Resting voltage down to 12.0....

[ptcary]

Ok guys, need your advice. I have stock alternator 136 amp, MLA module, Kinetik HC1400 under the hood, 2x HC600s in the car, 3100 watts RMS, 1/0 throughout. Nothing is staying on with the key off.

When I finished the PT I had ~450 RMS watts less going to mids and highs, and everything was happy, I ran the charger on the batteries every weekend.

This past week, I noticed that the PT has been taking an extra turn of the engine to start. Once it does it is fine and my meter is at 15.1 (14.7 normal, but cold temps outside).

After a full charge, then shutting off the car, the resting voltage engine off is 13.3 then immeditely starts dropping, takes about an hour to get down to 12.0, then stays there.

Since I am not getting an alternator light on the dash and am seeing the full voltage when the engine is running, the alternator is OK right?

Tonight I am going to run the charger on the batteries, then disconnect the rear batteries from the front one, and see if that one will start the car tomorrow after work. If it won't I can reconnect the rear two to start the car.

Am I going in the right direction? Thinking one of the batteries has gone bad and the others are compensating for it?

Any chance that running 3100 RMS off of "2600" worth of Kinetik batts could take its toll on the batteries in a week or two?

Edited February 2, 2010 by ptcary

[finkster]

the alt is fine. If your voltage is dropping down then your batteries are not healthy or something is draining them. test each battery individually.

[ptcary]

the alt is fine. If your voltage is dropping down then your batteries are not healthy or something is draining them. test each battery individually.

Thanks, I'll check the two rear batts when I get home tomorrow. Nothing is on after I turn the key off, so I can't think of what would drain them. I did go from one 4 channel amp on my mids/highs to two 2 channel amps temporarily, cause the 4 channel died on me.

I know I will need more battery if I am going to run an extra 450rms, but it has only been a few weeks. I hope I don't have to replace a battery, but it's cheaper and much easier than the alternator.

[Pauliesnite93]

i think u are giving the batt. memory if u are charging them every weekend. but i am 16. so ask around if that is what is happening to the batt.

[Decaf]

agms dont have memory, lol

u can charge an agm every night on trickle if u want/can

sounds like a few bad cells, likely those hc600s next to the amp(s)

if u got a HO alt ud barely be draining ur batts. the likelyhood is uve reached the lifespan of one of those batts because ive done too many discharges too deep

[ptcary]

agms dont have memory, lol

u can charge an agm every night on trickle if u want/can

sounds like a few bad cells, likely those hc600s next to the amp(s)

if u got a HO alt ud barely be draining ur batts. the likelyhood is uve reached the lifespan of one of those batts because ive done too many discharges too deep

Decaf, thanks. The 1400 underhood is resting at 12.3v, and the two 600s are at 13.1v on the buss bars. I am pretty sure that the 1400 rested @ 13v when it was new.

You think I should replace the 1400?

[Ray]

I would hit the 1400 hard on and off for a few days, try to bring it back

[ptcary]

I would hit the 1400 hard on and off for a few days, try to bring it back

Thanks Ray! So it is not completely dead yet? I'll give it a try. 12.9 is normal?

I found this quote from missing link on resting voltage:

"To rule out the battery 1st check its (resting voltage) use a volt meter first thing in the morning before you ever start your car (do not charge battery over night then test)

Simple #'s are 12v dead , 12.5 55%full , 13v full , if your pumping 14.5 to 15 volts into your battery it should be (resting) a solid 12.9+"

[uhoh_45]

could it also be that the back batterys are drawing power from the front batt draining it?

[ptcary]

could it also be that the back batterys are drawing power from the front batt draining it?

Since the back batteries (2 HC600s) are inside the car and resting at 13.1v and the 1400 is underhood and exposed to the engine heat and cold weather, and is resting at 12.3v, I am thinking that the 1400 is having problems.