number of batteries needed for inverrer

[bindas]

Hello there,
I have an Inverter 12V dc to 220Vac 3000W rated 6000W peack.
to use it for it maximun how many 12V 200Ah Gel deep cycle batteries are needed?

[Mike90250]

Can you double check the kind of batteries? GEL batteries are not suited well for Solar applications, but AGM are. Both are leak resistant, sealed types of batteries, but the AGM is able to handle rapid charging, GEL is usually for Exit lighting backup power, and not daily cycles.

Neither are suited for parallel operation. Instead, I would look at using 2V or 4V sealed batteries wired in series. Do you really need sealed batteries - they are rather expensive.

Your 3000w inverter is very large. Are you sure you need an inverter of that size ? It will consume a lot of power just being on, and you may be better served with a smaller inverter. If you really need 3Kw, you should be looking at a 48V system, not 12V. Internal losses will be much less with 24 or 48V than with 12V.

[bindas]

Thanks, Mike90250,
my configuration (off grid use) is:
4 solar pannels 12V 200W monocrystalin
1 solar charge controller CM3024Z
1 Inverter 12V 3000W rated pire sin
3 Gel batteries 12V 200Ah.
I have 2 extra solar pannels same not installed.
When using not reach 24hours,
exemple, I start it at 7am it run till 2 or 3am and the inverter stop, that why I want to know how many batteries do I need for the inverter not go off.
And if I use 6 batteries or more there will not be a risk to damage the inverter or other risk?

[Mike90250]

You have to read the labels on your appliances, and discover what the wattage of each appliance is. Then you multiply the wattage x Number Of Hours the appliance runs
Light bulb 75 watts x 4 hours = 300 watt hours

Do this for all your loads.

[bindas]

Hello,
yes I'll do that but I allready tested, I mean I put on all my equipments (fridge, freezer, all fans, lampes, tv, decoders. Only for that my inverter need more than 100Amp.
That why I ask if there can be a risk(for the inverter or other risk) if I use 8 batteries or more of 200Amp in parallel?
I know the good setting is to use 48v inverter,
but I allready have the 12v 3000w rated inverter, 12v solar pannels, 200Amp batteries, so re invest in 48v will cost me more, I can't.
That why Ineed your help to inform me.

[littleharbor]

With 8, 12 volt batteries in parallel you are going to spend more money on prematurely replaced batteries than you will on a 48 volt inverter with a properly wired bank of batteries.

[Mike90250]

Yes, the risk is Fire. Either inside the inverter, or the cables going to it.
3000w coming from a 12v battery is going to be 250 amps. Cable to handle that is expensive and internally in the inverter, the proper wire is seldom used, leading to fire or failure.

All you need is a 48V inverter. you can re-wire the batteries and panels to run at 48V

What was the daily watt hour usage you calculated ? You may be using more power than 10 batteries in either configuration can supply

[littleharbor]

Just checking on eBay I see 48 volt pure sine wave inverters at very reasonable prices. Of course I cant vouch for the quality of any but just saying they're not as costly as you might think.

[bindas]

Thanks a lot for your help.
In my house I have:
-1 air conditionner - 1 refrigerator - 1 congelator - 1 washing machine - 1 small water pump - 1 iron - 1 micro wave - 1 rice cooker - 4 fans - 2 hair dryer - 2 led tv 43'' - 14 led lampes.

With the 12v inverter I connected only: refrigerator, congelator, 1 tv, sometime fans and water pump.

To run all my home appliances which 48v inverter Ineed, 3000w, 4000w or 5000watts?
I have 8 solar pannels 200w 12v and 8 batteries 12v 200ah. (I'll add solar pannels but not now).

[SunEagle]

Thanks a lot for your help.
In my house I have:
-1 air conditionner - 1 refrigerator - 1 congelator - 1 washing machine - 1 small water pump - 1 iron - 1 micro wave - 1 rice cooker - 4 fans - 2 hair dryer - 2 led tv 43'' - 14 led lampes.

With the 12v inverter I connected only: refrigerator, congelator, 1 tv, sometime fans and water pump.

To run all my home appliances which 48v inverter Ineed, 3000w, 4000w or 5000watts?
I have 8 solar pannels 200w 12v and 8 batteries 12v 200ah. (I'll add solar pannels but not now).

You really have to determine the amount of watt hours you need to run from the batteries. Just saying 1 of this and 1 of that does not help us in helping you.

What are the watt value rating for each device and roughly how long do you want to run it? If you want to run multiple high wattage devices you will need a big inverter and a very big battery system. If you can run your devices at different times then you can use a smaller inverter and battery system.

Based on your 8 x 200Ah batteries you can get maybe 5000 watt hours a day no matter how it is wired or voltage it is rated. But 1600watts is too much to charge a 12v battery system. You have to go with a 24v or 48v system with 1600watts of panel. Which will require either an 80amp or 40 amp respectively CC.

[bindas]

Hello
for information if it will help, my electricity bill I pay for one month 420 kw, 510kw, sometime less than 420 kw per month.

[SunEagle]

Hello
for information if it will help, my electricity bill I pay for one month 420 kw, 510kw, sometime less than 420 kw per month.

Your terminology is incorrect. I beleive you mean 420 kWh or kilo watt hours. That comes to about 14 kWh per day (420kWh / 30 days = 14kWh/day).

Unfortunately that would require a battery system about 3 times as big as the one you currently have.

[bindas]

Thank you SunEagle,
So I must replace the Inverter.
If I use 24V 5000W it will be good?
I have noted for batteries.
You know why I ask for 24V, because if later I have to modify my installation for small use I could use the 24V

[SunEagle]

Well the problem with a 5000w inverter on a 24v battery is that the wires will need to be able to handle more than 200 amps which will make them big.

The other problem is that with a 5000w inverter you can easily drain your battery system. As well as have a static load of a couple of 100 watts due to the inefficiency of that big of an inverter.

At this time I really can say what size inverter will support your needs because without the watt rating of your loads we are just guessing.

[jflorey2]

You have two things you have to heed.

The first is max current. At 12V, 6000 watts is 500 amps. So you need wiring to handle 500 amps, and batteries that can handle a 500 amp discharge. You would likely be looking at a great many in parallel. Check out the battery specs.

The second is energy. You have to size your battery so that you use less than half of its capacity during times of no sun - and 3-5 days is usually a good rule of thumb. So if you use 20kwhr a day that's 20*5*2=200 kilowatt-hours. Each of those 200ah 12V batteries is 2.4kwhr, so you'd need roughly 100 batteries. However, you can't parallel more than 2-3 strings and have them last very long, so that won't work.