Replace SG-1100 power supply: 1A sufficient?

Cabledude

I found this topic about SG-1100 power supply. Mine is quite finicky and it’s all because of the EU pin accessory. When I attach the US pin and wire it the device gets power.

Anyway I do have a box of unused power adapters and I found one that outputs 12V / 1A max. And another one that outputs 12V / 0.5A max.

12V x 1A = 12 Watts max, which should be fine as the SG-1100 consumes less than 5Watts.

So could I simply use that power adapter? Or is it better to issue a ticket at Netgate support?

AndyRH

@cabledude Perhaps an US to EU converter for the plug?

Cabledude

@andyrh Good idea and certainly feasible. But I don't have one of those lying around. Adopting one of my idle power supplies would be much easier.
I just opened a new ticket at Netgate support. Let's see what they say.

Thanks,
Pete

mer

In theory as long as your substitute power supply physically fits the 1100 and has the same specs (check both voltage and current) you should be fine. But that is only my opinion as an electrical engineer and not official in any capacity :)

Cabledude

@mer said in Replace SG-1100 power supply: 1A sufficient?:

In theory as long as your substitute power supply physically fits the 1100 and has the same specs (check both voltage and current)

Well it’s the same voltage (12V) but half the current (1A vs 2A on the original). I’m a civil engineer so I’m not as refined as you but remembering my high school physics lessons I think The 1A should be okay.

I am assuming that the “current” or A value (ampere) specified on the power supply is the maximum it can supply, the real current is what the attached device is drawing to operate. Is that correct? If So, then if for example the appliance consumes 6 watts, then the actual current is 6 watts divided by 12V equals 0.5 ampere.

mer

@cabledude ha :) So you drink your tea with your pinkie finger sticking out.
The netgate website says "3.84W idle", so 12V*2A is 24W, your 1A is 12W. I would imagine that the 24W is more than a bit overkill (roughly 6x idle) so your 1A would probably be fine for normal use. If you are pushing everything max in the 1100 it may fall over, but if not, you are likely fine.

Cabledude

@mer said in Replace SG-1100 power supply: 1A sufficient?:

@cabledude ha :) So you drink your tea with your pinkie finger sticking out.

Well, ummm, that’s what some folks practise across the channel. I’m living in the Netherlands and the Dutch generally don’t bother

I went through my old adapters again and look what I found: here is the power supply belonging to an old fritzbox router. 1.4A. That would give me some room for peace of mind. What do you think?

mer

@cabledude Ahh, so you grab the beer mug two handed :)

If the other end fits the 1100 correctly, it winds up in the middle and should be fine.
Worst case is the 1100 doesn't have enough power under load and it shuts itself off.

stephenw10

I would expect that to be fine. But I can't really condone using anything but the supplied PSU as that's what the unit is tested with. Anything else is outside the warranty.

The supplied PSU has to be capable of powering the unit at maximum load and that includes both USB ports supplying 500mA (at 5V) and the internal mPCIe slot populated. It's unlikely you would ever see that in normal use.

Steve

Cabledude

@mer said in Replace SG-1100 power supply: 1A sufficient?:

@cabledude Ahh, so you grab the beer mug two handed :)

Will do that especially for you next weekend :)

If the other end fits the 1100 correctly, it winds up in the middle and should be fine.
Worst case is the 1100 doesn't have enough power under load and it shuts itself off.

Right.

Cabledude

@stephenw10 Hi Steve, I totally agree with your caution and I would love to order a replacement power supply for the sake of warranty and to keep on the safe side but my local official reseller doesn’t list them. so I called to ask and they are willing to contact netgate to see what they (you) can do. This may take a while though.

Cabledude

@stephenw10 : also, how can I be 100% certain that the plug polarity required is as follows?

Barrel / conductor / outside: minus
Tip (inside): plus

This is the most common plug type but if it’s reversed I may damage the unit.

Thanks,
Pete

[edit: never mind that, it's written on the bottom of the device]