Originally Posted by RC Man

Don’t try to use your multi meter to measure internal resistance that will burn out your meter. That’s the biggest mistake that some beginners make.



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Thanks but I'm not excactly sure what you mean, and I read this after trying out my multi meter.

I bought a very cheap UNI-T UT33D

I set it to 200m first because I wasn't sure...
Then I put the red cable to the red on the battery and black to black and it showed around 04.5.
Red to black and black to red and I got around -05,0.

The polarity is correct on the batteries, but you need to set the meters voltage range to the 20V position. Let us know what reading you get at that setting.

If you read only 4.5 volts your batteries are way to low and that is why the charger will not charge them.

Youir charger recognizes your batteries cell count and voltage by the voltage it reads when you plug the battery into it. If it is to low it will not go into charge mode and you will get a message similar to what you got in the beginning. Basiclly, what is happening is your charger is set to charge a 3 cell battery, but it is only detecting a one cell battery, so it will not go into charge mode cause it thinks you have the wrong battery plugged in.

If your batteries are infact that low they may be ruined or at the very least they will have a short life.

If you shorted out the wires when you were replacing the connectors that could be the reason for the low voltage.

You can try manualy charging on your chargers Nicad settings, without plugging in the balance connector, to bring the batteries up to about 9 volts, and then switching to the Lipo Balance charge and see if the charger will complete the charge.

BE AWARE !! If you try this you need to constantly monitor the Nicad charge so the voltage just gets to about 9 volts.

There are some threads that may explain this in detail for your particular charger and if you are not that familiar with battery charging you should do some searching and read up on doing this.

Try this sticky.

http://www.rcgroups.com/forums/showthread.php?t=1074181

I 'm sure he meant 20V and not 20A. If you put it on 20A you will blow the fuse in your meter.
Set it on the 20 range in the V section. You have it now set on 2000 millivolts or 2V.

With the meter on the 200m or 200 millivolt range, a reading of 4.5 is 4.5mv, not volts. You have an open somewhere in your wiring to the battery.

Let us know what it reads with the meter in the 20V section.

hoppy, thanks for the correction. Sometimes type faster than I think ! Edited my respose.

I set it to 20V and tested on both batteries and it reads 0.01. I then tried it on my other lipos and they are around 12.55.

Check voltage at balance connector. On the top of the connector you will see slots and metal down in them. Carefully touch one probe to the first slot and the other to the last slot. You should see 11.XX volts. What do you get? If tips are too big to get into slot, tape a small wire to the probe tip and tape it on so that only a little bit of metal is showing on the end.

Be careful not to let the probes touch each other or kabam!!! short.

Okay I did what you said but it still reads 0.01 or 0.00.
If it makes a difference I also tried to touch one probe to the red wire on the MPX and the other to all the slots on the balance connector, and when I touch the yellow one it reads 3.80.

The balance connector has 4 wires. Measure (carefully) 1 & 2, 2 & 3, 3 & 4. What do you get. Make sure the probes are touching the metal inside the connector and don't let them touch each other.

With red touching red and black touching yellow I get 3.87.
Black touching black, red on white 3,86.

Put that in terms of 1, 2, 3, and 4. Just to be sure, that would be one probe in slot one and the other in slot 2. and so forth Just move the probes down one pin at a time.
1-2 ?V
2-3 ?V
3-4 ?V

Sounds like a bad solder joint or the new connectors you soldered on could be defective.

Originally Posted by kjur

With red touching red and black touching yellow I get 3.87.
Black touching black, red on white 3,86.

To test the main power leads, push a needle through the insulation of the red lead near the connector. Push another needle through the wire insulation on the black wire near the battery. It doesn't matter exactly, you just don't want them to accidently touch one another. Measure the voltage here. If it's 11.xx something, resolder your connectors. One or both of them is not connected.

Kjur,

What's happening?

(DELETED)
Good luck on this. The probes through the insulation is a must at this time.
Rick

Did you figure out what the problem was?