Wattsup Power Meter vs smart battery monitors

[tacomabill]

What is the advantage of a smart battery monitor like the Victron BMV 712 or Trimetric 2030 over a a far less expensive alternative like the Wattsup power meter?
Both measure volts, watts, amps and amps consumed over a 24 hour period(resettable). I have a single 12 volt AGM battery in my camper and will be adding a small compressor fridge and solar panel to support it. I want to monitor the battery state and be aware of how many amps are being fed into and out of the battery so I can prevent over discharging it and, if necessary, add more solar.

 

[SoCal_80]

I have been using a wattsup for years and have no issues. I use it to measure my solar efficiency as well as real time battery voltage. This setup has served me well


Sent from my iPhone using Tapatalk Pro

 

[john61ct]

Both measure volts, watts, amps and amps consumed over a 24 hour period(resettable).

That last is AH, amps cannot be consumed over time.

The difference is a proper BM is trying to track SoC as accurately as possible.

So you need to program the monitor with the Peukert coefficient and charge efficiency factor for your specific bank, as well as updating it with the actual residual AH capacity, as that declines over time.


If SoC is important to you, a SmartGauge is both much more accurate (3-8%) and requires none of those complexities.

It doesn't measure amps in or out however, so many use both approaches and just rely on SG for the SoC part.

Check out https://marinehowto.com/programming-a-battery-monitor/ and other battery monitor articles there.

Actually, everything about DC electronics there is worth studying closely, if you're so inclined.

 

[tacomabill]

I skimmed thru the referenced article from marinehowto. It seems it may be dated, tho the principles obviously havent changed. But, it references the dated Victron 602. I wonder if the newest model has not resolved some of the issues. I think it automatically handles the peukert value, but not sure. Big takeaway for me is that these systems are not entirely accurate and to get maxiumum accuracy you really have to stay on top of them. I want to be camping not spending my time on this. So I think I will just go with the Wattsup, or maybe even just a simple voltmeter.

 

[Rando]

The big issue is that the Watts up and the like can only measure uni-directional current, not bi-directional current. You can integrate the current flowing into or out of you battery but not the the net SOC of your battery. I guess you could run two of these in series (one reversed) and reset them on a regular basis and do the maths. But if you just want to go camping, just buy the Victron, set it up once, then let it do its thing.

 

[john61ct]

I think it automatically handles the peukert value, but not sure.

No AH counting BMs do.

The cheap ones ignore the finer points and as a result are less accurate.


Charging to 100% full is easily calibrated with a $40 ammeter, including Watts Up long as we're talking low amps.

If your cheap AH counter then just lets you know the total discharged, roughly is good enough to stop before you get to 50%, then charge the bank back to Full, you'll be taking good care of your bank.

A voltmeter is not nearly accurate enough unless you have a cheap bank and don't need to optimize longevity.

 

[Rando]

Having a solar panel also makes it much harder, as you will often charge without getting back to 100% full, meaning you won't know when to reset your Ah counter. Again, if you want simple, just buy the right tool (Ah counting BM or a SmartGauge).

John is also right about AH counters and Peukert. The better ones at least take Peukert into account, but some (Trimetric in particular) just ignore it.

 

[tacomabill]

I ordered the Morningstar SunSave controller, which has 4 stage charging. Will that unit not get me back to 100%?

 

[Rando]

Depends how much sun you get and how long you get it for.

 

[john61ct]

The whole point IMO of having a decent monitor is to train yourself to not use more than you will be able to replace each cycle.

Income and expenses have to balance, and if you don't get back to 100% (not 99%) a couple / few times per week, you'll be replacing your bank more frequently.

BTW Bogart's stuff is great, 2x SC-2030s controlled by a Trimetric is a great integrated solution.

 

[Rando]

Bogart's stuff was the bee knees at one point, but there are much better options out there now - but that is a discussion for another thread.

 

[tanokosohana]

Wow, congratulations. I also thought about this recently. My energy supplier just infuriates me because every month he refers to possible bankruptcy and as a result constantly raises tariffs. I’m tired of it and I decided to install a smart meter in order to monitor the energy consumption. I did not think that this would really work, but in the end I managed to save more than 600 bucks. This is a pretty good amount. So I'm glad that I read the article at https://usave.co.uk/ and thought about it. Also, I am now thinking about installing solar panels on the roof. It seems to me that this will also help in increasing the energy efficiency of the house ...

 

[dreadlocks]

congratulations, is there any particular reason you replied to a 2 year old dead thread with nothing to contribute?