Checking ampherage draw
11-18-2007, 09:24 PM
#11
Charter Member
Sony DVD head unit,
JL Audio 300/4 amp
JL Audio 250/1 amp
Cabin has both rope style lightsfor lack of better descriotion, and several flouracent (sp) tube lights.
Sharp 13" flatscreen TV
on board 10 amp battery charger, BUT thats 5A to each battery. Only 1 battery powers all the ACC. The other is just a starting battery.
After an hr or so of playing the stereo in the slip with the shorepower/charger on, the stereo/amps would shut down for lack of juice. Have even been watching a movie thru the headunit but with amps off, and the rope lights on and the DVD would quit playing do to low voltage. Even with the charger on. I'm thinking of going to a 30 amp charger: 20 amps to house battery, 10m amps to starting. battery. Just want to make sure it's big enough, hence the draw testing. I'm just not sure doing it right.
Yes, the probes were in either the 10A or lower AMP value plugs depending on range I was using.
Fuse is good. Checked it.
Thanks
JL Audio 300/4 amp
JL Audio 250/1 amp
Cabin has both rope style lightsfor lack of better descriotion, and several flouracent (sp) tube lights.
Sharp 13" flatscreen TV
on board 10 amp battery charger, BUT thats 5A to each battery. Only 1 battery powers all the ACC. The other is just a starting battery.
After an hr or so of playing the stereo in the slip with the shorepower/charger on, the stereo/amps would shut down for lack of juice. Have even been watching a movie thru the headunit but with amps off, and the rope lights on and the DVD would quit playing do to low voltage. Even with the charger on. I'm thinking of going to a 30 amp charger: 20 amps to house battery, 10m amps to starting. battery. Just want to make sure it's big enough, hence the draw testing. I'm just not sure doing it right.
Yes, the probes were in either the 10A or lower AMP value plugs depending on range I was using.
Fuse is good. Checked it.
Thanks
11-19-2007, 02:30 AM
#12
Thanks.
Yes, testing is just for while docked referencing only. Just a check to see what draw each item has for a baseline.
I did do the test light last summer. With my stereo amps off, both (independently) would make the test light flash. Never would go off. Was told because of the capacitors in the amps.
An dedicated deepcycle battery has been considered for house use, with 2 starting batteries for the motors. Just seems eccessive to have 2 batteries just for starting the motors, hence the reasoning of the dual purpose one.
Yes, testing is just for while docked referencing only. Just a check to see what draw each item has for a baseline.
I did do the test light last summer. With my stereo amps off, both (independently) would make the test light flash. Never would go off. Was told because of the capacitors in the amps.
An dedicated deepcycle battery has been considered for house use, with 2 starting batteries for the motors. Just seems eccessive to have 2 batteries just for starting the motors, hence the reasoning of the dual purpose one.
11-20-2007, 08:38 PM
#14
Truer words have never been spoken.
4 fuses later at $10 a pop, this trouble shooting chit is going to be costly.
I know that the 'A' is straight amp reading when the probe is plugged into the mA/A socket. Meaning 1 A, 3A, so on up to 10 A. I think....
The milli and micro range terms are foreign words!
But when checking for something like the memory draw on the radio, it shows something like 0023. Is that .0023, .23, or 2.3 amps? Don't recall the exact reading as after the 2nd fuse popped, US1 wasn't a happy camper and was just looking for something to do anything to make numbers pop up. Tried different combos of probes/dial settings. Course the wrong ones ended up in blown fuses.
2 probe choices, A and mA/uA
2 dial choices: mA/A and uA
Which ones do I use? and what will the readings be as?
What I did see is an inconsistancy betweeen the 2 stereo amps. One had a lot lower number than the other (0039 vs 2250) while both off. (remote turn on signal wire switched off) So I assume this means 1 has is drawing current even while off. Just don't know what the actual numbers mean.
I see I can get AC/DC clamp meters that go up to 1000A. I assume these have no fuses to be blown? Do these have straight forward readings such as .5 or 5 amps?
11-20-2007, 10:30 PM
#15
Registered
There are two main current "Ranges" on most digital multimeters.
You have, amps, and milli/micro amps. Basically to combine both ranges would make for a terribly inaccurate measurement, so they separate them. You have to know ahead of time what measurement to expect before you try and measure.
If are unsure of what to expect, then start on the high range and work down. So, measure Amps (anything over 1A, or 1000mA). Put the probe on common, and A plug. If the measurement is close to zero, or .00 something, switch to the milliamp mode. Then, move the probe to the mA/uA plug, and measure in milliamps. Is it still zero, then switch the dial to microamps. Once you get a reading you will know your in the range with a good accurate number.
Now, all that you said is going to draw way more than 10 amps, so you can not measure it with a current meter. There are two ways to measure after that. A shunt, or a current transformer (ct/clamp meter). The clamp meter goes around the wire transmitting power, and through inductance has a proportional output. You then use the clamp meter, or a DVM hooked up the the CT to calculate current draw.
A shunt can be place in series with the main lead, and it has a resistance, which causes a voltage drop. The voltage at the max current the shunt is rated for is usually 50mV. So a 100amp shunt will output 50mv between the terminals for 100amp draw, 25mv for 50amp draw.
Thats how its done.
You have, amps, and milli/micro amps. Basically to combine both ranges would make for a terribly inaccurate measurement, so they separate them. You have to know ahead of time what measurement to expect before you try and measure.
If are unsure of what to expect, then start on the high range and work down. So, measure Amps (anything over 1A, or 1000mA). Put the probe on common, and A plug. If the measurement is close to zero, or .00 something, switch to the milliamp mode. Then, move the probe to the mA/uA plug, and measure in milliamps. Is it still zero, then switch the dial to microamps. Once you get a reading you will know your in the range with a good accurate number.
Now, all that you said is going to draw way more than 10 amps, so you can not measure it with a current meter. There are two ways to measure after that. A shunt, or a current transformer (ct/clamp meter). The clamp meter goes around the wire transmitting power, and through inductance has a proportional output. You then use the clamp meter, or a DVM hooked up the the CT to calculate current draw.
A shunt can be place in series with the main lead, and it has a resistance, which causes a voltage drop. The voltage at the max current the shunt is rated for is usually 50mV. So a 100amp shunt will output 50mv between the terminals for 100amp draw, 25mv for 50amp draw.
Thats how its done.
11-20-2007, 11:06 PM
#18
Registered
yeah, kilo amperes, amperes, milliamperes, and microamperes.
A third deep cycle battery, with a good charger and isolator should solve the problem. We sell battery chargers, but not for marine enviroments.
A third deep cycle battery, with a good charger and isolator should solve the problem. We sell battery chargers, but not for marine enviroments.
