Battery reading on a VAFC2 with a EK9

[INPHAMISTICS]

Hello guys,

I find it a bit strange because my on my vafc2 the battery ranges from 12.7v - 14.4v. It ranges a lot when I drive, sometimes I could be at 14.4v and drop right down to 12.8v. It also stays in between these ranges from time to time. When it does drop from 14.4v to 12.7v I can feel the car lag a little and also the light dim and don't keep charge. On my BB4 it tends to stay right on the dot 14.4v and remains at that at all times. I know that the battery on my BB4 is twice the size at the one I have in the EK9, if I get a bigger battery, will this solve my problem? Is there something wrong with my car?

Cheers

[d16a7]

mine used to drop a little from time to time like when at the lights with the headlights on it would read 12.* volts.. but whenever on the motorway or anything it was always high 13's to 14.4 Volts


possibly battery or alternator

easiest way to tell is does your VAFC turn off if you leave it to "boot up" at on.. and then go to crank it.. then your battery may possibly be on its way out... but also the alternator might not be charging fully....

mine used to do the whole turn off thing until i changed my battery to a new one as it died :cry:

[Horny_Devil]

i wouldnt worry about it as long as its above 12.5v its fine

i believe the ECU looks at heaps of different parameters to change the voltage to improve fuel economy. dependant on the driving conditions.

[-KONIG-]

The same thing happens with mine, changed the altenator and battery and still continued, i think it is just the way honda is, ie altenator not running the whole time...

[ScottG]

voltage stabilizer may help

[INPHAMISTICS]

Originally Posted by -KONIG-

The same thing happens with mine, changed the altenator and battery and still continued, i think it is just the way honda is, ie altenator not running the whole time...

Yeh I think it maybe just a thing with EK9s because I bought a new battery like 4months ago.

voltage stabilizer may help

That maybe the answer

cheers guys, just about to start working on the ignition on my car, if the voltage doesn't stabalise, is that not good?

[Horny_Devil]

did u not read my post? the ecu swtiches the alternator on and off to vary the voltage between 12.5 and 14.4v depending on engine load contiotions etc.

nothing to worry about at all.

[INPHAMISTICS]

Originally Posted by Horny_Devil

did u not read my post? the ecu swtiches the alternator on and off to vary the voltage between 12.5 and 14.4v depending on engine load contiotions etc.

nothing to worry about at all.

yeh I get that, but shouldn't every car do this as well? or is it only for civics or is it different for every car? My first post explains that a BB4 does not do this, it stays at 14.4v at all times.

[Horny_Devil]

not all cars do it. depends on how the ecu is set up. as long as its above 12.5v and below 14.4 volts give or take a lil dont worry urself about it. the battery is working and charging fine

[VTAKYO]

Mine sits on 14.4/14.5 steady as. Never seen it sit on 12/13 or whatever. I'd possibly check the earthing, as the VAFCs are very tempermental on how their earths are set up (1cm apart).

[Horny_Devil]

cant be 100% sure as im reading off a us manual but they run a electronic load detector and its dependant on about 8 sensors as to weather the ecu decides to turn the alternator off or not.

[Moclov]

Yeah uhh, I'm with Horny_Devil on this one

I would imagine any piece of vehicle electronics would have it's own voltage regulator inside it anyway. This takes the messy, spikey voltage created by the alternator, and leaves you with a relatively clean and smooth 12v (or whatever your particular device requires). The 0.5v - 2.4V over and above 12v just gets discarded anyway...

This is part of what I study day in and day out at Uni btw

[-KONIG-]

Originally Posted by INPHAMISTICS

yeh I get that, but shouldn't every car do this as well? or is it only for civics or is it different for every car? My first post explains that a BB4 does not do this, it stays at 14.4v at all times.

New computers guys, OBD1 prob isnt advanced enough for this, agreed with horny devil...

[Shadow Sol]

0.5v - 2.4V over and above 12v just gets discarded anyway...

not discarded - if its not there your alternator cant charge the battery - the output of the alternator has to be stronger than the 12V held in the battery in order to force a charge back through it.

11v from the alternator cant charge a battery holding 11v

[Moclov]

Originally Posted by Shadow Sol

not discarded - if its not there your alternator cant charge the battery - the output of the alternator has to be stronger than the 12V held in the battery in order to force a charge back through it.

11v from the alternator cant charge a battery holding 11v

I know...
I said that the electronic devices running off the cars electrical system don't really care what the voltage is as long as it's over 12.5v, as their voltage regulators do, in effect, just discard anything over 12v :wink:
I'm just trying to reinforce the idea that he's worrying over nothing

[DrTec]

I think your worrying way too much about it.
My ITR did the same thing. DOnt fret over it. So long as the car starts every time you go to drive it, its working correctly.