Cheap battery load tester?

[catmcaw]

I see a load tester at harbor freight is $20.00. Anybody ever use one on golf cart batteries?

[cgtech]

It will identify a totally screwed battery, but won't do anything to tell you just how good they are. Won't tell you "ok", "good", "great". It can't put a load on the batteries for long enough to get you great info.

[mgray70]

I bought the 500 amp one they have at Harbour Freight, and it works pretty good. I'll try to find a pic of it.

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[mgray70]

It doesn't have a 6 volt setting, but you can dial the amps up to what the battery is rated for and see what the voltage drop is. The 100 amp isn't enough load to really tell anything.

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[55BigBlock]

Why won't this work? Charge the pack completely. Measure the individual battery voltages. Attach the meter to each battery and drive the cart. Record the voltage under load for each battery. The batteries reading the lowest voltage while driving are the weakest.

[mgray70]

Originally Posted by 55BigBlock

Why won't this work? Charge the pack completely. Measure the individual battery voltages. Attach the meter to each battery and drive the cart. Record the voltage under load for each battery. The batteries reading the lowest voltage while driving are the weakest.

It works pretty good as well. I have done that many times. I have just found that tester to be a little easier, and I can dial the load to whatever and see where the breaking point is.

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[JohnnieB]

Originally Posted by 55BigBlock

Why won't this work? Charge the pack completely. Measure the individual battery voltages. Attach the meter to each battery and drive the cart. Record the voltage under load for each battery. The batteries reading the lowest voltage while driving are the weakest.

That's probably the best way to load test the batteries in your golf cart batteries if you don't have access to an automated load tester for quantitative results such as run time minutes to 1.75VPC.

I use a DVM with a Min/Max function and a short, steep hill close to my place.

[catmcaw]

Mgray70, when you talk about dial in and breaking point I see me melting a battery down (ha ha). As little as I know about electricity I better stick to the meter and hill thing.

[scottyb]

Originally Posted by catmcaw

Mgray70, when you talk about dial in and breaking point I see me melting a battery down (ha ha). As little as I know about electricity I better stick to the meter and hill thing.

I recommend the in golf cart test. The meter and hill thing is a very legitimate test. You won't get any false results. I see easy 300 amp draws in the monitor files I scan.
If you have a newer Alltrax controllers collect a monitor file while charging the hill, preferably with 2 friends on the cart and post it here... I looked at a file today where the fella was complaining about a new motor not reaching enough speed. Reviewed files & the 48v pack went from 51 to 37 v with a 300 amp draw. I think we found the problem

[mgray70]

Originally Posted by catmcaw

Mgray70, when you talk about dial in and breaking point I see me melting a battery down (ha ha). As little as I know about electricity I better stick to the meter and hill thing.

I really didn't mean that literally . You can turn the dial around 200 amps, and watch the volts and see how much they drop. I do it both ways, but this is a handy tool to have. Here is the one I have.

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