Discharge rates

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Bigger the Better

Bigger the Better

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I would like to know a bit more about discharging.

This is what I "think" I know:

NiMH batteries do not need to be discharged like there predecessors the NiCad's. This is because they say they do not suffer from as bad a memory effect.

NiCad hold a charge in storage better then a NiMH.

NiCad batteries need a lower charge rate.

NiMH have larger mAh's then NiCad's.

Please if any of this is wrong, let's debate....

What I would like to know is the opposite of what I "think" I know.

What is the discharge rate of cycling a NiMh? :laugh: I want to cycle my batteries. Why? Because over the month or so they went dead and they false peaked at a low mAh on my charger. I have had this happen once before and after cycling them a few times I have got them to come back and take a strong charge once again.

Please help the electronically illiterate. :blush:
 
Bigger the Better said:
I would like to know a bit more about discharging.

This is what I "think" I know:

NiMH batteries do not need to be discharged like there predecessors the NiCad's. This is because they say they do not suffer from as bad a memory effect. TRUE.

NiCad hold a charge in storage better then a NiMH. NICADS SHOULD BE TOTALLY DEAD AND STORED WITH THE LEADS SHORTED OUT.

NiCad batteries need a lower charge rate. FALSE, NICADS CAN BE CHARGED AT A VERY HIGH AMPERAGE.

NiMH have larger mAh's then NiCad's. TRUE.

Please if any of this is wrong, let's debate....

What I would like to know is the opposite of what I "think" I know.

What is the discharge rate of cycling a NiMh? :laugh: I want to cycle my batteries. Why? Because over the month or so they went dead and they false peaked at a low mAh on my charger. I have had this happen once before and after cycling them a few times I have got them to come back and take a strong charge once again.

Please help the electronically illiterate. :blush:
Click to expand...

I have never discharged a Nimh any higher than 1 amp. This is what I have been told over the years, but I don't know "for sure" it is 100% correct.

If you think about it though, it doesn't really matter because batteries are for flashlights!

Trip..
 
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What about the various technologies of the specific types of Nicad...like SC/SCR/SCE. I know an SCR cell could take a heavy amperage charge and not die off like an SCE.

That's going back to my racing days though so perhaps they no longer make batteries like that? lol
 
Sanyo still makes them, (tower sells them) but that design is becoming obsolete with the lipo invasion.. I love the old scr cells, I have a few 1400 Gonzo packs and a bunch of 1700 and 2000 packs too.

Trip..
 
No wonder my NiCad;s never lasted. :laugh:

So, if I discharge them at 1amp, then charge them with the new rule of thumb I hear Timmahh explain:
mAh = amps (2200 pack at 2.2 amps, 3300 pack at 3.3amps, 4000 pack at 4amps)
That should work?

Great info for me, thank you!:cool2:
 
Yup and yup :) If you are going to store them for any period of time, COMPLETELY discharge the pack, I use 3, 1157 (automotive tail light bulbs) until the lights will not glow at all, then short out the leads and toss it in the freezer, until whenever..
 
I remember back in the day you could supposedly 'give' the battery a discharge memory by changing how its charged. i.e 8 amps for x mins, 4 amps for x mins, 2 amps for x mins etc.
 
discharge for memory depends what you are using them for. in electric racing for example, you are running a stock motor which is averaging about 25-30 amps of pull. you will want to cycle at the same kind of draw to discharge the battery down so it stays linear...

nmh have memory fx the same as nicad though not as common, but still these batteries should be cycled. lipos have no memory and don't need cycling as there is no crystaline build up. same with lead acid batteries which actually hate being drained (lipos too hate being over discharged).

dead shorting nicads was old school to drain em dead and help break up the crystal when they needed some help.

if you don't have a high amp discharger, an auto headlight works pretty good
 
Another battery question

When I discharge my battery my charger/discharger will take the battery cells down to .9v each. With this said is there a mAh value to what is left or is that zero?
I ask because when my charger starts charging after discharge it starts counting over from zero. Is the total mAh it shows when done charging and peaking what the battery has?

Thanks in advance.:)
 
Once a battery hits its discharge cell voltage any capacity left is pretty redundant so you can assume it to be zero. :) If the charger records the mAH value when it charges then that can be taken as the capacity of the battery.
 
It's a type of battery construction - Nickel Metal Hydride

Like Lipo batteries are 'LIthium-POlymer'

:)
 
I discharge the same way as trip..use 1157car bulb...I normaly recycle about 3 times
to get full usage.....Timm is correct on the charge rate....
I do the same for ni-cad as well as the mah batterys....
seem to last long time.....Slawhammer
 
How long do you think a NiMH battery should last? I have an old 3300 venum battery I bought back in 06 that I've been just now cycling about 6-10 times and I think its shot. I cant get more then 1900-2000 mah's in it peaked.:(
 
There's no way to tell really, all depends on how the battery has been treated and the quality of the cells. Sounds like it's on the way out though, 1300mAH is a lot of loss.
 
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