diy solar

diy solar

The "Meg" Build

cass3825 said:
Inductive loads are difficult for the DC converters to handle.
Click to expand...
The lingering few seconds of inductive loads may be a ‘converter problem’ but the initial drop, spike, and flutter can also happen on direct connection equivalent voltage power from a battery (bank).

An oscilloscope read of what happens when a load is applied to a line will reveal some interesting ’reactions’ to voltage when the samples per second is high and plotted on a curve. It’s the same kind of thing that burns out radios, stereos, and sonar on a boat when one turns the key engaging the starter motor; an event of high voltage occurs both when the key is engaged to ‘start’ position and then again when released from ‘start.’ The release is the more violent but shorter in duration.

I’m no EE but in this case I think that while the capacitor will work for what is basically buffering while the electronics react to the sudden load- inductive or otherwise- it is masking what happens electrically. Probably figuring out how to isolate lights vs. motor loads is the best approach even if a capacitor is used.
Like I said I’m no EE so someone with engineering background can probably confirm or destroy this information- I’ve never seen a scope reading from a power-on event with a power supply/ converter. I was just reading this and this clicked on some brain cells about inrush spikes from boat experience.
 
12VoltInstalls said:
The lingering few seconds of inductive loads may be a ‘converter problem’ but the initial drop, spike, and flutter can also happen on direct connection equivalent voltage power from a battery (bank).

An oscilloscope read of what happens when a load is applied to a line will reveal some interesting ’reactions’ to voltage when the samples per second is high and plotted on a curve. It’s the same kind of thing that burns out radios, stereos, and sonar on a boat when one turns the key engaging the starter motor; an event of high voltage occurs both when the key is engaged to ‘start’ position and then again when released from ‘start.’ The release is the more violent but shorter in duration.

I’m no EE but in this case I think that while the capacitor will work for what is basically buffering while the electronics react to the sudden load- inductive or otherwise- it is masking what happens electrically. Probably figuring out how to isolate lights vs. motor loads is the best approach even if a capacitor is used.
Like I said I’m no EE so someone with engineering background can probably confirm or destroy this information- I’ve never seen a scope reading from a power-on event with a power supply/ converter. I was just reading this and this clicked on some brain cells about inrush spikes from boat experience.
Click to expand...

Of course a small 48V to 12V sized for the lights and other constant loads and a bigger converter (cap is likely still needed) for the transient high power loads would be best.

But when retrofitting existing RVs it can be tough to do this separation as they tend to run shit all over the place that is not easy to get to.
 
Last edited:
12VoltInstalls said:
Curious.
What is your source asking retail for that? I haven’t looked recently but in the northeast they used to to be ~$2250 for a 20 and ~$3000/3500ish for a 39.
(No prices online anymore it seems)
Click to expand...
I'm in Cali, and we "apparently" have a huge shipping container shortage. Now i work in a sheet metal shop, where we process millions of pounds in Stainless Steel a year, and getting material in the last 6 months has been very difficult, and every one of my suppliers has told me its because of the shipping problems from China, etc. I've had a few of them tell me that China is hoarding all these containers but idk if its true, or why.

Anyways, to answer your questions, a 20' container is roughly $2500 here, and a 40' can be anywhere from $5-6000. Last year they were less than half of that.
 
12VoltInstalls said:
Curious.
What is your source asking retail for that? I haven’t looked recently but in the northeast they used to to be ~$2250 for a 20 and ~$3000/3500ish for a 39.
(No prices online anymore it seems)
Click to expand...


I hear there are a bunch of them floating in the ocean. Maybe you can tow one home.

1627825218788.png

www.quora.com

What happens to cargo containers that fall from cargo ships and are floating in the ocean? Are they being collected?

Answer (1 of 33): I been inside and transported many shipping containers, never did I see any bung holes they do have very small vents to keep the moisture from building up they are not hermetically sealed. Encountered a few that visible damage from crushing water waves. Sanitary products wash ...
www.quora.com www.quora.com
 
12VoltInstalls said:
The lingering few seconds of inductive loads may be a ‘converter problem’ but the initial drop, spike, and flutter can also happen on direct connection equivalent voltage power from a battery (bank).

