Measured FWC power use

[RC Pilot Jim]

I ordered a Trimetric Tuesday morning.

 

[DesertDave]

I have found the following with my trimetric readings:
4 lights - anything above 12.4 volts
3 lights 11.9-12.3 volts
2 lights 11.8 or lower
1 light - I've never discharged the battery below 11.8 to find out

Has anyone else with a volt meter had similar data?

Yes,

I once ran three days with no charging from solar due to shaded spot - battery was at 12.1V and that was the only time I have ever had less than 4 lights on the FWC 'idiot light' meter. Since my battery is 12.9V at full charge I was probably only at 20 or 25% of full capacity at 12.1V.

 

[Ethergore]

This thread needs to be pinned.

 

[billharr]

I ordered a Trimetric Tuesday morning.

Just watched a video on the Trimetric

 

[DrJ]

Bill - that's a great video thanks for posting.
That gives a great explanation of the real time data you get with the monitor.

When I measured all the FWC equipment earlier in the post it was very similar to that video.
Anytime you turn anything on or off it tells you exactly how many amps just changed.

My favorite is watching the amps and voltage go up with the solar system in the morning on a sunny day.

You know that you are going to plenty of cold food and power for the heater that night!
Or at least you to adjust your power usage if it isn't working out.
No more guessing.

If anyone is interesting in how I installed this, I could put some pictures and explanation on a different post.

 

[Kokopelli]

I would love to see how you installed it and what was needed.

Thanks!
-Rick

 

[captainphx]

I have just started draining down the batteries for my experiment but looked at the Trimetric meter this am.

With the truck just idling the meter showed 13.4 volts. It was at 93% state of charge and charging at 3.5 amps/hour at that moment.

Should be interesting to see the voltage and amps with the truck at 2000 rpms.

What is the charging amp rate while driving? Just curious, because I had this discussion with FWC a year ago and I was told that the truck will recharge at the rate of 1 amp/hr and that my 80 watt solar panel recharges at 4.7 amp/hr. This seems correct, as sometimes after a long day of driving (with my Dometic 110 frig on) I still show up at a camp site with only 3 lights showing. Very frustrating. I have a couple of group size 27 batteries. Gonna have to get a trimetric too. Have any pics of where it is mounted? Thanks for all this info. Any install info would be greatly appreciated!

 

[photohc]

Captainphx, I too have had similar experience driving and very little improvement in my battery state. At that time I had a 100 watt solar on the roof. I have a dometic 80L ref that uses around 4.3 amps when cycled on. The 100w solar can just barely keep up with the fridge let alone charge the 2x group 27 batteries. This is especially true while driving in the desert heat. I think if I had the dometic turned off, the charge improvement would have been better. I have since added a 150 watt panel for a total of 250 watts and have not had a repeat of the low charge while driving.
I have a trimetric installed and never thought of checking the charge current coming from the truck. Need to do that on my next trip in October. For those that don't have a trimetric, it is impossible to determine the state of your battery without having this device. It's not cheap but worth the cost and effort to install.

 

[Casa Escarlata Robles Too]

This is sorta on topic.
First, I purchased a watt meter an inexpensive one $13,don't laugh it has great reviews and seems to do what i need from a meter.It's
a AODE LCD digital Voltage checker. I watched the posted videos and it's hooked up correctly and gives great info.
I will post some at a later time.

Second, and here lies the question.
I have 2 solar panels,a 45w and a 60w,both are moncrystalline and hooked up correctly.
Together I show about 40w on our sunshine here,(some clouds) when I cover the 60w only the system drops to about 32w. when I cover the 45w only the system drops to about 7w.
So my 45w panel is most likely producing at a good %. But the 60w panel is only at about 10% or less.
I can judge about what % a solar system here should produce as I have solar on my house and it runs on a day like today at about 80%
The 45w panel seems ok % wise but the 60w isn't doing the job.
Any ideas?
I want to get input and ideas before I contact the solar panel company.
Thanks.
I have been following this thread and a lot of the info is very useful, thanks to Dr.J. and others who have added info.

Frank

 

[DrJ]

Here's my report on the truck charging data:

Drove 2.5 hours - mostly interstate speeds 75 mph
Replaced 26 amp hours total.
Average charging of 10.4 amps per hour.
Voltage remained around 13.0.
My highest voltage recorded was 13.1.
My battery bank went from 58-70% of charge.

I disconnected the solar system so that the only possible charging could be from the truck.

My compressor fridge ran the entire time. I wanted it to be just like my usual traveling power use.
When I turned the camper master switch off the amps of charging increased to 15 amps from 10-11 amps. This makes sense since my fridge uses about 4.5 amps per hour.

The camper batteries were fairly discharged at 58% so I'm assuming the batteries would accept as many amps as could be pushed to them from the truck.

