New Voltmeter conversion from RT-ENG.

[ShelbyDogg]

Just when I was about to cut the back of my cluster to install a voltmeter from a Dodge Van, Greg at RT-ENG came up with another good one. You can use a water temp gauge for the amp meter in a rally cluster to read voltage instead of amps and get rid of the dangerous Ammeter. You have to buy his 5v voltage limiter and the special sending unit.   Here is the link showing the standard cluster using a fuel gauge.

www.rt-eng.com/mediawiki/images/f/f6/Stealth_Voltmeter.pdf

See text below:


Stealth Voltmeter
Keep the Stock look when adding a Voltmeter
The voltmeter consists of:
The Voltmeter is a standard mopar fuel gage with an ammeter face.
A special "VOLTMETER SENDING UNIT" is used in place of the fuel sending unit.
This allows the meter to have the same response as fuel, oil, and temp gages.
How to read ammeter scale:
The normal alternator voltage has been moved to agree with the center of the voltmeter.
13.5V was the average voltage at the back of the instrument cluster with a good alternator.
The lower and upper markings are 9V and 18V as in a standard voltmeter.
Fig 1 Ammeter face / Voltage Scale
Fig 2: Gage and sending unit hook-up
Sending unit connections:
Only two connections,
1.) The IGN (ignition) tab is connected to battery voltage a jumper wire to the limiter is quickest.
2.) The GAGE tab is connected to the sending side of the gage (the other gage lead connects to the limiter).
Sending unit:
Works like an oil, temp or fuel sending unit except it sends voltage information;
Will work only with the new replacement limiter;
Like all the dash gages -accuracy is affected if the limiter voltage is not accurate;
The sending unit will not work correctly if the limiter has been replaced by a linear regulator.
Bypass original ammeter:
Disconnect original ammeter wire from ammeter, then connect two wires together with a bolt and nut tightly cover
connection with electrical tape. For additional improvement run wire from output of alternator to starter relay stud, this
leaves the fusible link in the circuit to protect your wiring.
Built-in Indicator Lights
The SU (sending unit) light's brightness and pulse rate will be proportional to the voltage at the IGN tab.
This gives an indication that the voltmeter sending unit is following the battery voltage.
The GP (gage power) light will flash when the limiter applies power to the gage.
This light was included as the stock limiter and gives no indication its working.

[GoodysGotaCuda]

Redline Gauge Works has a ammeter to voltage conversion gauge. It's in my dad's challenger looks factory. It is for the standard gauge setup however.

[quapman]

I like it, but I'm afraid to ask the price. 

[ShelbyDogg]

I paid $50 for their solid state gauge voltage limiter just because it wont short out if it dies like a 7805. I guess that it's probably $50 too.  But how much would you pay to have your car back after a meltdown?

My car lived through one of the those.  The ammeter leg shorted to the cluster pod and the red and black wires melted inside the wrapped harness all the way through the bulhead connector, till the fusible link melted and the car died.      Scary stuff. That's why my ammeters are bypassed and I need a way to monitor voltage.

[brads70]

Redline Gauge Works has a ammeter to voltage conversion gauge. It's in my dad's challenger looks factory. It is for the standard gauge setup however.

Do you have a link to that? I looked at Redlines website but can't find it?

[GoodysGotaCuda]

Do you have a link to that? I looked at Redlines website but can't find it?

Email them, they do it.

[brads70]

Email them, they do it.

Ok Thanks!

[LAA66]

 Yeah, I remember that redline conversion also just never got around to sending the guage pod in.

 My Amp meter is somewhat by-passed as the alternator wire goes direct to the relay, only the red "Battery" wire is feeding through the gauge. It's not accurate to the D--C  plate as it reads low. Once you get used to it you can tell when its charging though. 

[ragtopdodge]

Get one of these:

http://cgi.ebay.com/ebaymotors/Sunpro-CP7985-Gauge-CustomLine-Voltmeter-8-18-V-2-in_W0QQitemZ370361124689QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item563b3e4751


Face comes off easily.   Would have to fine a place like Redline to get a custom face that would be calibrated w/the sun gauge.

