I've got a Bluesky 2512i MPPT charge controller. <br>I've also got BlueSky's IPN pro remote which monitors amperage and counts amp hours into and out of the batteries. A very great tool to have which has taught me a lot, as i watch it a lot, and have seen 3 different sets of batteries through their lifecycles over the years.<br><br>The IPN pro remote also allows me to change Acceptance voltage and duration as well as float voltage and current of the charge controller. It controls some other functions related to the charge controller too.<br><br>I've heard good things about Morningstar products. And the Trimetric is kind of the standard, for a battery monitor.<br><br>Those 'watt's up' meters only count current in one direction. You would need two to measure current into and out of the battery banks and do some light math. As said above, the wires are not really thick enough to pass alternator or starter currents. So any driving would make the amp hour counter inaccurate.<br><br> Also I think they stop counting at 68 amp hours or there abouts.<br><br>Their price is right though. I'd definitely consider installing 2 if I were monitoring a modest battery system that was not going to see much, if any alternator current. Since some think 10 awg is sufficient to recharge a distant battery from the alternator, this meter would show how little long lengths of 10 awg add with no real danger to the meter or its wiring. <br><br>I rewired all my vehicle grounds to run through the required 500 amp shunt via multiple 2 and 4 awg cables, so that the IPN ProRemote monitor can see and count the alternator current. Since my whole alternator charging circuit is beefed up, it can show that my alternator(rated 130 amp) can briefly, at high rpm when cold, send 100+ amps into the house batteries. This much current would turn the watts up meter into a cloud of magic blue smoke.<br><br>My Monitor is not super quick to read amperages, but I have seen that the starter pulls upto 150 amps. Likely the actual current is significantly higher, but my engine catches before the monitor has had time to catch up to the real number.<br><br>
<br><br>Hall effect sensors can also be pretty accurate in measuring current. They do not require opening up the circuit and putting a shunt inline to measure current.<br><br>If you just want to check to see how much current the panels are making here or there in different conditions, and not necessarily have an expensive monitor always in place doing its job, a DC clamp on Ammeter is another great tool to have.<br><br>I recently bought this one. You can just clamp one wire in the circuit and see with pretty good accuracy how many amps are flowing through.<br><br>
http://www.sears.com/craftsman-digital-clamp-on-ammeter/p-03482369000P<br><br>It is a full featured digital multimeter too which is, IMO, a vital tool to carry for a Van Dweller. It is pretty accurate compared to my Shunt based meter, but do use alkaline batteries in it, not Nimh or Nicads. <br><br>Note that many clamp on Meters ONLY measure AC current, not DC current. In general you are not going to find an AC/DC clamp on Ammeter for much less than 50$ new, whereas you can find an AC clamp on meter for 10$, so don't shoot yourself in the foot bargain hunting clamp on ammeters<br><br><br>