Sealey BT102 12V Digital Battery & Alternator Tester

Very keen price and extremely quick delivery from ONE SAFE SOURCE (despite the slightly odd name of this supplier!) The tester appears to work well - does what it says on the tin. Except that there is no tin - the tester would benefit from coming in some kind of storage case, box or at least a bag, to stop the leads dangling untidily when not in use. And it would benefit from having slightly longer leads. As Keith B says in his very helpful 2014 review, this tester - as distinct from the otherwise very similar BT101 - will also test a car's starting system and charging system. Sealey's newer BT103 battery tester (reviewed in the July 2016 issue of Car Mechanics) seems to be neat and slick to use and has an LCD display (easier to see in bright sunlight than the red LED display of the BT101 and 102) but only tests the battery, not the starting & charging systems. Which is why I bought the older but more versatile BT102. Some other reviewers have severely criticised the poor visibility of the red LED display on the BT102, but once you realise that you need to shade it from bright sunlight in order to be able to read it, that is a trivial issue with what is a neat, small, reasonably priced, useful, versatile and fairly straightforward-to-use piece of equipment. If it saves you buying a new battery when you don't need to (a battery may be perfectly sound but just need charging) or if it saves you wasting time struggling with a battery which may look OK and be fully charged but which is actually clapped out and unable to hold its charge or to deliver a decent starting current, then this little tester will have earned its keep. Especially if you share it with your mates or a neighbours. Recommended.

This seems to work very well for car batteries, which my river boat engine has, but it's not designed to work with leisure batteries, which my yacht has. With no starting handle, and no decompressor, its nice to be able to check that if starting isn't fairly fast, it's something other than the battery's CCA that's at fault. If I'd had this sooner, I'd have saved myself six weeks worry and head scratching through December and January. The Yanmar in the Yacht has a decompressor and a starting handle, so CCA is less important.

Well I had VW come out and they said the battery was good, but using this to see that the battery had lost over 100Ah cold cranking it was clear the battery was cream crackered, new battery installed and I've never looked back since! Worth the money.

does what it says on the tin, checks voltages, gives a cold start voltage and I bought it to check cca, seems to be correct. In the end I decided alternator charge voltage was on the low limit, so pointed me in the right direction as the battery seemed good

Love this gadget, answers a lot of expensive questions

first class bit of kit simple to use and give you the right readings all the time well happy with product

excellent tool

Good price and quality