If you know the terms, and the differences between, say, Eneloop, NiMH, NiCd, Lithium - then this, or a similar charger, is what you absolutely need to have around.
Rechargeable batteries are great, but they have their quirks. Enter the following players to spice things up:

1. Memory Effect:  

Cause:

Partially discharging batteries and charging them to "top up" would result in the battery gradually having decreasing total capacity. The battery would then “memorize” this smaller capacity – hence the term “memory effect”. Almost human – we remember only what we want to remember, and the way we want to remember. This effect applies, for the most part, only to NiCd batteries.

Remedy:

Discharging the battery to less than 1.0 volts per cell, and charging it back up to full, will reduce the memory effect. Care must be table while avoiding a “deep discharge” – discharging to zero or close to zero capacity – which can permanently damage the battery. For this controlled discharge to be carried out correctly, each battery must be separately discharged, i.e. not discharged as a multi pack.

2. Charging at high temperatures / rapid charging

Cause:

Many battery chargers bought off the big box retailers will promise “rapid charging” modes, claiming to charge in an hour or two. Charging at high currents raises the risk of permanently damaging the battery, just like a short circuit may damage the battery beyond repair.

Remedy:

“Cold charge” – reduces the current flow during charging so that the battery stays cool to the touch, while taking longer to charge up.

3. Battery life, and the remaining capacity in the batteries

Cause:

Well, this is not really a cause and effect situation – any more than life and death are a part of everything. Batteries die out. Fresh batteries charge better, and their capacity continues to go down as they go through repeated charge and discharge cycles. Even if your battery said “1800 mAh” on it, it may have a reduced capacity

Remedy:

Again, not a remedy as such, but we need to know the correct capacity a battery – and to do that, we need a controlled discharge and measure the power from the discharge.

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The La Crosse 700 Alpha battery charger addresses each of the above issues. This leads to your batteries being better maintained, better utilized, and when they do slowly die out, give you an accurate estimation of the remaining capacity in them.

Side note on definitions – the Ampere is a measure of current, 1 ampere being a certain number of electrons flowing through a point in 1 second. The Ampere Hour (Ah) – or milli Ampere Hour (mAh) – shows the capacity of a battery – how many electrons can it supply in how much time. For example, a battery of 1800 mAh capacity can sustain 1800mA – 1.8 A – for 1 hour, or 900 mA – 0.9A – for 2 hours, or 100mA for 18 hours. Roughly speaking. mAh is a measure of the charge in a battery, not the energy stored.
Let’s see how.

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Features

The charger comes with the following features, just to set the records straight (from the product manual)
- Charging rechargeable batteries in various currents (200, 500 or 700 mA).
- Fast charging – 70 minutes to charge up 2000 mAh batteries
- Individual LCD display for all compartments
- Charging both “AA” and “AAA” rechargeable batteries simultaneously
- Overheat detection to protect rechargeable batteries from over-charging
- Minus delta voltage (-dV) detection for charge termination
- Damaged batteries detection
- Discharge mode (first discharging and then charging) to remove memory effect of rechargeable batteries
- Refreshing old rechargeable batteries by discharging/ charging cycles
- Test function to check the capacities of rechargeable batteries
- Charging/ discharging functions can be launched independently and simultaneously to each rechargeable battery in the compartments
- Various display modes during charging/ discharging – the charging current (in mA), time elapsed (in hh:mm), the terminal voltage (in V) and accumulated capacities (in mAh or Ah)

Operating Modes

The operating mode is slightly tricky to choose – not as intuitive as one would like. When you place one or more batteries in the slots, the display blinks for a few seconds – pressing mode for 1 second will allow you to switch between the different modes. Just checked the manual – you have 8 seconds from inserting the batteries to change the mode. Pressing a button increases the timer by another 8 seconds. Once 8 seconds pass without any button activity, the mode will be locked in place. If you don’t get the setting right – as I’ve done many times in the initial days – just unplug from power and plug back in. Andplease do read the manual.

Charge Mode

This is probably the most commonly used mode. In fact, anything but this charger – and similar high end chargers – would only have this one mode.
The important choice in this mode is charging current – how long can you afford to wait for the batteries to get charged. This is inversely related to how hot the batteries get through the process – quicker charging means higher current, which means the battery will get hotter, which has a potential to decrease battery life.
Once you pick the mode as charging, you can use the left button – “Current” – to switch between 200 mA, 500 mA and 700 mA. The lower is generally the better for battery life, however general opinion seems to say500mA for AA and 200 mA for AAA are optimum choices.
The manual says a 2500 mAh AA battery will take around 3 hours at 700 mA, 5 hours at 500 mA, and 13 hours at 200 mA.

