Off grid partially mostly used for power outage usage. Why won't it pay for itself??

[Mike90250]

Is it just the batteries that are the downfall of the system because of replacement. The stories that batteries can last 8 years if well maintained are garbage?

Yep, the batteries have to be replaced. They seldom last for more than 5 years. That expense quickly erases any electricity savings.

We are about 15 cents a KW here at peak times and about 10 in the off peak times.

If you had a simple Grid Tie system without batteries, those actually get a payback, which is why they are popular. You have pretty low rates, so your payback will be longer.

[Stix]

They are made by east penn. Made in the USA.

They are rebadged and this is what they are if ya google it.

East Penn Promaster 0250.pdf

[Stix]

Yep, the batteries have to be replaced. They seldom last for more than 5 years. That expense quickly erases any electricity savings.


If you had a simple Grid Tie system without batteries, those actually get a payback, which is why they are popular. You have pretty low rates, so your payback will be longer.

Got it. I do not want a grid tied though because all the permits and hassle. Especially since there is no incentive for me to do it. I would only get a rebate if I owed the feds. You're right though I would not make anything massive with solar alone and would take a perfect scenario to come out ahead. Well as long as the batteries last 2 years I could make them up. Hopefully by the time they need to be changed a better battery solution will be out...... Not likely though.

This whole project has taught me alot on how to save energy and is really dropping the bills. This billing cycle will be my first fully implemented solar/conservation methods. So we shall see how I did.

[Bala]

I think you are fudging numbers to come out with a cost saving.

The reason why people on this forum play devils advocate is to ensure people gets both sides of a story. you admit to being new to solar and believe you had put in place a reliable back up that will save you money.

I don't think you have either. Unless all your family understand the limitations of that system your back up will fail when you need it.

My wife knows if our batteries are down and it's raining she can turn the key to the genset from the house and it will run the whole house as well as charge batteries and heat watet

Sorry post is a bit short and to the point in using a phone as away from home

[Stix]

I think you are fudging numbers to come out with a cost saving.

The reason why people on this forum play devils advocate is to ensure people gets both sides of a story. you admit to being new to solar and believe you had put in place a reliable back up that will save you money.

I don't think you have either. Unless all your family understand the limitations of that system your back up will fail when you need it.

My wife knows if our batteries are down and it's raining she can turn the key to the genset from the house and it will run the whole house as well as charge batteries and heat watet

Sorry post is a bit short and to the point in using a phone as away from home

How can I be fudging numbers when I posted the difference from bill on first page. If you wanna think I am fudging that is fine. Being new does not make me a liar. I never said I was done. Amazed how many do not read all the posts.

No need to be sorry. Short and to the point is fine. Calling someone a liar is a bit different though.

[Sunking]

Stix it is very simple. Some of us replying have over 35 years of electrical engineering experience and know darn good and well you are cooking the books. We know from many years experience it is impossible to save money with any off-grid system. We know for fact just in battery cost alone it is 4 to 6 times more expensive than buying it from the power company. That is for every day use, not Emergencies Stand By which makes the cost astronomical off the map. Batteries last 3 to 5 years if you use them or not. No way you can justify th ecost with only using them a few times a year which still requires a generator for extended outages.

It is simple, you cannot BS us. We know better. That is why you are catching so much resistance.

[Stix]

You're right sunking I am a newb. I am a liar. If only you knew. Have a great night guys. I will goto the next forum and share my experience elsewhere. The solar gods have set in stone the knowledge needed. Been a pleasure talking with you all. Good luck on the future.

[ButchDeal]

Got it. I do not want a grid tied though because all the permits and hassle. Especially since there is no incentive for me to do it. I would only get a rebate if I owed the feds. You're right though I would not make anything massive with solar alone and would take a perfect scenario to come out ahead. Well as long as the batteries last 2 years I could make them up. Hopefully by the time they need to be changed a better battery solution will be out...... Not likely though.

This whole project has taught me alot on how to save energy and is really dropping the bills. This billing cycle will be my first fully implemented solar/conservation methods. So we shall see how I did.

Well you don't have to "owe" the government to get the rebate. You just have to have paid something to them through your pay check deductions etc.
you already mentioned as well that you did "other" efficiency and energy use reductions, that is we're all your savings are coming from.

[Stix]

Last time ...... you are all right. Set in stone is what you all of 35 Years know. Heck I dont even know my own personal taxes anymore. Good night all. I wish you all the best. With people like this... you need it

Sad day Not sure why all the negativity

[lkruper]

Last time ...... you are all right. Set in stone is what you all of 35 Years know. Heck I dont even know my own personal taxes anymore. Good night all. I wish you all the best. With people like this... you need it

Come back and tell us how long your batteries last. I am going to guess at 255 cycles (days) their capacity will have dropped.

[inetdog]

Come back and tell us how long your batteries last. I am going to guess at 255 cycles (days) their capacity will have dropped.

The cutoff most manufacturers use for battery life is 80% of original capacity. Most RE folks are happy to go beyond that, but the decline from that point is more rapid and eventually will impact their autonomy numbers.

[Stix]

Come back and tell us how long your batteries last. I am going to guess at 255 cycles (days) their capacity will have dropped.

No worries I won't be back Enjoy my friend. Was a pleasure atleast talking to you. My last and final post here. Have a awesome year all and sorry ya stuck with these kind of people. To be called a liar even with proof is a sad day. Kinda like politics.

[Sunking]

STIX math is what gets you into trouble. 500 watts of panels on a grid tied system can only generate 2 to 3 Kwh per day. Same panels on a battery system is 1 to 1.5 Kwh per day. It is very simple 5th grade math. Depending on where you live the POCO only charges 9 to 20 cents per Kwh, 11.2-cents national average.

So do the math.

3 Kwh x 11.2 cent = $$0.336 per day or $10 per month grid tied.
1.5 Kwh x 11.2 cents = $0.168 per day or $5 per month battery system.

No one called you a liar. We are not stupid and know what can and cannot be done.

[Legacy]

Sadly Sunking i think he is mistaking that people think he is not saving the money
he is when in fact the problem is he seems to be putting too much weight to savings
he believes are coming from solar instead of the fine work he has done on conservation.

Myself when we moved into this place we would use around 13 -14kwhs per day in the summer
and 23-24kwhs in winter. by conservation in a lot of forms I have been able to bring the summer
amounts to 9-10kwhs and winter to 19-20kwhs and that is with electric water heater and range.

[Stix]

First I would like to apologize and ask for a redo if possible. After Having the system a bit longer and having problems and revisiting this thread. I see where the confusion set in about me saving money. I was trying to include my conservation savings along with my solar. I was trying to explain and looking back i may have done it in a bad way..... I was considering the solar install and the power saving practices to be all in one (hence the why would it not pay for itself). The reason being is it would have never come about (Conservation part) if I did not add the solar and see it was gonna take more than just solar to make this work. I have been a lot more conscious of my power usage now. Thus the huge reduction in bills and the solar during the day just adds to it. Yes most is from conservation.

I took things the wrong way and apologize to all. Now I can go back to hiding and just read the forum until I learn more.