Rectifier in 1990 Jag? - Snowmobile Forum: Your #1 Snowmobile Forum

brideauj · 12-03-2006, 04:36 PM

Hi,

I was about to install a new battery in the Old Jag Delux we bought last month. It's a 1990 Jag AFS Delux. It has electric start, and seems to work when you "jump" it off another battery. I figured i should check the battery charging circuit before I risk wrecking a new battery. (have to wait while i charge it anyway). I found that the wires to the battery terminals have only 12VAC and not 12VDC. Where is the rectifier supposed to be? The AC parts diagrams don't mention a rectifier anywhere and the voltage regulator is the same part number on all the 1990 vintage sleds...

How is this system supposed to work?

Thanks,
Jeff

**smallengineguy** · 12-03-2006, 06:33 PM

When it's running you should have 13-14VDC to charge the battery, not AC.

brideauj · 12-03-2006, 07:56 PM

Thanks,

I had assumed it was supposed ot be DC, that's why i'm trying to find where the rectifier is supposed to be. I'm defintly getting AC at the battery terminals.

I had read in another post about the voltage regulator being replaced by a rectifier, so i looked to see if the parts diagrams from Arctic Cat had another part number for this piece. Unfortunatly, the 1990 sleds all display the same voltage regulator.

I noticed in a much later year a diode installed in the wire that runs from the ignition switch to the battery terminal but dont see it refrenced in the diagrams for th 1990 (or 91) vintage slegs.

I did find a universal voltage regulator for sleds with electric start at MFGSUPPLY.COM, but I'm pretty sure I can make one for a lot less money with Radioshack components...

brideauj · 12-05-2006, 09:19 AM

I've been unable to find how this circuit is supposed to be wired and unable to identify where the recitfier is supposed ot be. So, i decided to build a basic AC-DC power converter. The MOSFET i got from radioshack is only rated for 1amp but i think that should be enough to charge the battery. If not, i think i can solder another in parralell to the same circuit to double the capacity. The Rectifier is rated for 4amps. Attached is a picture of the completed assembly.

Now i need to disconnect the AC power from the battery terminals to isolate the AC and DC circuits. The starter solenoid should allow me to do this without rewiring the start switch circuit.

mmrosshere · 12-05-2006, 11:08 AM

Question How did it come about that it has Vac going to the battery? careful with your circut the bread board is nice but I would "pot" the whole unit for vibration dirt and water. Do you have a current limiter. ya dont want to cook the batt.

brideauj · 12-05-2006, 04:58 PM

Hi,

Well, I cant really be sure. I just bought the sled a month ago. It had the battery and the electric start installed at the time. The PO started the sled via the electric start using a jumper cable when we bought it to verify that it worked.

However, when I was about to install a new battery, i decided to check the voltage in the charge circuit while i waited for the new battery to equalize and charge. I set my meter for VDC and got only about 3 volts or so. Natrually i suspected AC and switched to VAC and read 12VAC with a little throttle.

Nobody seems to know how this sled is supposed to be wired. I have a manual for a 91 EXT (same chassis diffrent motor) and it doesnt reveal any secrets. The parts diagrams from AC dont talk about a rectifier for electric start either. So I am guessing at this point.

As for "potting", once i know it works i'll probably encase it in epoxy when i know for sure it works. For now, it's slobbered with hot glue on front and back for insulation.

For current limiting, i didnt make any provisions. This circuit is only capable of delivering 1amp. Once the battery is 'full' no current will flow anyway. An inline fuse will make sure there are no fires if i'm wrong. I've seen a few peak detecting circuit designs out there but i think thats overkill.

**smallengineguy** · 12-05-2006, 08:33 PM

You're going to cook that unit. After you first start it, the current charge to charge the battery at first will toast that unit.

mmrosshere · 12-05-2006, 09:26 PM

Quote:

Originally Posted by mmrosshere

Do you have a current limiter. ya dont want to cook the batt.

should have said battery circuit.

Did this have a batt and start on it OEM?

Dose the lighting circut connect to it? If so you could be drawing well more than that.

A small battery can draw much more than 1amp. As soon as you hit that starter it will try to draw through your new circut as well as the battery.

Over all I am a little leary on the setup. Let us know how it finally all works out.

mmrosshere · 12-05-2006, 09:29 PM

One more thought. If this is a stand alone (isolated) starter and batt. circuit perhaps charge the batt. at home and use it that way. I take it you still have a pull start rope.

brideauj · 12-06-2006, 03:52 PM

I spoke to an Electrical Engineer where I work. He generally agrees with you guys. Althogh the IC's are both internally thermal and current limited, he said you shouldnt design arround that feature for reliability.

He pointed out this simple add-on for the output current limiting:

An Add-On Current Limiter For Your Power Supply

An adjustment of the resistor values to bring the current limit up to 700mA would make the system a lot more robust. The second diagram with the LED would also add a troublshooting aid.

I'll have to add this onto my breadboard.

**smallengineguy** · 12-06-2006, 06:39 PM

Particular reason you don't just buy a regulator for it?

brideauj · 12-06-2006, 10:38 PM

Yes, no part number. I stated earlier that the parts diagrams dont list the rectifier for the electric start version. Only the standard voltage requlator, and that only limits the AC voltage from the magneto to 12VAC. To charge the battery, it needs ~13VDC.

I only have $12 in my little project...

**RJ Gleason** · 12-07-2006, 01:15 AM

In the Parts Unlimited Catalog.
Part numbers for all Jag and Jag Dlx.

Jag 75-76 01-154-26
Jag 340 77 01-154-24
Jag 3000 F/C 79 01-154-27
Jag 80-81 01-154-27
Jag/Dlx. 97-98 01-154-27
Jag 340/440 Dlx. 99 01-154-18
Jag 440 99 01-154-27

**smallengineguy** · 12-07-2006, 06:29 AM

Problem solved!

brideauj · 12-07-2006, 07:43 AM

I don't beleive this is a 12VDC regulator. I have a 1991 EXT besides my Jag. And this is the exact same regulator that is installed on that sled. This will not provide DC current.

kccats · 12-07-2006, 09:25 AM

Almost all cats use the same regulator. It's either a 2 wire or a 4 wire. I think you are just over thinking this whole thing. Put a $10 regulator on it and a battery and go with it. I myself have reworked the batery holder to use a lawn mower battery, there cheaper and have more crank.

brideauj · 12-07-2006, 09:47 AM

What is P/N for the $10 4 wire regultaor (since all my other sleds have 2 wire regulators, i assume the 4 wire has dc output) and where does it connect to the harnesses?

kccats · 12-07-2006, 09:56 AM

Sorry they're $13.75 in HPE. the only difference is the plug
the 4 wire has jumpers.

brideauj · 12-07-2006, 10:00 AM

who's HPE?

kccats · 12-07-2006, 10:05 AM

High Performance Engineering I'm a dealer for them.
Hi-Performance Engineering