Cellpro Multi4 Announced - Page 37 - RC Groups
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May 25, 2017, 09:38 AM
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bob_nj's Avatar
Old thread.
Cool that I was the last post in 2011

Anxious to hear the answer.
Have a good weekend
Bob
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May 30, 2017, 04:03 AM
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ggcrandall1's Avatar
Quote:
Originally Posted by Ampbomber
Hi,
I have 2 Multi 4 chargers running V 1.67. I charge a lot of small 2S 120 mah packs during indoor flying. Can you tell me why both chargers will most times declare "cells no add up" msg requiring aseveral restarts? I monitor the cell voltages and they are always the esame within reason below 4.20v after discjharge but the msg comes up often on 1C, 2C or even 50 ma settings.
Thanks for the help.

George
The pins and sockets on the balance connectors are subject to minor corrosion. (This is true of all brands of charger and connectors.) When a little corrosion occurs the charger cannot see the true value of the individual cells and posts a Cells Do Not Add Up error. Cleaning all the contacts on your charger and balance connectors with an electronic contact cleaner should cure the problem. I use DeoxIT D5.
https://www.amazon.com/s/?ie=UTF8&ke...l_8f6nrkjtnu_e

Glen
May 30, 2017, 05:24 AM
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Ampbomber's Avatar
Glen,
Thanks, I'll give it a shot.
Bob,
Old thread but still being watched.
Last edited by Ampbomber; May 30, 2017 at 05:32 AM.
May 30, 2017, 08:13 AM
AMA 1042906
swimmer's Avatar
Quote:
Originally Posted by Ampbomber
Glen,
Thanks, I'll give it a shot.
Bob,
Old thread but still being watched.
Had this same problem also several years ago until I replaced the battery adapter after speaking with FMA. I mistakenly blamed the charger but since the new adapter have had no problems. Cleaning the pins and sockets on battery and adapter was not successful for me but you may experience different results.
Last edited by swimmer; May 30, 2017 at 08:22 AM.
May 30, 2017, 08:45 AM
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Quote:
Originally Posted by swimmer
Had this same problem also several years ago until I replaced the battery adapter after speaking with FMA. I mistakenly blamed the charger but since the new adapter have had no problems. Cleaning the pins and sockets on battery and adapter was not successful for me but you may experience different results.
What do you mean "battery" adapter?
May 30, 2017, 09:21 AM
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swimmer's Avatar
Quote:
Originally Posted by Ampbomber
What do you mean "battery" adapter?
Part number CP/GP/KO-US
May 30, 2017, 10:21 AM
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Ampbomber's Avatar
OK, thanks for info. I'll try all suggestions.
Aug 22, 2017, 12:10 PM
Webmaster, MMCNE
RCBoater's Avatar

Best way to charge a 2000mAH 4.8 NIMH?


I have a multi4. I want to charge my 2000 mAH receiver packs. What's the best program to use?

Program 18, the NIMH fastcharge with trickle, seems like the best, but this is a receiver pack, and not really meant for fast charging. So I'm charging it at C/10, which is 200 mA. My problem is that it times out after 4 hours if it doesn't detect a peak. That forces me to sometimes launch another session to continue charging.

What is the best way to charge one of these large Rx NIMH batteries?
Aug 23, 2017, 03:15 AM
BEC
BEC
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You'll never even get a peak to speak of at C/10. Without knowing anything else about the particular cells you are using, if it were me, I'd try maybe 1C.
Aug 23, 2017, 09:42 AM
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RCBoater's Avatar
Guess I should have been more specific.. I thought all those 2000mAH Rx packs were basically the same....

I have a couple of Hydrimax ultra 4.8V 2000 mAh NiMH batteries. Manufacturer states a 200mA 11 hour charge rate is recommended.

I charged one over the last two nights-- First session, the charger timed out after 4 hours. Second session, hit the 4 hour timeout again. Third session, it charged for about 90 minutes, and then alerted and dropped into trickle charge.

I would think a smart charger could handle this......?? (So I'm thinking I'm doing something wrong.)
Aug 23, 2017, 10:10 PM
BEC
BEC
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As I said, charging NiMH that slowly won't yield a voltage peak for the charger to detect. The Cellpro chargers are intended for fast charging and not for the kind of charging that is clearly recommended for your Hydrimax cells. Much more detail here: http://batteryuniversity.com/learn/a..._metal_hydride

I'm actually kind of surprised that the Cellpro charger detected a peak at all on your third attempt.

Given the added info you've supplied, I think you're looking for a simple charger that can just put out 200 mA and then depends on you to take the pack off of the charger after the recommended interval. I have an old Ace Varicharger (coming up on 40 years old) that I could dial a current on - so if I had such a receiver pack I'd probably be using the Ace for it. Failing that, an old radio system charger's receiver side would likely put out about 50 mA and charge your Hydrimaxes in about two days each. Not a great solution either.

Failing THAT....I'd choose C/3, so that the Cellpro can do it reliably in one cycle and take the long term life reduction of the pack as collateral damage. Actually if I really needed 2AH receiver capacity these days I'd get a 2s 2000 mAh LiPoly pack, hook that to an external BEC (does Castle Creations still make something like that?) and then use a 1C-2C LiPoly charge program on the Cellpro to recharge it when needed. The self-discharge of LiPoly is so much less than NiMH that it could sit around unused for months and still have nearly a full charge.
Sep 18, 2017, 06:29 PM
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RCBoater's Avatar
There's nothing that I see in the specs or the manual that say the charger doesn't support this-- the specs say voltage detection is accurate to +- 1 mV. Nowhere is there a disclaimer that it is "not really intended to charge your radio system batteries".

I use these batteries in my small RC boats-- so I'm not that keen on switching to LiPos. They are used as the drive battery in small plastic model conversions-- where you use a 2 channel radio, the battery, and a disassembled servo as the combined motor/ESC. In some of those boats, I charge the battery inside the model, as it isn't easily removed--- something I wouldn't want to do with a LiPO.

Fortunately, it does seem to reliably detect a peak-- If the battery was only slightly used, where it only needs a couple of hours on the charger, the M4 will detect the peak and drop into trickle before it times out. Or if it was half used, and I expect it to need 5-6 hours to fully charge, it will time out after 4, then finish off the during the second 4 hour session.
Last edited by RCBoater; Sep 18, 2017 at 08:49 PM.
Sep 21, 2017, 01:30 AM
BEC
BEC
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They are fine, precise chargers....so if it's working for you, that's great. I'm a little surprised....but it's a happy surprise.


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