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Old 01-14-2002, 08:13 AM   #1
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Default Charging Batteries

Hi, may i know whats the best amp range to charge Nicd and Nimh batts safely?

i know that its best to discharge Nicd fully before charging up again, but what about Nimh, can i use it halfway and safely charge it up again without worrying about memory effects?..or is it even any good for the batteries?

PS: Is there any site where i can look up the properties of the batteries?

Thanks.
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Old 01-14-2002, 08:42 AM   #2
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Dragon,
http://www.balakracing.com offers some good tips, like its battery maintenance page and the soldering page if you're making SBS or saddle batts.
Quote:
Hi, may i know whats the best amp range to charge Nicd and Nimh batts safely?
From my personal experience so far, both nicad and nimh react similarly - if u charge at high amp, they give u good punch, and lesser run time. If u charge low amp, less punch and more run time. But what amp is good, abit difficult to say.

My unmatched cells I charge at 4A. nimh/nicad. I got matched packs, those I charge at the rating stated on the cell's sticker.

http://www.team-orion.ch/battery-faq/ has a battery FAQ, there is a motor FAQ too.

HTHs.
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Old 01-14-2002, 08:48 AM   #3
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BTW, I swapped my charger over to a Orbit Microlader, so... the bugger can pump in up to 8A of current into the battery, depending on the battery capability to accept charge. So can't tell u my charging rates as it fluctuates as it charges

Performance wise... dun see too much diff... At my level. VS my old charger. ANd the old charger has 20A discharge
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Old 01-14-2002, 08:58 AM   #4
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so its like dont go below 1 amp and dont go over 6 amps izzit?

the balakracing site never say about the properties of Nimh ley.... its about the memory effects of the Nimh that im more unsure of....some told me got no memory some told me got...so im now blurr liao....
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Old 01-14-2002, 09:08 AM   #5
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if you go below 1A, basically the battery will just take like forever to charge. A 3000mAh battery will take 3 hours to charge

Probably will charge up to 3200mAh or more? My GP pack charges up to 3200 anyway @ 4A charge.

Well if you ask around the track, I'm sure some people will tell you they charge at like 6.5A, 7A with nicads. I think it kills the cells.

IMHO get nicads for trouble free maintenance, charge, play, discharge, equalize on tray, forget about them until 1 day before play day/race day, and then take 'em up to "gain" back their charge.

OTOH, many ppl have told me nimh is trouble free:
a) Dun need to discharge/equalize
b) Can use multiple times a day.

My feelings on nimh are mixed - my GP cells are holding up good after 1/2 a year of torture. Whereas my matched sanyo 3ks died after like 3 - 4 months or less. Both NiMH, and the sanyo 3ks were supposedly better maintained. Ahhh well.

Anyway my next set of cells will be nimh. For one reason: I can drive my car more consistently with niMH VS nicad.

There is a sanyo HV thread, got lots of info. HVs seem to be the way to go.
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Old 01-14-2002, 11:40 AM   #6
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You might check out www.smc-racing.com - A matching company with good reputation. There are good tips for different battery types, that is, 1700, 2000, 2400, Sanyo 3000 NiMh HV, Panasonics and more....

Try charging the same pack at, lets say 4 amps and 6 amps a couple of times (drive it in between ). I'm quite sure you'll feel the difference.

I'm charging my 1700, 2000 and 2400 NiCd with 6,5 amps (the highest rate at my charger). The car definately is faster this way and since I'm running in stock class, I don't care about the slightly shorter capacity/runtime.

I do recommend an equalizer. Both for NiMh and NiCd. It'll enhance battery life AND performance.

