Nov-22-2015 07:42 AM
Nov-23-2015 10:32 AM
Nov-23-2015 10:15 AM
Nov-23-2015 09:58 AM
Nov-23-2015 09:49 AM
Nov-23-2015 09:19 AM
Nov-23-2015 09:13 AM
MrWizard wrote:I am trying to measure the house batteries. My shunt is connected between the frame and the neg post of my house batteries.
Are you trying to read chassis/engine batteries or house batteries
Any measuring device (the shunt)
Must go in between ALL CURRENT FLOW in and out of the batteries
Is the negative from ALL your charging systems connected to the chassis and not to the battery negative
Nov-23-2015 08:46 AM
Nov-23-2015 08:43 AM
BFL13 wrote:I did not know this. I charge my batteries inside of the MH off my pos and neg posts of the inverter under my dinette seat. I just plugged the MH into shore power the resting volts where 12.58v and the amps when from -.3 to 0. So with my old Magnatech converter it is charging at 13.06 volts and .3 amps. I will try your setup to the frame with the B&D charger.
You probably know, but when you use the portable charger, its neg clamp goes on the outer end of the shunt same as where your chassis ground wire is, not on the battery post end of the shunt. Or you could just put the neg clamp to the chassis (frame) somewhere and the neg path will go to the outer end.
Nov-23-2015 07:55 AM
Nov-23-2015 07:46 AM
CA Traveler wrote:The shunt is wired from chassis ground to the neg battery terminal as my diagram shows. Is that what you are asking?
Is the shunt wired to the battery post so that it reads all of the battery amps?
Nov-23-2015 07:02 AM
BFL13 wrote:Mine will read amps. With nothing on it reads -.4 amps. I assume that is the Co2 detector. Each light that I turn on adds about -.4 amps. I just question the amps from the alternator, I thought I would get more than 5 amps. I will recharge with my 40 amp B&D charger and see if it compares closely to it. My batteries have been disconnected with no charge since Oct 1st but are probably still better than 90% so they won't take many amps.
I figured out a way to get it to read amps both ways (if I can get it to read amps at all) using a small throw-type A-B switch I have in the spares box. A set of wires (opposite ways) from the shunt to the switch to A and B, then single set to the display? That way you don't have to swap wires on the shunt to see amps the other way, just throw the switch. (if it works)
I thought I had mine working when I had it jury rigged a few inches from the shunt. It was showing 33 amps, 14 amps, and 2 amps for different loads I tried.
Now at 15 ft away from the shunt using Trimetric cable wires it won't show amps at all. (you have to pick the right black wire of the two) Might need fatter wire than Trimetric uses?
Nov-23-2015 06:12 AM
Nov-23-2015 04:46 AM
Gjac wrote:
My meter reads from 0-200 volts and 0-200 amps. The shunt is 200 amps and 75 mv.
Nov-23-2015 03:52 AM
doughere wrote:Doug if I understand your post if I take a voltage reading between the two large nuts across the shunt(as shown in BFL's post)and trust my voltmeter I could adjust the amp pot to match that reading. Is that what you are saying?
Your shunt is a resistor. Your ammeter is actually a voltmeter reading the drop across your shunt. If you know the shunt's value (usually expressed as Amp to millivolt drop) you can read the voltage across the shunt and calculate the Amperage. My shunt is 50 Amp to 50 mV; so if the volt reading across the shunt is 35 mV, my meter should read 35 Amps. The most common shunts are designed for 50 or 100 mV at max current reading.
Doug
Nov-22-2015 06:43 PM
BFL13 wrote:That looks like the same one.
Must be the same one I got:
http://www.ebay.ca/itm/DC-0-300V-200A-Shunt-Voltage-Current-Panel-Meter-Digital-LED-Voltmeter-Ammete...
Note the display resolution is 1 amp. First you have to get the festering thing to show any amps at all! Landyacht warned about that. I get sporadic readings of amps, mostly says zero. Not sure what the matter is --connections ok.
Do I need to use fatter wire from display to shunt for the amps to read anything? The Tri was with a 500a shunt- this is a 200. I am using the same wire the Trimetric has at that distance (15 ft?) from the shunt. I got the voltage calibrated easily enough.