Rechargable batteries

[cliffsrr]

I always try to keep rechargable batteries ready for my MRC wireless controler. My question is,

"Is it allright to leave batteries in the recharger for long periods of time ?

Thanks

Cliff

[jeffrey-wimberly]

 ?

[cliffsrr]

Oops! Hit a key and away this post went! Sorry

[jeffrey-wimberly]

 It's been my experience (many years as a fire fighter) that batteries left on the charger develop a 'memory'. I've even seen it happen on batteries that are memory protected. The battery charges and the charger stops. The battery discharges to a certain point and the charger starts again. This tops the battery up but it also creates a 'marker' in the battery that it won't charge past. In simple language, you've lost some of the batteries capacity. If tyhe battery is allowed to stay in the charger for an extended period, say a few weeks, over half the batteries potential capacity can be lost. This will result in faster rundown times and even lower voltages.

[rrinker]

 Most chargers are not very 'smart' - they can reduce the charge rate when the battery is fully charged, but they CONSTANTLY provide a trickle charge and never shut it off. This eventually destroys the battery. And there are also plenty of chargers out there that claim to be 'smart' and do exactly the same thing.

 Bottom line - once the battery is fully charged, remove it. If they are dead in a few days just sitting there - you need to buy better quality batteries. A quality rechargeable battery has a high enough internal resistence that it won't self-discharge in a week or so.

                                                     --Randy

 

[Stevert]

jeffrey-wimberly

 It's been my experience (many years as a fire fighter) that batteries left on the charger develop a 'memory'.

It depends on the chemistry of the battery in question.

Ni-Cd (Nickel-Cadmium) batteries develop a "memory effect".

Ni-MH (Nickel-Metal Hydride) batteries do not develop a "memory effect". 

Li-ion (Lithium ion) batteries do not develop a "memory effect".

  However, they all have different characteristics, so the important thing is to make sure you're using the best type for the particular application in question, and maintain the battery properly based on it's type and usage.

  And for pointers on how to maintain them properly, just Google "proper xxxx battery charging" (without the quotes, and substituting the battery type for xxxx).

HTH,
Steve

[jeffrey-wimberly]

Stevert

Ni-MH (Nickel-Metal Hydride) batteries do not develop a "memory effect". 

I wouldn't put money on that. The dept bought an entire batch of them and every one of them went bad due to "memory effect" problems.

[Stevert]

 

jeffrey-wimberly

Stevert

Ni-MH (Nickel-Metal Hydride) batteries do not develop a "memory effect". 

I wouldn't put money on that. The dept bought an entire batch of them and every one of them went bad due to "memory effect" problems.

 

 You are correct.  I should have said:

Ni-MH (Nickel-Metal Hydride) batteries do not develop a "memory effect" to the extent that Ni-Cd batteries do.

But preventing that goes back to what I said about maintaining them properly based on their type and usage.  If you do that, none of them will develop the memory effect.

Steve 

[rrinker]

 Yes, it's commonly said that Ni-MH batteries don't have a 'memory' effect. This is false. It takes longer than a NiCad, but if you partially discharge a Ni-MH battery and then charge it it will eventually develop the same memory effect that a NiCad does. I actually suspect Li-Ion batteries also do the same thing but it takes so many cycles that usually the batteyr is past useful life on recharge cycles before the memory effect becomes apparent - so you never see it.

                             --Randy

 

[MisterBeasley]

The charger itself is a transformer.  If you feel it when it's unplugged, it's room temperature.  Once you plug it in it will warm up.  I'd guess that it warms up more when it's actually charging something, but even if there is nothing plugged into it, it's still drawing some amount of power which is dissipating as heat.

In short, think a bit green.  Unplug chargers when not in use, and save a small amount of power.

[modelmaker51]

I keep all my charges plugged into switchable power bars. The best way to prevent memory buildup is to fully discharge a battery before recharging. With my wireless throttles, I use a spring clamp to hold down the throttles button (with the system shut down) and then recharge them. I do this the day before an operating sesion.

[tricky_trev]

Lithium Polymer (shortened Li-Po or Li-Poly) is the go if you are prepared to modify your battery case. no memory effect, fast charge (most are 2C or more), high discharge capability. in fact, once charged, self discharge is almost non-existent (even after a year or more). LiPo REQUIRES a special charger however. Not mainstream yet in model railways, but fully adopted as standard in radio controlled planes (i know many also installing in transmitters instead of the trusted NiCd (because NiCd had a slower discharge roll-off), because you can install a longer lasting battery for the same size as a NiCd.

[Graffen]

tricky_trev

Lithium Polymer (shortened Li-Po or Li-Poly) is the go if you are prepared to modify your battery case. no memory effect, fast charge (most are 2C or more), high discharge capability. in fact, once charged, self discharge is almost non-existent (even after a year or more). LiPo REQUIRES a special charger however. Not mainstream yet in model railways, but fully adopted as standard in radio controlled planes (i know many also installing in transmitters instead of the trusted NiCd (because NiCd had a slower discharge roll-off), because you can install a longer lasting battery for the same size as a NiCd.

 

I wouldn´t recommend Li-po cells for the "normal" user due to the dangers with overcharging them and so on. It isn´t really a good practice to rebuild a device to fit a Li.po cell inside it, if something happens it is all your responsability! A somewhat safer cell is this:

Lilo cells

It has the advantages of the Li-po without the drawbacks, and as model railroaders don´t mind the little extra weight compared to Li-po´s, they would make a better replacement. It is however up to you to decide if the rebuild is sound.

[tricky_trev]

good point. not for beginners, but shows that the battery options are getting better over time....

[dragenrider]

I use this type of charger and batteries:

I have used the same batteries, rotating between sets, for almost a year with no noticeable loss of function or charge.  They work well.

Full link is here. 

[TomDiehl]

modelmaker51

I keep all my charges plugged into switchable power bars. The best way to prevent memory buildup is to fully discharge a battery before recharging. With my wireless throttles, I use a spring clamp to hold down the throttles button (with the system shut down) and then recharge them. I do this the day before an operating sesion.

There's a simpler way to do this, get a flashlight that uses the same size battery, put the batteries in the flashlight and turn it on. Leave it on overnight, well past the point that the flashlight produces visible light. The newer LED flashlights may not work well for this due to their lower current draw, try to stay with an incandescent lamp flashlight.