Running stereo off auxillary battery

Thanks Bonz and Allan.

Might even put a fuse box for the auxilary in the glove box for future use.

I have the volt meters already installed, connected to where the battery positives connect to the isolator, but they both read the same volts always. I expected this while charging but even when the start battery died both meters read 11V. I will move the feed to direct to the battery and see if that helps.

And no subby...just 7 hours of The Verses, The Waifs, Sam Hawksley...all good aussie music.

Hi Wainy

Some people have a pre-conceived notion of what music and men (or women) are made of.

I am 59 yrs old, and still play AC/DC, Doors, etc. Loud. Perhaps 'cause i suffer industrial deafness, (or maybe 40 yrs of loud music, old time drummer).

No, I don't play it in the vicinity of others, just for my own enjoyment,,,, (read QUIETLY when others are around),,, and not while camping.

Sorry, can't help you with the electrical side of things, Allan B (Sunshine Coast) will get you on the right track.

Happy camping... It's a long way to the top......

Cheers, Dave

Sorry, didn't mean to single out Allan as the only source of advice... many, many people on here with great electrical knowledge, just saw Allan's reply's is all.

Cheers and apologies to all, Dave

Aw and LOL Dave

Tell you what though.......... ever since I had a whinge on thread 84238, 'Forum Etiquette', everyone has been spelling my name with both LL's. Thanks guys, I'm chuffed!

G'day Allan

Got a BIL with the name Alan,,,, with one 'L'

Gotta admit I dislike people spelling my name incorrectly, so I TRY to make as few errors as possible..... no, not Dave.... my surname, lol.

Take care, and cheers ALLAN,

DAVE

Exactly I charged both my batteries for 24 hours each after the car wouldn't start after sitting for a week.

Both had 13.5 volts in them 2 hours after I removed charger.

Car wouldn't start.

Why.

Instead of putting out the 650CCA they were supposed to they both were under 350CCA.

End result 2 new batteries.

Its what they do under load so volts virtually means nothing when just sitting.

Why do you think that? 7 hours of 6 x 50 watt speakers at abt half volume. When I say the battery was "dead" there just wasn't enough to crank over. (solinoid clicking). I still had stereo, int lights, gauges etc. Volt meter was reading about 10.8 volts.
I would have thought that pretty normal.

For crying out loud. No wonder. What did the neighbours say. Thank god you weren't near me.

Phil

Don't bother responding. I don't want to know about it.

You're assuming I have neighbors!

Hi Wainy, Last year at Logue Brook Dam we had some idiots playing "doff doff" music until 1 am. I am so so so sorry their battery did not die. Their ski boat sat in the water all weekend with trailer. I don't mind the Waifs (good Albany band) but when people go away with a disco set up (these had a mixer and all including disco lights) they need to reconsider.
You could also fit a push button switch to the redarc that will allow you to bring in the aux battery if the main is flat to start. Have that on the troopy and works a treat.


Cheers

Mark

Hi Boeing....Yeah, I hate that too. Did they have a mirror too?

How would I wire up such a switch?

For the record the vacuum cleaner was louder than the stereo outside the car.
Please don't all get beat up on the noise pollution & respect of others issue here. That was not the situation.

Allan, thankyou for your useful and relevant input.

That was my original assumption that the isolator should prevent the cranking battery from going flat. I have since read many many articles on-line that allude to the isolator only isolating batteries for charging - not draining.

Is this true for some systems?
(I wish I could find a branding on the isolator)

Wainy, You said ...."I have since read many many articles on-line that allude to the isolator only isolating batteries for charging - not draining."
No, it's the other way around.......... dual-battery isolators connect the batteries together only for charging, and isolates them for draining, thus not allowing the cranking battery to become discharged by the accessory loads. All systems follow this procedure.

This is what the Redarc SBI isolator looks like:
Image Could Not Be Found

The black wire with a ring terminal is connected to earth. The blue wire serves two purposes...... it operates a LED on the dash to indicate that the isolator is active and when connected to positive causes the isolator to close allowing the auxiliary battery to assist with cranking. There can be some problems with this..... the cables to and from the isolator must be of a size to carry the cranking current without being overloaded and also the cranking current is being carried by the isolator contacts which may cause wear on them. On the hopefully rare occasions of needing to jump-start using the auxiliary battery I would prefer to simply use regular jumper leads between the batteries. You DO carry jumper leads, don't you?

Your isolator may look similar but not identical to the photo above.... there are similar products to the Redarc but may not have the blue wire for indicator and override control.

A simple way to check if the isolator is stuck in the "on" position is to switch on your headlights without the engine running and all accessories switched off. Within a minute or two the voltmeter on the cranking battery should be showing lower than the voltmeter on the auxiliary battery. If they continue to read exactly the same it indicates that the isolator is NOT isolating. If that is the case you would do best to replace it with a new genuine Redarc or similar. ( Just had a thought... if yours is a Redarc check that the blue wire is not connect to anything. If it has been connected to one of the main positive terminals it will keep the solenoid energised)

"Moving the voltmeter feeds to the battery should be no better than where they are on the isolator."

My theory exactly
Definitely no short between the two posts.
But the voltmeters each have a wire to accessory so that they don't drain the battery while the ignition is off. Could this be the cuplrit?

Meter wiring is....

To Battery - I have these connected to the relevant post on the isolator, being 1 meter connected to crank post, 1 meter to aux post
To Earth - both grounded to body
To Accessory - both connected to accessory feed from ignition
To Lights - both connected to dash lights wire

Wainy, from your description of the voltmeter wiring it would appear that they are digital meters with their power being supplied from the ignition accessory source and have internal illumination fed from the dash light circuit. The voltage sensing wiring coming from the isolator terminals. That all looks good to me and should not be causing a problem.
A sure way of testing the isolator is to lift both positive connections off the batteries and use a multimeter set to resistance (ohms) range to measure across the isolator terminals. There should be a very high (infinity or OL) reading. If the reading is zero or more likely less than a couple of ohms then the isolator is closed when it should not be.

Hang on a bit, I just realised that you may not get a "very high" ohmmeter reading using that method because the meter will see the loads (in series) connected to the two batteries. That still will not be zero ohms but could confuse.

Before taking the meter reading lift the cable from one terminal of the isolator and the foregoing instructions will be OK. High reading = isolator contacts open, zero or low reading = isolator contacts closed.

Allan (with 2 'L's)

Thanks for all this advice. I certainly didn't expect so much response on my first post.
I think I will just take it to a auto elec to test and do a bit of re-wiring in the mean time. It's getting a bit techy for my skills.

Cheers

Dave (Wainy)

Fair enough Dave. Could be a wise decision.