[till its over]

I have a 300 amp alternator and a xs power d3400 under hood with big 3(x2 overkill just cuz) with two positive runs to the back and a negative run with another d3400 in back and 3 grounds in trunk. How many more d3400s will I need to run two rockford t2500-1bdcps safely.Would like to stick with the d3400s so its all the same...thanks!

[justin0943]

so you have a ho 300amp and a d3400 under the hood and in the trunk should be plenty but you can always have more.

[P4killer_]

it just depends on how you like to play. demo all day? full tilt for long periods? if so youd prolly need more batts. but electrical is one of those grey areas,, ppl run big amps on lawn mower batts all the time. ppl also get like 40 batts for 2k .. so

but if your wired at 1ohm each you might get away with what you have assuming that alt does 300a. but imo you prolly want 2 more d3400s for 7k or so. but you might be ok now it depends on that all making all 300a. so id say watch your voltage if it gets to 12.x or below youd need more batts.

[alaskanzx5]

for every amp in the system do the following

rms rated watts divided by efficiency the divide that by voltage.

that gives you the estimated power draw (ah) of each amp in the system

add all those estimated numbers together plus the amperage draw of the vehicle itself

subtract the alternator output then the total batteries ah rating and what's left is what is estimated that you will need.

I would use 13volts as you could have voltage drop and estimate at 13v would tell you to have more ah then if done at say 14.4 volts. this math was taking from a sonixelectronics youtube video. its just an estimate of what the power draw will be to give you a good starting point. may need more but its a safe start imo.

for 2 2500.1bdcp im getting 549 amperage draw, that's using a 2500rms rating and not the birth sheet since the birth sheet isn't a good guideline since they list the power it made on a resistive load and real world application you will have impedance changes.

[gr8handogoatness]

When in doubt add batteries.

[MECHMAN]

IMO i would definitely stick with D3400's. I wouldn't recommend running Multiple +'s off of the alternator just because the regulator could get overheated due to the resistance between the two connections. It would be better to come off of the alternator with a larger cable to a distribution block then to the batteries

[till its over]

Thanks guys I think ima buy a couple more batts

[gr8handogoatness]

Mechman knows electrical better than most of us, myself included, listen to him before you listen to me. My post should probably say when in doubt get a Mechman alternator.

[justin0943]

what brand is the ho alt

[MECHMAN]

I have a 300 amp alternator and a xs power d3400 under hood with big 3(x2 overkill just cuz) with two positive runs to the back and a negative run with another d3400 in back and 3 grounds in trunk. How many more d3400s will I need to run two rockford t2500-1bdcps safely.Would like to stick with the d3400s so its all the same...thanks!

How many watts RMS are you trying to power ?