Bosch C30 Charger
(22 reviews)
The charger you find in every other garage: simple, robust, rated for batteries up to 120 Ah, and made by the world's largest automotive supplier.
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Characteristics
- Output: 3.8 A, 6 V and 12 V batteries
- Capacity: Batteries up to 120 Ah
- Compatibility: Lead-acid, EFB, gel, AGM, SLI
- Function: Automatic trickle charging
- Bosch expertise on stop-start batteries
Detailed overview: Bosch C30 6/12 V battery charger
Bosch's C-Line range was recently renewed, and the C30 sits at its heart. It is an automatic, electronically controlled charger designed for 6 and 12 volt batteries in scooters, motorcycles, cars and leisure boats. Its 3.8 amp output aims at maintenance or recovery charging rather than a quick rescue.
The stated compatibility deserves attention. Beyond conventional lead-acid and gel, the C30 supports EFB and AGM batteries. Both technologies equip stop-start vehicles, which make up the bulk of the recent fleet. An AGM battery charged on a standard lead profile receives an unsuitable voltage and ages prematurely, so the distinction is not marketing: it has a real effect on service life.
Admissible capacity reaches 120 amp-hours, placing the C30 above many chargers of comparable size. A city car battery sits around 45 Ah, a diesel saloon around 70 to 80 Ah, a large MPV or van can reach 100 Ah. The unit therefore covers the entire private fleet without falling short.
Once the battery is full, the charger switches automatically to trickle mode: it monitors voltage and feeds current back only when needed. That is what lets you leave it connected for weeks on a vehicle that is not being driven, with no risk of overcharging. A carrying case and a wall bracket are supplied.
If you want the same function with more talkative reporting and a gentler price, the Einhell CE-BC 4 M charger offers an LCD screen for some twenty euros less. And if your vehicle or motorhome uses lithium batteries, you will need the CE-BC 5 M LiFePO4, which the C30 does not replace.
Comparison
At around sixty euros the C30 faces rivals better equipped on display but less trusted on modern battery handling. Here is the positioning.
| Criterion | Bosch C30 | Einhell CE-BC 4 M | Noco Genius5 | Bosch C70 |
|---|---|---|---|---|
| Max current | 3.8 A | 4 A | 5 A | 10 A |
| Voltages | 6 V and 12 V | 6 V and 12 V | 6 V and 12 V | 12 V and 24 V |
| Rated capacity | Up to 120 Ah | Not stated | Not stated | Considerably higher |
| Display | Indicator lights | LCD | Indicator lights | Indicator lights |
| Observed price | ≈ 59 € | ≈ 39 € | ≈ 79 € | ≈ 90 € |
The choice comes down to trust and to battery size. The CE-BC 4 M does the same job for twenty euros less, with a more informative screen and a declared IP65 rating; it is the better objective value. In exchange the C30 brings the backing of a battery manufacturer and a clearly stated 120 Ah capacity, a reassuring argument on a large diesel. If you need to handle 24 volt batteries or heavy vehicles, step up to the Bosch C70. And for lithium, neither will do.
Related video
Video: Bosch C-Line Battery Charger - Published on 14/10/2024
Our tester's review: Christophe Delpuech
There is a simple reason the C30 has become the shelf reference: Bosch understands batteries better than anyone, since the supplier builds them for half of Europe's carmakers. That expertise shows on one specific point, the handling of EFB and AGM batteries. These technologies now fit every stop-start vehicle, they demand specific charging voltages, and many cheap chargers treat them as ordinary lead-acid, which shortens their life. The C30 applies the right profile. The second argument is admissible capacity: 120 amp-hours, where most chargers of this size stop well short. In practice it is not limited to the city car, it also copes with the large diesel saloon and the family MPV. At 3.8 amps charging stays slow on a deeply flat battery, but that is the very principle of this class of device: gentle charging wears the plates less than a brutal one. In use the housing is sturdy, the clamps are decent, and the supplied carrying case saves you from finding tangled cables in a corner of the garage. Two honest remarks. Status reporting is limited to indicator lights, with no screen: you know roughly where charging stands, not to the percentage, which the Einhell CE-BC 4 M displays for twenty euros less. And like most lead-acid chargers, it does not handle LiFePO4 lithium. At sixty euros it is a purchase of peace of mind rather than a bargain, but the reliability is there.
Frequently asked questions: Bosch C30 6/12 V battery charger
Yes, and that is one of its strengths. The C30 handles EFB and AGM technologies, fitted to stop-start vehicles, which require specific charging voltages. A charger treating them as ordinary lead-acid shortens their service life.
Bosch states batteries up to 120 amp-hours, covering the whole private fleet from a 45 Ah city car to a 100 Ah MPV. At 3.8 amps, however, expect a full night on a large, deeply discharged battery.
Yes. Once the battery is full the unit switches automatically to trickle mode and only feeds current back when voltage drops. It is the right solution for a classic car, a stored motorcycle or a lightly used vehicle.
No. Like the vast majority of garage chargers, the C30 is designed for lead-acid, gel, AGM and EFB chemistries. For lithium iron phosphate you need a dedicated unit such as the CE-BC 5 M LiFePO4.
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Published on 26/07/2026