12vdc watt meter to monitor usage over time

[johnm1]

I want to measure our rv's 12vdc accessories, over time. The main one is the 12vdc compressor fridge.

What's the simplest way add one between the fuse on the panel box and the accessory in the rv? It'd be simple to make a short little wire harness to adapt to the spade fuses. and, if needed, I can easily run power to it from another source.

What do people recommend to do this?

 

[Pappion]

I'm interested too. I have been using the bluetooth battery shunt to estimate. No history data.

 

[pollenface]

You can add a shunt and power meter fairly easily

 

[TacomaJoe]

I like the idea of something that could just pop in the place of a fuse (will need a connection to the negative as well). The normal shunts measure the current in the negative leg wouldn't work in the positive (fused) leg. My bluetooth BMS has been my tool to measure usage. Works great for fixed loads. I can get a value for a light or fan no problem. A variable load like a refrigerator or furnace takes more work. While sitting at home, I can turn off charging and monitor how much the refrigerator uses in 24 hours but it will be relative to ambient outside temperature but gives a good base.

 

[Pappion]

Plenty of DC shunts available. Nothing found with daily KWH, like my AC kilowatt hour meter.

 

[johnm1]

Plenty of DC shunts available. Nothing found with daily KWH, like my AC kilowatt hour meter.

The kill a watt meter (but for dc, not ac) is what I'm looking for. Also in the price range of the kill a watt meter, not like some of the $300+ diagnostic tracking meters like I've seen.

 

[OzSolar]

The kill a watt meter (but for dc, not ac) is what I'm looking for. Also in the price range of the kill a watt meter, not like some of the $300+ diagnostic tracking meters like I've seen.

I don't believe there's anything that counts DC energy (kWh) AND logs like a Kill-A-Watt for future analysis in the $30 range.

Here's the widest range of meters I know of listed in one place.

https://powerwerx.com/digital-meters

 

[DIYrich]

At the fridge, put a shunt on the negative side of the fridge connection.

 

[TommySr]

What do people recommend to do this?

Johnm1, while I'm not recommending you do this, there are low cost ways to get long term data.

to get the data



to record the data



to send the data



to display the data

 

[johnm1]

TommySr - I wish I had a clue on how to use something like that. I need something MUCH simpler ... more plug and play than your suggestion but thank you!

 

[Pappion]

I don't believe there's anything that counts DC energy (kWh) AND logs like a Kill-A-Watt for future analysis in the $30 range.

Here's the widest range of meters I know of listed in one place.

https://powerwerx.com/digital-meters

Close but no cigar. The powerex watt meter has no Restart Button. Only counts Wh from last startup. Also no daily clock and several day history.

 

[OzSolar]

Close but no cigar. The powerex watt meter has no Restart Button. Only counts Wh from last startup. Also no daily clock and several day history.

Isn't that what I said?

I do see that the Powerwerx Watt Meter now has a separate power supply option so that might help is save what little memory it has but still there's no substituting something like the Victron Smart Shunt.