Battery charger recommendations

Hello!

I would like to purchase a new battery charger that is also suitable for maintaining the voltage in the vehicle, or preventing the voltage from dropping too low during diagnostics or flashing (especially in newer vehicles).

What is the minimum AH (Ampere-hours) this should have, or can someone recommend a product?

The charging current is specified in Amperes (A), not Ampere-hours (Ah).

In most forums, the company CTEK is highly praised. A common device (MXS5.0) costs around 80€ and provides 5A. While it takes significantly more than 10 hours to fully charge a discharged battery in a modern vehicle, this is a relatively rare occurrence, and this device is sufficient for maintaining the battery's charge.

Subjectively, from the perspective of an electrician, I believe the device is very well marketed. In other words, there are much cheaper devices available that are just as good. Even Aldi occasionally offers comparable products without a brand name for around 20€.

Overall, the offered 5A of power isn't particularly generous, but it's perfectly sufficient for tasks like jump-starting, as long as you don't have the headlights, ventilation, or seat heaters running. And even this buffer allows the battery to last for several more hours, so it shouldn't be a problem for a one-time flash.

However, if you want to run the auxiliary heater and ventilation while crafting, you will need a device with a power rating of at least 20A. However, this is less common and therefore more expensive. (Electricians often use modified PC power supplies or laboratory power supplies for this purpose).

Greetings.
Guste.

Hello,

The CTEK MXS 10 has proven itself both for charging and as a continuous power supply (for diagnostic tests). Regarding the price, I can't say much other than that I'm satisfied because it works.

Best regards, Rainer.

Speaking of Aldi, Aldi.ch had a charger (a switching power supply, not a heavy, humming transformer) available just a few days ago that, based on its specifications, looked quite good and was relatively inexpensive.

Aldi Süd also had the same product back in stock that I had previously shown.

https://www.aldi-sued.de/de/angebote/angebote-ab-montag-14-oktober/detailseite-kw42-mo/ps/p/auto-xs-kfz-batterieladegeraet-1/


However, unlike the larger Cteks, it is not intended as a complete replacement solution.

Quote:

I use a similar device, but the model without the lighting for outdoor use. The charger seems to be working so far.

Disadvantage: It may incorrectly identify severely discharged batteries as either 6V or not recognize them at all, making charging impossible.https://www.aldi-sued.de/de/angebote/angebote-ab-montag-14-oktober/detailseite-kw42-mo/ps/p/auto-xs-kfz-batterieladegeraet-1/{MARKER}

I once heard that the battery in an A6 4F, for example, can discharge at 40 amps when the ignition is on, but wouldn't a charger with a maximum of 10 amps be too weak?
I currently have a Fronius with 20A in use, and I thought that this might be too low for charging.

chriskross wrote:

I once heard that the battery in an A6 4F, for example, can discharge with 40 amps when only the ignition is turned on. Wouldn't a charger with a maximum of 10 amps be too low in that case?

Here comes the exact, ultimate, and most accurate answer: "It depends."

When switched on, it certainly draws a high current, which can be as high as 40A. This is because, among other things, all the ECUs (Engine Control Units) first activate and draw a corresponding inrush current; but more importantly, because our diesel engines start pre-glowing at that moment.

Once the pre-heating is complete and all the control units are powered up, 5A should be sufficient. And even if it were 6A or even 10A: the diagnosis and flashing process should be completed within a few hours. Even if it takes 3 hours and 10A are flowing, the battery would consume (10A - 5A) * 3 hours = 15Ah. If our 70-90Ah batteries can't survive this discharge (with immediate recharging), then they certainly wouldn't have been able to provide enough power to start a motor for very long. (And these numbers probably represent the upper limit).

Greetings.
Guste.

I have the CTEK MXS25, with a maximum charging current of 25A. It costs approximately €220-240.

I own, among other things, the Lidl battery charger "ULG 3.8", which, according to its name, can deliver a maximum of 3.8 amps. The trickle charge rate is a maximum of 0.8 amps. I also use it for buffering power when working on my vehicles, and for maintaining the charge on vehicles that are not driven for extended periods. This includes our Clio, which my girlfriend sometimes only takes out of the underground garage every 4 weeks. During periods of severe frost, I also left it connected overnight to the battery of my diesel Peugeot, which I have since sold, in the garage. Then there was also the coolant pre-heater (brought from Finland), which plugged into the socket and prevented the engine from starting in freezing temperatures, while also speeding up the subsequent warming of the vehicle, which otherwise had rather poor heating.

The Lidl charger has been available for several years and has never caused any complaints. It is apparently offered regularly without any changes, and the price was slightly less than 20 EUR. For short-term, higher power demands, I have an older device that can supply a maximum of 12 amps, but I absolutely will not leave it unattended or running overnight while connected to a battery.

I bought the MXS25, which has a maximum charging current of 25A. When you're working on your car, it charges without any problems, even while the radio and amplifier are running, and it also handles all the other "extra features" of smaller devices, like maintenance charging. If you often have dead batteries or work in the agricultural sector, this device is excellent.

Originally, I really wanted to get the professional version with a charging current of 70(?) amps, but a thousand euros for it was a bit too much for me.

If I were to buy a charger today, I would probably go for a slightly smaller size – this thing is really big...

Hello everyone.

"I've been using the small Lidl charger with a maximum of 3.8 amps for 4 years now." For topping up the charge during winter with short trips, it's perfectly adequate. However, if the battery runs completely flat, then nothing works anymore.

However, I then bought a larger one because of the tractor battery (140Ah).
This is a product from the company Güde, and it's an inverter device with a maximum current of 15A. It features various charging profiles for different battery types and also includes a 12V cigarette lighter socket. It's fan-cooled, with the fan activating depending on the power demand. I think the price-performance ratio is very good at 49.99 on Lidlonline. The casing, controls, and cables with clamps are very well made. It has also survived a few crashes without any damage.

Regards, Mpire.