Is my math wrong?? My 200 watt panels are not even close to 200 watts..

[ArmorAbby]

or.... are my batteries shot...??

Or... is my math wrong??

Or am I just not understanding the electric correctly...?

I finally got a digital meter for my battery bank... and now Im more.confused...


So here I am... Waking up to 14* temps, put the heat on, bout to make some coffee.

Battery voltage checks in at 12.6, while the charge controller is nicely blinking cause the sun is up...
I dropped down to 12.1 overnight, but it raised quickly once the sun was up.

So, I put the coffee on. Its Uniox water boiler. Supposed to be about 50-80 watts...

Turn it on, Battery immediately plummets to 12.0, then 11.9.....8... water is almost there and the battery has now stopped dropping and is holding at 11.4.... .

The charge controller does not give an over discharge warning...

Turning off the boiler, it immediately jumps back up to 12.1.. then quickly back to 12.6...

Finishing my water, meter holds steady at 11.4 volts..

Sooo... is it also possible my meter is just wrong??

Previous to having the meter, Id just use the electric and everything was hunky-dory... Now, numbers are worrying me...

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[MikeRuth]

I'd be suspect of the batteries first. Assuming these are Lead Acid type, I'd get shore power charger and hydrometer out. Charge the batteries and make sure water level is correct, then test with hydrometer to make sure they are fully charging and no bad cells. Once complete and all checks out, then reconnect them and turn on the boiler and see how the voltage reads.
80 even a hundred watts should not be pulling the voltage down more than a tenth or two.

 

[highdesertranger]

that boiler draws between 6.6 amps and 10 amps, not an light load but not real heavy either. what type of battery(s) and how old? highdesertranger

 

[ArmorAbby]

Theyre sealed... no maintenance from what I understand... would I still need to check water levels?

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[ArmorAbby]

One is a Walmart the other is Windy Nation. About a year old...? I have overdischarged them a bit, especially when I first started. Thing is, I have no idea if its 'normal' or Im just panicking because I can now actually see my vokts..

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[ArmorAbby]

Less than a year.. actually, Feb 3rd marks my one year Vanniversary and I didnt get electric.til later... Lets go with six months old...?

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[highdesertranger]

will you be at the RTR? are they the same type battery? are they sealed lead acid(SLA), AGM, GEL? highdesertranger

 

[lenny flank]

Keep in mind that in winter the shorter days and less intense sun produce a LOT less electricity in the panels than in summer......

 

[ArmorAbby]

I believe AGM. Im in the front now. Killed my starter battery. Waiting for Roadside assistance to give me a jump. The two arent connected. I just killed it last night by leaving stuff plugged into the cigarette lighter. ..

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[MrAlvinDude]

I see the same rapid voltage fluktuations on some of my old batteries. And on new small scooter and motorcycle batteries.
Scooter and motorcycle batteries can be a small as 4Ah to 12Ah.

This is one of the reasons that voltage meters is not the only (or optimal) way to determine how much energy is actually stored in a lead acid battery.

The voltage only shows how well, those parts of the surfaces of the battery plates that still works, are charged.

But if you are down to only 10% of the plate surfaces are still functional, then you are down to only being able to store 10-20Ah of energy is those "old" batteries.


It seems that some lead acid battery designs can only be "deep cycled"  2 to 10 times, before they are worn to the level where they have less than 10-20% of their original capacity left. Even if they show being charged to voltages way higher than 12.6V

I have no idea of how many deep cycles your particular batteries can withstand, but  it sounds like they have been "deep cycled" more than 10 times.

For some AGM batteries I have seen  claims of three times as  durable. But if that is just three times more of 2-10 times, then it is still only 30 deep cycles before they are toast.
So my thinking is, that low cost sealed batteries, may still not have very many times they can endure the deep cycle, even if they claim to be better than......

So the advice to never take a lead acid battery below something like 12V (or even 12.2V) is probably good advise for most lead acid battery designs. And in particular for sealed designs.

 

[ArmorAbby]

Yeah... I can barely use my electric now... Next year, Ill have experienced all the mess ups and should run a bit smoother..

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[tx2sturgis]

Yeah... I can barely use my electric now... Next year, Ill have experienced all the mess ups and should run a bit smoother..

Thats the spirit.

I would have been cussing by now....

By the way, 'next year' is tomorrow.

 

[ArmorAbby]

LOL Time crunch is on.. [emoji14]

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[MrNoodly]

It probably isn't that your panel's not putting out 200W, it's probably that you don't understand how charge controllers work. The charge controller takes the power coming from the solar panel(s) and meters it down to the power necessary to recharge the batteries according to a programmed cycle. It CONTROLS the power coming in because the batteries can't handle dumping in a bunch of power all at once. Controllers aren't designed to pass through excess wattage so you can boil water or run other appliances. You're draining your batteries faster than they can charge.

