Interesting. Especially because I chose OPTION 3 for Y.Rose.
- Make it very difficult to use starter battery to power the house systems.
- Make it easy to use house bank either alone or to combine (boost) the starter.
Mark, good point. It's not really a third option, because what you've described is operationally exactly the same as the the dual circuit concept but with two switches, and with exactly the same deficiencies I've edited in the quote from your post.
I agree, the skipper REALLY has to understand how to choose and then how to use his system.
Interesting. Especially because I chose OPTION 3 for Y.Rose.
- Make it very difficult to use starter battery to power the house systems.
- Make it easy to use house bank either alone or to combine (boost) the starter.
Mark, good point. It's not really a third option, because what you've described is operationally exactly the same as the the dual circuit concept but with two switches, ...
No, it is not the same as the Blue Seas Dual Circuit concept. In the BS-DC implementation, the operator only has two options:
1. concurrently activate both the starter and house circuits as isolated circuits, or
2. combine all circuits.
My arrangement has different options:
1. Turn on the house bank while leaving the starter bank turned off.
2. Turn on the starter bank while leaving the house bank turned off.
3. Turn on both but keep them isolated.
4. Turn on and cross connect both.
5. Leave the starter battery disconnected. Use house bank for just starting the engine.
6. Leave the starter battery disconnected. Use house bank for house load AND starting the engine.
... and with exactly the same deficiencies I've edited in the quote from your post.
The only deficiency I have is the ability to use just the starter battery alone to power the house loads. But this would only be an issue if there was a serious problem with the house battery bank. And if that was the case, the bad battery could be disconnected or the whole bank disconnected by removing the appropriate power fuse. Now if the house bank was merely drained, I don't have a problem. I just start the motor and the house bank would begin to recover as soon as the alternator was generating power. My alternator has been upgraded and is spec'ed for 110A max. I don't realistically think it would be able to sustain that, but at the same time, my house bank would probably only absorb 60A during initial bulk changing phase (20% x 300 AH), so I have spare amps to run the house loads even with drained and charging house batteries.
I agree, the skipper REALLY has to understand how to choose and then how to use his system.
Absolutely agree with this.
But then again, we DO seem to have philosophically different viewpoints of the purpose for the #2 battery bank and circuit. You describe it below as a "reserve bank". I think of it as the "starter battery".
Conceptually, I simply disagree with these electrical system "design criteria" and would always want to have the ability to power LIMITED LOADS from the reserve bank WITHOUT COMBINING the two banks, which can easily be done with the two systems described above. Maine Sail made the case and explained the downside of combining banks in his referenced link in my last post.
Why? Because it is the HOUSE bank that is much more likely to be drawn down than the reserve bank.
Granted. And the BS Dual Circuit switch is not the answer, for all the reasons Maine Sail describes, and you and I agree both with.
And there is a subtle point to my design that I think was overlooked earlier. My variation of OPTION 2 attempts to reduce the impact on the battery banks when human error occurs. For identification, lets call the original description you posted OPTION 2A, and call mine 2B.
In 2A, there is a greater chance for casual human error to accidentally draw down the "starter" battery. All it takes is someone accidentally setting the [main] 1-2-B switch to the starter/reserve bank (or the Both) position when turning on power to the house DC distribution panel. Then the only way to get sufficient power to the starting motor is to either combine the weak and strong banks (which has the very problems described in the previous threads), or to disconnect the weak bank's battery cable first and then move the selector switch to "B" to get the strong bank to the starter circuit.
In 2B, there is no chance for casual human error to draw down the starter battery when turning on house power. It takes a specific and less likely set of actions to make that mistake. Yes, it is possible, but far less likely to be left without the ability to start the motor and recharge the batteries.
Good to see you back and active.
Sometimes life throws just too much stuff in our path and we just have to focus our limited time and energy resources. I have finally managed to shovel some of that stuff to the side. It is good to be back and active here again.[/list]
