Step 2: Information by battery chemistry


Capacity/mAH: The amount of energy a battery can store. mAH stands for milliAmp Hour or how many milliAmps are available for one hour. A 2500 mAH battery should be able to provide 2500 mA for one hour or 1250 mA for two hours.
C: Is the charge rate of a charger. 1C means that the charge current is equal to the capacity so a 3000mA battery will be charged at 3000mA for one hour. 0.5C means 1500mA for two hours.

 Load current or drain: The amount of energy that can be drawn from the battery immediately. A high drain product draws a lot of current continuously.

Self Discharge: Many batteries will slowly discharge if left in storage. This is especially true for NiCd and NiMH batteries.

LSD: A newer type of NiMH called Low Self Discharge. They won’t self discharge as much while sitting on the shelf or being shipped to the customer. While convenient, I don’t think they’re worth the extra cost, yet (2011).

There are two basic types of batteries: primary and secondary.

Primary batteries are disposable. The old dry cells were zinc carbon, the more common are the alkalines.

A newer type is the lithium (not Lithium Ion). The advantage of the lithium is higher drain performance. They are not rechargeable.

Secondary batteries are rechargeable.

There are three main types of secondary (rechargeable) batteries based on chemistry:

NiCd (Nickel Cadmium)

NiMH (Nickel Metal Hydride)

Li-Ion (Lithium Ion)

Do not confuse Li-Ion batteries with Lithium batteries. Lithium batteries are not rechargeable.

Lesser known are:

Lithium Ion Polymer

Reusable Alkaline


NiCd and NiMH batteries


Higher drain performance. They will last longer in higher drain electronics, like digital cameras with flash and cordless power tools.

Can be recharged many times.


Self Discharge Problem: When not being used, Nickel-based batteries will lose some of their capacity over time. Wikipedia says NiMH will lose 5-10% after one day and another 1% every day after at room temperature.

Self Discharge Fix: Some suggest leaving NiMH batteries on a charger, trickle charging. I, and most websites suggest removing the battery within a day of being charged because leaving them on can lead to overcharging and overheating. However, they may require a recharge before usage which is often inconvenient.

Another possible fix is freezing or refrigerating (See separate step).

 Memory Problem: NiCd batteries and to a lesser extent, NiMH batteries have something called ‘memory’. What is actually going on is controversial but what it means is that after many partial discharges and recharges, they have less capacity than before. In other words a full charged battery will not last as long.

Memory problem Fixes: To reduce this problem, most websites recommend that NiCd batteries should be fully discharged once a month. Technically, this means the battery is discharged from 1.2 V to 1.0 V. Practically, this means running the device, drill, cell phone, whatever until it no longer works or shuts off. Be careful with some products like flashlights that may discharge too far, much less than 1 V.

Another possible fix is freezing (See separate step).


Now if a NiCd or NiMH battery still has a memory problem, there often is a another way to repair it. This is called reconditioning and will be discussed in another Step.


Li-ion batteries

Good: Higher drain performance.

Li-ion batteries do not have the memory problem.


Lifetime Problem: They do have another problem which is a limited life time strictly due to aging.

Lifetime Fixes: Do not fully discharge the battery.

Leave the battery or device on the charger even after it’s fully charged.

Try to keep battery cool.



Some products can use different types of batteries.

My Canon camera can use alkaline or NiMH batteries.

For some cellphones (I think), you can buy different types of batteries


Products with standard size batteries, AAA, AA, C and D can often work with different types of batteries.


One of the main advantages of using rechargeables is cost. Alkaline and lithium batteries have to be discarded after they are discharged. Rechargeables may be a little more expensive than alkalines but they can be recharged many times.

For most applications I would recommend rechargeable NiMH if they work because:

NiCd batteries contain Cadmium which is toxic. Probably for that reason, they are not as popular and harder to find.

NiMH have less of the ‘memory’ problem then NiCd.

