Trombetta relay Questions

Multi-step coil circuits need hysteresis to prevent chattering which will kill a relay faster than a bullet.

Some systems reduce the control voltage to the relay to keep it running cooler. When you see the higher voltage using the emergency start button it is simply bypassing that circuit and applying full battery voltage. There is not harm in doing this. My relay is run by full battery voltage when one bank or the other is getting charged and the relay gets hot to the touch. This is normal for my setup.

Assuming the Trombetta is working properly, you need a complete circuit to charge through the Trombetta. Power needs to come through from the charging battery to the Trombetta, so connect up a battery charging cable from the charging battery negative to near the Trombetta, then measure the positive and negative at the trombetta. Should be the same as at the charging battery.

Then using the same negative jumper cable, measure from the positive house battery to the negative from the charging battery. I am thinking you might find good voltage there. If you do find good voltage there, then connect that negative from the charging battery to the negative on the house battery, and see what the voltage across the house battery is now. If you find that is is the same as the charging battery, you have just proved that the negative terminal on one of the batteries is not connected to the negative terminal on the other.

Many many times people think power is not getting there, but it is, just not getting back. Hope this helps.