7 replies to this topic

[Doff]

We recently got our new FWC hawk and we've been trying to figure out what the three different power displays mean and how we can apply them to daily use in the camper. There are 3 displays. The first is the round one with a blue light. It has multiple settings we can toggle through. At FWC they told me to keep it on “volts” and make sure it stays about 12. Not sure what that means. The second display is when we turn on the USB outlets. It also has a numerical display that we were told to make sure it stays about 12 as well. But those two don’t seem to be related…? Last there is the button to push for the battery…it says if the battery is 1/3, 2/3, or full. But that as well doesn’t seem to relate to the others. Can anyone explain what all
These mean and how we practically apply them?

[lokidisc]

I also just went through this process with my purchase. I am choosing to keep the "blue light" display, on the setting that shows the power coming in from the solar panel (Not the volts, as mentioned). I chose this so I know when I am getting sufficient sunlight to my solar panel. You will know the proper setting as its a constantly changing number (unless there is no sun at all). 

 

The "USB lights", I use as a gauge for power available. I have dual 6 volt batteries, so my understanding is that I can go quite a bit lower on this than 12 volts. 

 

I dont use the "battery button" which I am assuming you are talking about the button the water power switch panel. But when I have checked it, it has correlated to power available from my batteries. I only use that panel for water tank level in the camper. Although that seems to be a bit off as well. 

 

I am definitely still figuring it out, so if any of this is incorrect I would happily learn better information. 

[Doff]

That’s some good insight….thanks! Any idea how to know if there’s enough power in the batteries to keep the fridge, fans and such running?

[bsharp007]

The blue light gage is basically a solar charger monitor which is a rebranded Victron solar charger and it keeps track of the energy coming into your batteries from the solar panel as well as the voltage of your battery.  It is not a battery monitor per say and can't tell you the state of charge of your battery/batteries.  What I think FWC was telling you was the most important number on that gage is the voltage of your batteries and to keep it above 12 which is basically a fully depleted (approx 50%) for a lead acid type of battery.  As far as the other FWC monitor I would ignore it because it isn't very accurate IMO.

 

Get used to the voltage number on the round gage when your battery is fully charged and understand that 12v is basically a deleted battery, over time you'll get used to understanding what the voltage number means in regards to how full your battery is.

Hope this helps.

Edited by bsharp007, 05 August 2021 - 01:27 AM.

[Doff]

So a 12 on the monitor means that the battery is fully depleted? We’ve seen it down to 11.8…is that bad?

[Jon R]

Here’s a ballpark guideline:

https://duckduckgo.c...cid-battery.ppm

[veryactivelife]

Of the 3 systems the read out on the Overland Solar MPPT display is probably the most accurate, being the most precision instrument of the 3. That said there are some caveats to consider. Accurate voltage readings require a rested battery, 12 to 24 hours ideally. In daily application this is of course not possible. The greatest deviation will be when there is either a load or charging being applied to the battery. Reading the voltage while say the fridge or furnace are operating will give an artificially low reading. Conversely reading the voltage while the battery is charging, particularly in Bulk phase will result in a higher voltage.

The best way to determine the state of charge, SOC, is with a proper battery monitor which will track all the amps going into and out of the battery. Many people like the Victron BMV 712 Smart. The BMV is Bluetooth and can be networked with your solar controller by plugging Victron’s Bluetooth dongle into the controller. Then with the Victron app you can see and control everything on the phone or tablet. Much has been discussed here on WTW concerning the subject, a search should point you in the right direction.

As to 11.8v, that’s not something you want to do regularly. Continually drawing down below 50% will significantly reduce the life of the battery. The 50% guideline will typically result in average life expectancy, 60% or 70% above average. Average is 5 years +\-. It’s also very important to achieve a full 100% SOC as often as possible.

Hope this is helpful,
Dean

[Vic Harder]

+1 to what Dean said.  None of the 3 devices you mentioned are actually good battery monitors.  Cheaper options than the Victron BMV are available.  You have to get something that uses a "shunt" to measure all the dis/charge happening.  Installing something like that sounds like it might be outside of your comfort zone though.  Do you have a good RV shop or electrically savvy friend nearby?