pure sine wave inverter or uninterrupted power supply

Adding an all in one computer to the boat and need to decide whether to use a UPS (uninterrupted power supply) or add a small pure sine wave inverter. Have a very nice Magnum Energy inverter charger that would be fine, but the computer would shut down every time I went from inverter to battery charger when the generator was turned on. A UPS would solve the problem, so would a 300 watt stand alone inverter. Wondering what people do with sensitive 120 vac electronics on board such as computers, large screen TVs, cable TV boxes, etc?

Ted

Interesting. I don't have that problem with my Magnum inverter/charger. I have used it with three different desk top computers and none have shut down. Do you use the pass through feature whereby the shore power/generator is passed through the inverter /charger or do you circumvent the inverter when you are in charge mode?

Your computer power supply must be very sensitive to loss of power. Inverters with the "pass through" feature mentioned have an internal transfer switch that goes from shore power to inverter power or visa versa in less than 20 ms, about one cycle. Most electronics power supplies have enough capacitive flywheel effect to make the switch ok.

Other inverters, the Mastervolt ones I think, sync the two power sources and smoothly make the transition, so there is not even one cycle lost. True UPS' work differently and the AC power is always supplied by the inverter circuitry and it has a charger circuit to supply the DC required as well as charge the batteries. There is absolutely no change in power output until the batteries run down.

So maybe your best solution is a small inverter to power your computer continuously, like a UPS and let the shore power charger keep the batteries up.

David

Maybe I don't have a problem, as I haven't tried it yet. Everything on the boat that was electronic 120 vac, had a battery internally like a laptop before I started the refit. Guess I need to try it before assuming I have a problem.

Thanks!!!

Ted

Bay Pelican said:

Interesting. I don't have that problem with my Magnum inverter/charger. I have used it with three different desk top computers and none have shut down. Do you use the pass through feature whereby the shore power/generator is passed through the inverter /charger or do you circumvent the inverter when you are in charge mode?

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I don't know. Will have to read the manual and check the settings. All I remember is that it would seemlessly switch bank and forth from inverter to charger after sensing or loosing external 120 vac.

Ted

I have a 1500 Watt UPS that I use to isolate the DVR, TV and Desktop computer from any fluctuation on the 120 AC circuit and it also provides about 15-20 minutes of power for those times when power goes out (either Brown-out or Black-out) for short periods.

Another path you might consider would be to replace the powersupply in the computer with a DC based model. I thought about going that route but then decided to stick with Laptop computers.

Marty.......................

We have a krill black box processor which is basically a solid state dc powered computer that gets its power from an inline ac to dc power converter. When we upgraded to the latest processor the manufacturer recommended not bypassing the converter by connecting directly to a 12 volt system. Over time we've found this system works best when plugged into a ups even though the boat's 120v ac power comes via a pure sine wave inverter. A small apc 650 backup ups should be an easy solution.


Via iPhone.

We've never had a problem with any of our on board computers (various generations of iMacs) or TV or anything else shutting down, using a Magnum MS4024. If you think about they're just a big sophisticated UPS.

My issue with UPS's is the batteries only last 3 years and are not economically replaceable. So you end up replacing the UPS every three years.

We have good sized UPS in our equipment cabinet.

It was easy, just plug it into the inverter fed outlet that powers the cabinet, so no fooling with DC.

It serves another function as well. If the inverter goes out we will get a series of emails and text messages until the UPS dies as the alarm system and network gear is plugged into it.

Donsan said:

My issue with UPS's is the batteries only last 3 years and are not economically replaceable. So you end up replacing the UPS every three years.

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Not sure what make and model you're using but have had good luck with APC units. Batteries last about 4 years and then can replace them at the local battery store for less than half of a new UPS.

Ted

Haven't tried using a UPS in five years. The unit I tried would not accept the output from a MSW inverter. Ended up with two inverter / chargers so that if one is down I can switch to the other.

No expert here but a UPS is nothing more than a battery set and a small inverter.

Just add a small dedicated inveter. Smaller and simpler I would think and do the same job. Then the shore charger looks after the batteries.

One day I noticed a foul smell in our house--not the boat---the house we lived in before we moved aboard. I couldn't find the source of the odor which became worse each day. In desperation I called the fire department to come with their "sniffer" device. They arrived with 2 fire trucks, one EMS ambulance, and 2 police cars, all with sirens and lights ablaze at 11 pm. Woke all the neighbors.

Turns out the odor was coming from a red hot UPS hooked to a computer. They picked it up with insulated gloves and threw it out onto the front lawn. They said it would have ignited soon and caused a major conflagration. It was made by APC. I don't think I will ever own another one.

Howard

I installed a new Magnum Pure Sign Wave inverter about a year ago. Had the same problem with main ships computer shutting down with Gen shut down. With the correct settings it will cycle on in less than 20 ms. The tech support guys at Magnum Energy are very helpful. Give them a call. Once properly set up mine never misses a beat with any equipment we have.