This year I have purchased a large greenhouse my intention is to heat the greenhouse with solar panels and also maybe attach a battery charger from the house just to keep the batteries boosted not sure how this can be done or what battery charger would I need I have also attached a a file to the batteries specifications appreciate any help and advice
Connecting a battery charger to a solar panel bank continuously
- Thread starter Getaway
- Start date
If you're talking about using solar to make electricity, and electricity to make heat, you need to do some math. It will be the most expensive heat you've ever heard of. Solar doesn't work for that on an economic basis.
Figure out how many watts of heat you'll want. One small space heater is 1500 watts. Let's say you just need two of them. For 12 hours a day that's 36 kilowatt hours of power. A 45 kWH lthium battery will handle that. The battery you mention will run them for a few minutes. That's 9 of the EG4 batteries, at about $1800 each, $16,200 or so. Throw in another couple of thousand for an inverter, a thousand for a charge controller, and maybe 5 thousand for panels, you're looking at around $25,000 startup costs, and remember, that's for just two small space heaters.
Figure out how many watts of heat you'll want. One small space heater is 1500 watts. Let's say you just need two of them. For 12 hours a day that's 36 kilowatt hours of power. A 45 kWH lthium battery will handle that. The battery you mention will run them for a few minutes. That's 9 of the EG4 batteries, at about $1800 each, $16,200 or so. Throw in another couple of thousand for an inverter, a thousand for a charge controller, and maybe 5 thousand for panels, you're looking at around $25,000 startup costs, and remember, that's for just two small space heaters.
Hi thank you for this information it does seem a lot if I were to do that way but my intention really was not to use an inverter use everything directly from the batteries using PTC Car Fan Air Heater for Small Room Space (12V 100W) like the one I have attached and put 1 in each of the 6 large propagators that would be covered then just use a battery charger from the house on a long extension lead just to reassure that I do not drain the batteries overnight .
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Have you checked to make sure that one of those will produce enough heat in your space? One adult person is roughly equivalent to a 100 Watt heater. If you can't stand in the space and keep it warm enough, you don't have enough heat. How hot do you need to keep the space?
Is it good enough to use heater wire on your benches and just keep roots warm? You can buy it in various Ohms/meter and basically any length you want. 100 Watts spread out like that will do a lot more good than putting all of the power in one small space.
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Perhaps you could get the heat set up how you need it with your extension cord, then size a solar setup properly based on what you know.
Hi thanks I've already purchased 6 from Amazon they are brilliant for large cold propagators I already have three batteries connected to a 400w solar panel in the daytime the batteries stay above 50% charged but it's at night-time I need to connect a small battery charger I can either add more solar panels and batteries but my preferred way was just to use a battery charger at night-time to keep the batteries topped up this is where I'm not sure what battery charger I can connectHave you checked to make sure that one of those will produce enough heat in your space? One adult person is roughly equivalent to a 100 Watt heater. If you can't stand in the space and keep it warm enough, you don't have enough heat. How hot do you need to keep the space?
Is it good enough to use heater wire on your benches and just keep roots warm? You can buy it in various Ohms/meter and basically any length you want. 100 Watts spread out like that will do a lot more good than putting all of the power in one small space.
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Perhaps you could get the heat set up how you need it with your extension cord, then size a solar setup properly based on what you know.
I grow lots of starts, many 1,000's for a market garden. I have a room in my shop for starts, 8'x8', insulated, with 2 shelf units.5 shelves high. Two of the shelves are insulated all around with 1.5" foam board and they have a 2'x4' thermostatically controlled heat mats under them. I use those for heat sensitive seeds, eggplants, peppers, tomatoes, etc. After plants germinate they go on a shelf with T5 lights over them to grow bigger.
The lights run 16 hours a day and they are enough to keep the room at about 70 degrees all the time without any other heat. I run all these off my solar system, the constant draw is about 1000 watts for the lights and heat mats, or 12 kWh per day. It's nice getting dual use out of the lights, they give light and act as heaters at the same time.
