Crazy Internet improvement After Switching Router to DC Sola

[edcastrovalley]

I have a 12vdc solar system with a 300 watt pure sign wave inverter that I powered my dsl modem and wireless router with and since both the adapters for each device output 12vdc I decided to get rid of the adapters and power them directly off my golf cart batteries. What I didn't expect was a drastic improvement in internet speed. Before I was getting around 50bps with lots of halting and now I'm seeing at least 200kbps on my 720kbps service.

The improvement is drastic. I watched a 1:30 minute high res you tube video that halted more that a dozen times before that now plays through without ever stopping. My son watched a Netflix video and my son said it switched to a high resolution format that was displaying prefectly WHILE I was downloading a long linux update.

There's only a couple of things that I figure could cause this:

1) The 12vdc power from the golf cart batteries is smoother and cleaner.

2) The ac cord was too close to the modem (about 1 or 2 inches) causing interference in the modem.

Either way whatever the reason, I'm super happy. Maybe someone like amberwolf might know why this is.

 

[amberwolf]

1) The 12vdc power from the golf cart batteries is smoother and cleaner.

It is also higher in voltage--it is not 12V, but at least 13-15VDC, depending on what the charger/solar converter is doing at the moment.

If the AC adapter for the devices was really just 12V, then depending on how they power things like the transceiver for wifi in there, it's possible it's now using a lot higher power outputs than it should, which will let your wifi computers receive better. If you are directly connecting to the router with wires, then that's not likely the issue, as there are other regulators for lower voltages for those transceivers. If it is indeed powering the wifi higher, it also means it gets hotter, and there's a chance it will shorten it's life.

it's possible that the adapters were putting out dirty power for whatever reason, and/or low voltage (you'd ahve to checkt that while loaded with the devices, using an oscilloscope), causing issues with the modem or the wifi. If they're properly designed their output should be very clean, but if defective or badly designed or made, all bets are off.

2) The ac cord was too close to the modem (about 1 or 2 inches) causing interference in the modem.

That's possible, but not very likely--most of those have good shielding to keep RF from inside them getting out and interfering, so would also do the reverse.



Eitehr way, it is an interesting result, and I am curious as to the actual cause.

 

[Jeremy Harris]

My guess is as AW says, you had a lot of RFI coming from the inverter that was causing a lot of errors on your connection, so slowing the speed right down. Running things on clean DC has restored the performance t what it should be, by reducing the bit error rate.

 

[Ricky_nz]

Slightly more technical explanation:
DSL modems can be rather susceptible to noise from the power side, especially if their line interface circuit is slightly unbalanced. Inverters are a great source of noise when cheap or poorly designed.

The switching frequency of the sinewave generation is likely somewhere around 4KHz (in the inverter) and it creates lots of harmonics (frequencies on multiples of that frequency above that frequency). these harmonics are right where ADSL tries to operate, just above audio frequency and the signals on a long line can be really weak.

 

[edcastrovalley]

It is also higher in voltage--it is not 12V, but at least 13-15VDC

That's true, the original adapter put out 12.2 vdc and the golf cart batteries put out up to around 14.2 (I've seen as high as 14.5) but, I loose about 1/2 volt on the 20 to 30 foot wire run disance to the modem/router.

If the AC adapter for the devices was really just 12V, then depending on how they power things like the transceiver for wifi in there, it's possible it's now using a lot higher power outputs than it should, which will let your wifi computers receive better. If you are directly connecting to the router with wires, then that's not likely the issue, as there are other regulators for lower voltages for those transceivers. If it is indeed powering the wifi higher, it also means it gets hotter, and there's a chance it will shorten it's life.

That was always in the back of my mind and thus, the one year delay in switching over directly to battery power. I like to feel the modem case for temperature and it feels cooler now. On warmer days the modem would actually freeze and I actually had to reset it and place a small fan blowing on it. I'll know more if we have another heat wave this year.

it's possible that the adapters were putting out dirty power for whatever reason, and/or low voltage (you'd ahve to checkt that while loaded with the devices, using an oscilloscope), causing issues with the modem or the wifi. If they're properly designed their output should be very clean, but if defective or badly designed or made, all bets are off.

It would be neat to see the actual sign wave of a Morningstar Sure Sign 300 inverter.

That's possible, but not very likely--most of those have good shielding to keep RF from inside them getting out and interfering, so would also do the reverse.

I figured they would protect against that unless it's a specific problem with using the inverter.

I watched a new tv show for the first time, "Breaking Bad", on our 55" LCD TV through my son's Netflix account (The TV uses wireless). It played perfectly with 720p like resolution and no interuptions. Nice! Great show too!

 

[edcastrovalley]

My guess is as AW says, you had a lot of RFI coming from the inverter that was causing a lot of errors on your connection, so slowing the speed right down. Running things on clean DC has restored the performance t what it should be, by reducing the bit error rate.

That's got to be the problem. I'm thinking it's the inverter. I wish I tested everything on house power first although I would hate to pay extra amount if I left it there. I know when I placed my old modem on solar my electric bill shrank $10/month.

 

[edcastrovalley]

Slightly more technical explanation:
DSL modems can be rather susceptible to noise from the power side, especially if their line interface circuit is slightly unbalanced. Inverters are a great source of noise when cheap or poorly designed.

The switching frequency of the sinewave generation is likely somewhere around 4KHz (in the inverter) and it creates lots of harmonics (frequencies on multiples of that frequency above that frequency). these harmonics are right where ADSL tries to operate, just above audio frequency and the signals on a long line can be really weak.

Thanks, Ricky. That pretty much confirms everything with the using the inverter. Great explanation here - this gives my an idea of what's going on. I know we have harmonic protection devices at work for our server rooms (in-going line power) although I work more on the heating and cooling side of things myself.