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  #1  
Old 08-19-2019, 03:34 PM
Davea320 Davea320 is online now
 
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Default Electronic Ignition: Two alternators or two batteries

Looking for electrical power and backup for electronic ignition and I am asking for the pros and cons of a two battery system with one alternator or a two alternator system with one battery. Thoughts?

Dave
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Old 08-19-2019, 03:42 PM
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Which electronic ignition?
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Old 08-19-2019, 04:09 PM
Bavafa Bavafa is offline
 
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Based on my personal choice and safety assurance;
Two alternator, one main alternator that runs/supports the whole ship's power and one that is built-in to the EI and works a self generating EI.
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Old 08-19-2019, 04:11 PM
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N546RV N546RV is offline
 
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I'm planning on an SDS CPI2 ignition. My intent is to have two alternators, as well as the integrated backup battery solution offered with the CPI2. I'm leaning towards the two-alternator system because, to me, it offers fewer concerns in the case of a primary alternator failure. That is, rather than needing to worry about battery capacity, I can effectively fly indefinitely. If I have both alternators fail, then the backup battery will give me enough juice to get on the ground.
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Old 08-19-2019, 04:25 PM
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I wonder how many of us have actually used that second alternator that we haul around 100% of the time. I have. It allowed us to continue a week long trip without a care in the world until we got home. ONCE. We're all different, and I've gone back and forth, but I think that one use, saving our vacation enjoyment, was worth it to haul around the ballast for the last 12yrs. Hmm, or was it. A personal choice that the math can't always support.

I've also failed both at the same time in a distant foreign country across a big body of water... (which we won't talk about).
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Old 08-19-2019, 04:33 PM
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N941WR N941WR is offline
 
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Install two P-mags and you will not have to ask because you won't need either.
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Old 08-19-2019, 04:49 PM
Bevan Bevan is offline
 
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Quote:
Originally Posted by Davea320 View Post
Looking for electrical power and backup for electronic ignition and I am asking for the pros and cons of a two battery system with one alternator or a two alternator system with one battery. Thoughts?

Dave
It’s good to define what each is best suited for. You need at least one of each, but for a third supply of electrons, which form of supply should it be?

A) Batteries are a short term reservoir of electrical power with decreasing capacity over time, capable of high loads for a short period of time, and topped up by the alternator.

B) Alternators are a constant supply of electrical energy good for supplying some/all constant loads and recharging the battery (reservoir).

Choosing one or the other involves considering failure modes of components and of the electrical system in general.

I have 2 Pmags (they self generate electrical power) one lithium battery, one main alternator, one smaller standby alternator. That makes 4 alternators total and one battery, which is easily changed during routine maintenance. To each their own but these are my choices.

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Last edited by Bevan : 08-19-2019 at 04:51 PM.
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Old 08-19-2019, 04:55 PM
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Do those alternators work well with the battery disconnected?
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Old 08-19-2019, 05:45 PM
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One battery, one alternator, one electronic ignition, and one engine. A manís man.
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  #10  
Old 08-19-2019, 06:03 PM
Davea320 Davea320 is online now
 
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Thanks for all the quick replies. Leaning towards two alternators and one battery.

Dave
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