Quote:
Originally Posted by Ip485
I ike the sound of that system.
So I understand you have the shunt shifter on the positive supply into the house batteries and another shunter system (the same Blue Seas one) on the supply to the main distribution panel.
Both shunt shifters are connected to the one meter, with a rocker switch to select which shunt is being read?
I am guessing you could have two meters and do away with the switch?
Is this the ultimate system in terms of very accurately measuring the input and output of the house bank?
It makes me wonder why there isnt a "commercial" product configured in this way which uses the the information from both shunts as it seems to me it would be more accurate that the usual stuff on the market.
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Yes, you pretty much have the system down.
No reason you could not use two meters but I'm always replacing an existing analog meter and only have one hole. Easier to fit a small hole for the switch than a large hole for another meter.
As far as "ultimate system"... u
funny mon!
I like and use Blue Seas stuff on a daily basis. But I'll be the first to tell you that some times "their" supplier's retail
price is lower than Blue Sea's, Jobber.
Also remember that all of this
equipment is mass produced with production line tolerances. And Murphy will kill you with "accumulation of tolerances"!
Before you open any of the box's, you could have a 5% to 10% error laying on your bench.
This is not lab grade
equipment. Nor does it need to be.
But even if all of the
parts and pieces are dead on as far as spec's, the installer can (and most likely does) cause more error to be introduced.
I.E.
Are the connectors crimped with a "real" crimper?
Were they and the connection points burnished before assembly?
Any
sealant applied after wards?
Are the sense wires true twisted pair
sensor wire or just twisted "speaker" wire?
And what is the twist ratio?
What is the switch rating? And I don't mean
current rating.
Etc...etc..etc
As you can see, lots to get wrong.
Not your typical
DIY project. Heck, quite a few ABYC Electricians don't know the right questions to ask let alone able to do it properly.
I don't know about your last question.
I personally blame the inv/charger manufactures for going
cheap and installing the shunt on the neg side to save a few pennies.
But that is my own personal war.
I can think of dozens of reasons for a positive shunt and only a few for a neg one. And both of them are economics'.
Final thoughts:
I like this set up and that is the reason I recommend and have installed several of them.
Is it perfect...NO.
Is it better than some other system...Depends, If the other system delivers the requested info., in the desired format and method, then no it is not better.
If system "A" is lacking in some or all of the above... then yes, this system "MIGHT" be better.
The existing system is always going to be cheaper than my way.
As far as accuracy, we are dealing with
boats here. Not rocket ships.
We don't need 0.001% accuracy. Even with 10% accuracy, who cares if your meter shows 9~11A for a 10A load.
It's still more accurate info than most have.