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Post by Mike Harding on Nov 1, 2023 14:02:04 GMT 10
I recently upgraded my caravan to the following:
800W (4 x 200W) solar panel
Victron 100V/30A MPPT controller
4.8kWh of LiFePO4 cells at 24V
An eBay 2kW inverter
This system has been running for about two weeks and seems to perform well so I thought I'd cook an all electric meal (peas aside) ans see what happened, the following numbers provide the answer - I'm impressed:
Power consumption with lithium setup.
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Microwave = 1320W
5m on high = 100Wh
Air fryer = 1440W
Warm up time = 46Wh
Chips from two large potatoes for 15m = 250Wh (inc. warm up)
Shop bought quiche: 10m at max, 10m at 150C, 10m at 130C = 145Wh
Before starting the above the battery reported 100% when finished it reported 96.7%.
NB. Cooking was done at 1400h with all panels in full sun generating about 500W.
After the above the thinnest wire in the system showed no indication of temperature rise.
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And this in a forest in central Victoria. Not bad I reckon
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Post by yobarr on Nov 1, 2023 16:27:18 GMT 10
Yes, most impressve Mike. As you're aware, my van is full Solar with a Diesel heater and no gas appliances. Batteries are 540ah Victron LifePo 4, and I NEVER have run out of power despite spending winter in the deep south of WA, near Albany. Could you please explain 4.8kwh in comparison with my 540ah of Lithium?
My inverter is 5kw Victron and I can run my 2.5kw AC, electric frypan, toaster, microwave etc all at the same time. Cheers
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Post by Mike Harding on Nov 1, 2023 17:51:15 GMT 10
Hi Yobarr
For the amp hour (Ah) figure to be of use one needs to know the voltage of the battery pack, in your case it's probably 12V so 540 x 12 = 6480 therefore you have 6.48kWh of available energy, in reality it'll be more like 5.5kWh but that is still a goodly amount. Keep in mind however, this is akin to having a large bucket, you still have to find the water to fill it.
For off-grid use lithium (LiFePO4) batteries are certainly a game change, their ability to accept and return large amounts of charge whilst retaining a flat voltage curve makes them idea for this application and once their price drops by, say, 50% they will flood the market.
Here in Victoria, and especially in forests in the winter, I will struggle to rely 100% on solar I think but if I have to run the generator for a few hours every three or four days that's a price I can live with.
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Post by yobarr on Nov 1, 2023 19:37:54 GMT 10
Hi Yobarr For the amp hour (Ah) figure to be of use one needs to know the voltage of the battery pack, in your case it's probably 12V so 540 x12 = 6480 therefore you have 6.48kWh of available energy, in reality it'll be more like 5.5kWh but that is still a goodly amount. Keep in mind however, this is akin to having a large bucket, you still have to find the water to fill it. For off-grid use lithium (LiFePO4) batteries are certainly a game change, their ability to accept and return large amounts of charge whilst retaining a flat voltage curve makes them idea for this application and once their price drops by, say, 50% they will flood the market. Here in Victoria, and especially in forests in the winter, I will struggle to rely 100% on solar I think but if I have to run the generator for a few hours every three or four days that's a price I can live with. Thanks Mike, Now I've got to try to remember the formula! You are correct that it's all 12 volt. Although I carry a Honda 2.2 generator "just in case" it never has been used, and the DC to DC system that I was convinced I 'needed' has never even been connected to the car either. Cheers |
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Post by yobarr on Nov 1, 2023 19:47:56 GMT 10
Hi Yobarr For the amp hour (Ah) figure to be of use one needs to know the voltage of the battery pack, in your case it's probably 12V so 540 x 12== 6480 therefore you have 6.48;kWh of available energy, in reality it'll be more like 5.5kWh but that is still a goodly amount. Keep in mind however, this is akin to having a large bucket, you still have to find the water to fill it. For off-grid use lithium (LiFePO4) batteries are certainly a game change, their ability to accept and return large amounts of charge whilst retaining a flat voltage curve makes them idea for this application and once their price drops by, say, 50% they will flood the market. Here in Victoria, and especially in forests in the winter, I will struggle to rely 100% on solar I think but if I have to run the generator for a few hours every three or four days that's a price I can live with. Thanks Mike. It is indeed 12 volt. Now I've just got to remember the formula. Although I carry a Honda 2,2kw generator it never has been used, while the DC to DC system that I was convinced I "needed" has never been connected to the car, as I've always managed with Solar. The 1650 watts of Solar that I have usually has the batteries back to 100% by about 10.30am, but in winter, in the deep South, sometimes it took all day, failing only once to reach that figure. However, I cannot use the reverse-cycle system to heat the van in winter, but the Diesel heater sorts that! . Cheers |
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Post by Mike Harding on Nov 1, 2023 20:58:25 GMT 10
Diesel heaters are the work of the gods  |
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Post by yobarr on Nov 1, 2023 21:20:00 GMT 10
Diesel heaters are the work of the gods Yes, mine heats Hot Water to 60degrees in 20 minutes, and uses 1 litre diesel in 8 hours overnight when outside temp is below zero. |
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