So I'm beside myself here. Bought this alternator to give myself some room under the hood of my roadster with gm style wiring harness. I did not wire the car bought it the way it is. So plugged it in and charged fine but ended up with a dead battery a few hours later when it was off. So I have battery to the main post, all the time hot (battery) to the top blade and switched to the bottom. When I unplug the top blade plug (hot) I don't have a drain. Obviously this alternator is different than what was it. What do I need to do to make this on work properly? Thanks
The internal diode has probably gone bad so it is back feeding and draining the battery. I went through 4 "new" alternators before I got one that worked last summer that did the exact same thing. You can get an alternator that works (easier said than done these days)or put the diode inline.
search the tractor forums (that's what the alternator is for, you know), maybe you'll find a wiring diagram similar to this and note that it is NOT wired like a GM alternator. You need to switch the sense wire, you can't leave it connected all the time. (this diagram may or may not work with your alternator)
That's a Kubota tractor alternator or lawn equipment alternator. Arrowhead AND0212 AND0212 Alternator Replaces Case 1002111670 1002114520 Grasshopper 1002114520 Gravely 1002114520 Kubota 1002111670 1002114520 - Jacks Small Engines It puts out either 30 or 40 amps depending on who sells it. Depending on where you buy them they can be pretty cheap though Amazon.com: New DB Electrical AND0212 Alternator Compatible With/Replacement For Case 460 1994-2001, 1825B 1997-1999, Gehl 3825 All, 3825SX All, Grasshopper 928D All, Gravely PM460 All 125564A1, 121960, 12179N: Automotive
On " squirrel's " diagram the switched live and the ignition light wires after the fuse box go the terminal on the ignition switch that has power when the ignition switch is turn on. The Denso alt is internally regulated.
The only wire which should be hot all the time is the bigger "batt" wire. The others are for excitation. Squirrel's post shows that.
Agreed. Actually the switched sensor terminal also seems to be a good idea with the 10si & 12si units. Some regulators seem to leak more than a few mAs thru this terminal even though it senses the voltage OK. Jack E/NJ
I had a similar problem on my 37 when i started using it,we had to rewire the car,it is still the 6 volt pos ground.I used a "tractor" regulator from a early ford 8N,it showed a charge at the guage but the battery kept going dead,it turns out the charge was going nowhere,changed the wiring a bit and all was well,that could be yor problem,juice is moving but not in the right place? Harvey
I always run the sense wire to a switched source on a 3 wire alt like the Denso or GM Si units. You can even share the same fuse as used for the dash idiot light. EDIT: Some guys just run the sense wire to the BATT terminal which I have seen drain the battery from internal leakage of the regulator.
Interesting. Have you ever measured the voltage drop in the circuit that feeds the sense wire, when you do it this way?
Fab50>>>EDIT: Some guys just run the sense wire to the BATT terminal which I have seen drain the battery from internal leakage of the regulator. >>> This sensor leakage is most important. Some SI regulators have been as much as 100mA. Over 2 AHr per day. Voltage drop varies depending on length of switch wire, fuse resistance, & switch resistance. Mine's less than 0.1volt the way Fab50's diagram goes measured at the batt terminal vs measured at sense connection near the idiot light engine off. Jack E/NJ
I haven't measured drop. However it all goes back to load on the circuit. I never use actual ignition switches for any load in any car I have built or wires for someone else. I relay everything either under the dash and/or under the hood. So generally speaking I'd use a relay just for the sense wire which would be very close to the battery. For what worth, my preference is Bosch alternators and I have had good results with their Bosch internal brush/regulator assembly and if there is some type of odd setup with excessive voltage drop I use an aftermarket regulator with a voltage adjustment. I shoot for 13.5 volts at the battery. I have found that to be best for battery longevity. Even though it is technically slightly undercharg.
Wonder what is wrong with my parts store rebuilt one wire GM alternator ! Still running after nine years and 20,000 + miles. Amp/charge indicator bypassed and use a volt meter. Did I do something wrong for this to still be working? Ben
No, nothing wrong. Some of them just end up with a draw through the sense wire. That is all we are discussing.
Interesting....GM built millions of cars with 10SI alternators, as far as I know none of them had the sense wire going to switched power, and they mostly all worked fine.
You dont need to switch the sense wire. The point was that it provides some insurance if the regulator has excessive leakage current which some of the rebuilt with Chinese parts do/will. The Bosch units I like dont have a sense wire and are effectively connecting it directly to the BATT terminal.
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