where do you store a spare battery? in the charger constantly?

[tdrake]

I have a spare battery for my 1930. I dont use it very often, maybe like once a month I might need it. It stays in my briefcase, but is there another place I should keep it.
I did not know if I could leave it charging the charger constantly or if I can carry ut with me and not have it be used but like once a month if that.

Thanks for the replies.

[Myrddin]

It's healthier for the battery if you leave it on the charger :)

[dmacburry2003]

I'm looking to get an extra battery for my 1935. It eats battery on wi-fi like a hog. The battery is very small, and so is the unit itself, so they both will fit easily into an average size case I purchased a little while ago.

[blang]

I posted the same question in another forum and I was told to keep it off the charger and charge it about once a month. It will last longer that way.

[Kati Compton]

From what I understand, there's no problem with "overcharging" the battery. The only problem is that the battery may get hot, which could adversely affect the lifespan of the battery.

But I don't really have a strong grasp of battery technology - this is just what I've gathered from glancing at a couple different sites.

[Steven Cedrone]

Here is a great battery page. (http://www.technick.net/public/code/index.php?load_page=http%3A//www.technick.net/public/code/cp_dpage.php%3Faiocp_dp%3Dguide_bpw2_00_toc) You have to get past the ads though! :roll:

Steve

[dmy]

Depends on the battery, Depends on the charger......

<Too much information mode ON>

For the battery, "Memory" is the main issue... more accurately termed "Voltage Depression". This is a tendancy for rechargable batteries that are not fully discharged between charger cycles to "remember" the shortened charge cycles. The effect is that the battery thinks it's fully charged but loses it's capacity more quickly. NiCads are the most prone to this effect, NiMh are next, LiIon are the batteries most typically used in our devices that have the least memory (Lead Acid have almost zero memory, but if you look at your car battery they're pretty bulky for a PPC)

Next, there are 3 types of chargers..... Trickle, Cycling, and Conditioning. Trickle chargers will charge your battery, then reduce the charge to a constant trickle.... and this is most likely to cause a memory effect in batteries. Fortunately in the last 5 or 10 years, these types of chargers have become rare in products.

Cycling chargers check the battery when it's inserted (or when power is applied) and if the battery is (typically) 98% or more of a full charge, it goes into standby mode. If it's less than 98%, it charges the battery to 100% and then goes into standby mode. Once in standby mode, no charge is applied to the battery until it reaches some level of discharge.... typically 40%-50% (which can take a VERY long time under zero load), then it's charged to 100% where the cycle starts over again. This type of charger is used almost exclusively in current products.

Conditioning chargers are used only rarely in certain applications.... these chargers charge the battery to 100%, then put it under a nominal load till it reaches 1% of capacity, then repeats the process.... basically filling and draining the battery continuously. This is the best type of charger to eliminate memory effect, and can actually REVERSE memory in a lot of cases..... problem is that the battery is never really full, so as an every day charger it's the worst.

So if you have a trickle charger and NiCad batteries, your best bet is to pull the battery off the charger once it's charged, and don't put it back until it's somewhere between 2% and 10% of capacity. You'll still get memory effect over time, but it'll maximize the life.
For that matter, this process is better regardless of charger if you have NiCads, or regardless of battery if you have a trickle charger. Again, both are unlikely with your 1930. For those who are really anal, charge your batteries to 100% and then take them off the charger until they're run all the way down to 1% (NEVER take a rechargable to ZERO.... it will not recharge at all if you do).

For the more likely event of a Cycling charger, your use of once a month or so is good enough to reduce memory to about as low as you can get it.... When you swap, just leave the batteries swapped.

Other than that (for those who have backup batteries) just make sure that you swap batteries to your backup every few months at least, and occasionally (once every few months) run the battery down kinda low (under 50%) before putting the device or the battery back on the charger and you'll get a good life/hassle ratio.

Cheers,
David.

[tdrake]

DAvid -- Thank you -- that was very informative and exactly what I needed spelled out. Thanks for taking the time to do it.

Tdrake

[Kati Compton]

Conditioning chargers are used only rarely in certain applications.... these chargers charge the battery to 100%, then put it under a nominal load till it reaches 1% of capacity, then repeats the process.... basically filling and draining the battery continuously. This is the best type of charger to eliminate memory effect, and can actually REVERSE memory in a lot of cases..... problem is that the battery is never really full, so as an every day charger it's the worst.

So if you have a trickle charger and NiCad batteries, your best bet is to pull the battery off the charger once it's charged, and don't put it back until it's somewhere between 2% and 10% of capacity. You'll still get memory effect over time, but it'll maximize the life.
For that matter, this process is better regardless of charger if you have NiCads, or regardless of battery if you have a trickle charger. Again, both are unlikely with your 1930. For those who are really anal, charge your batteries to 100% and then take them off the charger until they're run all the way down to 1% (NEVER take a rechargable to ZERO.... it will not recharge at all if you do).
I thought for LiIon batteries that this would actually be worse - I read you should try to keep that type above 40%...

[dmy]

David -- Thank you -- that was very informative and exactly what I needed spelled out. Thanks for taking the time to do it.


My pleasure.....

I thought for LiIon batteries that this would actually be worse - I read you should try to keep that type above 40%...

Well.. if this is the case, I'm in deep doo-doo. For better or worse I tend to run down my Cell phone, Ipaq, Bluetooth headset, and Laptop pretty far on a regular basis.... not much below 5 or 10% on any..... usually above 30% but less than 50%. All have LiIon batteries.... and then there's my bluetooth mouse that I use on my desktop system that gets below 5% on a daily basis. never a problem with any of them.

David.

[cftarnas]

I thought for LiIon batteries that this would actually be worse - I read you should try to keep that type above 40%...

Well.. if this is the case, I'm in deep doo-doo. For better or worse I tend to run down my Cell phone, Ipaq, Bluetooth headset, and Laptop pretty far on a regular basis.... not much below 5 or 10% on any..... usually above 30% but less than 50%. All have LiIon batteries.... and then there's my bluetooth mouse that I use on my desktop system that gets below 5% on a daily basis. never a problem with any of them.

David.

Hello all, I'm new the the board, names Chris (iPaq 4355). I have done some research on batteries recently for some RC things I was working on.
LiIon and LiPoly should never be fully drained, typically no less than 20% -30% (note that that is actual battery charge, most devices already compensate for that when they display the charge and set the displayed 0% baseline to something else for the battery). If they do get drained to low, on the next recharge they could get into a state that could lead to an explosion.

Lucky for us all regular consumer LiIon and LiPoly batteries have safeties that usually prevent this. In the Model R/C world (mostly planes and Heli's) they do not have safeties, they usually have to be really careful. One person had a Lithium battery short out and it torched the interior of his Lexus, his insurance company considered it a total loss. With my phones, laptops, palmtops and iPods, I usually just stop using the device when it shuts down the first time and don't turn it back on for just a bit more use


Having said that, the best way to keep a lithium battery in good condition is to keep it cool, and at about a mid-level charge. Charge it when you need it, but do not get too concerned about what the charge is, just keep it from getting hot. Also note that Lithium batteries age wether you use them or not, so never buy an extra battery ahead of time to use after the current one no longer can keep a good charge. I'm getting a second one, but will use it for plane trips when I swap it out, not as a future replacement.


Also of note is that in NiCad and NiMH batteries, they should never be drained completely. If that happens, one cell in the pack can reverse its polarity and that ruins the whole pack. Typically this happens in lights (like on a bicycle) when people keep turning them off and then back on to get that last bit of light on the trip home.


Hope this was useful[b]
cheers,
-chris