Convenient battery charger with automatic function and clever charging tech to rescue ‘dead’ batteries

Battery chargers. They’re all the same, right? Not quite, it seems. If you’ve tried to use one of the modern electronic chargers on an utterly flat battery then you’ll know that they often don’t work, since they need to sense a certain voltage to switch on.

It’s something which has caught us out a few times, and meant we’ve had to resort to the 30-year old charger lurking in a dusty corner, with all the dusty electrical burning smell and loud buzzing that entails.

All of which meant I was intrigued by the Optimate 6 charger which promises fully automatic operation and the ability to revive entirely ‘dead’ batteries.

The ‘6’ in the name indicates its 6 amp capacity and the makers reckon it’s good for all automotive batteries up to 144Ah including regular batteries, the AGM types used for stop-start systems and gel-type leisure batteries.

Using it couldn’t be more simple as it is indeed fully automatic: simply connect it to the battery, turn on the mains supply and wait. The Optimate performs a series of tests to determine the battery’s condition and then automatically charges it as appropriate. Indicator lights on the unit tell you what it’s doing, from the ‘rescue’ mode through to regular charging and then eventually the low-voltage maintenance mode which can be left connected permanently.

Optimate claims its ‘Ampmatic’ technology can determine between a battery which is simply discharged and a heavily sulphated unit which needs rescuing, employing a multi-stage pulsed charging desulphation programme to rescue it.

Testing

In tests I found it charged a regular flat battery from non-start to fully functional in a couple of hours, while I also hooked it up to a presumed dead unit due for disposal and was impressed to see it switch into rescue mode within a couple of minutes and duly revive the battery overnight.

Weatherproof to IP54 standard (direct water spray for at least 10 minutes) and to -40°C, the Optimate is supplied with the usual crocodile clips and also an insulated connector which can be fixed permanently to the car, allowing the charger to be quickly plugged in as a trickle charger – ideal for little-used classics.

An extension cable for this purpose is sold separately but I was pleased to find the unit came with a generous length of mains flex which avoided having to dangle it in the engine bay during use.

Optimate 6 battery charger: our verdict

This is a clever unit which can be used as a regular battery charger or a long-term trickle charger and which can also recover batteries which were deemed to be scrap. Given the cost of a big-capacity battery, just one successful recovery will cover its purchase cost.

Specifications

RRP: £90-£120

Manufacturer: Optimate

Max capacity: 144Ah