I had FWC install my campers wiring system.
My truck is a 3500 silverado duramax.

Here's what I learned:
You can expect about 15 amps per hour of charge while driving with all electrical equipment off. If you are running a compressor fridge you would still get reasonable charging. At least 200-250 watts of solar in good sunlight is a fair comparison.

If you are running a 3 way fridge on 12 volt while driving, it probably works but don't count on much battery charging too. You would have to check your manual, but I think 10-15 amps would be close for many of them in power draw.

There is definite voltage drop from truck to camper batteries. Running a larger wire from the battery to the camper maybe very helpful if you rely on truck charging as a main source of battery charging.

13.1 volts is not great for reaching a full charge even on longer drives. I don't think my system would ever get back to 100% on driving alone. However, I could probably replace enough to get by until I got more sunlight or 110 outlet.

I'll try this again with just the truck idling and see what kind of charging I get then too.
I've tried this before to recharge the batteries with varied success while just idling.

 

[PaulT]

If you know the length of the wire from the truck battery to the camper battery and the current being carried by that wire, the voltage drop for a particular gauge or the wire gauge for an acceptable voltage drop can be determined.

With the Trimetric showing the voltage at the camper battery and the current going into the battery, measure the truck battery voltage and you have the data you need.

Better to measure and know than guess.

However, my guess is that 10 gauge is too small to use the truck to charge the battery with any significant load. It looks like 4 or 6 gauge might be needed. Replacing the truck wires is easily doable but replacing the wires inside the camper could be problematic. You would also need to replace the truck to camper connectors to accomodate the larger gauge wires.

Paul

 

[photohc]

This is sorta on topic.
First, I purchased a watt meter an inexpensive one $13,don't laugh it has great reviews and seems to do what i need from a meter.It's
a AODE LCD digital Voltage checker. I watched the posted videos and it's hooked up correctly and gives great info.
I will post some at a later time.

Second, and here lies the question.
I have 2 solar panels,a 45w and a 60w,both are moncrystalline and hooked up correctly.
Together I show about 40w on our sunshine here,(some clouds) when I cover the 60w only the system drops to about 32w. when I cover the 45w only the system drops to about 7w.
So my 45w panel is most likely producing at a good %. But the 60w panel is only at about 10% or less.
I can judge about what % a solar system here should produce as I have solar on my house and it runs on a day like today at about 80%
The 45w panel seems ok % wise but the 60w isn't doing the job.
Any ideas?
I want to get input and ideas before I contact the solar panel company.
Thanks.
I have been following this thread and a lot of the info is very useful, thanks to Dr.J. and others who have added info.

Frank

It really depends on how you've connected the panels. If in "series", then blocking the sun on one panel will seriously deteriorate the total output as the panel out of the sun will hinder the output of both. If in parallel, then blocking on one panel, should not deter the other from pushing out it's maximum output. The advantage of connecting in series is that both panels connected in this manner produces a higher voltage and lower current to reduce any voltage losses due to wire size and length. In parallel, current is higher and voltage drop is more as this is determined by the wire size and length. The advantage of parallel connections is to eliminate power drops due to one panel being in a shadow. Setting up your solar panels, like other things in life, is a trade off in features.

Parallel connection:
Pros
1. Reduces effects of one panel in shadow affecting total output of 2 or more panels.
Cons
1. Requires larger wire size due to larger current flow.

Series connection:
Pros
1. All panels add in voltage and current flow is smaller (best to have MPPT controller in this instance)
2. Smaller and longer wire runs will not affect voltage loss as much.
Cons
1. Any one panel in shadow will severely affect the total output.

 

[Ethergore]

This is sorta on topic.
First, I purchased a watt meter an inexpensive one $13,don't laugh it has great reviews and seems to do what i need from a meter.It's
a AODE LCD digital Voltage checker. I watched the posted videos and it's hooked up correctly and gives great info.
I will post some at a later time.

Second, and here lies the question.
I have 2 solar panels,a 45w and a 60w,both are moncrystalline and hooked up correctly.
Together I show about 40w on our sunshine here,(some clouds) when I cover the 60w only the system drops to about 32w. when I cover the 45w only the system drops to about 7w.
So my 45w panel is most likely producing at a good %. But the 60w panel is only at about 10% or less.
I can judge about what % a solar system here should produce as I have solar on my house and it runs on a day like today at about 80%
The 45w panel seems ok % wise but the 60w isn't doing the job.
Any ideas?
I want to get input and ideas before I contact the solar panel company.
Thanks.
I have been following this thread and a lot of the info is very useful, thanks to Dr.J. and others who have added info.

Frank

I would try measuring the voltage output of each panel. If they are both good then you know is due to wiring. If not its something with the panel.

 

[Ethergore]

I would love to see how you installed it and what was needed.

Thanks!
-Rick

I would really like to see this too. I'm clueless as to what the "shunt" is.

