Steven Di Maira

+ Follow
since Aug 15, 2019
Apples and Likes
Apples
Total received
2
In last 30 days
0
Total given
0
Likes
Total received
5
Received in last 30 days
0
Total given
11
Given in last 30 days
0
Forums and Threads
Scavenger Hunt
expand First Scavenger Hunt

Recent posts by Steven Di Maira

Hi Bill,

Most of the answers are already given, and are fine.

Here is just my 2 cent on it:

The input of a solar charge controller is designed to suck the most current (wattage to be precise) as possible out of the solar panel. (PWM or MPPT based charge controllers).
So even if the generator could supply a matching DC voltage, you risk overloading the supply source (the generator).

The (mppt) based) charge controller would "think" like this:

<mmpt program inside>
Ah, I'll start slow: gimme 10W watts.
Ok, that went fine, now give me 20W... Ok, still fine, 30W please. Oh that supply voltage still looks good, 40W please...50W...60W...70W.....
.....and it wont stop until it either the charge controller is at it's limit .... or the supply source is overloaded.
</mmpt program inside>

For a solar application this is great because you would want to extract as much enery out of the solar panel(s).
Once you hit absorbtion, the algorithm will change, and only draw as much current as is needed for maintaining the absorbtion voltage (for the attached batteries).


Greetings,
2 months ago

Sam Stephens wrote:

Jay Peters wrote:Hi Mega Brain,

. Screw the fridge, but I can't live without a freezer...




Back in 2014, I spent 6mos offgrid and very broke in central Texas.

I had a 100w panel, 2 old RV batteries, a cheap,cheap,cheap 1000w MSW inverter and a $30 PWM solar controller.

After messing with different scenarios,  I put a timer on the freezer power cord and set it to turn off daily between 2200 and 0900.

It worked enough to get by.


SS



Hi Sam,

That's a very good solution!
I run my apple fridge the same way in the summer-autumn.

It's a small fridge with a little freezer compartiment
I have the freezer compartiment filled with frozen water bottles. During the night everything is kept cool from the melting water bottles.
During daytime, the fridge runs on the excess solar electricity. (and freezes the water again)

For a pure freezer you could wire the 'superfrost' button in (or something like that) in Aduino/PIC microcontroller, or just into a timer.
So that you make an extended cooling run of the freezer (cold reserve), during the peak-hour of the solarday (when energy is excess/free/wasted anyway)
The excess cooling is then used to bridge the gap between the night and the next solar day.

What do you think of this idea?

Winter is a different problem however

Greetings,
Steven.












6 months ago

Meni Menindorf wrote:Thanks for your feedback Steven.  This is what I am hoping to hear.  Sure seems like they are happy batteries charging like this, and so much easier to work with than lead-acid!  Also I should mention, with all the "sizzling" I have discussed in this post, I still have not seen any observable change in the water level.  All ten batteries still hovering around the max fill level.  I am also not terribly concerned about Carbon build-up, and a freshening of the KOH should certainly solve that issue.  Side note about reconditioning...  I have reconditioned lead-acid batteries with an Eposom Salt solution, and I am astounded by how well this works!  It costs $5-$10 to recondition, and the resulting "mineral battery" as I am calling it, responds much more like the NiFe batteries do.  They don't heat up from solar-direct charging and they continue to give out pretty rad amperage even at 9V.  So stoked it is an option to recondition, lead and otherwise~. I probably never would have bought NiFe if I knew how well reconditioning worked

Sounds like a really fun project with that Arduino!  I am going to make a new post for HHO~. But before I go here, could this be a way to store HHO from my NiFe?  

https://www.hho-generator.de/en/mcgiver.htm



Regarding lead acid batteries:
Nice the you used the epson salts. (not having done that before)
I do have one of these pulsing devices that charge up to 30v for short peaks. This also to combat sulfation.

One disadvantage that remains is plate corrosion, with lead acid batteries.
Problem is that you cannot undo this type of damage. Over time the plates start to crumple, degrade, break. This is because the active materials are going in and out of the elektrolyte.
(You can check the state of charge with the specific gravity on lead acid.)

