Monitoring percentage of charge (Solar - alternator) on Trimetric

[RC Pilot Jim]

Yesterday I observed a 5% rise in bat full condition (89 - 94%) after charging battery 4 hours on alternator/solar combination. This morning voltage down to 12.6. Percent full 89%. The only load is point one - volt meter and point one -Trimetric. Battery age 2.5 years.

While solar was charging voltage read 13.9 and amps 1.9. I wonder if 4 hours isn't enough time to hold 94% charge,

When monitor shows it as full-battery , have observed the fall off of 1% per day.

Anyone know reason fall- off is larger when battery not 100%full?

 

[Casa Escarlata Robles Too]

First off,my system works great. But I was looking at some solar controllers from Renogy,and other outlets. Some of the units have a "positive" ground. They specifically use those words.
My question is,how can you use a positive ground controller with a negative ground system? This seemed to be common on many controllers.
Just some thoughts.
All this solar info is interesting and helpful.
Frank

 

[RC Pilot Jim]

Frank, sometimes think I was better off not knowing the amps and % of full. Now I have something else to interpret (worry-about).
Oh-well its all good.
Keeps days from being boring.

 

[Casa Escarlata Robles Too]

Frank, sometimes think I was better off not knowing the amps and % of full. Now I have something else to interpret (worry-about).
Oh-well its all good.
Keeps days from being boring.

Since a lot of that type of controller give the warning don't know where to stand.
But does the controller need to be grounded?
If you get a chance go to the Renogy site and check out the info.
Not worried as my unit isn't a positive ground.Just was curious.
Yes I sometimes think we get too much info.
I go out and look at my watt meter some of the readings I understand and some I don't.
I guess your right keeps from getting boring.
Frank
Frank

 

[RC Pilot Jim]

We don't have the REnology controller.

We use the MonringStar SunSaver 20L - negative ground.

My friend with the Kestral bought the Renology suitcase portable panel (weighs 32 pounds ) that has a very complicated
built in controller. It took me a couple hours to figure it out and program it properly. The MorningStar was much easier as there is nothing to program.

 

[billharr]

I have a Renogy controller. I read about the positive ground on the unit. I am not running anything off the load side and controller is mounted on wood no contact to frame. Works fine.

 

[Casa Escarlata Robles Too]

I have a Renogy controller. I read about the positive ground on the unit. I am not running anything off the load side and controller is mounted on wood no contact to frame. Works fine.

Thanks Bill.That was my thought about their units.
Frank

 

[RC Pilot Jim]

Bill your Renoly controller is simpler than the unit on the portable.
Once I figured it out its easy too. There instructions menu donesn't tell you there are 9 programmable folders as the display only shows 4 choices and there is only one the user has to program - folder 5 -. Number of batteries, amp hours, type of battery - Gel, AGM, flooded.

I was reading the controller instruction booklet....NOT the very large "Quick start" book. Screwed myself up.

 

[RC Pilot Jim]

This morning checked the monitors. Point 1 load . Voltage 12.6. Percent of full 84.

Voltmeter shows it 90% full. Trimetric doesn't agree
Truck parked 1.5 days in under carport roof.


The following I copied off Dr J's comment on his Post "Measured FWC power Use"

"Here is a link for the percentage of charge based on battery voltage:
http://modernsurviva...harge-chart.pdf

The problem is always that the voltage is always based on a resting battery. So if there are loads on the battery it is not always accurate.

Then the battery monitors are always very optimistic. It may show a full battery at 13-13.5 volts when it wouldn't even be close to charged at that point. The trimetric won't show 100% until the amp hours are all restored or the voltage and amps meet the criteria you set.

It's very frustrating trying to make a decision on your power use if you don't really know what's happening."

 

[alano]

To make matters worse, I believe the voltage measurement without load (or charge for that matter) should be after an hour or so of resting. How often do you go without the fridge running for an hour unless it is pretty cold?

I decided not to spend the money on a Trimetric because it measures current very precisely but you still set the criteria for full so you don't really know for sure where you are although you do know whether you are gaining or falling behind. When you charge the battery from the solar charge controller, you are limited to the charge controller's idea of full anyway even if the battery is really only 90% full. The batteries that came with my Hawk say they want 14.4 Volts +/- 0.2 volts to be fully charged. The Morningstar charge controller doesn't go that high for sealed batteries. Now what?

