I just got off the phone with Greg at RT Engineering, the company making the nice solid-state instrument cluster voltage regulators. It seems he has the same difficulty I do in my automotive lighting gig: neither of us has had the time to update and expand our websites to reflect our expanded and evolved activities.

Turns out Greg has devised several really ingenious (and much-needed) options for improving our cars' compatibility with upgraded charging systems. He can rework the ammeter itself for much lower internal resistance, thus greatly bolstering the ammeter's robustness — high current will still peg it, but won't hurt it. He can create "stealth" ammeter to voltmeter conversions by means of a custom "voltage sender" (like a fuel gauge sender or engine temp sender) driving a fuel/temp gauge with the original ammeter face on it (or, for extra money, a custom voltmeter face can be created in the style of the original ammeter). He can build a widget containing a new chip which, if I understand it correctly, will send up to 100A right through to the battery while providing a lower-current "drive" for the original ammeter. He can build another widget which alters the voltage regulation such that a modern alternator can be used for its strong low-RPM charging but kept from putting out current higher than the car's wiring can safely handle.

The active shunt idea (discussion here and here) is a good one, but every such build seems labour-intensive and cumbersome, and the resultant devices need cooling fans and are rather conspicuous (large) in the engine bay. We've long needed a compact, easy, drop-in solution, and I think we now stand on the edge of having several really good, easy, cost-effective options for same.

I'm inviting Greg to drop in on this thread to talk over the options and get a sense of what might be the market for such creations. This is exciting, eh?

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EXCELLENT!!!!

vm

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vm

hi greg, i will be reading your posts with great interest.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

Real Time Engineering does have several options today that we can offer for upgrading the stock mopar ammeter. First off, lets talk about improving the current ammeter in your car.

We can take any stock mopar ammeter and rebuild it to have 10 times lower resistance than stock. We charge $60 for this service. We take the back off the ammeter and we mechanically bond the ammeter pins to the ammeter copper. We have a milli-ohmeter that we use, and good stock ammeters typically measure .010 Ohms. Bad stock ammeters sometimes measure as high as .1 Ohms. After we get done reworking the ammeter, the resistance is .001 ohms (typical). You might think that .1 or .01 ohms is not much, but remember that ammeters have 40 Amps going through them, and they will get hot as they dissipate power. The power dissipated by the ammeter is I*I*R, so for .01 ohms, you will get 16 watts of heat. This is quite a lot of heat. Also with .01 ohms resistance you will get some voltage drop of V=IR, or in this case .01*40=.4 Volts. We made up a neat little chart showing the range of good versus bad ammeters, which you can see here:

http://rt-eng.com/mediawiki/images/4/4d ... ttages.pdf

That is all I have time for right now, but in this same thread later we can discuss some of the other options we have available now, such as the voltmeter conversion kit we offer.

The other ideas Dan mentioned are things I have thought about building, but so far haven't done so because I wasn't sure that there was demand for these products.

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Greg Garner
www.rt-eng.com
Home of Mopar dash related products

I've been beating around this bush for YEARS, starting with when I put Chrysler 100A alternators in my '66 and '73, and continuing with the current Nippondenso 130A (I think- its Dakota-type) in the '66.

I'm VERY careful every time I deep-discharge my battery for fear that the ammeter will roast itself during the recharge. So far I've been able to avoid damage by slow-idling the engine during the first few minutes of charging after a deep cycle, but it sure would be nice to know that I'm not going to burn up the ammeter either recharging my own dead battery or offering someone a jumpstart.

Consider me "interested!"

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Hi Greg,

I really could use some sort of ammeter fix for my Dart, as I'm finishing up one of the biggest projects that's kept me from working on my Dart and hope to get back to that one soon. I've got a 100 amp Denso alternator and had been meaning to build a shunt, but this is a great alternative.

Matt

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

I would definitely be interested in this.

When I had my 79 Ramcharger I got it with the "standard" 60-65A alternator; when I stripped/scrapped my 76 Charger SE, I made sure to save its 100A alternator and bracketry; I put it onto the truck; I always have a set of jumper cables with me, and am known to offer a jump to most anyone that I see with the hood up.
After I did the 60 (65?) amp-to 100 amp alt swap on the truck, it worked out beautiful--- until I gave that 1st jump start. Upon doing, as soon as I heard the electrical "whir" noise that told me that the alternator had "kicked in", I looked over to my truck, to see a huge smoke show coming from inside!!!!!
I bought a Stewart Warner ammeter rated for I believe either 100 or 120A (the "good stuff" was still available back in the late 80s) and put it in the same hole in the dash, where I now had a melted glob in the dash cluster. Volt meters were not that "common" yet, even in aftermarket gauges you see these days.
When I get the Volare done, I'd like to put a larger-than-65 Amp alt on there, and DON'T want the same result!!! (I know the "open cage" type Mopar alternator was made up to 78 A in the mid 80s; I may just go that route, so I don't have as big a search for bracketry, etc. most cars old enuf to be carbd, RWD and /6-V8 in my area 'yards were crushed years ago. and the 100A setup was not as common, so will be more of a PITA to find.

This is the amp gauge out of a 1965 AP6 Australian Valiant.




Does it look like it is able to be reworked as mentioned on RT Engineering's site?
As you can see it doesn't have a body,it mounts to the instrument cluster on the inside.

This is the limiter which mounts on the back of the cluster and connects to the 2 white wires in the photo,it also has a different mounting lug to the one on RT Engineering's site.

Does upgrading your limiter give you a better electrical circuit or does it just give you better instrument gauge function?
Also,if my amp gauge is not reworkable,would running a shunt like this be acceptable.
http://www.sw-performance.com/index.php ... s&p=407616
Would the 100 amp shunt be able to be used with anything up to 100 amps(ie,amp gauge,alternator)or would it have to be perfectly matched to suit my amp gauge?
Cheers in advance.
Greg
Ps:How would the shunt be wired into the wiring circuit ?

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