shunts

[thirteen]

I am putting together my solar system and to me they over fuse stuff with disconnects but I'll do it their way. But just what does a shunt do for your system. Just what is it supposed to do?
24v system in some parts of the instruction books they say you don't need one and can use the grounding post and in the other book it says to hook it up to a shunt.

[birdhouse]

shunts are many times used with a ammeter to gauge amount of current going in or out.  why does the one book say you should add one?  some more details would make this question make more sense!

adam

[thirteen]

my inverter has one in the pictures and it says to hook the negative (-) lead to it  the outback charge controler hooks direct from the battery but says you don't need one and can use the grounding post provided that is grounded to the case. ?? 

[ghurd]

my inverter
the instruction books

?

It would be easier to answer if we knew what you were talking about.
G-

[thirteen]

Gurd what does a DC shunt do? It is in line on the negative side going from the battery to the inverter. Do I really need one and what is it for? I'm not sure how to explain it differently 24v solar system, 24v battery system  Magnum Energy inverter, Outback FLEXmax 80  a Midnight MNDC250 breaker box with places for a shunt to be installed. On the same page it shows it without a shunt and just hooked the neg leads going to the inverter from the battery to this post. It is already mounted on the box and has a lead going to the grounding terminal which connects to everything else that is grounded. 

[bart]

    The Magnum ME-BMK batttery monitor kit for my MS-PAE invertor comes with a shunt for reading battery voltage, state of charge etc. Why it is required or what it does I'll leave to the experts.
   You probably don't need it if your not doing the above.

[thirteen]

Bart, I am just trying to get through this winter and correct and expand my system next year. I do not know what I will need for a total system until I spend the winter up there. I only get about 1 1/2 hrs of sunlight each day during the winter Dec- Jan. I got a good buy on some 8D 12v batteries $76.oo ea. I figure I will toast them over the next year before I get through messing around. But they were cheap enough. The store was redoing there floor and I told them for $150 bucks I'll get the batteries out of the way. They said $76 ea. so I said yes and accually talked them into letting me work 6 1/2 hours longer to pay for them. Good old barter system.  I was hauling junk to the dump for them.  Once I get all of the things I'll need then I will spend the money for for some good batteries and upgrade my system with voltage monitors and usage sensors. and a remote start for my generator as I get older.
It just confused me that one part says install and the next says you don't have to use one.  I just do not understand the usage of a shunt at this time. If it is for a warrenty then I'll get one and install it.

[hydrosun]

A shunt in that position is for an amp hour meter like the trimetric to keep track of all the amps flowing in and out of the battery bank. That will tell you when the battery is full and when it needs to be filled up. You can get a general idea without it by looking at the battery voltage. But the investment of $160 for a shunt and amphour meter is well worth it in keeping your battery bank healthy for longer. If you put in the shunt now you won't have to rewire when you add a meter later.
Chris

[thirteen]

hydrosun,
thank you. Next year a lot of this will change. I'll have different batteries and will try and start to install a micro hydro system and install more of a better solar system. I understand now and I will be adding a small seperate portable bank that can be used in the other cabin I'm building. So my system will be different, I think I will just wait until I get more information as to what I will need. And will add one next year.
I run out of good water for about 3 1/2 months during summer and during the winter I will run out of sun for abot 3 months but the water runs most of the time during the winter unless it gets down below -20- for a month then it will freeze. A trade off. It will be spendy but it will also pay for it's self in about 6-7 years.

[ChrisOlson]

It just confused me that one part says install and the next says you don't have to use one.  I just do not understand the usage of a shunt at this time. If it is for a warrenty then I'll get one and install it.

The shunt in those boxes is for like an Outback FlexNet DC or Magnum MS-BMK battery monitoring system.  It's like the fuel gauge in your car.  Put electricity into the batteries and it measures that, and it also measures how much goes out so it gives you a real-time reading on how much you got left in the tank.

You don't need it for warranty or anything.  You only need it if you intend to install a battery monitoring system.  Typically all the Magnum panels, Outback panels and MidNite Solar E-Panels designed to mount Xantrex/Outback/Magnum inverters come with the shunt in there.  On the MNDC250 it's optional - something you can put in there if you want it.
--
Chris