alright, just got done moving my batteries to the bed, i'm running a dual optima setup

put it on the dyno today, and all of a sudden, the a/f starts going to like 13's or so. reason was the maf was going to like 800 and then pegging out, just bouncing, 800, 805, 800, etc...

after hours of playing on the dyno, we decide the mafia has to be bad. got one on order. the guy at diablosport says that the only time they heard of that happening was on a battery relocation

we decide to run a jump on the ground, doesn't change anything

anyway, i call ken to ask if the mafia will be in tomorrow, he said prob wednesday, he says brandon mentioned that last year when my engine blew, it was right after i put the 2nd battery in

so, for ****s and giggles, they pull the 2nd battery, make a pull, perfect, make a 2nd pull, a/f is perfect again, maf transfer working fine again

put the 2nd battery back on, and boom, back to 13+ a/f's

what the heck is going on?

the reason i added it was elec fan, intercooler fans, bottle heater, intercooler pumps, etc.. running at track

why would adding a 2nd battery screw with the functions?

 

wow, good info.... I WAS about to move my battery to the bed..... I think I am gonna wait this out and see whats wrong with yours.... I dont want to have any problems....

 

Beefcake, The first thing I would want to know is the voltage on those batteries, is the alternator putting out full juice, your running alot of electrical accesories if it pulls down the voltage it could cause the variation in the MAF your reading, I've read this before that a bad battery or a low charge could cause issues with the computer.

 

that wouldn't be the case, actually, becuase of all the accessories, mine always seemed a little on the low end, with the 2nd battery i'm about 13.5 v's which should be perfect

i originally had the batteries wired in series, which i read on nloc was not right, but brandon said he has them wired parallel, and were still having the problem

i have 2 yellow top optimas btw

 

Beefcake, I've read and also obviously agree with that a bad or low cell in a battery will cause voltage issues and can create havoc with the computer, creating all kinds of tuning issues, like a pegged MAF and so on, I also read your post on NLOC, wiring the batteries in series will double the voltage, not the effect your looking for, if your reading 13.5 with everything running thats fine, have you checked the voltage while making a full boogie run on the dyno? Todd

 

the 13.5 was during the datalogging

 

Have you actually tried it with the batteries in parallel? That your truck freaked out with 27 volts coming into the regulator does not surprise me.

 

yes...pos to pos, neg to neg, is the only way you can do it!!

 

well, they are currenty wired parallel at least that is what brandon told me

the data logger only shows 13.5 volts

 

Right, but is the OBDII sensor after the regulator?

Just check the wiring. As stated above, red->red, black->black is parallel.

 

combining batteries wouldn't raise your voltage....example...two batteries supporting 12.6 volts wouldn't mean you are running 25.2 volts.

All it would mean is that you have a greater reserve of amps for use with efan, bottle heater (which is worse than the fan), ect.....

The problem would be that when you wear the voltage down and counting on the alternator to recharge them........you would have to be running alot longer than you normally would also because you have to charge twice the battery.

I don't understand how running two batteries could cause your issue Beef. Definetely wierd. The only thing I can think of is there is an issue somewhere in the wiring. Maybe the wire going back to the batteries from the alternator has a bad connection........isn't big enough to travel the extra length.....but i'm sure this is stuff you checked and pre thought out.

How about a ground issue?? Maybe try running an accessory ground strap from the motor to the frame??

I don't know??? Should be interesting. Sorry your the guinnea pig. I know it sucks. Good luck.

 

Whats a mafia ? Must be an east coast Sopranos thing

If you hooked them up with pos to neg you certainly would get 26 volts

Thats how all the battery operated devices you have work - Your maglight flashlight for example - a 2 d cell ( 3 volts ) is not as bright as a 3 d cell ( 4.5 volts ) which is not as bright as a 4 d cell ( 6 volts )
And they all have different bulbs in them to take best advantage of the voltage increase. The batterys are stacked on toe of each other neg to pos and the voltage is addded to make the total .

Doug

 

Only if they are wired in parallel. That's the whole point of the series versus parallel discussion.
Series=additive voltage
Parallel=additive current

Imagine that the resistors below are batteries:



Top diagram: voltage = V1+V2+V3+V4
current = (A1+A2+A3+A4)/4

Bottom diagram: voltage = (V1+V2+V3+V4)/4
current = A1+A2+A3+A4

Edit: just found this on point graphic

 

i thought he said he had them in parallel. Hooking them up in series would definetely cause some issues.

 

I own a hardware store so I'm all over that. This week must have been science fair week at the middle school. All the parents came in with their shopping lists!!!!

I only need 1 nail, why do i have to buy the whole box???

It's only a dollar for the fricken box lady!!!!!