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Renewable Energy / Re: Where do I start with solar?
« Last post by paulca on Today at 07:18:22 PM »
C/10 is generally suggested.  Since this is an electronics board I would think you would want to build something.  I have 2KW of panels and I control them with an arduino. Total elecrtronics cost in my setup is only about $20.  I usually tell people who want to use a 100W panel to just give up and wait becuse there is not much you can do with that much power.  It sounds like 20W is really your limit space wise and I would use a couple old lap top batteries with a BMS board.  Grab a couple 2596 regulators for your USB and Li pack.  These can be made into power point controllers with just the addition of a few parts.  Lead acid batteries suck.  If you use one, just buy a new one for your car and use the old one for solar.

Thanks.  I like this approach.  I only just discovered that 18650 cells are expensive, but brand new laptop batteries are not and contain 6 18650s.  They may not be top of the range regards peak current etc, but I'm not sure I care yet.  £8 for a 6 cell Toshiba battery.  So I have an experimental 3s2p setup including balance lead, in the post.

For charging it, I could just use the Accucel 6 directly connected to the solar, it will take 11-18V on input, then buck or boost for the battery.  The downside is it requires attention, in that it won't auto start charging without you pressing buttons.  I have seen people using them on Youtube.  I'm not too sure how suitable they are regarding MPPT and what not, but it seems comfortable with a whole range of voltages regardless of what it's charging.  I charged two 3s lipo batteries in series (25.2V) from an 11.6V supply for example.

It might give me "Iteration 1" though.  I'm starting to apply methodologies we use in software in work to my hobby projects to prevent scope creep meaning things never get finished and there is always something else to order.  "Iteration 1" would be successful if I can charge my phone from a solar panel charged battery, for example.  Iteration 2 would advance based on feedback from Iteration 1 as to what is most important to do next.  Most likely an automatic interaction free charger.

I have an off the shelf regulator with a USB outlet and while it gets hot charging an eCigarette at 1.6Amps it works.  (I think it's s dicky little surface mount regulator, I'm probably torturing it, but hey, it was about £2).  Runs off a standard XT60 LiPo plug and while they are not everyone's cup of tea they are great up to 60A and what I will be fitting to my 18650 pack.

On space.  It's a BIG window.  Probably about 6 foot square.  So even a 1m square or 1x1.5m panel.   There are cupboards and fridges across the front of it anyway, so blocking the lower half of it with a solar panel is perfectly acceptable and the panel can lean back against those cupboards.
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I've made a first test now (PSU was turned off over night) and during initial one hour I can measure positive drift of not more then 3.7 mV with mentioned 3.5 V and 470R as load. I'll repeat it a couple of more time over a day.
That is far better then what you reported, but also maybe my construction is a little bit different! Please note thermal pad that is placed underneath Power board PCB (see Fig 14.). Nearby TL783 (IC3) is considerable source of heat (about 1.5 W) but that has a "bad" and "good" side: the good side is that you can count with more predictable PCB temperature over wider ambient temperature range. Therefore if we wait that temperature is stabilize and perform calibration then we can expect more predictable output voltage over the time (of course with connected load you have to use remote sensing if better precision is needed).
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Looks very interesting as well .Thanks again folks.
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Thanks for the comparison. It seems even the cheapies are not too shabby.

Screenshots please!   As it is a USB scope it should be easier to do than most of us.

The risetimes indicate much better than 4 GHz bandwidth, probably >10 GHz. If the pulser itself really is 31.8 ps, then your scope manages approximately 41 ps. (rise times of source and scope add as root-sum-of-squares). Even using the more conservative conversion factor of 0.45/Tr, you get ~ 11 GHz estimated bandwidth.

I'd be very interested in seeing the shape of the pulse (overshoot, ringing, etc.).

I had never heard of this USB scope before, but I am very interested now.

It was interesting how much the speed went with price, but I suppose that shows the effort that went into getting the performance right. Law of diminishing returns there too!

I've attached a couple of plots. I should start another topic sometime for more plots from it, but too many other things I should be doing at the moment...

There have been some threads related to the DS800, like:
http://www.eevblog.com/forum/testgear/10-ghz-usb-oscilloscope-by-darwin-sabanovic/
but there's not really that much out there on it.

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Ferrite beads should be over-rated for current, because they stop acting as a ferrite as current increases.
http://www.analog.com/en/analog-dialogue/articles/ferrite-beads-demystified.html
Quote
With 50% of the rated currents, the inductance decreases by up to 90%.
So, go with the bigger one, and over specify on the rated current, not on the [email protected]
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Test Equipment / Re: Siglent Technical Support join in EEVblog
« Last post by skander36 on Today at 07:05:23 PM »

This ^ is being looked at in greater depth. Thanks for bring it to Siglents attention.
Thanks !
They will sending me a new mainboard as soon as in Hamburg will arrive the new boards (next month).
It seems that Siglent really care about customers .  :-+
[/quote]

Yesterday I received the new mainboard (a green one instead of red) that greatly improve the accuracy of the autosetup function from 30% to  75-80 % success .
The 2 capacitors missing (compensation issue) was already soldered in place .
Now the using experience of this scope is greatly improved .
The communication with Siglent Europe support (Michael Zeng)  was very pleasant .
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Sorry to hear about your troubles. I kinda do/done this for a living (former PayPal employee here, what I do in an electronics forum is another matter). With the Internet nowadays we do take transfer of value across the planet for granted. Here is a nice list of the ways your bank can do this https://www.iban.com/whatis.html. Can you be ripped off using any of these? Probably. What is specific about wire transfers is that they are manual (always go through a human, that's why cost money) and can not be reversed, unlike say ACH. As an engineer, what's the way of the future, can't tell (most probably not crypto currencies though)...
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General Chat / Re: T568A or T568B Wiring?
« Last post by cybermaus on Today at 07:03:38 PM »
If I am not mistaken, cross-over is not allowed in the 1000Mb specification. It was in the 100Mb, but not in the 1000Mb
So even though it may work due to auto, it is not allowed.

Also, not all pairs have the same amount of twists per length. Orange has the most.
The reason T568B is the more common variant is that it uses those two pairs with the most twists for the 100Mb variant.

Not sure if that is still relevant for 1000Mb variant as it uses all 4 pairs.
But I would default to the T568B

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Thermal Imaging / Re: 12 Days of Thermal Riddles
« Last post by Rerouter on Today at 07:02:06 PM »
I'm going to take the obvious one and say an orange, or similar member of the citrus family,
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