hey! I read almost all of it! just wonder this how do u let it discharge? leaving it run application until it shuts down or how? such as for my samsung tablet. thankss!
Most current tablets use Lithium Ion batteries. Generally, I wouldn't discharge these. If you're having problems, I would turn it on without AC and let it discharge until it shuts down. <br><br>LOG
<p>I was looking for info on the &quot;memory problem&quot;, but didn't know how to phrase it. Thank you very much!!! I wanna do things right since I'll be busking, a portable bass amp is HEAVY on batteries.</p>
<p>Currently, I use Li-Ion if at all possible. For NiMh I prefer to use Panasonic Eneloop. They're more expensive but have a better shelf life. </p><p>LOG</p>
<p>Thank you, I already bought Energizer, they seem to be holding up nicely. I figured it would be good to know how to charged them smarter so they perform at good capacity after many recharges.<br><br>Li-Ion isn't an option for me, the bass amp only has a slot for 6 AAs</p>
<p>I was check out this website before buying ebook step by step battery reconditioning - http://bestbatteryrepair.blogspot.com. now I know how to repair battery, reconditioning old batteries is a great way to help the environment. Most people will throw out old batteries not knowing they can be restored to their original glory? Batteries are not cheap! Before throwing out any battery you should test them to see if they can be restored. restored to their original glory? Batteries are not cheap! Before throwing out any battery you should test them to see if they can be restored.</p>
<p>I went briefly through the article, there and found many wrong information:</p><p>&quot;NiCD - Once every month or so, discharge all the way and recharge.&quot;</p><p>yes, but do not make a deep dischagarde. once the tool getts sluggish, go and recharge. DO NOT turn it on and off repetably to discharge even more!</p><p>&quot;Li-Ion Leave the battery or device on the charger even after it&rsquo;s fully charged.&quot;</p><p>Why the hell would you want to do that? Li-Ion should strictly not be charged over 4,2V, that is why your charger stops charging at that voltage. If it would not, the battery will catch fire or explode!&uml; Depending on your charger, charger will be turning on and off to keep battery at 4,2V. This is also what happened in old poorley designed laptop battery - and as we all know destroyed te battery over time. So, NO, do not keep your Li-ION (or li-poly) connected to your charger for longer periods of time (etc. more than a day).</p><p>&quot;NiCds are supposed to have higher capacity for heavy duty power tools than NiMHs&quot;</p><p>WTF? NiCd are having LESS capacity than NiMHs, and they are more sensitivy to the memory effect than NiMh. Why are they still used? Because they can handle far greater currents than NiMh.</p>
I have a canon camera battery which seems to have developed a memory! It'll charge for 5 minutes but will only last about the same amount of time! <br>Question is how does one remove the 'memory' from batteries to allow them to take a full charge again?! <br>
Do you know what type of battery it is? Does it look like several cells in a pack. <br>If it's a memory issue, then it's probably NiMh or NiCd. For memory problems, I had the best luck in fully discharging the battery then recharging several times. Unfortunately, with a camera, it probably won't allow you to discharge very fully. What I would suggest is discharging it with a heavy resistor or maybe some LEDs. No guarantees. <br> <br>If it's several cells in a pack, then probably one of the cells is depleted. In my experience, there's probably not much you can do about that. <br> <br>LOG
It's an Li-Ion battery! a sealed unit for a canon camera ( BP-511 battery number)
The latest theory is that li-ion batteries do have memory issues. I found a website discussing problems with the BP-511. <br>http://photography-on-the.net/forum/showthread.php?t=1108699 <br> <br>I would suggest you try the last entry: <br>&quot;To correct the situation I would turn the camera on, set the screen to be constantly on and then allow things to totally discharge. I would have to do this 2 or 3 times and then the battery would be good for several hundred exposures (as intended).&quot; <br>Doing this should drain the battery slowly but more thoroughly than taking pictures especially using the flash. <br> <br>Hope this helps. <br> <br>LOG <br>
You should not mix different types of batteries. Nimh, nicad, alkaline. If your device uses 2 batteries, try to keep them together till death. Otherwise a new and old will not last as long, They will balance and will not last as long. Doodado
Rechargable engizier
I used to put my plain alkaline batteries in the freezer for a few hours take them out and use them again. It works for low power devices like for a Walkman. <br> <br>The trick is you don't just place them inside your freezer there is a way of doing it.
I am impressed I tried the method of freezing NiCd batteries. And it worked like a charm.
Oops I meant to freeze and then give it a good whack.
I'm glad it worked for you. I figure once they stop working, it's worth a shot trying different methods since they useless otherwise.<br><br>LOG
I had good luck with the battery packs for my drill but not much luck with AAA NiMh batteries.<br><br>LOG
Now I don't have to buy new drill batteries
Hay guys .. Do you know how to make a inverter dc to ac?????????????
DC to AC is pretty hard to do. One of the easiest ways is to buy a power inverter. But they only converter 12Vdc to 120VAC.<br><br>Here is a circuit to build a converter:<br>http://www.eleccircuit.com/dc-to-ac-inverter-by-ic-555-and-tip41-tip42/<br><br>I suspect it's not very efficient however.<br><br>LOG
Hey I have the same tooth brush.
WOW! <br><br>It seems all around you is rechargeable. Are you rechargeable, too? ;)<br><br>A bit: when you say &quot;...This is rather messy as (I believe) this is an acid.&quot;, that is not an acid, is an alkali. But it is so corrosive (or perhaps more) than an acid of the most common. <br><br>Great Instructable!
Some days I wish I were rechargeable.<br><br>You are right about it being alkali. I should have guessed when they're called alkaline batteries.<br><br>Thanks,<br><br>LOG

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Bio: Lazy Old Geek
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