We recently posted about the new Bosch 18V 6-port cordless power tool battery charger. Bosch boasts that it has a 2-stage charging cycle, where it fast-charges batteries to 80% before topping them off to 100% using a slower charging step.
They weren’t very clear about how the fast partial charging worked with this new charger, and so we asked for clarification.
I asked: Does the Bosch GAL18V6-80 charger have any user interface where users can set a battery to stop charging at 80% once quick-charge is complete and before the top-off charging cycle starts?
The way I saw it, there were two options.
1) Each actively-charging battery is recharged to 100% before the next battery starts charging.
2) Each actively-charged battery is recharged to 80%, and then it moves on to the next battery.
Possibility 2 would be more preferable, as it would provide you greater charge capacity in a shorter time. Let’s say you are charging a high capacity Bosch 18V battery, say a 12Ah battery. It’s going to take a very long time to fully recharge before the next battery starts to charge.
Update: It actually works in the 2nd manner, not the 1st, the new post about this is here, what follows below is not accurate.
Here’s what Bosch got back to us with:
Although you can stop the battery from charging with the top-off cycle, once the charging process has completed the charge to about 80%, the user can see the charging status of the batteries via the 5 LEDs in each of the battery bays. When four of the 5 LEDs light up, this indicates that the battery in that bay is charged to approximately 80%. The user can then take the battery out of the bay for use and doesn’t have to wait for the top off cycle to finish.
Okay, so it’s the first design possibility. What does that mean?
Basically, you have to babysit the charger in order to take advantage of the 80% fast partial charging mode, switching to the next battery manually once you see 4 out of 5 indicator lights illuminated.
Or, just let the charger do its thing and let it run unattended. But then this isn’t much of a feature, is it?
Consider this – let’s say it takes x-number of hours to fully charge a selection of 6 different batteries. You place all the batteries in the charger, and come back before all of them are charged to 100%. The way Bosch designed this charger, you’ll have a couple of batteries charged to 100%, and one battery in the process of recharging.
If the charger were to fully utilize its 80% fast charging mode, you would have more batteries at the ready in the same time.
This isn’t a big deal, it just seems like a missed opportunity.
Bosch has been releasing tools with unspecified “Bosch Bluetooth-Connected” features. Maybe they could have added a Bluetooth module to the charger, so that users could select which type of charging cycle configurations they prefer?
Or, the partial fast charging might have been more beneficial in a simultaneous charger. As a reminder, this is a sequential one-at-a-time charger, similar to the Milwaukee M18 6-port charger that came out 8 years ago.
The charger is compatible with all Bosch 18V Li-ion batteries.
We also asked Bosch about their newer single-port chargers, but have not yet received a response. Their new budget-priced holiday season specials feature a new charger, and I haven’t been able to find more detailed information about it yet. Maybe one of you will be more successful at digging up some details?
What’s the charging rate of the GAL 18V – 20 charger compared to the 40 charger? I also see it has one led indicator rather than two, is this because it lacks dual-cycle charging or some other reason?
I agree the other option would have been better. The price isn’t too bad though. If it was designed the other way it would have been more of a bargain, but it still seems alright for what you get.
Don’t all chargers kind of do this? There is a different charge profile up to 80% than it “trickle” charges to 100%. Whether it’s obvious to the user or not is a different story. But it doesn’t seem they are doing anything particularly special here except adding more LEDs.
I believe so, and some also have “80% ready!” LED indicator signaling so you know it a good time to pull the battery off the charger a bit early.
Bosch’s emphasis and marketing language led me to think they might be doing something different here, but it turns out that’s not the case.
80% indication can be useful on a single charger, much less so on a 6-port charger when you connect multiple batteries.
It’s no difference to the user who’s charging a bunch of batteries overnight or otherwise during a long stretch of downtime.
No, you have this wrong. The office admin from Bosch didn’t even address your question, so no new information there.
All batteries are charged to 80% in sequence – THEN they are topped up to 100%. I think that’s reasonably clear in the original sales blurb. But here’s the crystal clear language from the user manual:
The batteries (1) are charged one after the other in two
– In the first charging cycle, all inserted batteries are
charged up to approx. 80 % of their capacity.
– In the second charging cycle, all inserted batteries are
charged from approx. 80 % to approx. 100 % of their ca-
pacity. The second charging cycle begins when all inser-
ted batteries have been charged to approx. 80 %.
The charging process begins as soon as both the mains plug
and a rechargeable battery have been inserted. If the char-
ging process is started with multiple rechargeable batteries
simultaneously, they will be charged one after the other in
the direction of the imprinted arrows (6) (anticlockwise).
If the rechargeable battery has a state of charge of over ap-
prox. 80 %, it is skipped during the first charging cycle and
charged in the second charging cycle (from approx. 80 % to
approx. 100 %). If a new rechargeable battery with a state of
charge below approx. 80 % is inserted during the second charging cycle (from approx. 80 % to approx. 100 %), it is
charged immediately. Once this rechargeable battery has
been charged to approx. 80 %, the charging sequence is re-
defined. The next rechargeable battery that is charged in the
second charging cycle (from approx. 80 % to ap-
prox. 100 %) follows the sequence of arrows (6) on the
Thanks to the intelligent charging process, the state of
charge of the battery is automatically detected and then
charged up with the optimal charge current depending on
battery temperature and voltage.
In this way, the battery is treated with care and remains per-
manently fully charged when it is stored in the battery char-
I essentially asked Bosch USA if a user can set a battery to stop charging once it’s been partially fast-charged to 80%, so that it could automatically move to the next one to fast-charge and they basically said no, and that one has to monitor the LED indicators if they want to charge to 80% and then manually move to the next battery.
Wouldn’t their answer have been different if this was done automatically by default?
I have seen some instances where USA and European tools were slightly different. I could not find a manual for this model yet, or any international equivalent.
It’s not a “Bosch office admin” providing these answers – I ask Bosch PR, they forward the questions to the appropriate Bosch USA product manager or engineer, and someone gets back to me.
There are some brands that truly don’t know a thing about the tools they market, but Bosch USA isn’t one of them.
I’ll ask Bosch USA for clarification again – thanks for the information!
The user can’t tell it to STOP at 80%, sure. But it could still visit all the batteries in sequence and get them to 80% before going around again and topping them off. The way you phrased the question, and they way they answered it, doesn’t actually map directly to the two modes being discussed.
Get the thing on an ammeter and we’ll know for sure.
I’d assume that an 80% around-the-charger cycle would have a user interface of some kind, for users to be able to set “fast” or “complete” charging depending on need or preference, similar to what I’ve seen in other products.
Sony’s charger, which has 2-stage charging, has user settings.
Many power tool battery chargers often have different charging rates.
It seemed to me that there MUST be user controls for such a setting to be activated or toggled.
Otherwise, what if you want that first battery charged to 100%, but you also want several other batteries on the sequential charger and that you don’t have to babysit it?
Plus, with this being a sequential charger, I thought it fair to presume that if charging behavior was different than for their single 2-rate charger, which goes to 80% and then 100% without pause, there might be some method of user control.
I have a fair number of 12v and 18v Bosch tools, most of which I really like and use, but a fair number are via eBay and other sources because one can’t actually buy them in the US.
I think this, compared to say Milwaukee, again illustrates that they aren’t really interested in the US market.
Great customer service but truly glacial new tool/innovation introductions.
I would rather have a 2 port simultaneous charger on a job site.
Assuming the manual is right and it does charge all batteries to 80% first, I’m glad they went this route. It’s better for the batteries and will get the most usable power to the batteries in normal use cases.