Battery Load Test
#1
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I have duel batteries with 3 on/off switches. They are a port/stbd and parallel switch.
When I load test both batteries, the batteries test good... Question?? If I disconnect the 2/0 battery at the Port on/off switch, can I load test the battery through the cable? I wish to check the cable to see if it's good. Can I load test through the switch?
When I load test both batteries, the batteries test good... Question?? If I disconnect the 2/0 battery at the Port on/off switch, can I load test the battery through the cable? I wish to check the cable to see if it's good. Can I load test through the switch?
#2
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If you are wanting to test the cable to see if it's good, why not just test the cable? Disconnect both ends and check resistance with an ohmmeter.
I have duel batteries with 3 on/off switches. They are a port/stbd and parallel switch.
When I load test both batteries, the batteries test good... Question?? If I disconnect the 2/0 battery at the Port on/off switch, can I load test the battery through the cable? I wish to check the cable to see if it's good. Can I load test through the switch?
When I load test both batteries, the batteries test good... Question?? If I disconnect the 2/0 battery at the Port on/off switch, can I load test the battery through the cable? I wish to check the cable to see if it's good. Can I load test through the switch?
#3
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That's the first thing I did. It measured good. So I want to put 1/2 the CCA through the wire. It should measure good with a Carbon Pile Load Tester if the wire is good, YES? NO?
#4
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Load tester removes surface charge from the battery. Same as leaving a car's headlight on for a certain amt of time (I like 10 minutes) and checking battery voltage after.
don't get what load testing thru cables would do,but I don't get much.
don't get what load testing thru cables would do,but I don't get much.
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What problem are you diagnoising?
#6
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I do it every day , Gives you and indication of complete circuit condition.
You would be surprised how much resistance you will find doing that.
After your load test , feel the cables and connections for heat , you found your resistance.
You wont believe how many Junk battery switches I find that will only take a 100 amp draw.
Testing individual components first is fine , but I like to test the whole circuit first , then go back and find the Culprit , usually more than one problem!
Ive done it that way on everthing from Airplanes , autos , constr equip , farm equip , you name it.
You would be surprised how much resistance you will find doing that.
After your load test , feel the cables and connections for heat , you found your resistance.
You wont believe how many Junk battery switches I find that will only take a 100 amp draw.
Testing individual components first is fine , but I like to test the whole circuit first , then go back and find the Culprit , usually more than one problem!
Ive done it that way on everthing from Airplanes , autos , constr equip , farm equip , you name it.
Last edited by dunnitagain; 04-22-2019 at 12:18 PM. Reason: Forgot to add something
#7
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When I load test the Batteries, they test sat. If I load test through the cable, it fails the test. I have taken a resistance reading of the cable and that checks good.
Now with 4 foot of 2/0 cable and the battery showing 12.5 volts the results should be, IMO, pulling 475 amps should be when load testing,
Voltage drop: 0.30
Voltage drop percentage: 2.37%
Voltage at the end: 12.2
So I'm thinking that there is a problem the ohm test is not picking up and I have a cable problem...
Now with 4 foot of 2/0 cable and the battery showing 12.5 volts the results should be, IMO, pulling 475 amps should be when load testing,
Voltage drop: 0.30
Voltage drop percentage: 2.37%
Voltage at the end: 12.2
So I'm thinking that there is a problem the ohm test is not picking up and I have a cable problem...
#8
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Load testing a battery does much more than that.....
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A large cable wont show much resistance on an Ohm Meter even if its bad .
Now start eliminating components and cables , you could have corrosion in the cables were the lugs are crimped .
Ive had cables rotted apart inside and look perfect , You can also do the stretch test! put one end of the cable in
a vice , put a screwdriver through the lug on the free end , and pull like hell. If the cable is bad it will stretch at the point of failure , or the
ends will come off. Any good crimp on a 2/0 cable should hold more than one man can pull. Sounds funny but it works.
Best bet is replace all the bad circuit cables and components that test bad , Make Sure your Grounds
are clean and Tight. Ive also seen the lead on battery post oxidize so bad that they have no connection.
you have to use a wire brush to clean all that **** .
Now start eliminating components and cables , you could have corrosion in the cables were the lugs are crimped .
Ive had cables rotted apart inside and look perfect , You can also do the stretch test! put one end of the cable in
a vice , put a screwdriver through the lug on the free end , and pull like hell. If the cable is bad it will stretch at the point of failure , or the
ends will come off. Any good crimp on a 2/0 cable should hold more than one man can pull. Sounds funny but it works.
Best bet is replace all the bad circuit cables and components that test bad , Make Sure your Grounds
are clean and Tight. Ive also seen the lead on battery post oxidize so bad that they have no connection.
you have to use a wire brush to clean all that **** .
#10
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Thanks for your response. All terminals are clean. I might have to remove cables, but seem tight