Interplanetary ship lost electrical power

[HorusKol]

So, my first probe out of Kerbin SoI and on the way to Duna "suddenly" lost power - even though it has solar panels.

Everything seemed fine - the ship launched, I got it heading out of the system, and once I'd done a few more Munar launches I decided to launch two more probes of the same design out to Duna and Eve. I'd set an alarm on the first probe out to prepare for an adjustment burn about halfway to Duna, but when I switched to the probe, it was dead in space - I couldn't even turn SAS off.

The other two probes are also out of Kerbin SoI - but they're working fine and the solar panels are keeping the batteries topped up at 100% easily enough (I see the charge dip when pitching/rolling and then return).

So - what happened to the first probe? Bug? Or is there something about being halfway around the solar system that will stop my other two probes?

Edited August 16, 2014 by HorusKol

[Pecan]

Are they facing the sun?

Are they eclipsed by another planet/moon?

Are they capable of keeping the whole ship charged - is there something draining all the power?

Mods?

[Taki117]

I'm inclined to think that the panels are in the wrong orientation, either they are not facing the sun, are being blocked by another part, or the sun is being eclipsed. If you right click the solar panel it will tell you its status. It will also tell you how much power it is producing and how much sun it is getting. If all else fails you could try warping a bit and seeing what happens.

[HorusKol]

I'm inclined to think that the panels are in the wrong orientation, either they are not facing the sun, are being blocked by another part, or the sun is being eclipsed. If you right click the solar panel it will tell you its status. It will also tell you how much power it is producing and how much sun it is getting. If all else fails you could try warping a bit and seeing what happens.

Both panels said they were in direct sunlight - but generating 0 power.

[HorusKol]

Are they facing the sun?

Are they eclipsed by another planet/moon?

Are they capable of keeping the whole ship charged - is there something draining all the power?

Mods?

They said they were in direct sunlight.

There's a stayputnik and I'd left SAS on - but this ship is the same design as two others that have left Kerbin SoI and they were happily running at 100% and staying these.

The only mods I have are the alarm clock and KER.

[jfull]

A screenshot would be helpful

[HorusKol]

A screenshot would be helpful

Unfortunately, I scrapped the mission from the tracking station and then went to bed...

[Pecan]

Direct sunlight but generating 0 power means they were edge-on to the sun; 'just' seeing it but not well enough to be useful. The 'angle of incidence' is important too - they will produce most power when they are at 90-degrees to the sun.

ASCII art ^^.

    |||     90-degrees, maximum power
   -----

    \\\     45-degrees, reduced power (it's logarithmic, I think)
   -----

 -         Low angle - 0 power
 -  -----
 -

[Monger]

Solar Panels need electricity to unfold and rotate. As soon as you enter an orbit around Kerbol you will face the sun from the same angle for a LONG time. If the panels didn't have the chance to readjust for some reason, they might be unable to face the sun.

Very unlucky. But especially for the reason of unfolding the solar panels first I always attach a non-foldable solar panel to my ships, just to maintain basic electrical tasks. Multiple, actually, because I lost more than one ship due to the fact that weren't facing the sun properly.

[MartGonzo]

I've had this bug too (on 23.5), triple checked everything and there definitely should have been power flow, it had several fixed panels in direct sunlight.

I don't know of a fix though, I scrapped that ship

[DavidHunter]

Did you deploy the panels?

[MartGonzo]

Did you deploy the panels?

I don't know if you meant me or the original poster, in my case they were the simple fixed panels.

[SRV Ron]

I don't know if you meant me or the original poster, in my case they were the simple fixed panels.

I have found that if a probe ends up with the fixed panels edge on, you will eventually lose all power. Just remember to reorientate the ship so at least one solar panels get fully exposed.

[Renegrade]

(it's logarithmic, I think)

It's actually like cos(x), where x is the angle between the panel's normal vector (the normal vector extends out from the surface at right angles to it, the lines in your first diagram are normal vectors..well, the center one is for sure a normal vector). It would feel kinda logarithmic though.

45 degree incident light would be 0.707 * panel_strength * distance_factor .. or about 0.53/sec at Kerbin's orbit for OX-Stats.

I like your ASCII art, btw

Solar Panels need electricity to unfold and rotate. As soon as you enter an orbit around Kerbol you will face the sun from the same angle for a LONG time. If the panels didn't have the chance to readjust for some reason, they might be unable to face the sun.

Actually they don't need electricity at all. The probe core does, and if it has none, nothing on the ship will respond to commands (although I hear there's a bug where you can enable/disable batteries and fuel tanks without an operable core).

A Kerbal on EVA could unfold the panels as well.

[MartGonzo]

I have found that if a probe ends up with the fixed panels edge on, you will eventually lose all power. Just remember to reorientate the ship so at least one solar panels get fully exposed.

Well, they were in direct sunlight, I'm used to running out of power because of my own stupidity, so I don't think that was it.

I'm 99% sure that particular instance was a bug but that ships gone now and I haven't had it happen since, so I can't be certain.

[DavidHunter]

I don't know if you meant me or the original poster, in my case they were the simple fixed panels.

I was talking to OP.

[HorusKol]

They were fixed panels - from the rest of the answers, I figure that the panels were edge on.

I've made sure to orient my ships effectively when coasting out to planets now

[Pecan]

Happy half-birthday to panels ...

Once on rails ships stop rotating. A panel facing the sun from Kerbin will, half a local year later, when the ship has drifted up/down to the orbit of another planet, be facing away from the sun.

[cantab]

That's why I put an RTG on anything heavy enough to not mind the mass.

[Kryxal]

I usually add 3+ panels to anything that needs them, then align perpendicular to solar orbit ... it works well enough.

[moogoob]

This is why I try to put an OX-STAT facing every direction, if possible.

[NecroBones]

That's why I put an RTG on anything heavy enough to not mind the mass.

This. I usually put at least a pair of them (symmetry) on everything that will ever have to operate independently.