Solar system 12v upgrade 24v ?

[frankz66]

Hello everyone, I currently have a 12 v solar system with 2.5 kw storage.

The plant is composed as follows:

4 solar panels ( PERC ) 12 volts 2s2p VOC total 46 volts 18 amps .

1 epever 6415AN Tracer

1 Pure wave inverter 1000w 2000w max 12 volts EDECOA

4 AGM batteries 110 amps 12v in parallel tot 440 amps and 2.6 kw available with 50 % DOD. .

In fact, I wanted to know some advice on what I can do to improve the system. In addition, if I connect the batteries in series to obtain 24 volts and 200 amps, what benefits do I bring to the system? I connected the refrigerator, which absorbs 500 watts for 1 second causing a voltage drop of 0.70 volts. If I connected the 24v battery system, will I improve something or not?

Clearly I would have to change the inverter to 24 volts .

The epever with 24 volts of batteries, the technical table tells me that it is able to errone in charging towards the batteries well 1500 watts.

 

[Rednecktek]

Do you have any 12v appliances? About the only advantantage would be the ability to upgrade your inverter to a larger one and get double the watts on the SCC. Do yoi need that much AC power?

 

[frankz66]

Do you have any 12v appliances? About the only advantantage would be the ability to upgrade your inverter to a larger one and get double the watts on the SCC. Do yoi need that much AC power?

So, I use it in a cabin, everything works perfectly and I can get the energy I get, indeed in the morning the batteries are still charged .... 12.45 volts! I wanted to optimize, and understand if by putting the batteries in series at 24 volts and changing the inverter to 24 v the cue of the 500 watts and conceived decrease in the voltage of the batteries can decrease. To be more explicit, with 24 volts batteries will the voltage drop be less?

 

[Rednecktek]

To be more explicit, with 24 volts batteries will the voltage drop be less?

In theory yes, but it's negligible. 12.45v on those AGM's isn't fully charged which is your real problem with the voltage drop, you should be seeing 12.8+ if they're fully topped up. You're down near 75% on your batteries which is the bigger issue. A 200Ah heated (because Canada) LFP battery or two and/or more panels would be a much better investment. Dollar per usable watt LFP batteries and AGM are about the same nowadays.

If you can get those batteries fully, and I mean really fully, charged AND the batteries aren't too old you'll probably have less issue. AGM only has so much lifespan and once the plates start getting deteriorated they not only can't hold as much charge, but also can't dump out real amperage without a significant voltage drop.

AGM's, like all flavors of lead acid, really REALLY need to be kept completely topped up as much as possible to avoid damage to the plates. I've destroyed more than a couple batteries, AGM and FLA, from not having enough charging and not keeping them fully charged all the time.

 

[JJJJ]

My personal experience with AGM, which is admittedly limited is that AGM batteries don’t do well with being idle. At least in my experience.

How often is the cabin used?

If the batteries are new then getting more new batteries makes little sense.

If you decide to DIY a 12v system with lithium iron phosphate then changing to 24v in the future simply means placing cells together and upgrading Bms.

If your needs are being met with 12v then as stated above $$& towards panels and batteries in the future is a good investment. On the other hand if you need more wattage then moving up the voltage chain makes sense.

 

[frankz66]

In theory yes, but it's negligible. 12.45v on those AGM's isn't fully charged which is your real problem with the voltage drop, you should be seeing 12.8+ if they're fully topped up. You're down near 75% on your batteries which is the bigger issue. A 200Ah heated (because Canada) LFP battery or two and/or more panels would be a much better investment. Dollar per usable watt LFP batteries and AGM are about the same nowadays.

If you can get those batteries fully, and I mean really fully, charged AND the batteries aren't too old you'll probably have less issue. AGM only has so much lifespan and once the plates start getting deteriorated they not only can't hold as much charge, but also can't dump out real amperage without a significant voltage drop.

AGM's, like all flavors of lead acid, really REALLY need to be kept completely topped up as much as possible to avoid damage to the plates. I've destroyed more than a couple batteries, AGM and FLA, from not having enough charging and not keeping them fully charged all the time.

First of all, thank you for responding. Yes, in fact, I know that I could still add two more 180 panels to get to 1 kw total moreover my scc epever could charge 750 watts towards the 12 volts that at 14.50 I could see almost 950 watts towards the batteries. I made the mistake that everyone makes, but in good faith dictated by inexperience. Now I would know what to do, maybe buy 800 amps of lifepo4 at at no more than 24 volts, put 2kw of panels leaving epever 6415 and change the inverter. Anyway, thank you, even if at the moment being the plant in a small house, I go there in the evening and I don't do without watching TV, cooking, lights, garden lights. Only the fridge is off as every 30 minutes it attacks the engine and makes me lower the batteries by 0.60 volts. At the moment I take advantage of the batteries that have about 1 year . In addition, with all this during the day 24/24 hours, I have a constant consumption of about 50 watts between cameras and PCs.

 

[frankz66]

My personal experience with AGM, which is admittedly limited is that AGM batteries don’t do well with being idle. At least in my experience.

How often is the cabin used?

If the batteries are new then getting more new batteries makes little sense.

If you decide to DIY a 12v system with lithium iron phosphate then changing to 24v in the future simply means placing cells together and upgrading Bms.

If your needs are being met with 12v then as stated above $$& towards panels and batteries in the future is a good investment. On the other hand if you need more wattage then moving up the voltage chain makes sense.

Thank you for responding . Yes, what you wrote is correct, you consider that now at the end of summer I consume daily at least what epever tells me is about 3kw a day and in the evening the batteries have a load voltage of 50 watts of about 12.75 (I should do it empty or with the shunt) ... However, I understand that if these batteries at the moment I wanted to put them in series at 24 volts and have 24 volts and 220 amps, the voltage drop towards the fridge would be the same ....