Battery bank draining fast

[Mike90250]

Well i guess i know where my tax return is going this year lol thanks for the help!
any recommendations for a good mppt cc with wind support? I'll get 4 more panels so 1400wsolat +400w wind

You will need 2 MPPT controlers, one for Solar, and one for wind. The only one I know supports wind, is the Midnight Classic. And it only supports the Charging. Once the battery is full, you need to either apply brakes to the turbine, or provide a 200% reliable dump load for it.

[Sunking]

Well i guess i know where my tax return is going this year lol thanks for the help!
any recommendations for a good mppt cc with wind support? I'll get 4 more panels so 1400wsolat +400w wind

Morton forget the wind turds. You do not need it. Stay away from Chi-Com electronics as they are counterfeits and fakes. Bite the bullet and buy a good quality MPPT Controller. Midnite Solar Classic is really good. Being in NV with good winter Sun Hours, 1200 watts is more than enough and you can get away with a Morningstar 60-Amp Tristar MPPT. At 24 volts will allow you to grow up to 1600 watts @ 24 volt battery or 3200 watts @ 48 volt battery.

[thastinger]

You could do all this for a good bit less money than SK is quoting.
- look on Ebay for some used 250W(ish) panels, you can usually find them for about 80 each shipped (I paid 820 for 10 shipped to a local freight terminal just last month)
- ditch the 24V setup and go to 48V, this will significantly decrease your battery costs, this way you can go with 8 of the 6V 225Ah batteries in series, batteries will last longer like this as well and will be more readily available if you have golf cart retailers in your area.
- you could wire 5 of those panels in series with a midnite classic 200 CC

My "starter set" of batteries was trojan T-605s, I got 5.5 years out if them and will replace them this weekend with T-105s. You won't have cores if you buy 6V so look for shops with lower core charges. Including the core charge, T-105s will probably cost you around 160 each.

[morton.bia]

Hmm correct me if I'm wrong but if I use 8 6v 225ah to make 48v wouldnt I have only 225ah at 48v? Which is 10800wh. If I got with 8 550ah 6v to make 24v I'll end up with 24v 1100ah which is 26400wh which is more than twice the capacity

[SunEagle]

Hmm correct me if I'm wrong but if I use 8 6v 225ah to make 48v wouldnt I have only 225ah at 48v? Which is 10800wh. If I got with 8 550ah 6v to make 24v I'll end up with 24v 1100ah which is 26400wh which is more than twice the capacity

You are correct but you would be paying much more for a 550Ah then a 225Ah battery.

[morton.bia]

Hmmm 550ah 6v rolls battery 339$, 225ah 6v 160$ (according to previous post) so almost same price if I want the higher capacity. How long would 11kw last me vs the 26kw? Is if simple division like 2600w a day equals to almost 4 days power on 225ah and about 10 days on the 550ah? Or is there more to consider on this calculation?

[thastinger]

Hmmm 550ah 6v rolls battery 339$, 225ah 6v 160$ (according to previous post) so almost same price if I want the higher capacity. How long would 11kw last me vs the 26kw? Is if simple division like 2600w a day equals to almost 4 days power on 225ah and about 10 days on the 550ah? Or is there more to consider on this calculation?

You stated your loads were 2.6Kwh/day and your night loads were significantly less than in the day correct? Successful off-grid systems are typically designed for 3 days of no Sun with that only taking the battery bank to 50%, for the worst solar month of the year. IIRC you also said you were in NV? I assume that means you don't have many overcast days in a row? Not sure why in the world you would need a 26Kw battery bank when your loads are 2.6Kwh/day with most of that being in the daytime (according to what you have said). If you're planning to put up 1200W of panels you'll never properly charge a 26KW battery bank with that.

The 160 for the T-105s was WITH the core charge, I assume the 339 for the rolls batteries is also WITH the core charge? If not, I struggle to see where twice the price is "nearly the same".

[morton.bia]

The 8 550ah 6v batteries numbers came from sunking who replied earlier

you are correct on the not many bad days in a row... except this last week that weve had close to sun for a good 10 days now lol generator usage is killing me lol

I see the t105 for 158$ or t105re for 178$. Even using them as 24v would make it way cheaper for sure

[morton.bia]

Sunking would you mind explaining how you got to the 8 550ah 6v batteries? And why youd recomend that instead of the 225ah 6v ones? Just wanna have all info to be able to choose the best option

[thastinger]

Sunking would you mind explaining how you got to the 8 550ah 6v batteries? And why youd recomend that instead of the 225ah 6v ones? Just wanna have all info to be able to choose the best option

Not to speak for SK, but I'm pretty sure he called for the larger batteries because you initially said your loads were 8ishKwh/day

[littleharbor]

Not to speak for SK, but I'm pretty sure he called for the larger batteries because you initially said your loads were 8ishKwh/day

That and as a rule you want to keep your battery bank to as few strings as possible. Ultimately a single string when possible.

[morton.bia]

So based on info here I want something that if I have no sun for 3 days I'll only drain batteries down to 50%. That means 2600w x 3 days x 2(for 50% margin) / 8batteries / 6v = 325ah batteries minimum

correct?

[thastinger]

So based on info here I want something that if I have no sun for 3 days I'll only drain batteries down to 50%. That means 2600w x 3 days x 2(for 59% margin) / 8batteries / 6v = 325ah batteries minimum

correct?

No, I don't think so anyway. Yes there are losses in the system but 59% is for PWM charge controllers. Quality MPPT controllers are significantly better than that and quality inverters are north of 90%.

Experts feel free to chime in (she says her panels are 50 ft away, my thoughts are higher V and less A panel config)
- Trash everything you presently have (you'll save money in the long run by going 48V)
- 5 250W panels in series to a Midnite 200CC, (will let you run smaller wire to the CC)
- 8 T-105 batteries in series for 48V
- Cotek PSW 1500W 48V inverter

It is pretty rare that you actually get 3 consecutive days of 0 watts, even on very overcast days I usually get 100W in for at least a few hours from my 1.2KW array. I recommended Cotek and Midnite solely based on me running both and having zero issues with either in 6 continuous use years, there are several good quality components to select from but I would stick to UL listed components.

[morton.bia]

Sry the 59% was a typo I meant 50% since you only want to run your batteries down to 50%

[Mike90250]

So based on info here I want something that if I have no sun for 3 days I'll only drain batteries down to 50%. That means 2600w x 3 days x 2(for 50% margin) / 8batteries / 6v = 325ah batteries minimum

correct?

No. 5 days ends up being real expensive, and obtaining a backup generator to handle the cloudy days is much better.

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