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HelicopterMain Discussion › battery question nicad -nimh
03-17-2009 11:48 PM  8 years agoPost 1
datidun

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N Ireland

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was wondering i know nicad batteries have a memory, but do nimh have one as well ,thanx.

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03-17-2009 11:53 PM  8 years agoPost 2
abc123

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va, usa

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Yes, they still do but not as much,however you should stick with lipos if you can.

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03-18-2009 04:19 AM  8 years agoPost 3
Aaron29

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USA

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http://www.hangtimes.com/nobsbatteries.html

http://rcbatteryclinic.com/

http://www.batteryuniversity.com/

Memory is a myth. The effects called memory are crystal formation and are completely reversable if you cycle once a month. Do some reading and you'll see that people who know, call it a myth. But don't take my word for it, or any forum "expert." I've included the links so you can read.

Cycle your battery once a month to keep crystalline formation and it'll be fine for a long time. Leaving it to "trickle charge" is what can cause NiCd problems.

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03-18-2009 05:16 AM  8 years agoPost 4
Dood

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Wescanson

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I would use NiMH before I ever used a NiCD.
Because:
  • Because NiMH requires far less, time consuming battery maintenance
  • Because a NiMH has no memory effect and NiCD does
  • Because a NiMH can be topped off at any time after every couple of flights without the need to be cycled
  • Because NiMH has more than twice the capacity of standard NiCd, meaning a higher Amp hour/Weight ratio
  • Because a NiMH of a given capacity weighs roughly half of what a NiCD pack of the same capacity weighs
  • Because the service life of a NiMH battery is 33% greater than a NiCD battery (1000 cycles vs 750 cycles)
NiMH is just a better technology. It should be a no-brainer decision.

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03-18-2009 09:32 AM  8 years agoPost 5
Hamo

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Ireland

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Dood, I think you are forgetting a few advantages NiCds have over NiMh.

1. NiCds are capable of delivering higher currents, important for digital servos which need higher currents. This is why power tools such as cordless drills use Nicds

2. NiCds have a lower self discharge rate

Hamo

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03-18-2009 09:43 AM  8 years agoPost 6
Saint728

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Honolulu, Hawaii

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NiCd do not deliver higher currents over NiMh cells. If that were true all RC car racers would be using NiCd cells. All the newer NiMh cells deliver way more current then any NiCd cell ever did. Don't forget the highest NiCd cell has a lot lower capacity then the NiMh cells.

Take Care,
Cheers, Patrick

Check the hotties in my Gallery
http://rc.runryder.com/helicopter/gallery/9019/?all=photo

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03-18-2009 12:34 PM  8 years agoPost 7
BarracudaHockey

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Jacksonville FL

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Older NiMH cells had higher internal resistance and dropped voltage under load, no big deal now.

Dood, call it crystal formation or whatever you want, if you charge and partially discharge NiCad batteries you will suffer capacity loss till you cycle them.

Andy
AMA 77227
http://www.jaxrc.com

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03-18-2009 12:38 PM  8 years agoPost 8
Leif

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USA

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call it crystal formation or whatever you want, if you charge and partially discharge NiCad batteries you will suffer capacity loss till you cycle them.
Not really. That depends on HOW you charge and discharge them. I use NiCD packs in my helis and recharge quite often. However, the discharge and charge rates are quite high (between 0.5C and 1C). There are no ill effects from doing this and I rarely cycle them all the way.

NiCD cells do NOT like to be trickle-charged or discharged at very low currents. THIS is what causes the crystalline formation, not partial discharging.

Leif

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03-18-2009 12:55 PM  8 years agoPost 9
datidun

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N Ireland

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ok after all nimh have no memory effect ,good to know

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03-18-2009 01:01 PM  8 years agoPost 10
datidun

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N Ireland

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im running 2700 mah nimh 4.8 v battery usually get about 5 flights i check the battery after every flight ,i have my last flight flight reading 5 volts ,then i try to drop the voltage below 4.8 v ,sometimes i discharge it a bit below 4.8 v at about 0.2 amp ,i do this before i give a full recharge.does this seem right

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03-18-2009 01:24 PM  8 years agoPost 11
Mutt

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M ca usa

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All I run are nicads and ninh for y rx batterys. Never a issue with them never a "memory" issue with them. Years ago we had some issues with the older nicads but the technology has vastly improved over the years. Nothing wrong with either battery. It is a cholice like fords or chevys buy what you like. As far as lipos some of us still refuse to add extra eletronic garbage to our helis that can and could fail i.e.l regulators etc heck search RR here and look at the failure rate of some of these regulators. I am a firm believer in the KISS program Keep It Simple Stupid and for me it has worked great for over 40 years of flying.

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03-18-2009 02:08 PM  8 years agoPost 12
BJames111

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San Diego,​California

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I would use NiMH before I ever used a NiCD.
Because:

Because NiMH requires far less, time consuming battery maintenance

Because a NiMH has no memory effect and NiCD does

Because a NiMH can be topped off at any time after every couple of flights without the need to be cycled

Because NiMH has more than twice the capacity of standard NiCd, meaning a higher Amp hour/Weight ratio

Because a NiMH of a given capacity weighs roughly half of what a NiCD pack of the same capacity weighs

Because the service life of a NiMH battery is 33% greater than a NiCD battery (1000 cycles vs 750 cycles)

NiMH is just a better technology. It should be a no-brainer decision.
Unless you're using sub c size Nimh, the voltage drop is much greater with nimh, than with Nicad. Nicad makes a better rx pack IMO. The smaller Nimh cells typically have a high internal resistance which allows the voltage to drop significantly under even a modest load.

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03-18-2009 04:44 PM  8 years agoPost 13
Hamo

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Ireland

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NiCd battery technology has the lowest internal resistance and this is why most power tools still use NiCd. Li-Ion also has low internal resistance, but not as low as NiCd and need special chargers. Do a search on Hilti or Makita cordless drills and you will find that most models use NiCds.
Hamo

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03-18-2009 04:50 PM  8 years agoPost 14
dialarotor

rrElite Veteran

Traverse City,​Michigan

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Been using Nicads for over 35 years. Easy to maintain. Fly some heli packs up to 5-6 years. Like the prices of the new Nimh packs, small and light but 3 times the capacity. Prices getting really low. Just don't let them go to zero, true of any pack.

RapRexSynLog Pilot

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03-18-2009 04:56 PM  8 years agoPost 15
nivlek

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Norfolk England

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NiCd battery technology has the lowest internal resistance and this is why most power tools still use NiCd.
Since nicads have been banned in Europe due the the ROHS directive , I found getting a cheap cordless drill nearly impossible . Well, that's not entirely true - I could get them dirt cheap with no batteries !
So , in the UK , which is better , nicad or nimh ,is a mute point these days !

At the end of the day , it gets dark .

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