The only thing to slow down the plate degradation is to limit the discharge to like 70-80%
Some of the higher quality Lead acid batteries do have thicker plates.
As you know, you have many types like deep cycle, Opz, marine battery, agm, gel or with very thin plates: car battery.

But they all suffer from this problem sooner or later.
See this nice document:
https://www.powerstream.com/1922/battery_1922_WITTE/batteryfiles/chapter15.htm

So, don't feel sorry for having bought a NiFe set

Greetings!












8 months ago

Alden Banniettis wrote:Thank you, Thomas and David.  Yes, I know what you mean about the voltage.  I was just wondering what to do with this old Targus thingy.  I do have a motorcycle trickle charger on the batteries that keep them fully charged.  I basically use these batteries only when the lights go out up here in northern Maine, which is often.



Hi,

You could always try.
But only if you are prepared that the adaptor might blow it's fuse/let magic smoke escape ...

Why?
Chances are the batteries want more then 6.5Amp. (constant current charging)
The batteries might look like a short circuit from the adaptor's point of view.
That will overload the adaptor.


Greetings!



8 months ago

Meni Menindorf wrote:
First on my mind.  I am still charging these batteries using the panels straight to the batteries (no controller) and I recently installed a voltage readout and a switch so I can manually turn charging on and off.  I am still somewhat financially challenged, so I can't afford a high end controller with user modifiable parameters.  (Seems like these are all in the $500+ range?). My question: am I damaging my batteries charging them like this regularly?  Or is there a certain approach with my handy manual on/off switch that would help prevent harm?  I have read that these batteries can safely charge up to 17.5V.  I very rarely see mine go above 16.5v (though we will see what the Summer brings). Does this mean I can continue to charge like the neglegent off-gridder I am, and sit on my couch expecting my NiFe to last 80 years?  Or with them sizzling away all the time like an HHO generator, should I expect them to have a 5 year life?



Hi Meni,

Glad to hear from you.
I think the voltage readout and switch are fine for the 'human' managed charge controller
Hovering the voltage around 16.5V is fine. I think at around 16.5V it would be a good idea to cut the switch.
17.5V would also be my maximum limit. It's not forbidden to get higher, but you wil gain very little capacity, but massive water loss.


Yes, you can charge them this way without damage. Just don't let them run dry.
You will not reduce the life of the batteries.

There are only two other things to consider when running without charge controller
- You need to add more water. Question: How often do you need to add water?
- Over time, the carbon build up in the battery (from the added destilled water), will increase slighty faster (how fast? I have no idea)
But at least you can make new KOH (fairly simple) and then the batteries are like new again.
They ware a discussion about refurbishement of NiCad and NiFe here:
https://permies.com/t/130801/information-Edison-Ed-Nicad-batteries


Can't help you with the HHO generation, but nevertheless I find it very interesting!

Latest addition to my battery setup is an Arduino like add-on that implements a "quit by absorbtion current" on the charge controller. It checks
if the absorbtion voltage is reached and the same time if the current into the battery bank is satified.
So absorbtion is dynamically varied according to the weather.

-Can have up to 5 hours absobtion on very bad weather and many loads.
-And just as short as 20 minutes of a sunny day with little power consumption.


Greetings!


8 months ago

Rachel Brylawski wrote:. (Check out this "Cabin Iron Sun" kit for $300, which includes the solar panel, NiFe battery set, lightbulbs, adapters, etc: https://livingenergylights.com/product/iron-sun-cabin-kit/)



Hi,

I looked at the link.
That Cabin Iron sun kit is actually very interesting.

For a low price it give you the opportunity to play with Nickel Iron batteries. Without the need to shell out multiple $$$$ for a big set.
Or the hassle to import a nife battery set from China. It's doable to import them yourself, but not for such a small order.

Reminds me bit to the lead acid batteries and charge controller kits you can find everywhere.


Greetings!

8 months ago
Hi Mark,

Mark Cunningham wrote:

Manufacturers recommend changing out the electrolyte periodically to remove K2CO3 accumulation.  ChangHong says every 7 years or 15%.

But if you replace  a portion of the electrolyte annually you will keep that percentage down to manageable levels and avoid the costs, both in chems and labor/hassle, of a total electrolyte swap out.

That means you keep keep less KOH/LiOH on hand,  you have less electrolyte to dispose of, refreshing your electrolyte has just become like a normal watering maintenance event.



