Capacity test Problem

[Baserati]

So I charged an individual 200AH Eve cell to 3.595 volts to do cacity test. I used the cheap tester as tested by Will (I've used it before so I know it works)

Connected my battery and then attempted to run test. As soon as I tried to increase the amperage it dropped the voltage to below 2 .6v and the low voltage disconnect happened?

Is this a problem with my cell or with the test setup. What could i be doing wrong?

Let me know

Regards

Gavin

 

[snoobler]

Was 2.6V on the display or measured at the battery?

If on the display, you need very high quality connections between the battery and tester - thick wire and everything tight.

If on the cell, you got a turd.

 

[Baserati]

It was on display. Voltage at battery was about 3.2V

 

[Supervstech]

Post pictures of your wiring.

 

[Alphacarina]

Post pictures of your wiring.

Yup - There's your problem. If you're testing a 200AH cell, your wiring had better be VERY substantial - There's a good reason they use copper bars to link the cells together

Don

 

[Baserati]

Images below. Wire is 12AWG

 

[upnorthandpersonal]

Those look like thin and long wires and not the best of connections. At a minimum, shorten the wires and improve the connection at the tester with a lug or something, and make sure those crimps are sound.

 

[snoobler]

What does the battery read with a voltmeter compared to the tester display?

2' (both ways) of 12awg @ 3.2V and 10.6A should have a drop of 0.07V. The tester seems to have about a .1V drop based on other posts.

Check the quality of your crimps and make sure everything is good and snug.

 

[squowse]

I've noticed the testers drop voltage internally as well. The Ah reading won't be affected so just crack on.

 

[Supervstech]

I would put the wires to the tester wrapped around the screw.

 

[upnorthandpersonal]

The Ah reading won't be affected so just crack on.

As long as his low voltage disconnect on the tester keeps kicking in he won't be able to get a full capacity reading.

 

[Supervstech]

And change the amps to 10.0

 

[MikeL219]

If on the display, you need very high quality connections between the battery and tester - thick wire and everything tight.

I'm wondering... If I use the wires that came with the tester, does this change anything (other than the voltage reading on the tester)?

 

[snoobler]

I'm wondering... If I use the wires that came with the tester, does this change anything (other than the voltage reading on the tester)?

Wire gauge, length, volts, amps and connection quality are all factors here.

 

[Bob B]

I'm wondering... If I use the wires that came with the tester, does this change anything (other than the voltage reading on the tester)?

Those wires often have cheap alligator clips on them .... the poor connections can cause voltage drop and current loss .... so, it will take a lot longer to charge because you won't get as much current.

In that situation, some people will try to boost the voltage to get more current and that has a good chance of resulting in damaged cells.

Best to replace with 10 guage wire or so and ring terminals on each end.

 

[squowse]

As long as his low voltage disconnect on the tester keeps kicking in he won't be able to get a full capacity reading.

if it's like mine the low voltage is adjustable and only gives an alarm. it doesn't disconnect.
looks exactly the same as mine

 

[MikeL219]

if it's like mine the low voltage is adjustable and only gives an alarm. it doesn't disconnect.
looks exactly the same as mine

Interesting. I've read that many don't disconnect. The one that I got both notifies with the alarm and also disconnects. Got mine from Ali.

 

[squowse]

Those wires often have cheap alligator clips on them .... the poor connections can cause voltage drop and current loss .... so, it will take a lot longer to charge because you won't get as much current.

In that situation, some people will try to boost the voltage to get more current and that has a good chance of resulting in damaged cells.

Best to replace with 10 guage wire or so and ring terminals on each end.

the current won't drop. only the voltage on the display. because some voltage is dropped (and heat given off) from the wires. there is a 4 wire version which would be necessary for accurate voltages. it's not going to affect an Ah test though

 

[squowse]

Interesting. I've read that many don't disconnect. The one that I got both notifies with the alarm and also disconnects. Got mine from Ali.

newer model?

 

[Baserati]

Mine seems to disconnect at 2.6 v