AEG Battery Charges and Batteries

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alisam

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#318634 5-Feb-2025 14:59

Over the last several months I have accumulated 3 battery chargers (1 x 3.2A, 2 x and 4.0A). and 5 batteries (1 x 2Ah, 3 x 4Ah and 1 x 5Ah). Some through a kit purchase and others by redemption. The 5Ah battery was via redemption. If I put the 5Ah battery in 4.0A battery charger, what is actually happening to the battery charging? What happens if I put the 2Ah battery (obtained via redemption) in the 4.0A battery charger?

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Dynamic

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#3339631 5-Feb-2025 15:08

Are the battery chargers identical? Can you supply us the model numbers?

For most battery operated tools, one charger will charge batteries of several different capacities.

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alisam

829 posts

Ultimate Geek

#3339636 5-Feb-2025 15:27

1 x 3.2A = #A18SPC30

2 x 4A = #BL1218

Ge0rge

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#3339648 5-Feb-2025 15:29

Assuming that the battery fits in the charger...

If I put the 5Ah battery in 4.0A battery charger, what is actually happening to the battery charging? Assuming a totally flat 5Ah battery, it will be 80% charged after an hour. Give it another 15mins and it will be full.

What happens if I put the 2Ah battery (obtained via redemption) in the 4.0A battery charger? Again from empty, the 2Ah battery will be fully charged after 30 minutes.

There will be some losses to take into account and a battery's charging profile is very rarely linear, so expect a little longer than the times I've written above, but that's the theory.

Dynamic

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#3339654 5-Feb-2025 15:41

If I'm reading correctly, the A18SPC30 will only charge 18v lithium batteries, where the BL1218 will charge several different battery voltages and types including 14v NiCd and NiMh and 18v lithium.

As best you can tell, are all three batteries 18v lithium? If yes, I'd stick with the A18SPC30.

In my experience, in the majority of cases, batteries will not physically fit in a charger that is not compatible.

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pdh

341 posts

Ultimate Geek

#3339662 5-Feb-2025 15:55

It can be really helpful (to understanding) to use a bucket analogy - when charging/filling batteries...

Think of your 2Ah battery as a 2 litre milk jug - and your 4 & 5 Ah ones as 4 & 5 L buckets.

The two chargers are like a kitchen tap (3.2 A) and a bath tap (4 A).
The bath tap is capable of a bigger/faster flow than the kitchen (in my house, anyway).

But you can see where this is going...
You can fill any container at any tap - it just takes more or less time, according to the flow capability of the charger/tap.

Just like filling a bucket, chargers & batteries slow down as they approach 'full-to-the-brim' - and if a jug/battery is smaller, it may not accept the full-on flow of a big charger/tap. So the operator (you for the tap, the charging smarts in the charger) modulate the flow down from max to whatever is acceptable to the jug/battery.

That's why it's important to have a charger that's designed to work with the specific battery - otherwise the wrong 'smarts' will F it up - like a kid learning to fill a jug from a hose ;-) Except you get fire instead of wet feet !

It's not a bad analogy to help see what's going on as you fill a battery.

pdh

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Ultimate Geek

#3339721 5-Feb-2025 16:13

And yes - I've got 6 of the AEG chargers and 12 of their batteries (1 to 6 Ah) and they all play nicely.

The 1218 is an older - but perfectly good charger. Back when it came out, there were still NiCd & NiMH (different chemistries to the current Lithium) batteries around (from older, 10+ years ago) battery tools. So it was given smarts to fill all three types of batteries.

The newer charger (A18SPC30) doesn't cater for the older battery types, because nobody has any (that still work) ;-)