Interesting! Another good way to think about it.


Mark Cunningham wrote:


One advantage of Nickel cells is that there is no equivalent of sulfation.    I feel for the L.A. folks, having been one.  It's not really a big problem to under or over charge.  Within reason.



Yeah, so true. Makes them very well suited for solar.

I do like to use the charge controller.
We'll see how it works out. But I can understand what you mean.

Concept:
The program will quit charging (go to float) when both voltage (High enough) and current (Low enough) are met.
If any of these two conditions are not met it will continue charging.

But indeed for the batteries it does not matter

You mentioned it in your document, there are some hostile users that seems to recommend lead-acid over NiFe or NiCd.
I do not understand either. May-be Lithium, for mobile applications. (still don't like the fact that you cannot repair any degradation).
But disliking NiFe/NiCd AND at the same time recommending LA is beyond me

Mark Cunningham wrote:

Making / storing D.W. is a practice I strongly recommend .... one bottle of pond water mis - marketed as distilled water from WallyWorld can ruin your day.  Especially if your running a L.A. bank.  

Overcharging counteracts the phase change in the nickel plate that most folks think of as cell memory.
Here is a good paper on Nickel cell memory



Thanks! Good paper!
The phase change chapter starts at "Capacity Fading"
But the other parts are interesting as well for the closed systems.
11 months ago
Hi Mark,

Mark Cunningham wrote:

Rejuvenation of Nickel Cadmium Aircraft Battery Electrolyte.

Ignore all of the apparatus and pay particular attention to the second and third paragraphs under the "Background of the Invention".  Think about what those dilution/rejuvenation tricks mean for the home installation.
 

Hope this helps



Good read!
I'll put it in my own words below:


Concept:

If you run a few charge / discharge cycles, the elektrolyte gets pushed in and out of the plates.
This has an advantage for us: The carbon and impurities gets pushed out of the plates. They are dilluted into the elektrolyte.

So, If you get some carbonated NiFe's or NiCad's. You could make some straight KOH (without LiOH).
Go for some good charge/discharge cycles. ....
[rinse and repeat if needed ]
Then fill with the defintive KOH + LiOH Solution
= Better result.

As a side note:
On my battery bank I am experimenting with 'end of absorbtion triggered by current'. This is a charge controller setting.
I have found that a general absorbtion with a timer (say: 2 hours, 3hour absorbtion) is not optimal.

- During summer, the absorbtion time is too long. ->Water consumption for nothing.
- During winter, the absorbtion time is too shot -> Undercharge.
- During a sunny morning, then clouds the rest of the day. -> Absorbtion reached, but timer 'times out' before finishing absorbtion because of clouds.

Long story short: If you have a setting like 'end of absorbtion triggered by current': try it.

The implementation of Studer is flawed in this regard (It only works from a charger, not solar).
So I programmed it using their RS-232 commucation module. I will not bother you with all the code, but below is the simplified concept:
(I got wild, and read out the temperature compensation too, and all that stuff)



















11 months ago
Hi Neil,

Neil Binderman wrote:Some bathroom reading for you
http://jes.ecsdl.org/content/162/10/A2036.full.pdf



I printed this out, just to have a good read.

Conclusion for the additives:
- LiOH do helps, performance a bit ~.
- But when a small amount of LioH is used with a moderate amount of Potassium sulfide we get the "magic" -> the best possible performance...

Anyone who wants to try?


1 year ago
Hi Mark,

Mark Cunningham wrote:
Nobody I've read to date has given a direct explanation of what LiOH does in the electrolyte.   I don't think that it has any effect on cell hydrolysis.
I remember reading that it was a preservative in one manual, (I forget which but it is in the references appendix).  I know that LiOH was the agent used in the Apollo emergency as a CO2 scrubber.

So my guess is that it is both a carbon scavenger and a rust preventative.



After carefully reading into Edisons patents...
...I think I have found Edison's patent on LiOH
This one.
It's a short read
http://edison.rutgers.edu/patents/00876445.PDF

I find it pretty amazing how accurate his work still is.

He also described "I am not able to explain why the addition of lithium hydroxid should result in such striking and noticeble phenonomens"







1 year ago