smkettner
Southern California
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Joined: 03/21/2005
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This is where I go back and recommend just a small inverter (300w) and use the generator for the heavy lifting. Simplifies the install too.
In which case I recommend GoPower or Morningstar
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jdiffend
Denver, CO
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Joined: 09/17/2010
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mena661 wrote:jdiffend wrote:And I'm going to check out how much power it draws before I decide if it's even feasible. It's certainly feasible but you may not have enough battery capacity to do this routinely.
LOL, I really didn't expect to be cooking frozen pizza every day. I figured using the microwave for a few minutes here or there on a daily basis and the convection oven once a week should be pretty reasonable. I just didn't want to suck down my propane running the generator if I didn't have to.
But after measuring how much power the convection/microwave draws I'm seriously having my doubts about running it without the genny. The oven draws 1457 peak watts while heating to 450, drops off a bit when up to temp, and bounces up and down in watts over the cook cycle. Towards the end of the cook cycle, the microwave kicks in for short bursts with a surge of over 1600 watts each time. It takes a total of just over .42 kwh to cook at 450 for 20 minutes. That's what? An hour's charge time off of 4 large solar panels at their peak output. The good news is that this oven requires shorter cook times than my convection/toaster oven so 20 minutes might not be required and most stuff doesn't require 450 degrees so this is like a worst case.
The peak wattage required by the microwave is clearly an issue for an inverter for it, however peak efficiency *might* be best at around 1450 watts due to longer cook times with the convection oven.
As for the fridge/TV circuit... I have to maintain enough battery to keep the fridge going and recharge with just solar panels. The big TV draws 122 watts peak. I haven't checked the 22" bedroom LED TV yet but it should take less than 1/3 the watts of the bit TV based on the yearly energy cost ratings of the two. I think I'll be looking at under 450 watts total for the entire circuit at any given time though.
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BFL13
Victoria, BC
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Joined: 02/15/2006
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The 1000w MW (1500w input required on PSW) draws maybe 110a on the 2000w MSW inverter. With three-27s capacity of say 330AH (rated 120 each for 360) that would be 110/330 =33% discharge rate. Never ran that for more than 10 minutes at a time, usually 5 minutes.
Maybe ran 15 min total (28AH) between recharges. That's out of a 50-90 (of 40% of capacity 330)= 132AH, leaving 104AH for everything else.
Using a PSW inverter that draw would be say 155a, so 155/330 = 47% draw--nasty! So IMO three 27s wouldn't do it on PSW very well at all.
Four 6s at 464AH capacity is 155/462 =33% which is more like it for short bursts. A 50-90 is now 186AH so 15 min of 155 is 39AH leaving 147 for everything else.
So if that 104 for everything else was enough before and still is, now you get an extra 147-104= 43AH for MW so at 155a that's another 16min so you can have 31 minutes of MW with four batteries at 464AH capacity with PSW inverter instead of 15 min with three 27s and MSW inverter.
More or less. 
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mena661
Southern California
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Joined: 03/21/2009
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A 2000W inverter (I like Go Power) will handle your needs BUT it all depends on your battery capacity AND how much power you use on other things. If you have 3 group 27's, they'll handle that task but based on BFL13's posts, you'll lose a bit more capacity after successive 50-90% recharges (but this happens to all batteries) so it's generally better to go with as much capacity as you can fit and can afford especially with MW/convection oven use. Three group 24's is a little light for that task though. How long do you normally camp off grid? If it's just a 3-4 day trip then it won't be a problem with group 27's.
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Bit Bucket
Brookings, Oregon
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Joined: 04/29/2011
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jdiffend wrote:mena661 wrote:jdiffend wrote:And I'm going to check out how much power it draws before I decide if it's even feasible. It's certainly feasible but you may not have enough battery capacity to do this routinely.
LOL, I really didn't expect to be cooking frozen pizza every day. I figured using the microwave for a few minutes here or there on a daily basis and the convection oven once a week should be pretty reasonable. I just didn't want to suck down my propane running the generator if I didn't have to.
But after measuring how much power the convection/microwave draws I'm seriously having my doubts about running it without the genny. The oven draws 1457 peak watts while heating to 450, drops off a bit when up to temp, and bounces up and down in watts over the cook cycle. Towards the end of the cook cycle, the microwave kicks in for short bursts with a surge of over 1600 watts each time. It takes a total of just over .42 kwh to cook at 450 for 20 minutes. That's what? An hour's charge time off of 4 large solar panels at their peak output. The good news is that this oven requires shorter cook times than my convection/toaster oven so 20 minutes might not be required and most stuff doesn't require 450 degrees so this is like a worst case.
The peak wattage required by the microwave is clearly an issue for an inverter for it, however peak efficiency *might* be best at around 1450 watts due to longer cook times with the convection oven.
As for the fridge/TV circuit... I have to maintain enough battery to keep the fridge going and recharge with just solar panels. The big TV draws 122 watts peak. I haven't checked the 22" bedroom LED TV yet but it should take less than 1/3 the watts of the bit TV based on the yearly energy cost ratings of the two. I think I'll be looking at under 450 watts total for the entire circuit at any given time though.
Practically speaking, don't expect to get more than a single evening out of 4 6's and a couple bags of popcorn while watching movies.
We have that setup, Magnum 2800 watt inverter off of (4) 6 volters and that about wraps up a single charge cycle.
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jdiffend
Denver, CO
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Joined: 09/17/2010
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Bit Bucket wrote:Practically speaking, don't expect to get more than a single evening out of 4 6's and a couple bags of popcorn while watching movies.
We have that setup, Magnum 2800 watt inverter off of (4) 6 volters and that about wraps up a single charge cycle.
That sounds pretty reasonable. I wouldn't mind firing up the genny once in a while but I'd rather not most of the time.
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mena661
Southern California
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jdiffend wrote:Bit Bucket wrote:Practically speaking, don't expect to get more than a single evening out of 4 6's and a couple bags of popcorn while watching movies.
We have that setup, Magnum 2800 watt inverter off of (4) 6 volters and that about wraps up a single charge cycle.
That sounds pretty reasonable. I wouldn't mind firing up the genny once in a while but I'd rather not most of the time. Define once in a while. Sounds like Bit is talking about running the genny once each day.
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jdiffend
Denver, CO
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Bit is talking about "a single evening" and doesn't mention how recharging is accomplished during the day.
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big whitey
raleigh,nc
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Joined: 03/21/2011
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smkettner wrote:This is where I go back and recommend just a small inverter (300w) and use the generator for the heavy lifting. Simplifies the install too.
In which case I recommend GoPower or Morningstar
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