Just bought this and need suggestions

[schmism]

Last month my kwh was 339, this month it skyrocketed to 684. Here's what it was in the preceding months: 355, 336, 325, 362, 437, 407, 448, 327, 395, 470, 443. This gives you an example of my kwh for the last year. With everything being about the same each month, I can't tell how the bill skyrocketed.

You need to check your billing. That looks like a projected billing type scheme and then there is a "catch up" month when they need to reconcile the actual usage to what they "estimated" you would use.
Its my understanding that virtually all new utility accounts are set up this way as the utility experience has showed them that people are really bad at budgeting and can not deal with the fact that in the spring/fall a $50 utility bill means a "windfall" month and then july/aug when you run the AC 24/7 they arn't prepared to pay $300 so the utility does the avg for them.
I had to specificly request to be not put on the avg-plan when I signed up last time.

 

[crucian]

You need to check your billing. That looks like a projected billing type scheme and then there is a "catch up" month when they need to reconcile the actual usage to what they "estimated" you would use.
Its my understanding that virtually all new utility accounts are set up this way as the utility experience has showed them that people are really bad at budgeting and can not deal with the fact that in the spring/fall a $50 utility bill means a "windfall" month and then july/aug when you run the AC 24/7 they arn't prepared to pay $300 so the utility does the avg for them.
I had to specificly request to be not put on the avg-plan when I signed up last time.

My utility company installed what they called smart meters that is supposed to give them real time data and even cut you off and turn you back on with the push of a key stroke. They came out and took out the old meter and installed the new one, I stood right next to the guy as he did it. If it's a smart meter then this shouldn't be any projected or estimated billing. I rarely ever believe anything coming out their mouths as it's usually all lies.

 

[crucian]

I'm assuming by watts per day you actually mean Watt-hours per day? If that's the case... YES THAT'S WHAT I MEANT

1.5X loss is ultra conservative. WHAT WOULD BE A GENERALLY GOOD PERCENTAGE OF LOSS TO USE?

25% loss applied a second time is also conservative WHAT WOULD BE A GENERALLY GOOD PERCENTAGE OF LOSS TO USE?

5.9kWh/day = 5.9/0.85 (DC-AC conversion inefficiency) = 6.9kWh/day

4 days = 27.8kWh/day

If using FLA/AGM, you need 2X that at 55.5 kWh (48V/1157Ah)
If using LFP, you need X/.8 that at 34.7kWh (48V/723Ah)

That will allow for 4 days with ZERO sun or backup generator based on the consumption you've given.

Thanks for the reply. Would it hurt to have too many panels/batteries? I'm using some used 250w panels. Do I have to stick with 250w panels? If I get 300w or more, can I add them to my solar array? I know batteries must be the same and once I start, I have a short window to add batteries but just wondering if I need 723Ah if it would hurt if I got say 1000Ah LFP.

 

[schmism]

If it's a smart meter then this shouldn't be any projected or estimated billing.

Again they may know exactly what the usage is, however you still may be on a "budget bill" "even pay" plan. In which case there is still a catch up month.

 

[morth]

Again, I live in the Caribbean so this would be a system to use rather than a generator in case a hurricane or tropical storm hits and we go without power for weeks as we did when Maria hit and we went months without grid power. Also, my local power company does these rolling blackouts sometimes. I'm also taking into consideration the panels aren't damaged by a storm.

I found a local guy who sells solar batteries and he says we work on 13 hours of sunlight here but to me, it's more like 10-11 hours of sunlight. I also did some research used an online calculator putting in which appliances and lights I'd need initially and here are my numbers, does that look right? The washer would only be used once a week and figured clothes can dry on a clothesline.

Appliance​	Quantity​	Watts​	Hours On per Day​	Watt Hours per Day​
Fridge - 20 cu. ft. (AC)	1	59	24	1416
Microwave	1	1000	1	1000
Box Fan	1	200	13	2600
16	2	200	10	4000
Ceiling Fan	2	120	3	720
Clothes Washer	1	800	1	800
TV - LCD	1	150	5	750
Bluray Player	1	15	5	75
LED Bulb - 60 Watt Equivalent	11	13	2	286

System Calculation Results​
Killowatt Hours per Month:	454 kWh
Peak Sun Hours:	11 hours/day
Solar Panel Watts:	250 W
Number of Panels:	7
System Size:	1.65 kW

The fridge and microwave numbers are too low and those are your main consumers. I have a 1000 Watt (cooking power) microwave and it pulls 1700 Watts when running . Check your microwave, there should be a sticker some place that will show the voltage and max expected Amp draw. Multiply those 2 and you have max Watts. Do the same for your fridge. My 21cf fridge/freezer hits 450 Watts on start, then settles down to 120 running. On the fridge, see if yours has a way to disable the defrost cycle. On my fridge, defrost runs for nearly an hour and consumes 300 Watts while doing it. I would leave defrost enabled for normal use. When running on battery, I would disable it.

Given your location, roof damage is a very real possibility during a hurricane. You may want to consider storing a few panels inside in a safe location just in case the roof system ends up on the other side of the neighborhood. I have a 200 Watt Renogy solar suit case, 12 volt system that is very portable and can charge just about any battery chemistry. With a 2000 Watt inverter and 2 batteries in parallel, I can run the microwave when needed and it will run my fridge for about 26 hours. It can't replenish discharged batteries quickly (only 10aH rate), but it's enough to keep the fridge going for a long time.