On my recent trip to try out my new solar panels I used the FWC button before the solar kicked in to give me a quick idea about the batteries over night: 4 = good, 3 = OK, 2 = low and 1 = too low. I also have a voltmeter to stick in the 12V socket which I found generally reads 0.1 V lower than my meter across the batteries for another level of detail. I'm trying to embrace the uncertainty. I also have a plan for adding a movable panel if circumstance seem to warrant it. I'm pretty sure that I can't keep up on hot cloudy days with just the 200 Watts of solar I have on the roof now and forget about parking in the shade of course.

Alan

 

[RC Pilot Jim]

Yes Alan. That is reason I will be taking my portable panel on "engine off" trips lasting more than 2 nights.

 

[ntsqd]

It's been a while since I went thru the process, but setting what is "100%" for the tri-metric's assessment of what is a full SoC wasn't difficult or ambiguous. I do not feel that it is a guess or a false number. The issue is that as the battery(ies) age what is a "100%" SoC will slowly drop. So eventually it will be erroneous and I'll need to dig out the manual and reset it. That should be pretty obvious when the SoC display starts to consistently show something less than 100%

Frankly that worries me less than noting that when we've been power hogs the SoC is rarely below 97% in the morning. I'm concerned that I'm not cycling the batteries enough.

 

[RC Pilot Jim]

Field Report
Last weekend in October we attended the SoCal owners Rally in San Clemente, Calif. Camper battery ran the Refer, interior light and Fantastic fan. The roof top solar panel maintained 94% battery full by sunset dropping to 87% at 6 am overnight. Sun comes up. Solar runs REFER and charges battery back to about 94%. Going down the road with the alternator in the "Bully or control" position battery climbed to 98%.

We brought the 60 watt portable....Left it in the truck.

The big test is our semi-annual trip to the Saline Valley which this year is Nov 10th - Returning the 18th.

 

[RC Pilot Jim]

Field Report
Nov 2014
Camped engine off 7 days Saline Valley. Air Temp High 40's to mid 80's. Cloudless sky. Camper in full sun all day. Used the fan, LED lights, charged the IPAD and plane batteries.

Trimetric - ;percent of full reading - range 87% morning to 98% when sunset behind the mountains at 4 pm. Time in shade 14.5 hours. Sunrise 6:30 am

We brought the 60 watt portable....Left it in the truck. 100 watt roof panel more than up to the task of running the refer and charging the batteries.


ice cubes stored in 1 QT container in fridge (39*) lasted 6-1/2 days - new record.

 

[RC Pilot Jim]

Field Report
April 3rd

This past week the rig has been parked under the carport. After 6 days Trimetric showed a drop in percentage of full to 83%.
Digital voltage reading 12.4 volts.

Since solar panel is blocked from the sun I plugged in the "shell-shore power". Checked Trimetric at 7:30 am this morning...Percentage of charge back up to 97%. Digital voltage reading 13.6 (maximum output for my small 1.5 amp charger-maintainer).

Its nice to have a battery monitor and digital voltmeter with easy to read red characters.

 

[Marco Cecala]

RC Pilot Jim;

I have found the perfect combination of ambient temperature and sun angle can really skew the numbers. Just got off the North Rim of the Grand Canyon and had great numbers.

My unofficial results...Cool temps are better for charging as well as less refridgerator compressor time. When the panels are warmer the voltage drops siginificantly. I have Global Solar panels which are direct glue.

Nothing can compete with a charging shot from shore power!

 

[RC Pilot Jim]

Wednesday night we returned from a 3 week trip on the East coast. The rig sat in the carport while we were gone with nothing charging the battery.

Readings (AGM battery):
Voltage 12.5
Percent of full 73%

Since 12.9 volts is full. 12.5 is 97% of full. I went on the Bogart Engineering website to review the Q and A answers and there was no mention of my question. I didn't call them yet. I was curious if anyone of the users have ever seen the percent full that low when the voltage is that high?

 

[pvstoy]

It sat for three weeks and what draw was on the system during that time? lp alarms etc? The shunt and meter measures how much goes out and in. The meter it's self has a small draw. To me that sounds reasonable if you had low draw over time.

 

[RC Pilot Jim]

Patrick,

Thanks for your input.

I turned off the Trimetric and the separate digital volt meter which each draw point one amps and the master switch.before leaving. We have the shell model so don't have any alarms.

Battery cables attached so it does lose voltage over time.

 

[pvstoy]

So for the three weeks the trimetric was removed from seeing the battery or just the screen display was turned off? If the screen is off only there is still a slight draw to keep the meter going and memory retained within. If power was severed from meter to battery then you'll need to reprogram the meter and set the 100 percent charge level again.