Autometer pyro

[m16ty]

Been looking to put a pyro in my deuce. I saw this one on ebay AUTOMETER Z-SERIES ELECTRIC PYROMETER GAUGE KIT 2654 : eBay Motors (item 260327149788 end time Jan-28-10 14:29:04 PST) and it seemed like a good price so I bought it.

The problem is that I didn't pay good enough attention to the description. It requries 12v to the gauge for it to work. Is there a way to get this thing to work short of getting a 24/12v converter? I thought about wiring the light and the gauge in series but I'm concerned that it will either destroy the gauge or it won't work right. I know you can wire two 12v bulbs in series and make them work but I'm thinking this gauge is a little more sensitive to voltage than a bulb is. Another possible problem with a series connection is that the gauge may draw more or less current depending on the EGT which would cause a voltage change.

Any ideas other than getting another pyro?

 

[Westech]

yes.. run a wire to the first battery and use a switch... I used the same one in my deuce. or you can use a relay and splice it in to the main power switch... use 12 to the gauge and 24 on the activation side.

 

[tm america]

if you had another item that was 12 volts and has the same draw you could wire them in series and run them off of 24 volts alot of people do that with lights

 

[m16ty]

Westech, I thought about that but was a little concerned about uneven battery draw. I guess the gauge doesn't draw enough to matter?

If I do go this route I'm thinking of using a relay that works off of the master switch. That way I won't forget and leave the pyro on and run down the front battery.



TM, I've thought about this but I wonder if the gauge has a constant draw? I've got a dimmer switch off of a Ford truck I've thought about. If it can handle 24v I can wire it in line and dial it in to the correct voltage if the gauge has a constant draw.

 

[pjpiche1]

I believe, If you put your master switch on the ground side on your battery cable, It should switch all of the power off to the truck both 12 and 24. Someone please correct me if I am wrong.

I use the Bully Dog mechanical pyro. I have been very happy with it's performance. It is a very well engineered unit. It even has a black bezel ,a black face with white lettering. It matches the stock gauges very well.

Philip

 

[tm america]

i wired my trailer lights for 12 volt like that and i killed two sets of batteries.in the end i cut the wire going to the relays .i still have my power outlet wired in like that but its not something i use all the time .i wouldnt run anything like that if it is gonna be used all the time as it will make the batteries charge unevenly .mine seemed to kill the front one from over charging it .you might get away with it if you rotate the battery locations every couple of weeks but even that is pushing it

 

[tm america]

i know running the wire of one battery will kill the front battery and changes in draw could put the gage at risk running it in series with something of equal draw. there really isnt a way to this safely without a power inverter or running a seperate 12 volt system i would tempt the series idea .but you could get a multimeter hook the gage up to a 12 volt battery and check to see if it is a steady draw or not as you would need to know the draw anyway .so you would know what you need to run it with in series

 

[pjpiche1]

Running things in series changes amperage not voltage.

 

[tm america]

the batteries on a deuce are in series this gives you 24 volts from 2 12 volt batteries.if they were wired paralel it would still be 12 volts .running things in series does lessen the amp draw to . for instance a 24 volt start uses half the amps as a 12volt starter to do the same job. christmas lights are wired in series if one goes out they all go out 2 12volt lights run in series =one 24 volt light .series is pos to neg to neg then pos to neg then pos to pos

 

[m16ty]

Running things in series changes amperage not voltage.

That is incorrect. You can run two 12v lights in series off of 24v. There will be 12v going to each light.

 

[frodobaggins]

Running such a low draw device off of one battery isn't going to hurt the batteries at all.

 

[m16ty]

I just read a thread where m35-tom installed a VDO electric pyro. He said the VDO has a constant draw so I'd say there's a pretty good chance the Autometer gauge is also. I'm going to do some checking and if everything seems ok I'm just going to install a resistor in the line.

I don't want to get overly complicated with the install. I would like to salvage this gauge (and my $130 I spent) but if I'm going to have to install a bunch of "banjo work" to get it to work I'll just scrap the whole project and go out and buy a non-electric gauge.

