opinions of Ramsond Sunray inverters

[rabbit]

Please chime in if you have something positive or critical to say about these relatviely inexpensive inverters. I'm considering the 1500watt true sine wave "Sunray" model. Thought I'd take the poll BEFORE buying as recently I bought a deep cycle battery about which brand I could find NOTHING negative and immediately got a gloom and doom report from a FGRV member who had terrible experiences with Deka.

jack

[Byron Kinnaman]

In my humble opinion 1500 Watt is pretty big inverter. At just 1000 Watts you be drawing about 83 Amps out of battery. For a group 24 battery that's less than 1/2 hour to a dead battery.
Plus you'll need wire from the battery to the inverter that can handle the full 125 Amps.
You might want to rethink inverter needs (wants).

[Greybeard]

What would you be using it to run?
Richard

[honda03842]

Jack,

Is the Sunray Inverter your are considering really their 1500 watt Inverter/Generator?

[rabbit]

Perhaps it is overkill, Byron. I realize it would demand a pretty big cable bundle into the trailer. Want to power Black and Decker 2.7 ft\3 dorm fridge recently "built in" to our Burro. I believe the fridge draws 1.5amps on motor start and .87 amps running. Am I wrong that this is about the same as powering a 100watt incandescent lightbulb? This is inverter only model, Norm. Yall must tell me what to get what to do as Ahm jest a pur countree boy an doan no nuttin! Well, I might know something but it sure doesn't involve DC electricity!

jack

[Thomas G.]

So you want to run a 110v refrigerator off a 12 volt battery by using an inverter?

If so, the issue is how long you can run the refrigerator off the battery. You don't want to discharge a battery more than 1/2 way to avoid damaging it. A 100 amp hour battery provides about 50 amp hours, then. At 12 volts you are drawing roughly 8 amps, which gives you 6 hours run time. If fridge runs 1/3 of the time, 18 hours total time, not counting lights, fans or any thing else.

[Byron Kinnaman]

Thomas if pretty darn close. It would be closer to 9 amps than 8 amps, could be close to 10 amps because of the efficiency of the inverter.

Short explanation
Power = Power now matter what the voltage.
.87 amps x 120 vots = 104 Watts (Close to a 100 Watt bulb)
104 Watts / 12 volts = 8.7 Amps (same power different voltage, means different current)
90% efficiency of the inverter would then make it 9.57 Amps.
Now you add the 1 Amp no load current. (That sucker draws 1 from your batter just because it's connected, I looked up the specs)

Depending the outside temperature your deep cycle battery would not last very long. That's just running the inverter and fridge. If you run stuff like TV, stereo, lights, I doubt your battery would make it through a week-end.

[honda03842]

We had a 4.2 cubic foot fridge and ran it off a 1200 watt Inverter with a type 24 battery. I recall our Fridge would run about 1 minute in 7 though I'm sure it could be more frequent in warmer climates.

Our larger fridge would not start on an 800 watt inverter. We still use the same Inverter and it is a $59 Black and Decker Outlet Inverter and definitely not pure sine wave Inverter.

We typically did not run the fridge while driving so probably had it plugged in only 18-19 hours a day. In the beginning we did charge our battery while driving from the tow vehicle. Later on we added solar cells that kept the battery charged.

If we were going into a boondock situation, we would often drive with the fridge on charging the battery from the tow vehicle and setting the temp lower, sort of like charging the fridge while driving. When we stopped we could than raise the fridge temp a little.

In looking at the various 4 cubic foot dorm fridges, they all seemed to have the same compressors.

If I missed anything please ask.

[rabbit]

Thanks all. Byron's formula rings a bell cause I've seen it in the "litchure" (shorthand internet discussions) and the way I arrived at the 100 watts for the B&D fridge (similar to 100 watt bulb). I don't understand how Tom gets from A to Q but as long as he gets there and we're all speaking the same dialect of Martian, I guess that answer is parsable also. I have an 80watt solar panel which hooks to the battery with 12awg cable. I have no idea how efficiently it charges the battery as I've never seen it on anything other than float for more than a few minutes. If the sun shines will I be OK for a gridless weekend? Enquiring dogs want to know.

jack

[Thomas G.]

Originally Posted by rabbit

......... If the sun shines will I be OK for a gridless weekend? Enquiring dogs want to know.

jack

I'd try it and keep an eye on the battery voltage - maybe pack some dry ice in the fridge to assist.

[honda03842]

We installed the dorm fridge in our 25 year old Sunline 15.5, and used it for three years. Most nights we were powered but in Labrador that was not the case plus we had some days we drove for more hours because we were averaging 25 mph.

I began by testing it in the yard for a few days to see how it would work. I began by running it on AC to determine what its normal duty cycle was once cold, i.e. minutes on versus minutes off, the higher the ratio the better.

Also we keep our fridge pretty full, it increases the cooling down time of the fridge when not powered. Think of a full fridge like having a block of ice in there.

Having the ability to charge from Solar panels and the tow vehicle should go a long way towards meeting your needs.

Here's a little perspective...

It may be true that the fridge draws 100 watts from the battery but as I recall it does it for less than 10 minutes out of every hour or about 15 watts an hour. Compare that to a traditional trailer light bulb. A traditional light bulb draws 2 amps or 24 watts an hour.

If your inverter draws 1 amp on standby an hour that's equivalent to 12 watts an hour or half of a standard trailer light bulb.

More Perspective.....

You did not mention the price of the Inverter. If it's very much, remember mine was only $59, you might consider getting the real thing, a 3 way fridge.

We installed a dorm style fridge because we planned to own that trailer just for the trip to Labrador, 2 months. Fortunately we liked it and that 2 month tri[p really extended into 10 months and now 5 years of towing small trailers. If I had been thinking long term I would have gone for the 3 way or at least 2 way fridge.

One more...
I liked our dorm Fridge better than our present Scamp fridge because it was bigger than the small one in the Scamp however I appreciate the 3 way when out of the way from the grid.

Hope this helps.

[rabbit]

It all helps; sometimes the problem is the quality of mind of him being helped. For instance, it would be the proverbial cold day in hell before I settled for a 3-way of the noncapacity of the one we have, even if it were running up to snuff. In fact, a cold day probably would be the ideal situation for it but I guess that is the case for all fridges. So, that's no help!

I've been performing the time to empty on the virtual guage experiment this afternoon with a Peltier fridge. Fours hrs.under load my voltmeter read 12.36 volts. I think the resting reading after I shut down the converter was 12.48 volts before plugging in the Peltier. Assuming the drop in voltage is linear over time, maybe I could expect to power the little Peltier for another 4 hrs. I have taken the load off the battery (new group 27) and will take the voltage "at rest" before putting the converter back in the loop. 4 hrs. is certainly an appreciable block of time and the voltmeter said I wasn't even close to approaching 20% down of the battery (12.2 volts). 8 hrs. is longer than the average summer nite. What I don't know is the time to recharge with 80watts solar. Anyway, I'm thinking for the time being I may put the little 1.3 ft\3 Peltier cooler in the back of the tug as I can certainly expect to use it on the 4runner accessory port while underway. Let this inverter biz percolate for a while.

jack