number of batteries needed for inverrer

[bindas]

Ok,
so it is better to look a 48v inverter.
I have:
1 refrigerator 190w permanant
1 congelator 140w permanant
1 air conditionner 200w 10 hours
4 fan of 88w = 264w 8 hours
1 rice cooker 850w 2 hours
1 microwave 900w 1 hour
1 water pump 100w 6 hours
1 iron 1200w 1hour
2 tv of 220w = 440w 8 hours
1 washing machine 1100w 2 hours
2 decoder of 22w = 44w 8 hours
1 hair dryer 1500w 1hou
I used a wattmeter to check.

I think that will help to know which Inverter to use

[bindas]

I forgot to add lamps
14 led lamps 15w

[Ampster]

Now that you have done that can you translate that into Watt hours like your electric bill is calculated? Even though you say your refrigerator is permanent it and some other devices probable only run part of the time unless you think your refrigerator actually uses 4560 Watt hours per day. (190 Watts times 24 hours)

Also, it would be a good idea to total the number of Watthours per day to give you an idea what your daily consumption would be. That will determine your battery capacity but you may need to add some cushion to that depending on what kind of batteries you are going to use. You have already stated that your electric bill is 420-510 kiloWatt hours per month and someone has calculated that to be a minimum of 14 kiloWatt hours per day.

The Inverter capacity which would be expressed in Watts would be your best guess about how many appliances that you might want to run at the same time. You probably want to group them in terms of those that you can control like washing, hair drying etc, and those like refrigerator and pump that have their own cycle.

[J.P.M.]

Bindas: NOMB or concern, but my guess is you would benefit more from all of this discussion if you were to somehow get familiar with the basics of electricity, how it comes into your home from a grid, how it's generated and stored by on site/off grid means, what's available to accomplish the off grid capability, and how various appliances use that electricity.

I suspect a lot of what's being offered here is going over your head.

Respectfully,

[TKB4]

I understand the need for load information etc. Just a few observations . His electric bill does not mean much if he is not powering all his loads from the solar setup. The size of inverter generally doesn't matter other than efficiency and standby loses as long as he doesn't surpass its rating and uses at least appropriate wire sizes for the loads he is actually running. If he checks the wiring temps etc and determines his current maximum amp draw and matches that to wiring it should be safe, NOTICE I DID NOT SAY TO CODE.

Biggest point : If bindas is getting what he wants from his current setup from 7am till at least 2 am then it is meeting his needs for at least 19 hours a day . Assuming he would have similar needs the other 5 hours and it is during a non solar period (night) then the answer is he needs to increase his useful storage by about 5/24 or allowing for some efficiency loss at least 1/4. This would equate to adding 1 more battery of the type he already has. This will actually increase his storage capacity by 1/3 .

The next question is can the panels and charger provide enough energy to charge the batteries. That is impossible to answer with the current information because we do not know whether or not it fully charges bindas current batteries. However since he has extra panels of same type I would estimate that adding one more panel to the current system and certainly adding both the extra panels to the current system would suffice. Again size of wiring etc needs to be adequate but if runs are very short that shouldn't be much of a problem. I would suggest taking temp readings with infrared thermometer or other device.

Binda
In short, I would estimate that adding one more battery like you currently have and adding one or both of the extra panels you already have would likely supply you for the full 24 hour day.
You need to make sure the wiring doesn't get too hot and that you don't overload the inverter or charger. First I would determine whether or not your current batteries are reaching full charge and not discharging too low. You could get an idea by checking their voltage near the end of charging for the day or more accurately by checking the specific gravity. The batteries you already have could be enough just not charged completely which might be corrected just by adding another panel and no more batteries. Note: I have not looked at maximum input for your specific inverter or charger other than advertised amp output of the charger.

Personally, I would try this then start saving for a more advanced system. you also might want to notice that I am a newbie here , but I am not a newbie by any means to physics and scientific and mathematical principles. I would advise studying the facts and coming to your own conclusions. I am not adverse to customizing to achieve goal but not necessarily code that may not apply if not using as grid tied.

The bigger question is how much energy you can get from the solar panels and can your current 30 amp charger supply enough energy to charge the batteries would need to know sun hours and remember you may get less than half the energy in mid winter as mid summer. Assuming a 5 sun hours per day you can charge around a max of 2000 watts a day . Your current panels are about 800 watts per hour but you may be using a lot of this during day as produced and not providing net charge to your batteries.
Basically this is just another way to think of how to solve your problem and answer your initial question.

