New Electrical System Questions

[Stu Jackson]

Originally Posted by exMaggieDrum

I've fired more than a few customers in my time.

Thanks, nice post.

So true. I recall another old adage: "Best project I never got!"

And I think that works both pre & post retirement time.

[mitiempo]

Originally Posted by GrahamHO

.....wire the anchor winch to the starter battery and run your engine.....

I, as well as Mainesail and Stu I am pretty sure, believe the alternator should be wired directly to the house bank as it is always the most in need.

In that case, what is the difference between using the house bank for the windlass with the engine running and using the start battery while running the engine - with the alt output going to the start battery?

[GrahamHO]

Originally Posted by mitiempo

I, as well as Mainesail and Stu I am pretty sure, believe the alternator should be wired directly to the house bank as it is always the most in need.

In that case, what is the difference between using the house bank for the windlass with the engine running and using the start battery while running the engine - with the alt output going to the start battery?

The big difference is voltage spikes created by the winch motor in the house circuit which will likely also have GPS, sailing instruments and radios in the same circuit. That is unless you have one of those $500 boxes protecting those accessories.

[transmitterdan]

Originally Posted by GrahamHO

The big difference is voltage spikes created by the winch motor in the house circuit which will likely also have GPS, sailing instruments and radios in the same circuit. That is unless you have one of those $500 boxes protecting those accessories.

It's pretty hard to have big voltage spikes at a big battery bank. So unless you wired your electronics at the windlass instead of at the battery then voltage spikes should not be a big problem.


Sent from my iPad using Tapatalk

[Terra Nova]

Originally Posted by mitiempo

I, as well as Mainesail and Stu I am pretty sure, believe the alternator should be wired directly to the house bank...

The alternator can be wired through a charge isolator. The start battery is quickly topped off before charge goes to the house bank.

[GrahamHO]

Originally Posted by Terra Nova

The alternator can be wired through a charge isolator. The start battery is quickly topped off before charge goes to the house bank.

Then the winch current runs through the charge isolator when the alternator is charging while winching, and it still doesn't avoid possible damage to electronics from voltage spikes.

[GrahamHO]

Originally Posted by transmitterdan

It's pretty hard to have big voltage spikes at a big battery bank. So unless you wired your electronics at the windlass instead of at the battery then voltage spikes should not be a big problem.


Sent from my iPad using Tapatalk

It is generally regarded as a fallacy that battery banks absorb voltage spikes. And of course the winch has to be wired with heavy cables to the battery, (naturally with a heavy circuit breaker near the battery) The electronics connection will usually be at a switchboard not far from battery, so they will effectively be wired together. You can overcome this possible problem by switching off the electronics before winching. Or you can buy an expensive isolation box to wire the electronics through. Or you can wire the winch more safely to the start battery.

Another way of looking at it; you wouldn't consider connecting your electronics to the start battery circuit, in case of spikes, so why would you have your winch on the electronics circuit?

[ramblinrod]

Originally Posted by GrahamHO

Then the winch current runs through the charge isolator when the alternator is charging while winching, and it still doesn't avoid possible damage to electronics from voltage spikes.

Again, this is incorrect.

It simply isn't so.

Wrong!

The battery bank isolator is connected between the alternator and batteries.

The maximum current it can pass, regardless of any load connected to the bank, is the full regulated output of the alternator. If you short circuit the leads of the battery, the isolator still can pass no more than the maximum output of the alternator. If the isolator cannot handle the full output of the alternator, you have the wrong isolator capacity.

[Terra Nova]

Originally Posted by GrahamHO

Then the winch current runs through the charge isolator when the alternator is charging while winching, and it still doesn't avoid possible damage to electronics from voltage spikes.

No, the isolator prevents that.

[transmitterdan]

A big battery bank is very effective at limiting voltage spikes. There are lots of boats that run starter, windlass and all electronics from one big bank. I have never heard a case where a starter or windlass caused a spike that broke something. I have heard of lots of cases where the voltage sag created by a starter or windlass caused the electronics to reset which is annoying but not fatal.


Sent from my iPad using Tapatalk

[ramblinrod]

Originally Posted by transmitterdan

A big battery bank is very effective at limiting voltage spikes. There are lots of boats that run starter, windlass and all electronics from one big bank. I have never heard a case where a starter or windlass caused a spike that broke something. I have heard of lots of cases where the voltage sag created by a starter or windlass caused the electronics to reset which is annoying but not fatal.


Sent from my iPad using Tapatalk

EXACTLY!

If DC motors on deep cycle battery banks caused voltage spikes that damaged electronics:

1. Every boat that started the engine with the battery switch in "BOTH" or egads, on a house bank with no dedicated starter battery at all, would have no electronics left.

2. Every electric fork lift would have no electronic speed control left.

3. Every electric golf cart (so originally equipped) would have no on-board GPS left.

4. Every boat with an electric halyard winch connected to the house bank, would have no electronics left.

5. Every boat with a bow thruster connected to the house bank, would have no electronics left.

6. Every boat with a stern thruster connected to the house bank, would have no electronics left.

The "voltage spike problem" running throughout this thread, is non-existent.

For the benefit of all others reading this thread, please don't accept the argument that a windlass should be connected to a starter battery due to "voltage spikes" or the "high current, short duration" loads as an "undisputed fact" or "valid justification". It simply isn't.

Electric windlasses, winches, thrusters, inverters, golf cart drive motors, electric forklift drive and lift motors, work just fine on deep cycle batteries, despite the presence of connected electronics, every second of every day in the real world.

Eliminate all the rhetoric and fiction, and what we have left is that connecting a windlass to a starter battery is bad practice. You risk killing the starter battery for absolutely no valid reason.

Ramblin' Rod
About Sheen Marine

[Frankly]

In over 10 years of operation on a single battery bank (6 GC batteries) I have never experienced any electronics failures, and Cbreeze is equipped with all the conveniences along with an electric windlass (75 amp PM DC motor) and a bow thruster (300+ amps series DC motor).

When I look at the schematic diagram of all the input isolation on my Raymarine X5 autopilot (they are significant, extensive, and this is a low $ AP) one might think about working this problem from the other end. If you are experiencing electronics failures when you haul in the anchor, maybe you should change the supplier of your electronics.

If I did have a separate starting battery it would be wired to the starter motor directly (via fuse and isolation/ emergency combination switch) so I would know it could be depended on. Everything else on the boat (including the alternator/ other charging sources/ distribution system) wired to the house bank. Automatic charging relay would replace the small amount of energy used in starting the engine. Any other configuration is sub optimal IMO.

________________________


"My Balmar is currently resting"

[exMaggieDrum]

Originally Posted by GrahamHO

It is generally regarded as a fallacy that battery banks absorb voltage spikes. A

Graham, I think you are in the minority on this statement. Could you please provide some evidence of this "general" knowledge? That would help all of us. Thanks.

[exMaggieDrum]

I found this interesting article using google-**. Looking for others.

Transients and Voltage Drops - Good and Bad Wiring Techniques for Electronics

The writer has only mediocre credentials: BSEE, MSEE, PE

[ramblinrod]

Originally Posted by exMaggieDrum

Graham, I think you are in the minority on this statement. Could you please provide some evidence of this "general" knowledge? That would help all of us. Thanks.

EXACTLY, reputable citation needed.

The equivalent circuit of a battery, is a series of RC networks. An RC network has the desirable qualities of being able to store an electrical charge. These are also sometimes referred to as "filters" for their ability to filter or smooth pulses in DC voltages.

In no way, shape, or form is it considered a fallacy by the knowledgable majority that batteries do not filter, and that Ohms Law does not pertain to DC motors.