History review of Bosch Nickel-Cadmium (Ni-CD) AL60 & AL60 DV chargers

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Kiriakos GR:
First ever released Bosch AL60 charger this shown in the market at 1992, this charger were designed to be first multi-volt charger this serving battery design of Bosch TYP:
7,2V 2607300001 1,2 Ah
9,6V 2607300002 1,4 Ah
9,6V 2607335176 1,7 Ah
12V 2607335014 1,4 Ah
12V 2607335180 1,7 Ah
All tuber type ( Knolle accu -> in German ) Ni-CD battery.

Difference of voltage output mostly translates to different length of half to bottom battery pack compartment.
Due pictures comparison it seems that 9,6V battery and 12V are brother models, and this translates that it is very possible 12V version to be easily clip on and be used at 9V power drill.

First released Bosch AL60 charger this came with Bosch label in which word of ACCU (battery) are capitalized.
This charger can do 4,8V & 7,2V & 9,6V & 12V, Bosch due their Ni-CD cells capacity selection it did limit Amperes output to 1.4A (entire series using 1.4Ah Sanyo).
Such charger also named as 1 Hour Bosch charger at 33W.
Code: 2 607 224 152

Later on, Bosch created first AL 60DV this be identical model to AL60, only difference for Europe this is product label with out German text.

Practically AL60 & AL60DV (rev1) these are well build chargers, both using real transformer and PCB this is using few smart IC and minimal amount thru-hole electronic components.
PCB other than having multi-volt detection, this also using temperature detection due a connection with in-battery located sensor.
Temperature sensor this is actually a resistor sensitive to temperature change, and resistance changes according to Celsius change.

Soon I am going to have one AL60 (AL60DV rev1) Bosch 2607224226 and detailed pictures will be presented.

Speaking of Bosch, they did produce several products by reusing AL60DV label and by adding further more numbers so to separate models, example AL60DV xxxx.
Such chargers are totally different in many ways and primarily they are incompatible with first AL60 or Rev 1 AL60DV.
Newer AL60DV xxxx these serving different battery case, additionally they use more modern but less reliable pulsing power supply this serving as mains transformer.
Additional issue looks to be that charging of half damaged batteries and because this process lasts longer, several components gets damaged due overheat.

My own research over the internet so me to find just of curiosity, pictures of AL60 (AL60DV rev1), this it did drive me in to pictures of later on made chargers, which several shown symptoms’ of damage.
Interestingly enough it seems that Bosch it did push the envelope of fast chargers to it limit.
I did spotted 4.8A and even 5.6A fast chargers.
Here are some facts that very few are aware of.
Made in Japan Sanyo batteries they were premium quality, but they are not made any more.
Sanyo Ni-CD cells (of the past) were able to tolerate higher charging voltage even up to 1.7V and also to be abused with out damage.
Within 2017 all that we can find this is “Made in China” compatible Ni-CD, them not build up to highest specifications’ of old SANYO Ni-CD.

Outcome of all latest changes this is that rapid chargers of old days, nowadays they will deteriorate much faster any latest produced “Made in China” compatible Ni-CD cells.

Naturally, charging current this is always related to battery capacity.
Therefore if we do purchase true capacity of 2000mAh (2.0Ah) Ni-CD, then C1 charge this is 2A and any specified as one hour charger this is up to specifications’.

From the other hand all Ni-CD will eventually deteriorate and cell capacity this becomes lesser and lesser.

Therefore and in conclusion, if you do seek for optimal charging current for maxed battery pack life, this is 2.0AH battery with 1.4Ah charger.

Kiriakos GR:
In above message I did a good analysis of two models of 33W ( AL60 & AL60 DV)
Next revision of AL60DV charger this is 44W 1.9A and at voltages range, much older 4.8V option this is now removed.

This AL60DV 44W charger can do 7,2V & 9,6V & 12V & 14,4V (Bosch code 2607224275)
Circuitry this is identical to AL60 or and 60DV at 33W, inner changes that Bosch did this is mainly two output transistors be replaced with ones having a bit larger case and dimensions.
Inside main component still is a robust transformer.

For unknown reasons there is no available any datasheet from old SANYO industrial Ni-CD 1,2V so me to discover ultimate allowed charging current.
Within 2017 only information's available are about SANYO Cadnica, this is 1800mAH and max charging current this is 2.7A
Therefore 1800 Cell & 2.7A max charging this math translates to C1,5 as Fast-charge rate.
Alternatively 2000mAh confirmed cells they would do C1,5 at 3A.
In conclusion neither AL60DV 44W this can not be considered as battery-killer simply because this is not powerful enough. :)

Kiriakos GR:
By assuming that I did steal proper pictures from what Google steal over the years, here is my composed picture this demonstrating slight component level change between 33W & 44W AL60DV.

Addition of heat-sink at its one active component this is possible, but I would not do it with out carefully removing these two components from the PCB, so to not stress components leads.

Kiriakos GR:
Bosch 2607224000 charger this is 1.3A and gives the impression that this is the father of AL60 & AL60 DV chargers.
It is made in West-Germany, and follows one wise design speaking of metallic contacts at charger compartment, contact points are wide as is battery contacts too.

Identical wide contact points they are also at my own (Slow charger Bosch 2607224200 this be 9,6V 400mA)

It does not makes sense even today of why Bosch changed product design about wide metallic pads and started to use thin contacts instead.

Chargers list with wide metallic pads:
AL60 - 2 607 224 152 1.4A
Bosch - 2 607 224 200 400mA
Bosch - 2 607 224 000 1.3A

Kiriakos GR:
Next topic which I did explore this is about Bosch NTC thermistor inside 9,6V (& 12V) battery pack.

At 90s, Chinese electronic parts industry was in the kindergarten, and Bosch battery pack was using European made thermistor (Made by PHILIPS).
Unfortunately even me I do not have original 6.8K NTC because I lost it over the years, by rebuild my battery pack over and over.
My current basic charger does not use NTC protection, but now I am aiming at eBay about getting faster charger with NTC support, and if I do succeed, then I will need to spent a bit more cash and get one NTC thermistor.

MAKITA battery packs also using NTC but this is 10K Ohm, and therefore this is not compatible for Bosch 9,6V or 12V Ni-CD that specific Bosch chargers expecting to cooperate with.
Wrong selection of NTC thermistor value this would cause problems, because charger this receives false information regarding actual battery cells temperature.
Wrong NTC will deliver fault alert and charger will not start or cut-off.
Bosch charger expects this to detect three conditions according to NTC and cells actual temperature:
a) Battery with NTC support
b) Battery too cold
c) Battery overheated

Practically entire series of Bosch fast chargers, they work with smart electronic control.
They automatically detect battery pack voltage range, they do charging by using pulses.
a) Pulse amplitude this defines output voltage.
b) Pulse duration this defines charging current (ampere).
c) Trickle charge this is just a different combination (setup) of amplitude and duration (Pulse parameters).
An exception this is AL60 that works with timer and does a hourly charging cycle with out sensing actual stored energy in the battery pack.

What this technology of 90s smart electronic control this is missing, this is detection of internal battery resistance. ;)

Bellow there is a collection of very interesting pictures, and I would say extremely valuable in 2017.
You may see original NTC of Philips (red) and also of another unknown manufacturer 6.8K NTC that Bosch factory did use in their battery assembly line.
Last picture this is great example of NTC thermistor operating theory.

Proper NTC thermistor selection for compatibility with AL60 & AL60 DV chargers, this is research that I am going to perform.