Ten pages from front. Ten pages from rear. Solar building

[frater secessus]

One, is it ok that the controller does not go through all three stages in succession every time?

Yes, but consistent failure to complete absorption is a sign to either tweak the system or switch batteries to something that doesn't care about 100% state of charge.

Missing even one full charge a week should be an anomaly directly attributable to some condition:  had to park under a tree, rainstorm, etc.

Two, while in first stage, MPPT, it is charging the battery... So is it OK to just stay there as long as I'm putting more into it than taking out?

Bulk charging is insufficient for lead-acid banks;   they require the long Absorption stage or they will suffer early death.  The easiest and cheapest way to get back on track would be to wait until Absorption commences to run nonessential loads.

Or.. should I be thinking that at any time of the given year, I'm a gonna want to just have the higher voltage of panels in series and call it good? 

The series part is a red herring, unless I missed something along the line.  Any increase in power output would have likely had the same effect.  But to answer your question, more power from the panels is generally better.  Getting the bank charged earlier and faster is better both for the batteries and for your ability to make effective use of power.

I am too lazy to put out external panels so I just stuck a bunch on the roof.  

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Tracer/Renogy are a good value for many uses (including mine), but the Boost terminology is a terrible choice.  Especially when "boost" is already a term used (rightly or wrongly in an MPPT context).  My other complaint is the SoC battery icon thing, which causes endless confusion on versions that have that.

I then hooked up a second 100w panel in series and within two minutes , the controller went into Boost mode for two hours and then down to float.

The two minute difference could mean:

• the system wasn't pulling in enough power for charging
• loads were preventing quick enough charging
• maybe even that the controller was 99.99% of the way to the next stage and the little shove did it.  

Knowing the cause would require knowing the voltage and loads immediately prior to the addition of the 2nd panel

 

[John61CT]

> Missing even one full charge a week should be an anomaly directly attributable to some condition:  had to park under a tree, rainstorm, etc.

I strive for that too, but note that many believe having to replace your bank a bit early is worth the lower hassle of just trying to get to full just most days, or say half the time.

I have not been able to find clear stats on % shortened lifespan vs % cycles at PSOC. Not saying it isn't a major care issue, just that we can't put a number on the difference between getting to 100% Full every day vs 90% of cycles vs 70% vs 50%. Rule of thumb used to be once a week was fine!

Chemistries that withstand regular PSOC abuse are rare for a reason: more complex to care for, very expensive, and may end up getting murdered early anyway, by accident or some other type of abuse.

With very cheap GCs so available, just not caring much about proper treatment is economically rational, even if it makes us uncomfortable.

 

[regis101]

Regarding this from post 41, *  My other complaint is the SoC battery icon thing, which causes endless confusion on versions that have that. *
I don't take the icon as gospel due to Renogy reading in the manual ,
(  NOTE: The Battery Capacity (SOC%) is an estimation based on the charging voltage.  )
I usually pay more attention the amp amount from the panels.

Yes, I want to believe that little extra push did the trick.
*  maybe even that the controller was 99.99% of the way to the next stage and the little shove did it.  *

IIRC, the controller is set to 14.4 for the second stage and I couldn't get off 14.3 with the one panel, ( regarding the - super long time- that I wrote)

Thanks guys.

 

[frater secessus]

Yeah, the manuals say the battery icon is driven by voltage, but my observations suggest it is also considering charging stage at least. When I get enough data to see the patterns clearly I'll post that.

BTW, I think the controller's display of amps going to the battery from the controllers is ok for a refererence point. IMO the current hitting a minimum and not dropping further is more indicative of being fully charged than a specific number. I say this because small background loads on the system loads can make the levelled-off current be numerically different even though it is stable.

 

[John61CT]

It's loads coming online that confuses things, best to read off a shunt at the batt.

 

[John61CT]

>> I have not been able to find clear stats on % shortened lifespan vs % cycles at PSOC. Not saying it isn't a major care issue, just that we can't put a number on the difference between getting to 100% Full every day vs 90% of cycles vs 70% vs 50%.


Regarding this "PSOC leeway" issue, I just found this from Maine Sail:

> After performing many, many, many hundreds of hours of battery testing I believe pretty strongly that that a typical deep cycle AGM battery (not all AGM's are actually deep cycle despite what the sticker may say) really need to get back to 100% SOC every 2nd or 3rd cycle for the best performance and longest cycle life. Ideally every cycle but that is simply not realistic unless you're in a lab.


The post is mainly about the unique PSOC abuse resistance of Firefly Oasis, but lots of good general info as well:

​http://www.trawlerforum.com/forums/showthread.php?p=604465

My understanding is that FLA is more robust wrt losing capacity from PSOC abuse.

 

[regis101]

Regarding this, * ...really need to get back to 100% SOC every 2nd or 3rd cycle for the best performance and longest cycle life. Ideally every cycle but that is simply not realistic unless you're in a lab. *

In my case, the vehicle only gets 2-4k miles per year. Weekend warrior. Sits in the driveway most of the time.
To achieve daily charging I leave the rooftop 60w worth of panels on 24-7. I also have a Samlex 15a charger installed and can run house power to the vehicle. Between the two, I would guess that batteries ( 2 - 55Ah AGM's ) should hum along nicely, yes?
Sidenote: When using one or both 100w Panels as remotes, I switch off the 2 - 30w roof panels.

 

[John61CT]

Yes.

The in-depth details are for those living away from shore power and deeply cycling their bank daily.