generator for context inverter

WaterWheel · November 2015

I have a Context XW+6848 grid tied with a small 395 amp/hr battery bank. We lose power here for 2+ days at a time occasionally, usually when the clouds limit solar. Rather than spending bunches of cash to enlarge my battery bank I'm considering just adding a gasoline/propane generator to recharge the batteries when needed during cloudy days. What is a smaller low cost generator that can run on either propane or gas that I can roll up outside the battery room and plug in during power outages. I'd wire things up in advance and hook the generator in when needed before switching power input to AC2 (gen support).

Currently I'm using the 12v auxiliary output to run the battery box fan so I'd need to start the generator manually.

So what is a reliable small generator that can easily match up to the 6848 inverter? During power outages I will seriously limit my power needs so even a 2000 watt generator would be large enough to top the batteries up to keep the well running.

westbranch · November 2015

Question is based on the loads you will be running? That will help you determine the size pf gen set needed..

vtmaps · November 2015

Does the XW+6848 require 240 volts AC? Most small generators do not make 240 volts.

Also, there are no small propane generators. There are plenty of kits to convert a small generator to propane. A propane conversion will void the manufacturers warranty.

--vtMaps

Ralph Day · November 2015

Most generator's manuals say not to run the 12vdc output while 120/240vac is in use.

Ralph

WaterWheel · November 2015

So a basic 240v generator is all that I need? I don't want to purchase something that won't play nice with the inverter. Currently I have a 3500 watt 240v manual start generator http://www.amazon.com/WEN-56352-3500-Watt-Gas-Powered-Generator/dp/B003N9AT5G/ref=sr_1_1?ie=UTF8&qid=1446826627&sr=8-1&keywords=3500+watt+generator )

that I'd like to just wire in to the AC2 line like I wired the Grid into the AC1 line. The generator would only be rolled up outside the house and plugged up when needed (once a year) and then started manually after cutting the AC1 (grid) input switch off.

Would the inverter qualify the lower grade generator and make it the new AC input allowing me to top the batteries off?

I'm asking because we are currently on day 9 of heavy clouds and rain here, and that's often when we lose the grid during this type of weather. With my small (395 amp/hr) battery bank I'd like the ability to top it off if needed. Once topped off my power requirements are low enough that I can go 24 hrs on just the batteries.

new2PV · November 2015

I am trying to do the same thing as you but with a honda eu3000is, I will let you know soon if the outback psx-240 transformer can work with a 120 volt generator to bump the voltage to 240 volts. The XW says it needs a 120v/240v input, but it also says it needs only 240v. I would assume if you had only 240 in you would only get 240v out and not 120 volts. The XW passes ac2 right to your loads and built in charger at the same time, so dirty in will be dirty out..

WaterWheel · November 2015

Since 240 is two 120v lines I would imagine they hook in the same way the grid power hooks in with two hot 120v wires.

mike95490 · November 2015

I have a 240-480V transformer I use as a step-up from 120 -240VAC. My 2Kw Honeywell inverter generator drives it just fine, ALTHOUGH I have heard it reported that in one case, the load of the PSX-240 was enough to trip the overload (when the transformer is first connected, the magnetic flux does not exist in the core yet, so there is a big power surge).The EU3000 should be fine.
AC2 input is a much wider acceptance range than AC1, and it should qualify nearly any generator in good condition that is not being overloaded.
The XW has a pair of internal transfer relays, so you don't need to disconnect things (but it does not hurt to be safe).

And when it's cloudy, I run the generator as often as needed to keep the batteries up, fuel is cheaper than a sulfated battery bank.

new2PV · November 2015

How much loss in watts do you lose in that transformer while charging at a high rate?

WaterWheel · November 2015

I was wondering about whether I should manually cut the Grid AC (AC1) off before firing up the generator. I've got my inverter's charger set at 220 amps (C/20 charging rate) so it hopefully won't try to keep the 3000 watt (continuous) generator running flat out. Fortunately my generator has 240v so I don't have New2PV's additional challenges.

new2PV · November 2015

The xw will limit to load to 80% of your AC2 breaker size setting. It will scale back your charge rate to accommodate your loads. You can go into the ac settings and set the grid prority to AC2, then it should disconnect AC1 when AC2 is active.

WaterWheel · November 2015

Thanks, Makes me feel better about tinkering with this. I'll try to get things wired up in a few days. I'm using 10ga wire for the Gen side with a 30 amp breaker. The AC1 side is a 60 amp breaker with 4 ga wire.

new2PV · November 2015

3500 watts@240 is only 14.6 amps, so if you want to max the gen, then set AC2 amps to about 18 amps, as 14.6 is 80% of 18 amps. You may want to enable gen support plus to balance loads.

WaterWheel · November 2015

Is Gen support plus so the inverter uses battery to supplement the energy from the gen? The idea of the generator is simply to top off the batteries is we get heavy ice or snow for more than day or two on the panels, Ice/snow that last more than 2-3 days is something we see here only once a year, of course you can count on the grid being down during those days.

mike95490 · November 2015

new2PV said:

How much loss in watts do you lose in that transformer while charging at a high rate?

No idea, but I expect it's pretty low, The housing does not even get warm, and with a 2Kw genset, there is no "high rate"

generator for context inverter

Comments

Categories