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- Thread starter SLICKSALZ
- Start date
SLICKSALZ,
Hopefully the little battery will run your caller long enough for you. It will certainly save you some money.
You are correct, to measure the current draw you need to connect the voltmeter in series. I'll explain how to measure the current draw based upon the pictures you posted.
First, plug the red lead on the voltmeter into either the receptacle marked 10A or the receptacle marked 300 mA. I would start out using the 10A receptacle because if the caller is drawing more than 300 mA you will blow the fuse in your voltmeter. The 10A receptacle is un-fused, so make sure that you don't short the voltmeter leads across the battery terminals after you have done this it could fry your voltmeter. Then, disconnect the red (positive) wire from the tab in the caller's battery compartment. Next, connect the black lead from the voltmeter to the tab you disconnected the red wire from. Then, connect the red wire coming from the battery to the red lead on the voltmeter. Turn the selector switch on your voltmeter to the A with the solid and dashed lines above it (for measurimg DC amperage). Then, turn on your caller and read the amperage draw measured by your voltmeter. Let us know what your results are.
Hopefully the little battery will run your caller long enough for you. It will certainly save you some money.
You are correct, to measure the current draw you need to connect the voltmeter in series. I'll explain how to measure the current draw based upon the pictures you posted.
First, plug the red lead on the voltmeter into either the receptacle marked 10A or the receptacle marked 300 mA. I would start out using the 10A receptacle because if the caller is drawing more than 300 mA you will blow the fuse in your voltmeter. The 10A receptacle is un-fused, so make sure that you don't short the voltmeter leads across the battery terminals after you have done this it could fry your voltmeter. Then, disconnect the red (positive) wire from the tab in the caller's battery compartment. Next, connect the black lead from the voltmeter to the tab you disconnected the red wire from. Then, connect the red wire coming from the battery to the red lead on the voltmeter. Turn the selector switch on your voltmeter to the A with the solid and dashed lines above it (for measurimg DC amperage). Then, turn on your caller and read the amperage draw measured by your voltmeter. Let us know what your results are.
I don't want to steal Dwise' show, but yes.
Amps times Hours equals Amphours(A x H = AH).
Also, 1 AH equals 1000 mAH(milliamphour), a 2500 mAH battery has the same capacity as a battery rated at 2.5 AH.
Unfortunately, the battery in the picture has a smaller rating than the D cells. But on the other hand, it can be recharged.
Rich
Amps times Hours equals Amphours(A x H = AH).
Also, 1 AH equals 1000 mAH(milliamphour), a 2500 mAH battery has the same capacity as a battery rated at 2.5 AH.
Unfortunately, the battery in the picture has a smaller rating than the D cells. But on the other hand, it can be recharged.
Rich
RichS,
Don't worry about stealing anybody's show. Sharing information is what this forum is about. More information provided is better. Thanks for speaking up.
SLICKSALZ,
Sorry I didn't get back to you sooner. I've been swamped at work trying to fix some problems with a machine that we are building. RichS' answer is correct, I am just going to expand on it a bit. To calculate the run time at half volume you first need to determine the discharge rate of the battery (in C). This link explains it (http://www.batteryuniversity.com/partone-16a.htm). At half volume the battery discharge rate will be about .28C (current draw/battery capacity = .37/1.3=.2846). Then using Table 3 on the link above and assuming the battery will see intermittent use, the effective capacity of the battery will be about 70% of the stated capacity. So at half volume, the battery will run the caller for about 2.46 hours, or 2hr 27min (1.3Ah*70%/.37A=2.46hr) based on the current you measured. Since the current reading you took was the highest value you saw, I would imagine that you will get some more run time out of the battery, maybe 3-3.5hr or more.
I noticed the time you posted the values you measured was about 3 a.m. Were you really up at that time playing your caller at full volume?
Don't worry about stealing anybody's show. Sharing information is what this forum is about. More information provided is better. Thanks for speaking up.
SLICKSALZ,
Sorry I didn't get back to you sooner. I've been swamped at work trying to fix some problems with a machine that we are building. RichS' answer is correct, I am just going to expand on it a bit. To calculate the run time at half volume you first need to determine the discharge rate of the battery (in C). This link explains it (http://www.batteryuniversity.com/partone-16a.htm). At half volume the battery discharge rate will be about .28C (current draw/battery capacity = .37/1.3=.2846). Then using Table 3 on the link above and assuming the battery will see intermittent use, the effective capacity of the battery will be about 70% of the stated capacity. So at half volume, the battery will run the caller for about 2.46 hours, or 2hr 27min (1.3Ah*70%/.37A=2.46hr) based on the current you measured. Since the current reading you took was the highest value you saw, I would imagine that you will get some more run time out of the battery, maybe 3-3.5hr or more.
I noticed the time you posted the values you measured was about 3 a.m. Were you really up at that time playing your caller at full volume?