why my solar system cuts out out intermittently on sunny days

[offgriddle]

Like so very few USAmerican people I do not consider spectating a sport, in fact I do not consider spectating an activity at all. So instead of forking over a queen's ransom to buy expensive sports pay tv programming or hideously expensive tickets to sedate myself while I ,"go large", watching communistic, millionaire athletes, (and the occasional temporarily free agent), cavort upon the field of battle in tax subsidized coliseums filled with proletariat, I have developed something called, (now stay with me here), "hobbies".

Whilst out taking in sun and yoga and enjoying some Fleetwood Mac on this sunny Sunday, I noticed that my solar provided electricity kept cutting out briefly, which I foud annoying. Ive been observing this condition for a month or two and Iv'e taken voltmeter readings coming in to the SCC from the panels and going out to the Lifepo's, and everything appears in order, YET, the output from the lifepo batteries, (with built in bms's), to my inverter must be cutting out thus interrupting my AC production and subsequently harshing my mellow.

I have deduced, that my el cheapo lifepo's which I suspect are primarily meant to discharge all day powering things like trolling motors and power equipment and then be charged up at the end of the day in the absence of discharge conditions, do not like being charged AND discharged at the same time. So when the BMS senses a fully charged condition, it hiccups momentarily and briefly interrupts battery output when switching from charging to a non charge state. Then, when the battery voltage drops to the level that calls for charging, the BMS performs another momentary battery output interruption as it switches back to charging.

I will live with it from now as this is just a basic system to use and learn from and I will be building my own battery in the not too distant future, hopefully with BMS's that do not hiccup.

Stay Active Murica

...

 

[kernel]

Great place for quarantine yoga and fleetwood. Play "Gold" for us if you got Stevie on tap!

 

[offgriddle]

Great place for quarantine yoga and fleetwood. Play "Gold" for us if you got Stevie on tap!

I sure will, thanks ! ?

 

[Craig]

How full are your batteries when this occurs?

Mine get charged up cut off solar for a few minutes and then solar starts again after they have spent a few Watts.

Basically my batteries charge faster than I can use the power.

You may be able to watch here http://redslto.com/ It will be charging away then stop once battery is full. If the link throws an error just refresh. Im am still working on my monitor.

 

[offgriddle]

How full are your batteries when this occurs?

Mine get charged up cut off solar for a few minutes and then solar starts again after they have spent a few Watts.

Basically my batteries charge faster than I can use the power.

You may be able to watch here http://redslto.com/ It will be charging away then stop once battery is full. If the link throws an error just refresh. Im am still working on my monitor.

How full are your batteries when this occurs?

Mine get charged up cut off solar for a few minutes and then solar starts again after they have spent a few Watts.

Basically my batteries charge faster than I can use the power.

You may be able to watch here http://redslto.com/ It will be charging away then stop once battery is full. If the link throws an error just refresh. Im am still working on my monitor.

Yes the batteries are full when I experience the intermittent output interruption from the batteries to the inverter input during full sun.
I do not experience intermittent battery output interruptions after the sun goes down and solar production has ended.
Oddly enough, I also do not experience intermittent battery output interruptions when shore charging the batteries.
I have two, "Amped Outdoors", 20 amp, 12 volt, lifepo batteries, each with their own BMS's, wired in parallel.

 

[Supervstech]

Could you switch the inverter connection off the BMS, and directly connect them to the battery?
See if the issue stops.

 

[offgriddle]

Could you switch the inverter connection off the BMS, and directly connect them to the battery?
See if the issue stops.

I cannot because the bms's are built in to each battery housing, I would have to do a Will style battery disassembly with saws and such!

I do have the spec sheet on my battery's and I know that the epever can be programmed more specifically via my MT-50, but the chinglish instructions are poor in key places and my understanding of the nonsensical, non standard terminology used in describing programming parameters is poor so I haven't spent huge amounts of time painstakingly performing trial and error custom battery parameter programming of the SCC.

 

[Supervstech]

I cannot because the bms's are built in to each battery housing, I would have to do a Will style battery disassembly with saws and such!

I do have the spec sheet on my battery's and I know that the epever can be programmed more specifically via my MT-50, but the chinglish instructions are poor in key places and my understanding of the nonsensical, non standard terminology used in describing programming parameters is poor so I haven't spent huge amounts of time painstakingly performing trial and error custom battery parameter programming of the SCC.

I had a feeling that would be the case, but hoped...

 

[boondox]

I'm with ya on spectator sports. I'v always loved playing sports but have never understood watching other people play them. Yawn. Porn is the same for me, if I want to see that I'll do it myself...

I have deduced, that my el cheapo lifepo's which I suspect are primarily meant to discharge all day powering things like trolling motors and power equipment and then be charged up at the end of the day in the absence of discharge conditions, do not like being charged AND discharged at the same time.

But back to the the subject at hand. I don't think a battery can be discharged AND charged at the same time. It is doing one or the other. I agree it is probably your BMS. Since you would have to take the batteries apart to play with that, as you said you will have to live with it.

 

[offgriddle]

Hmm .. so the charger is actually powering the load not the battery, unless the load exceeds the output of the charger, in which case the battery would begin to be drawn down. As the internal resistance of the battery drops, the charger would charge the battery as long as the load doesn't exceed the amperage output capacity of the battery and charger combo.. ~ I did notice that when the voltage feeding my invertor was momentarily interrupted, that coincided with the SCC charge current switching on or off. Yet, my shore power charger does not cause battery output interruption.

 

[boondox]

Exactly. If there is enough solar coming in the system uses it and charges the battery, if not then it comes out of the battery. You say it is connected with the SCC switching charge current on or off, can you tell us more about what is going on? When and why does the SCC turn on or off the current? At my place the solar charger never actually turns on or off but then I am always using power as an off gridder. Does it turn off when the batteries are full and there is no load or what is going on?

 

[offgriddle]

Exactly. If there is enough solar coming in the system uses it and charges the battery, if not then it comes out of the battery. You say it is connected with the SCC switching charge current on or off, can you tell us more about what is going on? When and why does the SCC turn on or off the current? At my place the solar charger never actually turns on or off but then I am always using power as an off gridder. Does it turn off when the batteries are full and there is no load or what is going on?

Ok, on bright sunny days when the batteries are full and powering my invertor, I will hear the invertor beep and there will be a brief, invertor output interruption as the SCC switches from charge to float.

 

[boondox]

That is odd. On a 12V system absorb charge is 14.4ishV and float 13.8ishV. I have no idea why the inverter would have a problem with that. I have never seen any combination of SCC and inverter I have had do that. In my case I would hook up a digital oscilloscope with a trigger and see if there is a greater drop in voltage than expected or maybe even a voltage spike.

 

[offgriddle]

That is odd. On a 12V system absorb charge is 14.4ishV and float 13.8ishV. I have no idea why the inverter would have a problem with that. I have never seen any combination of SCC and inverter I have had do that. In my case I would hook up a digital oscilloscope with a trigger and see if there is a greater drop in voltage than expected or maybe even a voltage spike.

The inverter is not having a problem, the voltage output from the batteries feeding the inverter cuts out momentarily and intermittently on sunny days when the battery's are full. The invertor is like a canary in the coal mine that tattles when the output of fully charged batteries supplying the invertor cuts in and out.
I also noticed one more thing, when the bms's are misbehaving, the two indication lights on the SCC go out; one indicator light is always lit when it sees battery voltage, the other light blinks when the SCC is charging the baatteries. This condition further indicates that either my BMS's are malfunctioning intermittently under certain conditions, or just as likely or perhaps even more likely, I need to properly program my SCC, (which I dread attempting again).