Bluetooth Smart Battery Monitor

[Alben]

Just installed a Bluetooth Smart Battery Monitor / DC Power Meter.
Made by Thornwave Labs. https://www.thornwave.com/products-btdcpm/

Checked the voltage and amperage readings against a name brand multimeter and the readings coincided. The bluetooth signal is so strong that I can even monitor my trailer from inside my home when it is parked in the driveway. Now I will be able to monitor battery level while towing long distances (while running the fridge on 12V), monitoring current draw while boondocking, and keeping an eye on it while parked in my driveway.

Below is a image of the installation. The installation is right on top of the battery itself. I used an inline 30A ATO fuse holder to make the final connection, which also serves as my disconnect (just pull the fuse).

It has features such as monitoring state of charge, and the ability to wire in a solid state relay to cut power if battery gets too low, excessive current, etc. Lots of flexibility.

[babock]

Doesn't even look like it's wired up correctly to measure current. Should have the negative battery post wired to the input of the shunt and the output going to the trailer. The fact that there are two leads on the battery means it can't measure current properly.

[ScottBrownstein]

It is wired to the plus side. All current will flow through the shunt.

[babock]

Originally Posted by ScottBrownstein

It is wired to the plus side. All current will flow through the shunt.

Duh...you are correct. Was a late night.

I am so used to having shunts on the negative side. Sure looks like small wire though compared to what is already on the negative side. This must be a very small trailer.

[OYO]

Originally Posted by babock

Duh...you are correct. Was a late night.

I am so used to having shunts on the negative side. Sure looks like small wire though compared to what is already on the negative side. This must be a very small trailer.

I'd bet it's an A-frame

[Larry-NC]

Originally Posted by OYO

I'd bet it's an A-frame

Uhh...Yeah. This is the "A Frame Campers" forum.

Larry

[OYO]

Originally Posted by Larry-NC

Uhh...Yeah. This is the "A Frame Campers" forum.

Larry

I never really understood the term "tongue in cheek", but our daughter-in-law refers to us as the smart ***** family. That I understand.

[OYO]

Nice setup Alben. I have a similar one, But I think yours is simpler, cheaper and just as good.

Sorry about the thread hijack.

[Alben]

I know having this on the positive side of the battery thew some people that were commenting off. The directions say that the positive side would be the more common way to mount this battery monitor. Although the directions do also say it can be wired to the negative side. I chose the positive side because the positive wire was only 12 gauge and easier to work with. The common negative wire is much heavier. Also it made sense to use a 30Amp fuse holder as my connecting wire to the positive post.

[Bluepill]

Looks like a well thought-out design. Please post your experience after you use it for awhile.

[garbonz]

Kinda like a Victron bmv700 without the readout. Brilliant idea, although many would want a external shunt to handle larger gauge wire and higher current. The Victron with Bluetooth monitor is double that price, and the trimetric doesn't have Bluetooth I don't think.

Good post.

[babock]

For the money, that device is good for low current applications.

My bmv-712 was $185.

[bcmcdonald]

following...

[pgandw]

A wired-in voltmeter (I installed just below the stereo in my A-frame along with an on-off switch, less than $10 total) will give me as much information as I want to deal with for much less money. I'm not knocking the OP's installation at all, just saying that if you are not hung up on your batteries, you can do something cheaper.


Upon arrival, checking the voltmeter gives me an idea of how much I depleted the batteries running the fridge on DC on the way. While driving, the alternator barely maintains the batteries. While stopped for lunch, gas, check-in, setup they deplete powering the fridge and CO/propane detector.


If at an electric site, the voltmeter confirms the converter (PI replacement) is doing its thing in recharging the batteries.


If dry camping, the voltmeter gives me an idea of when I'm hitting that 50% charge point, or how much I sucked the batteries down with the heater during the night.


Not perfect, but good enough for me.


Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan

[carlsbad]

Harbor Freight voltmeter is free...

[babock]

A voltage meter is useless unless there is zero load and really only accurate after no load for 20 minutes. It's also useless to determine what that actual current load is or how much current is going into the batteries either from your converter or solar controller.

[TitanMike]

If it works I that's great. What would concern me is having the electronics in the same enclosure as the battery. Even if the battery has the "Maintenance Free" caps there is the risk of corrosive vapor being present when battery is being charged at full rate.

Just look at most battery terminals after a year or two and note the corrosion that is usually present. Doesn't have to be the crusty white stuff that shows up on a battery that's overcharged and poorly maintained. More likely it will be enough that leaves behind some green corrosion where the terminals were crimped onto the copper wire. THAT's what will eventually affect the printed circuit board and connections to it.

If I were mounting a monitor like that I think I'd be putting it in an enclosure outside the battery box just to make sure NO electrolyte could reach it, splash or vapor.

[Bluepill]

Good point. Certainly not hard to wire externally.

[carlsbad]

Originally Posted by babock

A voltage meter is useless unless there is zero load and really only accurate after no load for 20 minutes. It's also useless to determine what that actual current load is or how much current is going into the batteries either from your converter or solar controller.

95% of campers don’t care.

[babock]

Originally Posted by carlsbad

95% of campers don’t care.

Then don't post on a thread about battery monitors if you don't care.