Note on displays showing “null” – the “null” display is generally for indicating slots that are empty. There are times when the display will show “null” even when there is a battery in the slot. This is because any battery with a voltage of under 0.9V is considered deeply discharged, damaged, or otherwise not chargeable. If you are sure the battery has some capacity left, and are not afraid to try out DIY tricks, you can give a shot to momentarily short circuiting the battery with another – good – battery. Coins and paper clips come in handy. Be careful, as short circuiting is not a friendly operation, and timing is important – too much and you damage the good battery. Once short circuiting gets the battery voltage above 0.9 V, the charger will be able to detect it as a valid battery.

Discharge Mode

This mode is for a controlled full discharge of batteries until they are completely discharged – and then charge it back up to its full capacity. This full cycle of discharge – recharge removes any memory effect that can be present in the battery.
Once you pick this mode, next selection option is to set the current. Options are 100, 250 and 350 mA. There’s a trick to this one – you are selecting the discharge current, but then the charging cycle that will follow the discharge will use double the set current to charge. Go figure. Going with our optimum choices in the section above, keep the discharge current at 250mA – this sets the charge current at 500 mA.

Refresh Mode

Think of this as the discharge mode, in a loop. If the discharge mode is a single spa procedure – manicure, pedicure, haircut – this is the works, a full spa session spanning multiple days. The batteries will be discharged and charged back up, and then the process will be repeated. It will stop only when the batteries show no perceptible improvement in consecutive cycles, or after 20 iterations of full discharge and full charge are completed.
Be aware of the time required for each cycle. At 500 mA charge setting, charging a 2500 mAh battery takes 5 hours, and discharging takes about 10 hours (250 mA for 10 hours is 2500 mAh). That’s 15 hours. If this is repeated for 3 cycles, that’s about 2 full days of the charger working on the battery.

Test Mode

The charge mode was just charge. The discharge mode was discharge then charge. The refresh was repeated loops of discharge and charge. The test mode is charge, then discharge – while measuring the battery capacity – and then follow up with a full charge.
There are no good ways of accurately measuring battery capacity other than a controlled discharge. Think of it as measuring the volume of a container – you fill it with water, then pour the water into a measuring jar, and then fill the water back up. Batteries are not like graduated containers – which means you can’t look at a battery and know its capacity off the bat. You have to “pour” the charge into a “graduated container” to measure what was stored.

Trickle Charging

Charging of batteries stops once the capacity is reached – this is the “negative delta” detection mentioned in the specifications. It is rather involved to explain “negative delta”, but consider it simply as a detection of the battery charged to capacity. Once charging stops, the battery charger moves automatically to “trickle charging mode” – it maintains a low current that keeps the battery in its full capacity. Without a trickle charge, batteries generally self-discharge and go down in capacity.

Display Settings

There is one more button we did not touch upon so far – Display. Use this to toggle between voltage, charging current, discharging current, trickle charging current, charging / discharging time elapsed, and battery capacity. The options actually available depend on the mode. The user manual has various tables that lay out the different display options in the various modes – there are quite a few combinations to go over in detail without having you, the reader, tune out.

Troubleshooting

The user manual does a great job of listing out various troubleshooting steps. In general, I recommend searching on La Crosse’s website for the user manual as a PDF, and saving it for future reference. There are too many options on this charger to remember off the bat. There may be just 3 buttons, but this is as complicated as it gets in charging, discharging and conditioning batteries.
I was thinking of copying over the troubleshooting steps from the manual, but a clause on the last page of the manual says “This handbook must not be reproduced in any form, even in excerpts, or duplicated or processed using electronic, mechanical or chemical procedures without written permission of the publisher”. Please do store a copy of the PDF on your computer for future reference if you do choose to get this charger.

Also read reviews on shopping websites - some of them are very technical and can answer many more questions than La Crosse has thought of putting on their manuals. 
Happy charging! Hope the warm fuzzy feeling of going green (with rechargeable batteries vs. regular batteries) and saving money by making your batteries stretch to new limits will keep your company for the years to come.

Recommended: Yes