Batteries and Inverters

[Tom]

I am gearing up to make the move. Found 20 acers with a house that has no electricty. With in a year I hope to own this place. After doing a lot reading I hope to be ready for the big change. I think I want to have 8 6 volt “golf cart” batteries hooked up for 24 volts. I think I want to use 2 4000 watt inverters. wind and solar for recharging. The question is can I or do want to hook both inverters on the same bank of batteries or have each inverter run off its own bank. Thanks for your exportise and advise.

Tooltime66

[Tom]

FYI… I have a 1 cylinder diesel engine with 24 volt altinator that came off an old sign board. I plan on useing it to help recharge the batteries. I hope that it will be fuel efficant. I need to test run it on a gallon of fuel to see how long it will run.

Tooltime66

[elnav]

Don’t split your bank. A customer of mine inherited such a system and it did not work. Why so much power? Save money, get a pair of 3kW which is plenty.

Whatever you do don’t go for a split center tapped system. It will give you grief. I have a better ikdea that works better and the system does not get unbalanced.

Do not assume you need as much inverter power as you would need in generator capacity. That is a fallacy. All my systems only need 6kW total even for driving air conditioners. Bigger inverters also have greater parasitic losses. I understand why you went 24V but 48V would be better for seveal reasons to do with battery service life, and there are 48V alternators available.

[Tom]

Thank you for your input. I will not plan on splitting the bank, that would have been my gut feeling. As far as the 6000 or 8000 watts I would not want to cut may self short I will powering a 3 bedroom house. the well, washer and dryer will be running off the generator one day a week. random LED or floresent for lights. TV, microwave, toaster. At first, a refrigerator untill I install a LP fridge. The wife thinks she would like to have a dish washer. up to 3000 watt draw, I dont think so.

The thought I had as far as going to 48 volts is up front cost. 24 seems to cheaper and easyer to find. But, I will still check out all my options before anything is bought.

Tooltime66

[gordo]

washer? dryer? tv? microwave?toaster? and fridge. washer isntnthat much but dryer(look for propane or line dry) with all the appliances and the fridge if you were going 24v would need a minimum of 8 l16’s batteries so you might as well set up 48 and get the extra surge. how deep is the well? what size is the pump. anything over 1/2 hp will be 240v which will be a need a transformer . however the groundfos SQE pump, little more expensive will run on half the surge amps but is a on demand style well pump so in the long run it may use more battery but require less start up watts/amp.

but seriously if you planning on having and using all those appliances your still gonna need a large battery bank so you might as well go 48v.

price wise all the major inverters seem to be about the same price regardless of there volts. same with the rest of the gear. its only the number of batteries to attain that would cost more. also the larger the bank the more resources(solar,wind,hypo) you’ll need to be able to keep up a good charge and maintain the batteries

my 2 cents

cheers g

[gordo]

washer? dryer? tv? microwave?toaster? and fridge. washer isntnthat much but dryer(look for propane or line dry) with all the appliances and the fridge if you were going 24v would need a minimum of 8 l16’s batteries so you might as well set up 48 and get the extra surge. how deep is the well? what size is the pump. anything over 1/2 hp will be 240v which will be a need a transformer . however the groundfos SQE pump, little more expensive will run on half the surge amps but is a on demand style well pump so in the long run it may use more battery but require less start up watts/amp.

but seriously if you planning on having and using all those appliances your still gonna need a large battery bank so you might as well go 48v.

price wise all the major inverters seem to be about the same price regardless of there volts. same with the rest of the gear. its only the number of batteries to attain that would cost more. also the larger the bank the more resources(solar,wind,hypo) you’ll need to be able to keep up a good charge and maintain the batteries

my 2 cents

cheers g

[elnav]

Tooltime. In my opinion running a genset only one time per week is a mistake.

I have seen countless sailboaters with ruined battery banks for this reason. Recently we had another poster with a bad bank ruined for the same reason. Lead acid batteries sulfate, you cannot avoid it since its part of the process.

Sadly there is a general lack of in-depth knowledge even among the people selling batteries as part of their product package. I just lost a post explaining details that took 15 minutes to write up thanks to a mis step on the keyboard. I haven’t time to rewrite it all. There are ways of avoiding problems with the system you propose but it is not conventional wisdom.

