Report for the CE-BC 1M ... Small charger/maintainer for any SMALL lead-acid battery (excluding lithium) up to 30A capacity, note that it is the slowest in the series, but 100% more effective for the life and duration of the battery charging with as low Amber

I was torn between a simple charger at half the price & only for lead ... and the CE-BC 1M...
The maintenance that the CE-BC 1M provides is worth every penny, because IF the battery is fully charged, with the simple charger the battery must be immediately disconnected because it will start to destroy it, while with the einhell it goes into maintenance charging & in case something happens and I have to leave or if I want to leave it for a long period of time, it doesn't need it, it always keeps the battery charged (long periods without use naturally discharge) ...
The pros are that it has a LED indicator for errors, full charge...
and the automation that detects the battery type & acts accordingly

In this particular model (I don't know about the others in the series, I say this because I think they have slight differences in the settings) we can manually select 6 or 12V (it also does it automatically)

The cables from the charger to the socket are 1.5m & to the clamps 1.5m, quite convenient with a total of 3m

It does not support charging at temperatures below 5C, it doesn't even have a button with the snow symbol like some models in the series, there it requires a few volts more (I think & A) which this device does not have, in the next model CE-BC 2M for below 5C & with double power (2A) faster charging

A big advantage, in this particular model (I don't know about the others in the series) if it stays on for a long period of time for maintenance and the power is cut off, upon restoration (after 10 minutes, 2-10 hours, etc.) it will automatically turn on again and reread the battery and act accordingly until maintenance

--> EDIT 21/11/22 <--
I just discovered that there is a RECOND MODE in the CE-BC 1M model that is not mentioned in the instructions, only for LEAD ACID (if the battery is fully discharged or new and needs to be charged for the first time) ... CAUTION for small batteries up to 3-4 Ah, do not leave it for more than half an hour and for larger ones more than 2 hours (or when you hear them boiling like many bubbles or getting too hot) because it has higher voltage and it does not automatically cut off (then switch to the normal mode for the rest of the charging) ... I measured that it gave 15.20 V & 0.25A to a small 3Ah brand new battery that I filled with liquid myself.
Press the mode button and while keeping it pressed, plug it into the socket, as soon as the 2 led 6 & 12V flash together simultaneously, release the button & it goes into recond, connect the completely discharged battery.

Performance 1st test
It automatically recognized and charged a 3+ year old 4Ah battery that I had on the side & I put it for testing (full of liquid but dead because it discharges to 12V in 1 day) it raised it from 7.8 volts to about 5 hours & kept it in maintenance where I left it for another 2 hours normally with 12.7V.

2nd test
A 6-year-old Chinese sealed type battery 1-2 volts/3Ah, I opened it, filled it with liquid, 15 minutes in a solar panel (I didn't know yet that the CE-BC 1M had a program for completely empty batteries) and as soon as it reached 8V I put it in the einhell charger and it charged it normally, at 11V I took it out (the charging took longer and it wasn't worth it, in a few hours it would go below 10V).

3rd test
Normally connected to the motorcycle, a yuasa yb4l-bs 4Ah battery, 2 months old, I took it from the store half-charged because I was in a hurry, it raised it in 6 hours from 12.3 to 13.1 volts, after 12 hours of being disconnected it sits at 12.5V (without the charger's maintenance).

In the 3 tests, the volts that I saw from the charger (with a multimeter) were from 13.8 - 14.5 with a considerable time/almost constantly 14.4 which is an average for all types of batteries... I also did an Amber measurement at 0.82 - 0.84 A (the manufacturer says the maximum is 1000, I measured 840).

EDIT1 in maintenance charging for a 4Ah battery relatively new, it keeps it at 13V, the old one at 12.7V, and every 1.5 minutes (about 90 seconds) it sends a pulse of about 14.5V to keep them charged at this level, note that in larger batteries the time may differ.

In 6V mode, the output gives 7.2 / 7.3V.

The current that this specific CE-BC 1M consumes while charging is really minimal, along with a router, a cordless phone, and this connected to the house that I used, I barely saw the meter turning, you can easily leave it in maintenance for a while if needed (the more powerful ones may have higher consumption).

I don't have a car at the moment and I went for this model, otherwise, go for the CE-BC 4M, much more powerful, more settings, good for small/medium cars, it also has the specific mode (12V M) for small batteries if available.

EDIT2 I see that for very small batteries up to 1.6 - 5Ah it is still powerful with 0.8-1A, it does my job comfortably & quickly with such small ones, I refill them occasionally now in the winter, no complaints, Excellent. But maybe a charger at 0.4A is more ideal for such small ones, let it be slower