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Old Aug 11, 2011, 11:45 AM
Mark
Joined Aug 2011
17 Posts
Discussion
Multi4 and Futaba NiCds

I have had some difficulty trying to charge Futaba 4.8v RX and 9.6v TX NiCd packs with my Multi4 (using the 2-wire non-balanced pigtail and appropriate adapters). The charger correctly recognizes the chemistry, but the total voltage on either type of pack quickly surges to >12v, so I stop the charger. This happens regardless of the NiCd preset selected, and the polarity seems right.

Ideas anyone? I'm stumped.

Thanks,

Mark
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Old Aug 11, 2011, 11:59 AM
President, FMA, Inc.
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Originally Posted by MLang View Post
I have had some difficulty trying to charge Futaba 4.8v RX and 9.6v TX NiCd packs with my Multi4 (using the 2-wire non-balanced pigtail and appropriate adapters). The charger correctly recognizes the chemistry, but the total voltage on either type of pack quickly surges to >12v, so I stop the charger. This happens regardless of the NiCd preset selected, and the polarity seems right.

Ideas anyone? I'm stumped.

Thanks,

Mark
Hi:

For a 9.6v NiCd (8 cells), the end charge voltage can be 12.4v to 14v depending on the age and condition of the batteries. If you're seeing this on a 4 cell pack, something is wrong. But if you're seeing this on a 8 cell pack, it could just mean that the battery is nearly full charged when you connect it.

If you have a problem with the Multi4 which would cause excessively high output voltage condition, it's likely you would get a Safety Code. Have you seen any Safety Codes?

Tim Marks
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Old Aug 11, 2011, 12:11 PM
Mark
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Originally Posted by Tim Marks View Post
Hi:

For a 9.6v NiCd (8 cells), the end charge voltage can be 12.4v to 14v depending on the age and condition of the batteries. If you're seeing this on a 4 cell pack, something is wrong. But if you're seeing this on a 8 cell pack, it could just mean that the battery is nearly full charged when you connect it.

If you have a problem with the Multi4 which would cause excessively high output voltage condition, it's likely you would get a Safety Code. Have you seen any Safety Codes?

Tim Marks
Tim:

Thanks for the reply.

I am seeing the surge to > 12v on the 4 cell packs, as well. No error codes (at least none before I quickly stop the charger).

Mark
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Old Aug 11, 2011, 12:14 PM
Mark
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And I should add that th TX pack in question was nowhere near fully charged before the charging attempt using the Multi4.

Mark
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Old Aug 11, 2011, 01:20 PM
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Originally Posted by MLang View Post
And I should add that th TX pack in question was nowhere near fully charged before the charging attempt using the Multi4.

Mark
Hi:

This may be a dumb question, but, what is your power supply voltage, and are you sure you are not looking at the input supply voltage as opposed to the charging (output) voltage? The various screens show both on the Multi4.

I'd also recommend you communicate directly with Howard on the matter via email as it will be much more productive. You can send him screen captures (if you're running the CCS), or photos so he can assist you further in troubleshooting.

howard@fmadirect.com

Tim Marks
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Old Aug 11, 2011, 02:10 PM
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Quote:
Originally Posted by MLang View Post
I am seeing the surge to > 12v on the 4 cell packs, as well.
What is the charge current at this point? I ask because if I try to charge NiXX and there is a bad connection somewhere the voltage will go high like you describe but the current is zero. After some time the Multi4 will error out, but it takes a minute or two.
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Old Aug 11, 2011, 04:12 PM
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What is the charge current at this point? I ask because if I try to charge NiXX and there is a bad connection somewhere the voltage will go high like you describe but the current is zero. After some time the Multi4 will error out, but it takes a minute or two.
Hi Steve:

Great point!

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Old Aug 11, 2011, 05:54 PM
Mark
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Originally Posted by SteveM732 View Post
What is the charge current at this point? I ask because if I try to charge NiXX and there is a bad connection somewhere the voltage will go high like you describe but the current is zero. After some time the Multi4 will error out, but it takes a minute or two.
Good point. I'll have to try it again and check. My recollection is, however, that there was some charge current.