An oscilloscope read of what happens when a load is applied to a line will reveal some interesting ’reactions’ to voltage when the samples per second is high and plotted on a curve. It’s the same kind of thing that burns out radios, stereos, and sonar on a boat when one turns the key engaging the starter motor; an event of high voltage occurs both when the key is engaged to ‘start’ position and then again when released from ‘start.’ The release is the more violent but shorter in duration.

I’m no EE but in this case I think that while the capacitor will work for what is basically buffering while the electronics react to the sudden load- inductive or otherwise- it is masking what happens electrically. Probably figuring out how to isolate lights vs. motor loads is the best approach even if a capacitor is used.
Like I said I’m no EE so someone with engineering background can probably confirm or destroy this information- I’ve never seen a scope reading from a power-on event with a power supply/ converter. I was just reading this and this clicked on some brain cells about inrush spikes from boat experience.
Click to expand...
I have my BSEE with 27 years experience in power distribution. The voltage dip on “start” and spike on “release” is characteristic of an inductive load. An inductor is basically just a coil of wire, which generates a magnetic field when current passes through it. When voltage is initially applied, the inductor is essentially a direct short until the magnetic field is generated. This is what causes the voltage dip during “start”. On “release”, the opposite happens. The inductor acts as the energy source until the magnetic field collapses, resulting in the spike you describe.
 
Inductive loads and motor loads are a bit different.

With an inductive load (e.g. 1 Henry in series with 1 Ohm), the current is drawn out of phase with voltage, and inverter has to accept current driven back into it part of the cycle. Total Volts x Amps it has to deliver is greater than actual Watts, so inverter needs to be oversized.

An amplifier (inverter) has to be designed to be stable with reactive (inductive and capacitive) loads. Often amplifiers go unstable with loads that move to far into other I/V quadrants. Some inverters will be better designed/tested than others.

Motor loads have an initial current of Locked Rotor Amps, about 5x running load. Inverter has to supply that for about a second more or less. So does the battery, so voltage drop on cables at high current matters. Large capacitor can help. While stalled the motor would look like an inductive + resistive load. Running it could be something different. I've seen funny current waveforms (like triangle, not sine wave) from my A/C.

The grid is so massive it can generally handle all that, and has rotating generators. Wires need to be thick enough.
 
Lt.Dan said:
I did finally get my hands on a 40' shipping container.


So since its a rental, I can't put any holes into it, and im looking into PV mounting systems that don't penetrate, and im thinking more and more about magnets ?
Click to expand...
Think about "pipe clamps." Or, at least the concept. Position a piece of unistrut (or some other long piece) across the 8' width on top of the container. Then, extend a piece of something downward at each end of the unistrut. Think of an open "C" facing downwards. Then some screw-type devices to "clamp" each end of the "C" to the sides of the container. Maybe also around the top edges?

Multiple "clamps" would be positioned on the top of the container. This should give you a strong, stable "foundation" assembly. Then, mount whatever you want to the unistrut assembly.

No holes in the container. It would be a mechanically-fastened system that might be stronger than magnets, especially going down the highway.
 
Shipping containers have these standardized oval cut outs at each corner of the cube. They are used to hold them to the stack on the he ship, for picking up with a crane, and holding it down to the trailer chassis. It would be much easier (and plenty strong enough) to tie into those on each corner and then magnets down the long side for extra stability.
 
400bird said:
Shipping containers have these standardized oval cut outs at each corner of the cube. They are used to hold them to the stack on the he ship, for picking up with a crane, and holding it down to the trailer chassis. It would be much easier (and plenty strong enough) to tie into those on each corner and then magnets down the long side for extra stability.
Click to expand...
I have thought about that, something I could easily attach to also.
 
For sure, especially with your metal fab equipment. I'm sure you could wip something up very quickly and easily.
 
Other than knowing that's how my crap gets moved around, I know very little about shipping containers. Dan, I'm curious, what do you intend to do with the shipping container? Why would you want to move it down the highway on a semi? Do they have seals around the doors to keep rain, dust, etc. out?
 
