MicroSquirt.com read only forum (Jan.15,2018)

My setup is killing batteries, the original vehicle did not have a battery and the oem equipment ran of AC power. My chassis is AC ground, so I've setup my DC power to be a floating system. My setup is as follows: I've got the 12V DC power from the regulator wired straight to the battery. From the positive lead on the battery the +12V is wired to the MS controller via the switch etc. The battery is grounding the sensors and has a wire running from the Negative lead to the engine.

The setup runs and start fine when the battery is fully charged. But my problem is that the battery is not keeping it's charge. My regulator is a AC/DC 3 wire type. With the three wires being AC, DC, and ground. Should I connect the regulator ground to the battery? Or do I need to add a separate battery charging circuit?

You've definitely got a problem there, as you need two wires to the charge battery, one to the positive and one to the negative/earth/ground. I'd say the battery ground has to be connected one way or another to the ground of the AC regulator, whether it's through the chassis or a direct wire is upto you.

A quick test is put a voltmeter across the battery before and after you apply the ground from the regulator, if the battery voltage climbs upwards then it needs to be, but watch it doesn't go too high.

If this is a shunt regulator that is NOT connected to the battery ground, you may have killed it already. Disconnecting one of the DC wires means the regulator sensing circuit gets confused and turns the SCRs / MosFETs on full-blast, leading to over amping in various components. I saw a pic earlier today of a regulator that had an AC pin completely melted away.

Is this a single-phase (2 AC wires) or three-phase alternator (3 AC wires) ? Most bikes these days are running 3-phase; the permanent-magnet types use 5- or 6-pin regulators - 3 AC input, one DC out, one DC ground.

It's a Polaris snowmobile OEM part, and its description is "REGULATOR AC/DC 14.3V". My regulator is nominal 12V up to a maximum of 14.3V DC. So I went into the manual to find out info on the alternator. The alternator is producing 6 pulses per revolution. Each pulse is a complete sine wave. From the Alternator there is only 1 wire to the regulator, and this is AC voltage. So there is 1 AC in and 1 AC out on the regulator. So to recap I'm not sure if it's 1 or 3 phase.

What is considered too high? My understanding is that most battery chargers, charge the battery to 14.4V then maintain at 13.2V.

Thanks for the help.

Shunt regulators are pretty simple critters. They have a setpoint based on the components in the controller circuit with variations between identical units due to component tolerances; if the controller detects a voltage across the battery higher than the setpoint, it dumps excess voltage to ground. Once it reaches steady-state, it's almost like a PWM effect. That unfortunately is the problem - if either the +ve or -ve wire is disconnected, the controller thinks there's zero voltage; the rectifier is left conducting flat-out, and can overheat rather quickly.

Most bike / sled VRRs don't have multiple setpoints (charge / maintain / etc).

From what I've seen, ignitors and black boxes start frying around 15v.

Thanks for the help, this gives me a point to work from. I will report back probably mid next week on progress.

So i got a new battery and redid the wiring. Everything seems in order. voltage on idle is right around 12V and reving the engine it doesnt go much over 13V. TIME FOR TUNING!!!!!!!