Voltage guesses the state of charge; a shunt counts it · review

ECO-WORTHY 300 A shunt monitor, 3.5-inch colour touchscreen, 0.5 mA review

A 300 A shunt monitor with a 3.5-inch colour touchscreen and a published self-consumption of 0.5 mA — the only self-consumption figure in this catalogue.

By Jean-Benoit Buisson

The bottom line The only instrument in this entire catalogue to publish what it costs to leave connected, and the only one to explain the commissioning step that makes its reading true. Its chemistry support is left to custom parameters alone.

A 300 A monitor that tells you what it costs to watch.

Half a milliamp

Published in the first bullet. Across every product in this catalogue — inverters, controllers, chargers, monitors — one publishes its own standing consumption, and this is it. A monitor is wired permanently across the battery it observes, and 0.5 mA is roughly 4.4 Ah a year: negligible against any real bank, and knowable rather than assumed.

The commissioning step

The third bullet: set the battery parameters, then charge the battery fully, and the status will display correctly. That is the single most misunderstood thing about counting monitors, and this is the only listing in the family to state it.

The display

3.5-inch colour touchscreen, adjustable brightness, backlit. The best in this family by a distance, and brightness adjustment matters on something mounted where it is read at night.

The lines this listing leaves blank

Chemistries by name. An accuracy figure. Any application — this monitor is read at its own panel.

Availability

German, French, Italian and Spanish Amazon stores quoted 60 € to 80 € when this page was compiled.

British Amazon store carries it too, priced in its own currency, which the euro range above deliberately omits.

American Amazon catalogue carries an entry for it, with nobody selling.

These figures are what Keepa reported on the day this page was last updated. Availability and pricing move without notice.

Prices quoted in this text were read on 16 September 2026. The live price is at the top of the page.

What it gets right, and what it leaves out

Strengths

It publishes its own current draw: 0.5 mA, which is the figure a permanently connected instrument owes you
A colour touchscreen with adjustable brightness, which is the best display in this family
A temperature alarm alongside voltage and current

Compromises

No chemistries named, only custom parameters
No accuracy figure
No application, so it must be read at the panel

Specifications

Measurement method	Shunt-based, from the title
Shunt rating	300 A, from the title
Accuracy	Nowhere in the listing
Chemistries	Absent as names; user-defined battery parameters are supported, second bullet
Display	3.5-inch colour touchscreen with adjustable brightness and backlight, first bullet
App	Nowhere in the listing
Alarms	Audible alarm when voltage, current or temperature is too high or too low, second bullet
Self-consumption	0.5 mA, first bullet — the ONLY self-consumption figure published anywhere in this catalogue
Installation requirements	The third bullet states that battery parameters must be set and the battery then fully charged before the status displays correctly
Amazon reference	B0DNJDDTDY (same reference on 6 Amazon marketplaces)
EAN	0810127136618

Questions owners ask about this one

Is 0.5 mA significant?

Over a year it is roughly 4.4 Ah — small against any real bank, and worth knowing precisely because a monitor is connected permanently. Publishing it is what allows it to be added to a standing-drain calculation instead of guessed at.

Why must the battery be fully charged first?

Because a counting monitor needs a reference point. The third bullet says so explicitly: set the parameters, then charge fully, and the state of charge displays correctly afterwards. A monitor installed on a half-full battery reports nonsense until that first full charge.