The house you propose sounds very similar to what my wifes two uncles live in off-grid. It can be done but will be a lot less troublesome if you avoid some of the common mistakes. Contact me for details.

[Tom]

Thank you for all your replys. I can see that I wont have to reinvent the wheel. I can learn from others mistakes. I can also see that there there can be some misunderstanding. I said that I was not going to run the washer and LP dryer or well pump off the batteries. Mr Gordo must have missed that. but thats ok. Mr Elnav does not want me to ruin my batteries so his input is great. I am guessing that you think that the generator will be my only soarce of recharge? I dont know, Like I said earlyer, batteries will be lights, LCD TV, and basic kitchen. I will have a one cyl diesel engine with altinator to run daily to recharge then bank. I am going to check the options of battery voltage 24 or 48. Mr Elnav, when I get closer to moving off the grid, I will make a point to contact you for more details to increase the life if the batteries. FYI, in west michigan, not sure how solar and wind will work for battery up keep.

Thank you.

Tooltime66

[elnav]

I live across the lake from Michigan for a quarter cedntury before moving to west coast region. My guess is you will experience peroids where you need more than the 3 day battery reserve most solar dealers recommend. We just finished a month long cloudy period. In our northern latitude solar must be supplemented with other means. If running a petro fuelled generator is counter to your personal eco-consciousness consider there are other fuel options. Propane, natural gas, and methane are the first that come to mind. With some effort you can also consider methanl home grown or industrial sourced. wood gas production is yet a third. Jean Paine produced his own fuel in big wood chip composters.

With respect to batteries, NiFe batteries cost more and take up more volume but has a much more benign eco footprint. The electrolyte is not an acid like sulphuric acid and the plates are nickel and iron not toxic lead. No one really knows how long they last because 75 year old Edison NiFe cells are still running. You change electrolyte every 10 years or so. Admittedly there is also a need to alter the charging regime. However premature battery failure due to lead sulfation is not one of the problems you need worry about.

Wind and waterpower are also options depending on geographic locations.

But often these are restricted for various reasons.

[elnav]

I live across the lake from Michigan for a quarter cedntury before moving to west coast region. My guess is you will experience peroids where you need more than the 3 day battery reserve most solar dealers recommend. We just finished a month long cloudy period. In our northern latitude solar must be supplemented with other means. If running a petro fuelled generator is counter to your personal eco-consciousness consider there are other fuel options. Propane, natural gas, and methane are the first that come to mind. With some effort you can also consider methanl home grown or industrial sourced. wood gas production is yet a third. Jean Paine produced his own fuel in big wood chip composters.

With respect to batteries, NiFe batteries cost more and take up more volume but has a much more benign eco footprint. The electrolyte is not an acid like sulphuric acid and the plates are nickel and iron not toxic lead. No one really knows how long they last because 75 year old Edison NiFe cells are still running. You change electrolyte every 10 years or so. Admittedly there is also a need to alter the charging regime. However premature battery failure due to lead sulfation is not one of the problems you need worry about.

Wind and waterpower are also options depending on geographic locations.

But often these are restricted for various reasons.

[elnav]

I live across the lake from Michigan for a quarter cedntury before moving to west coast region. My guess is you will experience peroids where you need more than the 3 day battery reserve most solar dealers recommend. We just finished a month long cloudy period. In our northern latitude solar must be supplemented with other means. If running a petro fuelled generator is counter to your personal eco-consciousness consider there are other fuel options. Propane, natural gas, and methane are the first that come to mind. With some effort you can also consider methanl home grown or industrial sourced. wood gas production is yet a third. Jean Paine produced his own fuel in big wood chip composters.

With respect to batteries, NiFe batteries cost more and take up more volume but has a much more benign eco footprint. The electrolyte is not an acid like sulphuric acid and the plates are nickel and iron not toxic lead. No one really knows how long they last because 75 year old Edison NiFe cells are still running. You change electrolyte every 10 years or so. Admittedly there is also a need to alter the charging regime. However premature battery failure due to lead sulfation is not one of the problems you need worry about.

Wind and waterpower are also options depending on geographic locations.

But often these are restricted for various reasons.

[Anonymous]

Great to read this thread.

[Author]

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