 

[Ethergore]

Here's my report on the truck charging data:
Drove 2.5 hours - mostly interstate speeds 75 mph
Replaced 26 amp hours total.
Average charging of 10.4 amps per hour.
Voltage remained around 13.0.
My highest voltage recorded was 13.1.
My battery bank went from 58-70% of charge.
I disconnected the solar system so that the only possible charging could be from the truck.
My compressor fridge ran the entire time. I wanted it to be just like my usual traveling power use.
When I turned the camper master switch off the amps of charging increased to 15 amps from 10-11 amps. This makes sense since my fridge uses about 4.5 amps per hour.
The camper batteries were fairly discharged at 58% so I'm assuming the batteries would accept as many amps as could be pushed to them from the truck.
I had FWC install my campers wiring system.
My truck is a 3500 silverado duramax.
Here's what I learned:
You can expect about 15 amps per hour of charge while driving with all electrical equipment off. If you are running a compressor fridge you would still get reasonable charging. At least 200-250 watts of solar in good sunlight is a fair comparison.
If you are running a 3 way fridge on 12 volt while driving, it probably works but don't count on much battery charging too. You would have to check your manual, but I think 10-15 amps would be close for many of them in power draw.
There is definite voltage drop from truck to camper batteries. Running a larger wire from the battery to the camper maybe very helpful if you rely on truck charging as a main source of battery charging.
13.1 volts is not great for reaching a full charge even on longer drives. I don't think my system would ever get back to 100% on driving alone. However, I could probably replace enough to get by until I got more sunlight or 110 outlet.
I'll try this again with just the truck idling and see what kind of charging I get then too.
I've tried this before to recharge the batteries with varied success while just idling.

I wish you would have had a few more hours of driving. I have a feeling the charging rate would stay slowing down pretty quickly once the battery was at a higher state of charge and really needed the voltage. I would also like to know what voltage you are getting at your aux battery when your battery is 50% or more discharged. At that point my separator will cycle on and off as my truck battery dumps everything it has in to the aux battery.

Thanks for your time and input.

 

[Casa Escarlata Robles Too]

I would try measuring the voltage output of each panel. If they are both good then you know is due to wiring. If not its something with the panel.

Thanks .I did measure each panel and I will do them again. I only get about 7to9 watts from the 60 w panel and about 32 watts on our mostly sunny day on the 45w panel.
Next week when I have more time I want to separate each panel wiring and check them that way.
I have just been covering the panels.
Thanks for the help.
Frank

 

[DrJ]

I wish you would have had a few more hours of driving. I have a feeling the charging rate would stay slowing down pretty quickly once the battery was at a higher state of charge and really needed the voltage. I would also like to know what voltage you are getting at your aux battery when your battery is 50% or more discharged. At that point my separator will cycle on and off as my truck battery dumps everything it has in to the aux battery.

Thanks for your time and input.

I have the same 2.5 hour drive back home tomorrow. Let me see if I can get the battery closer to 80-90% charge and then travel with just the truck powering it again. I think there is a good chance that the volts go up as amps go down. That was already starting at the end of the trip.
My highest volts - 13.1 was at the end. My lowest amps - 9.6 also at the end.

I recorded data every 20-30 minutes along the trip yesterday with the truck moving so I'm pretty sure it was accurate. I even tried putting it in tow/ haul mode and that didn't seem to make any difference at all.

My volt from my dash always show just over 14 volts when I'm traveling. I'm not sure if that's accurate for the aux battery but always assumed it was.

 

[RC Pilot Jim]

DrJ ....if you have any photos of the install- yes please post them.
Mine arrived yesterday and have been reading through the installation manual . Locating the "shunt" looks challenging.

 

[captainphx]

The 100w solar can just barely keep up with the fridge let alone charge the 2x group 27 batteries. This is especially true while driving in the desert heat. I think if I had the dometic turned off, the charge improvement would have been better.

According to my conversation with FWC, the camper batteries are only charged from the truck while driving, never the solar panel.

 

[RC Pilot Jim]

When I viewed Bill Harrs "Trimetric" video yesterday the presenter showed the -Uni-Solar - peel-N- stick flex panel or panels glued to his roof plus a very elaborate controller running everything.

Overkill for us , however shows that gluing them down poses no problem .As I have done research on flex panels over the last year I have seen many of these panels directly affixed to roofs of motorhomes and travel trailers with no adverse affects connecting them that way.

For me I have the one-piece roof. If I glue the panel down....and a panel lasts - say 10 years? ...That means me or the next owner will be scraping or dissolving glue to replace the panel..... If I get a regular panel...I remove 4-6 bolts and just swap it out in 10 years. ...Course Flex panel weighs less than 3 pounds and the 100 watt weighs 25 pounds = harder to lift the roof....Always trade-offs.....