No matter what I do - mornings start around 50 volts.

softdown · June 2020

Have tried a number of things that lower consumption. Daybreak always shows between 49.7 and 50.2 - depends on if the fridge is cycling.

Since my activities seem to have little impact I must conclude that the inverter is the major night time power hog. There seems little to be done about it. Except try to get by with a 1500 watt inverter next time.

Can two 1500 watt inverters be "stacked" for occasional 220 volt output? These are simple Cotek, now Samlex, pure sine wave units. Clearly only one such inverter would be used unless both are needed for unusual demands.

InCogKneeToe · June 2020

I am not sure about stacking. But my system, completely off over night. Charged to float @13.6 by the Genset, on awakening, it is sitting @13.1-13.2.

Leaving a 100w inverter running a small Bar Fridge, I am at 12.4-12.5 overnight.

Photowhit · June 2020

Voltage in an active system is a poor measure of the batteries State of Charge, SOC.

Think it's been discussed with you many times...

softdown · June 2020

Photowhit said:

Voltage in an active system is a poor measure of the batteries State of Charge, SOC.

Think it's been discussed with you many times...

Your are getting/got cranky. Voltage as a measure of SOC has been discussed here tens of thousands of times. It is why my voltage dips when the fridge compressor turns on.

mike95490 · June 2020

Only inverters with published stacking specs, can be stacked. They often require a data or sync cable to accomplish it..

softdown · June 2020

Does anyone start their mornings well over 12.5 or 25 or 50 volts? Those are strong numbers but efforts to significantly improve have failed.

To be fair while I have lowered some demands others have risen due to warmer weather or a new load etc.

The interesting thing is it doesn't seem to matter whether the evening is concluded at 50.8 volts or 50.4 volts. Once again pointing to the inverter as a chief culprit that never changes.

mike95490 · June 2020

Have you tried measuring each battery to see if there is one with a weak cell ?

BB. · June 2020

~50 volts in morning does not sound bad... The resting voltage for a FLA battery curve is pretty flat at 12.5 / 50 VDC.

http://www.scubaengineer.com/documents/lead_acid_battery_charging_graphs.pdf

Add in all of the issues with load at time of voltage measurement, accuracy of your volt meter, temperature, age of bank, initial specific gravity fill of battery, any sulfation (again age), etc... You are probably using less than 25% of battery capacity overnight.

Starting back with the numbers... What is the AH rating of your battery bank, the idle losses of your inverter, and WH/AH @ XX volts of your loads?

Do you have any sort of DC AH/WH meter on your system to measure the overnight usage?

-Bill

softdown · June 2020

mike95490 said:

Have you tried measuring each battery to see if there is one with a weak cell ?

Yes I have. That led to replacing three that were made in 2011. The one with a bad cell made a real difference. The two that were simply weaker? Showing 12.2 or 12.3 volts instead of 12.5 volts? Made a minuscule difference at best. Though one developed a bad cell a month later so it wasn't a real bad call.

I suspect that up to 90% of my night time energy loss is due to refrigeration and the inverter. Replacing the tv with a more efficient model didn't help as much as hoped.

Going to equalize pretty soon. We'll see what that does.

wellbuilt · June 2020

This morning I started with 50.4 this morning.
I have a small frig running with some other loads cell booster C pac charging phones , iPad , 5led night lights, the water pump runs if the toilet is flushed 60” ceiling fan .
If I just use search mode I save some power the frig runs a couple times a night .
My outback 3600watt inverter draws a lot of power , my loads don’t seam to make a lot of difference .

I can try to save power but it doesn’t make any difference if the inverter is on I seam to use about the same power nightly.
Today I was charging at 6am and stoped around 8pm this helps a lot .
If I turn off the inverter and check voltage I have 3 or 4 extra volts.
Winter time I’m down to49.7 some mornings if I leave the inverter on over night to run my C PAC but it’s to cold to sleep with it up there so I just kill the power

NANOcontrol · June 2020

I don't have anything running at night, but I do have a small microprocessor that runs everything in the house.I have a 100V DC relay connected to the 60V array and that relay closes when the sun comes up and turns off at dusk. You could call it an astronomic clock that follows the changing sun.

softdown · June 2020

I have the 3648 MATE complete with dancing LED lights. Unsure how much extra power is consumed.

softdown · June 2020

Been around 50.2 volts lately - likely due to warmer battery temps this time of year. Probably will avg. 50.4 in July.

wellbuilt · June 2020

Our systems are about the same , I don’t think the mate, battery monitor or even the fm80 draws much power at all .
The inverter must use much more power then they spec out , it’s a good size load .

My over night load is about the same if my inverter is on with no load or if I have the frig ,fan , C-pac , cell phone booster , night lights on
My battery’s stay around 60o and the temp will creep up after a few days of charging and discharging to 70o +- I’m still burning a fire at night .

softdown · June 2020

I do wonder about those dancing led lights. Plus all the motion activated outdoor lights. Unplugging a bunch of things like ultrasonic pest controllers did almost nothing,

Since nobody has mentioned a morning voltage well over that level - perhaps that is about the best one can hope for. I remember much, much lower voltage levels with an inferior battery bank. Plus I dedicated two more panels to the other 24 volt forklift battery system. Man alive, that battery boils like Old Faithful. Uses a lot of water.

BB. · June 2020

Crank down the absorb set point voltage? Sounds too high.

Remote Battery temperature sensor option ("hot bank", cold ambient)?

-Bill

Dave Angelini · June 2020

I think it is called summer offgrid. Really you will be fine.

Image: https://us.v-cdn.net/6024911/uploads/editor/bz/h1rwoldszeb6.png

wellbuilt · June 2020

I started having trouble with my Sg in January , I wasn’t getting enough charge in with the snow and I was cheeping out on generator run time .

My battery was at 49.7 in the am , I figured out a way to clear my panels of snow and started charging every morning with the genarator for a hour or 1 1/2 hours and the battery’s stay at 1.270 + to 75 I had one battery that stayed around 1.260 to65 or a little more .

Now that it’s a little warm my bank is staying around 12.75 even my problem battery it looking good ?

I leave my bank on float with one string of panels .

I don’t really worry to much this time of year I even leave my porch lites (8 of them ) on over night .

My out back seams to use most of the power over night

I don’t use a lot of power unless I’m working .

Photowhit · June 2020

softdown said:

... 24 volt forklift battery system. Man alive, that battery boils like Old Faithful. Uses a lot of water.

Yeah, my 8+ year old forklift battery uses about a gallon every 5-6 weeks during the heavy summer 'push-pull' running a window air overnight. I didn't get in my early summer equalizing, so will likely have to wait until mid August until we have cool morning temps n the 50's and afternoon in the high 70's so I don't overheat/stress the battery. Though I'll sneak in a couple hours here and there.

No matter what I do - mornings start around 50 volts.

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