36 replies to this topic

[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?

Edited by RC Pilot Jim, 21 November 2014 - 07:37 PM.

[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.

Edited by RC Pilot Jim, 07 October 2014 - 04:09 PM.

[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."

Edited by RC Pilot Jim, 08 October 2014 - 04:11 PM.

[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