None of my greenhouses are heated, once the seedlings get bigger they go out into greenhouse set up so I can put row cover over the at night to keep them warm. I'm in western Oregon , zone 8, I'll have tomatoes in the ground March 15 using this system.
Just sharing some ideas for my system I've developed over many years. It's a lot more efficient to heat the soil than the air, and works better for the plants.
As for a charger, you need a charger than can be configured for your battery. I don't remember if it's lithium or lead, but any battery charger that will handle the chemistry should work. Just figure out how many amp hours you need to put into the battery overnight, i.e. if your battery is 200 amp hours and it's half full, that's 100 amp hours you need to replace. If you charge for 8 hours you need at least 12.5 amps of charging, but of course you need more than that to make up for losses and inefficiency, I'd allow 50 percent more myself.
The lights run 16 hours a day and they are enough to keep the room at about 70 degrees all the time without any other heat. I run all these off my solar system, the constant draw is about 1000 watts for the lights and heat mats, or 12 kWh per day. It's nice getting dual use out of the lights, they give light and act as heaters at the same time.
None of my greenhouses are heated, once the seedlings get bigger they go out into greenhouse set up so I can put row cover over the at night to keep them warm. I'm in western Oregon , zone 8, I'll have tomatoes in the ground March 15 using this system.
Just sharing some ideas for my system I've developed over many years. It's a lot more efficient to heat the soil than the air, and works better for the plants.
As for a charger, you need a charger than can be configured for your battery. I don't remember if it's lithium or lead, but any battery charger that will handle the chemistry should work. Just figure out how many amp hours you need to put into the battery overnight, i.e. if your battery is 200 amp hours and it's half full, that's 100 amp hours you need to replace. If you charge for 8 hours you need at least 12.5 amps of charging, but of course you need more than that to make up for losses and inefficiency, I'd allow 50 percent more myself.
I much appreciate this information I've only really got back into gardening this last 2 years mainly due to the coronavirus hopefully that's now disappearing. the 10 m x 3 m greenhouse where the 1m Large Square propagators are inside the small 12-v heaters at night-time start draining the batteries down to 50% within about 6 hours but in the daytime this is not a problem the solar panels help keep the batteries topped up above 50% . got this sorted with an automatic smart battery charger with the help of a YouTuber who has got a similar setup explained to me what I need to do where everything should be connected and the charger will automatically turn on when the batteries get below or close to the 50% ?
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12VoltInstalls
life passes by too quickly to not live in freedom
That’s going to give you very short battery lifespan. I wouldn’t go that Deep consistently.
From what I’m reading I’d also suggest up to 50% more panel watts to take care of your daytime draw PLUS insure proper battery charging. The batteries shouldn’t hover at a partially discharged state for extended periods.
Also, be careful to cable your batteries in a balanced arrangement so they all charge equally and stay healthy
TampaSteve
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Thats exactly what we do in RVs - the batteries are usually always on a charger - DC-DC from the alternator, solar, or shore power and most often 2 chargers at a time. Lithium batteries can do 2000-4000 charge cycles before degrading by 20%.
Rather than set the charger to 50% mine are set to float at 13.5 volts, so they stay about 97% charged. Good chargers work to supply the excess current. Doing it this way means you aren't wasting 1/2 battery cycle a day. You will be using the same amount of electricity anyway.
While keeping Lithium batteries fully charged continuously will not give the longest life, its the best practical solution. You just need to use a quality charger, like Victron, that will keep them nicely charged.
Rather than set the charger to 50% mine are set to float at 13.5 volts, so they stay about 97% charged. Good chargers work to supply the excess current. Doing it this way means you aren't wasting 1/2 battery cycle a day. You will be using the same amount of electricity anyway.
While keeping Lithium batteries fully charged continuously will not give the longest life, its the best practical solution. You just need to use a quality charger, like Victron, that will keep them nicely charged.
