Handy and inexpensive.

I have hit a bad battery spell. The one in the two seater died, no start. The one in my 1975 BMW R90/6 died despite being just 14 months old. And the one in my scooter was beginning to sound weak. All batteries are maintained on a trickle charger in a heated garage.

Now I have been very lucky as all my recent battery failures have occurred at home, meaning I was not left stranded on the road. But this spate of failures left me determined to become more proactive about knowing the state of health of my vehicle batteries so I splashed out $23 on a Konnwei KW208 car battery tester. Maybe not the greatest choice of name, true, more like something you expect of the White House, but at that price hardly a great risk either.

First, the manual, in half decent English is printed in minuscule type. Click Konnwei instruction manual and you can enjoy a proper sized version.

The device can test batteries in or out of the vehicle, and this model is limited to 12 volt cells. If in the vehicle and still working you can also test the cold cranking amps (CCA) as a percentage of the rated value (it’s on the battery’s label under ‘CCA’). This is a key measure as CCA is the high current delivery required to activate the starter and turn the engine. Additionally you can test the alternator’s power delivery (the alternator keeps the battery charged when the vehicle is running) as well as the starter’s cranking efficiency. I tested all of these on a failing and then on a new motorcycle battery and the measurements accurately reported ‘Replace’ and ‘Good Battery’, respectively. For the good battery state of health (SoH) and state of charge (SoC) were both reported as high, as expected.

The cables are nice and long so there is no difficulty installing the clamps (remember to connect the red – positive – first and disconnect it last) and the clamps grip well. No battery is required as the tool uses the vehicle’s battery for power. The LCD screen is easy to read, unlike the instruction book.

As for getting stuck on the road with a dead battery, I carry one of these jump starters – it delivers the instantaneous high cranking current which a failing battery cannot deliver and, once the vehicle is running is disconnected as the alternator can pass sufficient current through the dying battery to keep the engine running.

I now feel better prepared for the inevitable battery failure(s) down the road …. or in the garage!