[Killer_Mopar]

Get one of these:

http://cgi.ebay.com/ebaymotors/Sunpro-CP7985-Gauge-CustomLine-Voltmeter-8-18-V-2-in_W0QQitemZ370361124689QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item563b3e4751

I bought one of those gauges last Thursday, I saw it in Mopar Action for charger's rallye dash & figured it was worth a try on the E-body rallye dash. The mounting studs are almost the same width and with a little work, the gauge bolts in. I figured I will bypass the Ammeter and run a circuit for the voltmeter. For the face I am either going to custom make one or more likely use one of the decal kits that can be bought on eBay (I already have it). Figured I really dont need to see the actual voltage, just know the range. Anyhow, I plan on finishing my little experiment in the next week or two(waiting on stuff from RT-eng) so I can post pictures when Im done.....

[UKcuda]

Has anyone here tried converting an original Rallye ammeter into a voltmeter ?

I think the original gauge works with a shunt resistor.  If you were to remove that and put a resistor in series it would become a voltmeter.

Obviously you would also have to re-wire things so that it was running in parallel accross the charging circuit.

I can foresee two problems:

1) choosing the correct resistor to get the right deflection

2) the gauge is centered at zero amps so running it as a volt meter it would only be using half the scale, unless you can mechanically realign "zero" internally to point over more towards the "D" end.

I have a spare Rallye dash here so I think I might pull the ammeter and take a look inside - maybe I can get it to act like a volt meter on the bench.

Shelbydogg said:

I paid $50 for their solid state gauge voltage limiter just because it wont short out if it dies like a 7805.

You can use a 7805 quite safely if you just put a 2 amp fuse on it; that's what I've done.  Also if you screw the 7805 "lug" to the back of the Rally dash pod in the same place where the stock regulator was it's nicely out of the way and it gives it a huge heat sink and a good ground (the 7805 grounds through the tab as well as the center leg).

BTW, it cost me about $2

[bb71challenger]

I forget who did a group buy a while back on Rallye gauges but most of us who did it got the volt meter upgrade. Its obvious only if you look at it, it blends right into the rest of the gauges. Sorry but I dont have an actual pic of the gauge itself, only the cluster with a the woodgrain sitting on it. If no one else chimes in with a pic I will take another one and post it if you want me to.

[ShelbyDogg]

You can use a 7805 quite safely if you just put a 2 amp fuse on it; that's what I've done.  Also if you screw the 7805 "lug" to the back of the Rally dash pod in the same place where the stock regulator was it's nicely out of the way and it gives it a huge heat sink and a good ground (the 7805 grounds through the tab as well as the center leg).BTW, it cost me about $2

The problem with the 7805 is if shorts internally you will have a full 14.5 volts to your 3 gauges which could wipe all 3 out at the same time.  Your "fuse" will only work if the 7805 internally shorts to ground.  With the cost of rallye cluster gauges being so high, I'll spend the extra $48,

[ShelbyDogg]

I forget who did a group buy a while back on Rallye gauges but most of us who did it got the volt meter upgrade.

But looking at yours, the "voltmeter" looks like it is already too far to the right.  Is it powered up right now or just sitiing off?

[UKcuda]

The problem with the 7805 is if shorts internally you will have a full 14.5 volts to your 3 gauges which could wipe all 3 out at the same time.  Your "fuse" will only work if the 7805 internally shorts to ground.  With the cost of rallye cluster gauges being so high, I'll spend the extra $48,

My fuse is not fitted in the regulator supply, it's fitted in the 5v feed to the gauges - it's not perfect I know but if that side goes to 14 volts it ought to blow the fuse before anything gets fried.  A 1.5 amp fuse would be safer but I only had a 2 amp handy  .  The gauges are already pulling close to 1 amp even at 5v.

I'm not dissing the RT unit though, it can do other things that mine can't.