Originally Posted by amirm
The cheapest meters like Harbor Freight are not auto-scaling which makes them more difficult to use (for both novice and experienced). Their probes are also horrible. I have connected them to batteries and have them not show the right value unless you really poke them into the terminals. I have a few of them I got for free and leave them in the workshop and such and not worry about getting stolen.
As someone mentioned, for RV work you really want one with a clamp meter as often you want to measure current without disconnecting cables.
A very nice but low-cost clamp meter is this Uni-T: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
It is small so doesn't take much space on board. And unlike a lot of cheap Chinese meters, its construction is decent.
That looks very much like the one I have and so far I'm very happy with it.
If buying something similar - especially in the lower price range - read the description closely to make sure that the clamp for measuring current will function on BOTH AC & DC current.
Some will only work on AC, but for RV work, it is handy to have both - for example, checking current flow to brakes