K8MEJ said:
Other than knowing that's how my crap gets moved around, I know very little about shipping containers. Dan, I'm curious, what do you intend to do with the shipping container? Why would you want to move it down the highway on a semi? Do they have seals around the doors to keep rain, dust, etc. out?
Click to expand...
I got it for storage for all of our stuff, and my RZR. I only plan on the container moving once or twice, incase I move to a different property, (which im looking at empty lots right now) and I don't want to pull down 24 panels and reattach them
 
Brainstorming stuff I shouldn't be thinking about yet... trying to maximize space in this compartment and I came up with this funny way to get 32 cells in a 2P16S config. Going to be interesting with bus bars, but I think it will work.

Reconfigured Battery.png
 
Hedges said:
I bought the $100 HF DC clamp 1000A meter (for the 60A 0.01A resolution range) and it also has inrush.
Click to expand...
Any comments on quality? Harbor Freight is hit-or-miss. Some of their stuff is really great for the price and some of it is lousy at any price.
 
FilterGuy said:
Any comments on quality? Harbor Freight is hit-or-miss. Some of their stuff is really great for the price and some of it is lousy at any price.
Click to expand...

So far so good. But I've only used it a handful of times.

It switches to DC Amps 600/60 with about 0.15A offset, I let it fluctuate a few seconds and settle before pushing "Rel" to subtract the zero offset. Reasonably stable after that.

It has a non-contact voltage detect setting, so if I put against romex with power in it, there is an indication of being live. But sometimes walking across the room it also alarms. Does that mean CIA is beaming microwaves at my head from a satellite again?
 
Hedges said:
So far so good. But I've only used it a handful of times.
Click to expand...
I ran down to HF and purchased one.... and it would not measure voltage properly. It was saying something like 6.5V on a 240V circuit. Then I noticed that if I pushed sideways on one of the probes where it plugged into the meter, I could get a good reading.
I was kinda desperate for it to work so I took it apart and sweated the solder joint where the probe receptacle connected to the PC board and now it is working....I have not decided if I should take it back.
 
At first I skimmed what you wrote, thought you said you sweated the banana plug into the socket.
But just U.S. labor assembling a Chinese clamp DMM PCB, that's OK.
I hope it works well. I looked up a bunch of brands, only a few had 10 mA resolution on DC clamp meter.

I need to get more fuses for my Fluke. I keep blowing them, both the 11A and the 44 mA.
I'll buy several of each. That'll cost me as much as the HF clamp meter

www.mcmaster.com

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
www.mcmaster.com www.mcmaster.com

I should make shielded banana plug fuse holders for my Tek high voltage differential probe. It's not rated for use with line voltages.
No, I didn't pay nearly this much for it, and it was new in the box :)

 
Well today I got to play with the cap and see if it makes a difference, and it does help about 80% of the time. I can hear when the pump kicks on, there is a split second of hesitation from max amp draw, and 9 times out of 10 it works just fine, but the 10th time it sticks and hangs. The volts drop down to about 8v. Which is better than the 6v it used to drop down to. Now my other 12v equipment doesnt shut of due to low voltage which is good.

I shouldve gone with the 18 Farad model instead of the 8 farad. I'm going to see if Amazon will allow a return, even though I threw away the original box. We'll see.

Bottom line, I think I shouldve gone with the 13.8v model and this 8 farad probably would have been just fine.
 
You must log in or register to reply here.

Similar threads

O
Solar trailer build
Replies
7
Views
976
OM617YOTA
O
O
Mount additional panels on side of solar trailer, or on separate stand-alone mount?
Replies
1
Views
124
grizzzman
grizzzman
B
EG4 18kpv + EG4 powerpro wall mount cargo trailer system
Replies
10
Views
431
42OhmsPA
4
Bob142
The Bucket
2
Replies
40
Views
2K
theLegion Within
theLegion Within
Lt.Dan
24' Enclosed Trailer Build
2 3
Replies
58
Views
4K
eXodus
eXodus

diy solar

diy solar
Back
Top