Alex Ronan

John Carr wrote:

Anne Miller wrote:I have read a lot about rubble trench foundations here on the forum and the use of drain pipe and synthetic geotextile fabric is new to me.

https://permies.com/t/121202/rubble-trench-foundations

That's interesting, because elsewhere on the web it's always presented as necessary to have liner and a plastic drain at the bottom. E.g. https://www.buildnaturally.com/post/rubbletrench

If it were a shallow foundation and it would be relatively easy to remove the stuff years down the line, I might be willing. But I have to go 5' to get to frost depth and I don't want my grandchildren to have to excavate out a bunch of plastic. I like the idea of a compostable house.

2b. If your permit office requires a drain pipe

Sigi, is talking about what is needed for a permit, this doesn't apply in your case.

In your case where you have clay soil and the water may no dissipate into the soil, I would recommend continuing the trench slopping away from the foundation and provide drainage for the water.

Note: Strictly speaking this is a modern addition to rubble trench detailing.  But it is simple insurance to make sure that your structure lasts for centuries.

She also notes about fabric being a new addiction. She doesn't state that it needs to be plastic.

A filter fabric, if you decide to use one, can be burlap, as suggested above, or even a old cotton or wool blanket that isn't used anymore.

Untreated cob is dusty.

Two cheap options are painting it with milk paint, with it being a floor it milk pain may need to be reapplied often. Second is wheat paste, if mixed in the top layer of cob it should be able to take some scratches and a little wear, as long as the layer is thick enough.

Crinstam Camp wrote:The manual says 13.5 is 100%

Usually LiFePO4 documentation say charged to 14.6. I charge mine to 14v.

13.5-13.6 is the 100% resting voltage.

LiFePO4 batteries are known for their relatively flat voltage between 10-90%, ie. 13.2 could be 70-80% full.

For individual cell voltage it doesn't start getting out of the flat part of the curve until above 3.4. So biased on video of testing, I don't have balancing start until the cells are above 3.45.

My guess the reason you don't want a lot of parallel batteries is that a 13.3 battery won't charge the 13.2 next to it because it doesn't have "force" to get over the internal battery resistance. That is the reason charging voltage isn't the same as full voltage. Instead small amounts is current goes between the batteries and is turned to heat by the resistance of the wires and the batteries. The more batteries in parallel the worse the problem.

For disconnecting a 12v system, the cheapest is an automotive battery disconnect.

I use two sets of 10g wires for my battery to solar controller. I don't know if 8g will fit. Also bought from my auto parts store.

The big wire from the disconnect should connect to a bus bar (or fused distribution center) and then you have your multiple small wires connected to that.

Crinstam Camp wrote:It should also mean we could add two more panels and switch it to a 3x2 setup?

For voltage, yes, you can have 3 in series.

But the max wattage for a 12v system with that controller is 720w, you will be WAY over wattage connecting 6 (3 series x 2 parallel) 195w panels. Even 4 panels (2x2) is pushing the limit if start getting closer to ideal conditions.

David Baillie wrote:Chances are that your controller is pooched then.

I think the controller is working as designed. If the controller was bad then it would be noticed when 2 panels are connected also. An even number of 200w output makes me think it is doing what it was designed to (a safety feature). Broken things usually have random results.

it was 79ish it was about 267 watts, as it went above 80v the wattage started to drop.

That is was I would expect from a safety power limit (hard limit was probably the wrong terminology). Once the controller goes over the max input voltage it starts lowering the amps until it reaches the power limit (which appears to be 200w).

Crinstam Camp wrote:I believe it is saying if it's over 60 volts, the controller will limit it.

That 60 volt limit is on output voltage not the input.

Input voltage range is 20-80v. While 84v is above that so maybe they are putting a hard limit for 200w to prevent overheating.

Crinstam Camp wrote:

James Alun wrote:

Josh Hoffman wrote:

James Alun wrote:Yes but you haven't been keeping the current the same, you've been keeping the power the same.

Okay, I see what you are saying with me keeping the power constant and not the current in my posts like I should be.

If his panel were producing 20 volts and 177 watts, it would be 91% efficient. That would be more inline with the tag on the panel.

But the 2 together are only producing the 177 watts.

So now there are 2 broad possibilities, well actually 3.
Either the panels aren't generating the power properly eg dirty, misaligned, very old etc.
Or the power is being lost somewhere eg very long cables, cables too small.

Or possibly measurement error eg measuring at the wrong time of day, measurement averaged instead of instantaneous, etc.

No, actually none of those are a possibility,

He is talking about your other problem, why those two panels are only producing at 45% efficiency?

Do you have any temperature readings inside the bell?

I am curious if the temperatures are high enough to allow for a modification to add a white oven.

Anyone try making curtains or wall/floor coverings out of faraday cloth? https://amzn.to/3CnJruk

I'm experimenting with different - and hopefully more effective - ways to drill accurately into roundwood parts.

Could you secure the piece of wood on the drill press instead of using a hand drill?