 

[tm america]

i didnt think running relays to run 12volt trailer light would kill my batteries but it did twice. first time is ruined brand new deka 6tl batteries second time it killed autozone dual purpose battteries . after i stopped using the 12volt tap off of the first battery i havent had a problem. i thought how is such a small load gonna mess up a battery .wouldnt they balance eachother out? not quit i found with a good alt it overcharges the first battery rather quickly .the 6tls didnt make it a year.the autozones made it about four months .i disconnected the 12volt draw and it has been over a year without problems .maybe others have better luck but this is my experience with doing that the resistor is probably the best idea worst case you kill the gage and the truck still starts and gets you home.trying the other way might ruin your batteries and then your alt to,

 

[badgmc56]

This is not a complicated install. Here is a picture of my boost gauge and pyro from Pro-Comp. I cut into my oringinal dash light circut and ran the lights in series so the lights would go on with the light switch. The gauges even come with a colored cover for the lights to match the red tint. First problem solved. Second , I knew I was going to want to add some items that were 12 volt so I ran a 10 gauge wire from the primary battery[ the one with the ground to the frame] to a fuse block under the dash. The fuse block has four 20 amp circuts to add accessorys to. I ran power from the fuse block to a lighted switch for my 12 volt pyro. There are a few different ways to do it but I like to be able to turn off my accessorys when I want to. The big deal here, at least the threads I have read about connecting into one battery is everyone seems to think that it will unevenly charge the battery and kill the other. I have not had this problem at all and I monitor the charging and load test my batterys often. The primary battery charges at 13.8 and the secondary at 27.5. I might add that these are inexpensive batterys that came with the truck a year ago and who knows how old they are. If your charging system is in good working order and all your connections are are tight with outside star washers on them anyone should be able to do this with no problems. Also a relay should never kill a battery unless it's installed wrong or faulty.

 

[tm america]

i'm sure the relays probably have water in them . but even a small draw on one of the batteries over a period of time will draw it down and when the alt trys to charge as it sees the voltage is down.it will charge the front battery more than the other .i suppose i could have just got a crappy battery twice two different brands .maybe you are the lucky one badgmcan it just so happened that your front battery does hold or take a charge as good as the other one.thus keeping them at the same voltage in the end .

 

[rchalmers3]

m16ty,

Have you contacted the gauge manufacturer? I know some manufacturers make the same gauges for 12 or 24v applications. Often it is a simple swapping of a controller unit and the illumination bulb and bingo, you have a 24v gauge.

Otherwise, I am a vote for the 24v relay installed to switch a 12v power tap off one battery. I am confidant the tap will not cause problems if you have strong batteries, a working charging system and if you wire the gauge to operate only during times when the alternator is working.

Rick

 

[m16ty]

Rick, I'm going to call them tomorrow and see what they say.

I'm pretty good with basic wiring but get confused a little when you start talking about amp draw, resistors, ohms, and such.
I've had a uncle pass away that was a TV repairman and he left me a bunch of fancy meters and testers. From the best I can tell ,using one of the meters, is that the gauge is drawing 75Ma (that's 3/4 of an amp isn't it?) when the gauge is hooked to a 13.8v CB power supply that I've got. I'm going to get on Google and try and learn a little more about all this and go from there .

I really wish I knew more about circuity so I'm learning.

 

[m16ty]

Been doing alot of researching on the net about this. Alot of it is still over my head but I'm learning.

Anybody ever heard of a linear IC regulator or a zener diode? Looks like either may work for small current 12v loads.

 

[jdr2710]

75mA is 0.075 Amps. Once upon a time I used to work electronics, before I decided that being zapped by 6,000 VDC wasn't fun anymore (I had a 'discussion' with the engineer who wrote the test procedure on that one!)

Putting two 12V bulbs in series is fine so long as they are the same size bulb, then they will each drop the same voltage. However for your gauge you'll need something that has the same current draw as the gauge.

At 0.075A at 12V you're looking at at 160 ohm resistor (volts = current * resistance, 12v = 0.075A * ?ohms) and you'll need a wattage of 0.9Watts (power = current * voltage, ?watts = 0.075 * 12). So you should be able to run down to radio shack and get yourself a 160 ohm 1 watt resistor fairly easily (if they don't have exactly 160 ohm just get a combination that adds up to that in series, e.g. 100 + 50 + 10).

As for the uneven battery draw I'd be surprised if 0.075A would cause much of an issue, but then again I've been surprised before!

 

[m16ty]

Talked to Autometer today and they said the current draw was "around" 200mA @ 12v. Don't know if my meter is wrong or I read it wrong to get 75mA @ 13.8v.