Mark
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Old Aug 11, 2011, 06:21 PM
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Good point. I'll have to try it again and check. My recollection is, however, that there was some charge current.

Mark
If you have a volt meter, you should check for pack voltage across the red/black pins of the connector where it plugs into the charger. Also, make sure your pack is wired between pin 1 and pin 5 of the connector (the outer pints), not pin 1 and pin 2. Some people make this mistake.

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Old Aug 11, 2011, 06:41 PM
Mark
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Originally Posted by Tim Marks View Post
Hi:

This may be a dumb question, but, what is your power supply voltage, and are you sure you are not looking at the input supply voltage as opposed to the charging (output) voltage? The various screens show both on the Multi4.


Tim Marks
Not a dumb question. The PS is 12v, but that's not what I'm looking at.

Mark
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Old Aug 11, 2011, 06:42 PM
Mark
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Originally Posted by Tim Marks View Post
If you have a volt meter, you should check for pack voltage across the red/black pins of the connector where it plugs into the charger. Also, make sure your pack is wired between pin 1 and pin 5 of the connector (the outer pints), not pin 1 and pin 2. Some people make this mistake.

Tim Marks
Thanks, I will check the pack voltage. No wiring mistake; I'm using pins 1 and 5.

Mark
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Old Aug 12, 2011, 03:06 PM
Mark
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I seemed to have solved my problem. Both packs were essentially "flat" when I initally tried to charge them with the Multi4. They haven't been used or cycled in a long time. After yesterday's difficulties, I put them on the old charger long enough to bring their charge state up a little bit. Then I put them back on the Multi4, which now seemed to "recognize" each of them and start a normal charge cycle.

It seems the very low starting voltage was the source of the problem, although I am not quite sure why.

Thanks for the input, guys.

Mark
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Old Aug 12, 2011, 03:39 PM
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Originally Posted by MLang View Post
I seemed to have solved my problem. Both packs were essentially "flat" when I initally tried to charge them with the Multi4. They haven't been used or cycled in a long time. After yesterday's difficulties, I put them on the old charger long enough to bring their charge state up a little bit. Then I put them back on the Multi4, which now seemed to "recognize" each of them and start a normal charge cycle.

It seems the very low starting voltage was the source of the problem, although I am not quite sure why.

Thanks for the input, guys.

Mark
Hi:

Glad to hear it sounds like your problem is resolved. The Multi4 should be able to handle a near-zero per-cell pack. I wonder if perhaps you just got worried when it showed +12v and didn't give it time to start putting some current into the packs? Otherwise, there may be a per-cell min that is actually a bit above zero volts per cell. But in this case, the unit would produce a Safety Code after a minute or so.

At any rate, hope everything is O.K. If you need further assistance, let us know.

Tim Marks
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Old Aug 12, 2011, 04:55 PM
Mark
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Originally Posted by Tim Marks View Post
Hi:

Glad to hear it sounds like your problem is resolved. The Multi4 should be able to handle a near-zero per-cell pack. I wonder if perhaps you just got worried when it showed +12v and didn't give it time to start putting some current into the packs? Otherwise, there may be a per-cell min that is actually a bit above zero volts per cell. But in this case, the unit would produce a Safety Code after a minute or so.

At any rate, hope everything is O.K. If you need further assistance, let us know.

Tim Marks
Could be. The "Total Voltage" for the 4.6v RX pack surged up to almost 9v, but quickly settled down to about 5.5v. The 9.6v TX pack jumped right up to the 12v range, and has very gradually crept up to 13.3v after 2 hours and 210 mah (at a pretty steady 100mah charge rate). Not quite sure what to make of that, but no error codes.

I am charging halfway between the standard 50 mah (C/10) rate and the spec'ed 150 mah "quick charge" rate.

Mark
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