For NiCd you can use the bulb types, there go all the way down to zero. For NiMh, you'll need an active one, with cut off at 0,6-0,9 volt. Robitronic got a nice one (www.robitronic.com)

Have a nice day.
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Old 01-14-2002, 08:11 PM   #7
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how should i charge my 3000hvs on an itellipeak deluxe?
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Old 01-14-2002, 11:09 PM   #8
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What is wrong?,
There is a sanyo 3000 HV thread there, it does detail how to charge HV's. SMC's website states stuff too.
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Old 01-28-2002, 08:27 AM   #9
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Default Discharging NiCds

I've read a lot of seemingly conflicting advice on discharging NiCds on various websites. Some people say to never discharge below 5.4V for a 6-cell pack. Others say after the pack has been discharged to dead-short it, which would definitely cause the voltage to drop way below 5.4V. What do you guys think?

Does it even matter for 1500 mAh practice packs?
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Old 01-28-2002, 04:34 PM   #10
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I've had very good luck on dead shorting NiCad's from 1700 and up. I use the RealTime 2 tray and make sure that they are 0.0V before deadshorting. I've kept up the voltage and have increased the voltage on some packs. Runtime remains good also.
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Old 01-28-2002, 05:58 PM   #11
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Quote:
Originally posted by was ist los?
how should i charge my 3000hvs on an itellipeak deluxe?
pulse charge will tend to false peak.
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Old 01-28-2002, 11:07 PM   #12
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From my understanding you should NEVER pulse charge a NiMH cell, they just don't like it.
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Old 01-29-2002, 11:37 AM   #13
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In general, the higher the amp rate you charge at, the more punch you'll receive but you'll sacrifice some runtime. Also, Sanyo states "Do not charge NiCad's no more then 2.5 times their capacity", you can but don't go too high. Example: (NiCad) 2.5X2400=6000, this means 6 amp is the highest amp rate you can safely charge your 2400's(According to Sanyo). Charging at a higher amp rate(7.5-infinity) will also reduce the life of the battery(NiCad or NiMH). With NiMH's, I wouldn't worry about discharging them to 5.40v before charging them. NiMH's do not create the memory effect like NiCad's do. As for info. on charging NiMH's, there is 3 differnat brands of NiMH's(Powers, Panasonic, Sanyo) along with 6 differant NiMH batteries. SMC, Pro-Match and World Class Batteries batteries has some info on charging and discharging them. These people make a living matching batteries so they aren't gonna sacrifice their business by giving you the wrong information. Also keep in mind, peak detection plays a big role in charging batteries, both NiCad's and NiMH's. Here's their links,

SMC
Pro-Match
World Class Batteries
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Old 01-29-2002, 12:46 PM   #14
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Battery Tray?

What exactly does a battery tray do? I've never seen one. Maybe someone could describe the circuit inside?
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Old 01-29-2002, 03:07 PM   #15
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Here you have one. There are two big classes of trays. The ones that cut the discharge when the voltage gets to .8V per cell and the ones that don't do it and discharge the cells to 0V.

The one you have on the photo has cut off. It's done by using a diode for each cell (notice the need to put the cells in a specific orientation due to polarity). The diode only allows the current to pass above a certain voltage (.8). When it drops below that the diode just cust the circuit.

The ones that don't do this allow you to put your packs in any orientation that want but may harm your cells if they are NiMh.

The Trinity ones don't have the cutoff at .8. Instead they have a very funny text printed on them:
Quote:
NiCd Cells
Discharged when lights go out. Leave in pack for deep discharge equalizing
and
Quote:
NiMh Cells
Remove pack when lights go out. Do not deep cycle
You see, if you forget the NiMh cells on the trinity tray you are deep discharging them and that's no good. A good tray forces you to place the cells in a certain orientation, but that's a minor problem whem compared with ruining 70 or 80 USD packs

Use a tray with cut off.

The idea of using a tray has to do with the need to have the cells discharged to a certain level. Not as a whole, but each cell individually. If you don't do that, on the next charge you may overcharge a cell in the pack and on discharge a cell may go so low that may invert polarity.
If you cells are in a similar state of charge/discharge the chances of this happening are very small.

Hope this helps.

Last edited by antoniop; 01-29-2002 at 03:11 PM.
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