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Forum Index : Electronics : Blue Sea DC Power Distribution Panel
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isaiah Guru  Joined: 25/12/2009 Location: United StatesPosts: 303 |
I picked up a Blue Sea DC Power Distribution Panel Model PN 8081 ( www.bluesea.com. ) at a swap meet in the rain and when I got home I discovered it needed a shunt to make the amp meter work according to their instructions. I contacted the manufacture and they replied that the shunt unit would cost about $16.00 more than I paid for the panel.This is too much for my budget So Im wondering If we could build in a inductive pick up for the amp meter? Something like the 8 & 9 n ford tractors used. The panel has the volt meter and a Amp meter in it but the amp meter is not hooked to any thing.www.bluesea.com. Im planning on using this panel in conjunction with my charge controller. Any help will be appreciated. URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Isaiah You can make a shunt out of a piece of 1/4 inch threaded rod. feed the main current through the rod from one end to the other a piece about eight inches long should work ok feed from end to end termination for the main power and connect the ammeter to the feed in end and place several nuts on the rod to terminate the second lead from the meter a short distance away, start with the meter leads close together and move them slowly apart to calibrate the meter, use a multimeter in series on the 10 amp scale to calibrate and a load of as close to ten amps as you can. All the best Bob Foolin Around |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Bobs idea is good, I use it on my power board. 
( from this page ). Its easy to adjust. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Gizmo Thanks for that, as they say a picture is worth a thousand words, I was wondering if my gibberish could be interpreted and then you have a picture, Top Job. All the best Bob Foolin Around |
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| isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
Thank you both for the reply and picture.'  '
Will this shunt put a constant drain on the main power source? Bub 73 has a amp meter that he used back when he worked on automobiles that just clipped over the wire and would give a reading.Don't know just how it works . We dug it out and put a new glass on the dial part and have used it for some testing on the wind generators. Ill see if I can get him to post a picture of it here. This process will not drain on the power source.' URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Isaiah It only works when there is current flowing in the circuit as it is really a volt meter reading the slight voltage drop over the shunt resistor, all shunts cause a slight loss of power as they are a series resistor but not enough to worry about at the currents we use in our setups. As you would know all electron flow meets some resistance to flow by all parts of the active circuit. The inductive coupling you mention doesn't take power from the circuit just money from your pocket to buy the batteries to power it. All the best Bob Foolin Around |
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Bub73 Senior Member  Joined: 10/12/2009 Location: United StatesPosts: 116 |
Hi all Here are the pictures Isaiah was talking about. His panel and my old induction pickup meter about 50 years old and still very useful. Sorry Bob no battery's required, I don't know just how it works but it always has. Bob 
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| isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
Ok it seems we lost interest on this subject . Today I was parting out a old Sears & Roebuck lawn mower and noticed it had a amp meter that works like Bubs test meter. This mower I dont think was over 10 yrs old. I have the meter but is in rough shape due to being out side the last several yrs . There is just a piece of steel( Tin ) that is formed with two small slots to go over the lugs on the meter then it is formed like a piece of tubing to hold the wire. The wire just lays in this . If any one is interested Ill see if bub will put up some pictures of it. Looks like a easy way to hook up a amp gage?   URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Isaiah I have seen these type of ammeters over the years and the ones I have used where an indicator rather than a measuring device as the accuracy wasn't to good, the inductive principle they work on can be really good under controlled conditions but that's not the case usually,and the quality of the cheaper units is a bit suspect. They are more of an indication of current flow direction than a measurement of absolute units. ALL THE BEST Bob Foolin Around |
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SSW_squall Senior Member Joined: 20/03/2010 Location: AustraliaPosts: 111 |
I recently took apart the current meter in my old Mcormick international tractor, and i think it uses a compass needle like that one in the photo above... The DC magnetic field around the cable repels or attracts the permanent magnet that is the needle. AB Einstein: Everything should be made as simple as possible, but not one bit simpler |
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