Since you should avoid taking your batteries below a 50% charge (which is about 12.3V to 11.9V, depending on the chart you consult and the temperature) you're shortening the life of your batteries by using them before they've had a chance to charge.

 

[ArmorAbby]

Yes.. this... My thought was that if 200 was coming in, 80 to the water, the rest to the batteries... or at least filling in the batteries faster as I boil the water...

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[MrAlvinDude]

Next year .......

you will also have a voltmeter!

So you can keep an eye on how voltages actually tend to change when moving between; being charged, just sitting there, and being used. 

So I suppose you will become more familiar with the nature of how slow lead acid batteries actually are to both let energy in, and let energy leave again.  And how strange that slowness translates into these voltage variations. 

Where as this year, you have not had any other indication but: working/no longer working! 


So I foresee a very bright and very enlightened future for you  :angel:

 

[MrNoodly]

Besides the wattage rating for panels assumes the sun is hitting the panels at a 90° angle.

 

[Trebor English]

The 200 watt panels won't give 200 watts in New Jersey in December.  Half of that, 8 to 10 amps, is much more likely.  If your panels were tilted to point to the sun at noon or tracking the sun all day it would be better but still not 200 watts.  

Your Walmart battery is most likely a flooded RV marine starting battery.  A $10 hydrometer can tell you what is going on with it.  A hydrometer sucks up some of the acid and it measures the density.  Concentrated sulfuric acid, H2SO4, has a specific gravity density over 1.265, 1.275 is better.  Plain water is 1.0.  The stronger the acid the better.  When a battery gets sulfated a lot of the sulfate ions are in the plates and buried under lead deposited by several partial charges.  Charging at high voltage, well over 14.5, maybe 15 volts, might recover some of the battery capacity.  The suggestions for how to "equalize" apply even if the cells are equal.

Your Windy Nation AGM battery is the same acid and the same lead.  It is sealed and you can't test it with a hydrometer.  The electronic testing gadgets for sealed batteries are as expensive as your battery.  

Since your batteries are different I would separate them when trying to rescue them with more charging.  Since they have been deeply discharged I would expect that they might be toast.  

What you can do is go to auto zone or a similar place that sells car batteries.  Ask if they can charge a battery and bring one of the batteries in.  They might hook up a charger and put in a bunch of amps.  They will stop charging too soon for a good charge.  If the battery is toast it will charge up quickly and then discharge quickly.  It will be a 5 amp hour battery instead of 100.  If they do put in a bunch of amps use your solar and keep on charging.  That might help.  

If your batteries need replacement I recommend a single 100 amp hour Walmart RV marine starting battery.  The AGM batteries have advantages but they are expensive and you can't see what you are doing to it.  More amp hours might be nice but you have to put back daily all that you use.  This will be your learning battery.  With the volt meter and hydrometer you will learn how to live with a battery.

When charging your volt meter should go up to 14.4 volts and stay there for a while, depending on use.  If that doesn't happen your battery will die soon.   

Your Walmart battery probably needs water.  I use a 20 ml syringe to put water in.  Don't over fill it.  Add just enough water so that the level is up to the level of the two curved plastic bits that extend down into the battery.  After adding water the hydrometer test will show that your acid is just water.  The portion sampled at the top is just water.  Serious charging will raise the level.  Before charging make sure the plates are covered but don't fill it up.  

One last thing, use propane to make coffee.

 

[tx2sturgis]

One last thing, use propane to make coffee.

^^^
THIS will fix a LOT of battery issues.

 

[rvpopeye]

(The last post I read before starting to slowly type this was #17 any posts after that could already contain this or some of this info !)
EDIT: as I guessed , #18 has some more good info for your lesson today...

It seems you were discharging the batteries pretty low and guessing they were recharged fully (but they probably weren't) before you got the meter . ?
Electric heating elements tend to create this problem unless the system is much LARGER !

The sulfur in the battery acid forms on the plates when you discharge and re-dissolves back into the acid when you charge. BUT is not fully re-dissolved if not 100% fully recharged asap. It hardens over time and reduces the battery's ability to charge OR discharge.
^ My guess of what you have now.^

This is a very common problem when first time campers learn the "ropes" !
Don't feel like it's just you !

The good news ? Now you know about this and can be more diligent about recharging fully .
The meter will have to do as your tool because sealed batteries can't be checked with a hydrometer.
AND Your next battery (ies) should behave much better for you with this boost to your understanding.


(I also learned this the hard way in my many years of living on wheels , ZERO copy/pasting was used in this post..) Just sayin'.....................