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[Closed] Fully discharge batterys before regharging?

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I'm talking about my Hope 2's and DX torch.

Is there a memory thing after the first charge or is this old fashioned nonsense?


 
Posted : 08/10/2009 10:49 am
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Li-Ion batteries apparently don't need it, but I don't think it hurts to give them a decent discharge every now & again, then put them on for a long charge.


 
Posted : 08/10/2009 10:51 am
 jim
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Old fashion nonsense. Modern batteries like to be charged little and often.


 
Posted : 08/10/2009 10:53 am
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Li-Ion batteries apparently don't need it,

don't like it. It should not cause harm but do not attempt to discharge them as it just uses up life of the battery

Modern batteries like to be charged little and often.

it depends on the type


 
Posted : 08/10/2009 10:56 am
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It's been asked before but you won't get a definitive answer, even the STW experts contradict each other.

Why not ring Hope and post their reply...I think your Hope 2 has the same battery as my Hope 4 so I'd be interested to know what they say.


 
Posted : 08/10/2009 11:21 am
 jim
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it depends on the type

Which batteries don't like to be charged little and often?


 
Posted : 08/10/2009 11:27 am
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Li-ion batteries are destroyed by a full discharge, so are fitted with a protection circuit to disconnect the cells to prevent it. They only have a certain number of charge/discharge cycles and supposedly theraputic discharging just uses up some of that needlessly


 
Posted : 08/10/2009 11:28 am
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Which batteries don't like to be charged little and often?

NiCd have much reduced life with this regime


 
Posted : 08/10/2009 11:29 am
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Was there not also a study which shows Li-ion degrade quicker if stored with a full charge? I think it might have been done for laptop batteries but the tech is the same?


 
Posted : 08/10/2009 12:02 pm
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Rechargeable cells (A battery is a colletion of individual cells) a have a finite number of charge-discharge cycles.

In the past, Ni-Cad rechargeables used to develop a memory effect if not fully discharged, and were best looked after by completely discharging them to reduce this.
Indeed when I used to race electric model cars, there were many different chargers on the market that would discharge the cells first, then charge them. We kept them flat as pancakes between uses, and only charged them just prior to use. This was the accepted way of doing it, and it worked. We also only used each set of cells once a day, as the demands placed on them were so high. The discharge rate (Fully charged to nearly flat in 5 mins) used to leave them too hot to touch. Seriously. A lot of effort was put into making packs of 6 'matched' cells too, so the max voltage and discharge curve of each cell in the pack was as close to identical as possible. This let each cell perform at it's best, and give maximum power. They weren't cheap: I had 4 packs, fairly decent ones, and they cost me about £52 a set.

These days that's pretty much all dead and buried. Cells still have a finite number of cycles in them, but don't need discharging and keeping flat between uses. They benefit from being kept fully charged. Also, if a battery is half used, then charged, you are only using 'half a cycle' if you see what I mean. Discharging them first would up that to a full' cycle', and shorten the life of the cells.

Just keep them charged, and charge them as soon as you've finished.
🙂


 
Posted : 08/10/2009 12:17 pm
 Del
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wot he said ^ applies to nimh packs. keep charged and warm.
li-ion should be kept half charged and cold.


 
Posted : 08/10/2009 12:38 pm
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And how exactly do you 'half charge' them?
😕


 
Posted : 08/10/2009 1:04 pm
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And how exactly do you 'half charge' them?

that is indeed an unexplained mystery. My best advice is to put the thing away uncharged after the last spring ride on the assumption that you'll not have needed to use it much on the last ride due to advancing daylight - in fact you could use it several times without charging...


 
Posted : 08/10/2009 1:13 pm
 Del
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err, don't discharge them all the way?


 
Posted : 08/10/2009 1:15 pm
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I seem to remember the advice for Li-Ions on the Lumi website is to store them at about 50% charge (might be 40%) and preferably in the cold, as they last longer. I tend to leave mine in a carrier bag in the fridge when I remember.

Don't put them in the freezer though. That is too cold.


 
Posted : 08/10/2009 1:34 pm