[Ampster]

Advising someone to not pay attention to the building code is negligent. The wire size should at minimum be protected by the correct fuse or circuit breaker not by how hot the wire gets.The building code is very specific about that and applies whether one is on the grid or off the grid. Besides, if the OP is trying to make his batteries last longer why throw away energy as heat?

[J.P.M.]

I understand the need for load information etc. Just a few observations . His electric bill does not mean much if he is not powering all his loads from the solar setup. The size of inverter generally doesn't matter other than efficiency and standby loses as long as he doesn't surpass its rating and uses at least appropriate wire sizes for the loads he is actually running. If he checks the wiring temps etc and determines his current maximum amp draw and matches that to wiring it should be safe, NOTICE I DID NOT SAY TO CODE.

You might want to consider clarifying or changing that.

Assuming an electrical code of some sort is in force where Bindas is located, it must be followed.

If there is a code in force and it is followed, including likely inspection before startup and maybe a plan review, it'll probably result in a safe(r) system, or at least a higher probability of a safe(r) system. Codes exist for a reason.

If some code is not in force, one can still follow the NEC code or similar international codes.

Checking system voltages, currents, temps. etc. is also necessary, but that says nothing about a safe design, especially when done by a person not experienced in such things.

Given Bindas' level of knowledge in such things, he would be well advised to follow some recognized code.

To make a statement that can easily be misinterpreted by the inexperienced is irresponsible and potentially dangerous.

[TKB4]

I was simply telling him what he already has on hand except for one battery may meet his needs but there is not enough information available to determine that. I did not advise him not to follow codes. When I go camping or hunting and hook up equiptment I use my common sense and I don't think there are any codes applicable but its still a good idea to check wire temps etc since even if all codes are met there may be a poor connection or internally partially broken wire etc than can cause fire or other problem even if it did meet the code for my home and this is also regardless of fuses or breakers . In fact, I specifically stated in capital letters that I did not say it would meet any code. He could obviously set up a much more efficient system but he says he may have significant difficulty purchasing much more equiptment at the present. No one else even tried to determine if his current batteries were being fully charged. I also said he shouldn't ignore the capabilities of his wiring or inverter etc. He may only need to add one battery and make no other changes at this time and since the panels and charger wouldn't be changed and his rate of use wouldn't change only the length of use unless he tries to power more things at the same time etc he should have no new risks. It is ultimately up to him to make sure he meets whatever codes that may exist wherever he is which apparently is not in US . It seemed to me the general idea was to help him by recommending things he may not be able to do rather than help him more economically until he can obtain a more efficient system.

[TKB4]

The real answer to his question is the answer cannot be determined without more facts about his current system which seemed to be overlooked and went straight to recommending essentially a whole different system . That was somewhat addressed. Yes the amp draw is potentially very high so I don't think he is following codes etc now.

[bindas]

Hello,
I am in Madagascar. sun shine.
For big current problem as you say, I look a 24v or 48v converter 3000w or 4000w,
I allready have 4 pannels 24v 380w mono and 4 battery 12v 200Ah. I'll use that for now and later will add pannel and batteries.
The problem with 48v need more investment.
If 24v no problem it will good for me.

[Ampster]

Madagascar? Good for you for trying to navigate this forum. Your desire to seek out the knowledge that people are willing to share says a lot. At the end of the day we may be thousands of miles apart but we are all looking at the same ball of energy in the sky.

[bindas]

4 pannels of 380w 24v
using in 24v or 48v inverter which one will be better?
and which one will run more time before battery discharge
for exemple 200ah battery.
I think same time for both?

[SunEagle]

4 pannels of 380w 24v
using in 24v or 48v inverter which one will be better?
and which one will run more time before battery discharge
for exemple 200ah battery.
I think same time for both?

I am not sure exactly what your batteries are rated but you are correct that if they can be arranged to generate 24v or 48v then they will provide the same amount of power.

Example: If you have 4 x 12v 200Ah batteries wired for 24V (2S2P) that will get you a 24v 400Ah system and be rated 9600wh (24v x 400Ah = 9600wh)

If you wire them for 48v (4S) you will have a 48V 200Ah system which will be rated 9600wh (48v x 200Ah = 9600wh).

So they will both get you the same amount of watt hours but the 24v system will require bigger wires because the amps will be higher at the lower voltage.

So exactly what are those 4 12v batteries rated in Amp Hours?

[bindas]

Ok thanks

[TKB4]

There would likely be a slight gain in length of time batteries last due to less energy (read heat) loss in wiring from 48 volt compared to 24 volt if considering same size wire for each but it would be negligible.