What Nav is saying is there will be a 10% drop across the wire itself. This is
on top of the serious drop caused by the 100 Amp load on the house bank.

Of course, the engine will likely be running, so the load might be partially
offset, depending on how the alternator behaves at low rpm.

BTW, my system has the windlass and inverter (i.e. microwave) off the house
bank. A few times I've noticed the affect of the voltage drops, especially if
it goes below 12, but I've never been "spiked."



"DSK" wrote in message
...
Nav wrote:
The voltage drop will be at the motor, not the house battery end.

If you have a 10% voltage drop at the motor, there will be a noticable
drop at the battery terminals too.

Ever notice the way an ammeter swings when you turn the starter? Hint:
very few cars wire the ammeter sensor leads to the starter terminals.

DSK

Jeff Morris wrote:
What Nav is saying is there will be a 10% drop across the wire itself.

OK, I did not read that into what he wrote.

... This is
on top of the serious drop caused by the 100 Amp load on the house bank.

Sure. You know that and I know that, but...


Of course, the engine will likely be running, so the load might be partially
offset, depending on how the alternator behaves at low rpm.

That's true, and it makes it more complicated to wire a charger to a
dedicated windlass battery.



BTW, my system has the windlass and inverter (i.e. microwave) off the house
bank. A few times I've noticed the affect of the voltage drops, especially if
it goes below 12, but I've never been "spiked."

Our inverter gets very unhappy and makes loud unhappy beeping noises, at
a frequency that loosens your fillings, if the voltage drops below it's
comfort zone. If the drop is large, it will shut off. That's the only
fancy electronics we have at present, but I understand a lot of things
(like radios) show signs of distress with low voltage. bad for motors
too. Of course good electronics will have a low votlage shut-off.

We ae planning to install a new bigger house bank and a windlass in the
near future, I'm still studying how I want to do it.

Fresh Breezes- Doug King

Electronics are rarely damaged by low voltage. Of much greater concern
is the switching of inductive loads (like motors) which cause voltage
spikes. Good capacitive supression at the motor is a very good idea if
you value your electronics. In this regard, the resistance of the wire
to the motor can be considered a protective element.

Cheers

DSK wrote:
Jeff Morris wrote:

What Nav is saying is there will be a 10% drop across the wire itself.


OK, I did not read that into what he wrote.

... This is
on top of the serious drop caused by the 100 Amp load on the house bank.


Sure. You know that and I know that, but...


Of course, the engine will likely be running, so the load might be
partially
offset, depending on how the alternator behaves at low rpm.


That's true, and it makes it more complicated to wire a charger to a
dedicated windlass battery.



BTW, my system has the windlass and inverter (i.e. microwave) off the
house
bank. A few times I've noticed the affect of the voltage drops,
especially if
it goes below 12, but I've never been "spiked."


Our inverter gets very unhappy and makes loud unhappy beeping noises, at
a frequency that loosens your fillings, if the voltage drops below it's
comfort zone. If the drop is large, it will shut off. That's the only
fancy electronics we have at present, but I understand a lot of things
(like radios) show signs of distress with low voltage. bad for motors
too. Of course good electronics will have a low votlage shut-off.

We ae planning to install a new bigger house bank and a windlass in the
near future, I'm still studying how I want to do it.

Fresh Breezes- Doug King