In Dash Voltmeter Perfect Fit

[mrdance123]

Here is a handy DC voltmeter that fits perfectly in an unused switch cut-out on the Tercel's dash instrument panel.
http://www.ebay.com/itm/380981614591

[marlinh]

Cool, how did you wire it?

[mrdance123]

Wired straight to battery, dedicated wire (small wire and fuse) no other load for accurate reading, to monitor alternator performance and battery charge state.

[dlb]

nice. do you have a pic of it in place?

[irowiki]

I was thinking the same thing but some way to turn it off when the car is off.

[jimcrazy]

how bright is the red? I was looking at some green ones may not be as bright,

[rer233]

I was thinking the same thing but some way to turn it off when the car is off.

Easy- just wire it to a switched hot lead.

[irowiki]

The idea is for it to get signal from battery but be switched!

I'm thinking finding one that has power, plus a signal lead.

[drege]

Ordered mine, I like the switch idea, I have a three drawer bin full of all kinds of switches.
Maybe one of the empty panels just near the clock set knob for a momentary.

[mtc1984]

wire it with a relay. pin 30 on the relay goes to the battery positive 87 to the red wire on the gauge. 85 goes to a switch 12v pos source and 86 is a ground. ground the black wire on the gauge.

[mrdance123]

It looks much better in person. Camera inflates and blurs the red LED light, makes it look twice as large and bright as it really is. There are green and blue ones available. It's mostly behind the wheel driving, so it's not distracting to me, even at night. Maybe put a tint film on it to tone it down. The battery drain it uses is nearly undetectable, do did not bother with switching it on off. I wired red wire directly to battery post cable for accurate reading and black to in dash hard ground (not a wire). Existing in dash wires have other loads on them, changing the voltage and giving false reading. With a decent charged battery and good alternator (not a half fried one) it will read about 13.8 with lights and fan on, up to 14.1 with nothing but ignition. At slow idle with all accessories and lights on it may drop below 13. If it cant rise above 13.4 with driving rpm's and all accessories on, there's a problem brewing.

[drege]

Put that 2$ volt meter in the corolla FX as I'm going to do all mechanical gauge cluster on door panel with the T4WD, wired it to the 'seat heater' circut on the fuse block as the car don't have seat heaters, and the ignition heats up this terminal.
But I've noticed something weird, when all lights/acccessories off and at idle the voltage reads like 11.5, though the idle feels really low, when I hold the gas pedal to 900RPM it really only increases the volts up to about 11.7 or so, cruising the highway its 14.x
What could this be?
I suppose I could use my handheld to measure the battery from its terminals and see if there is a difference, but I have a feeling that it will read the same.

[Petros]

the volatage regulator is just an "on/off" switch for the alternator, when the volage it senses at the battery is below a certain level it kicks on the alternator so it will up out 14.5 volts or so, once the battery voltage gets above some level it turns it off.

could be your sourse of volatage is after a resistor, or a weak contact, or your voltage regulator is sticking. try using another sourse of voltage before the fuse box to verify voltage. Also check the gauge accuracy using a hand held volt meter as well.

[drege]

It reads proper until there is load, headlights, brakelights, heater blower all drag it down.
This is the story my Etek multimeter tells me tapped directly to the battery.

[Petros]

that is normal. I discovered using a digital volt meter tempoarily wired to the fuse box, that with the headlights on, radio and blower on, with the car at idle, the battery is discharging (below 12-13 volts). with the idle speed above about 1800 rpm, the battery is changing (14.5 volts). As each item is used, it draws down the voltage.

This means if you let it idle for very long with the headlights on, the battery can eventually die.