Pylontech - The Right Buy for Me?

[omaigadlol]

That's the plan. We'll see how it matches with reality. I have one spot on the property that gets sun on 21 December and it's on a south facing hill just to the north of a thousand foot bluff. On the other side of the bluff is ocean. So the slope keeps trees from shading the horizon and then it drops off to the water. There are about nine small trees I will cut (and use for lumber) and then it will see the sun directly for the full four hours if it's sunny. Directly south facing ground array, one axis angle so I can tilt panels up but will be straight up and down (6 degrees from optimum--although I will set them to 6 degrees and if snow isn't an issue just leave them there) during winter to keep snow off.

The batteries will be stored six feet underground in a culvert with an insulated roof/floor and shed over top (shed and floor not shown). Two rows of panels. South facing row is down slope to prevent it from shading the north row of panels.

Looking down into the culvert you can see where the Pylontech batteries will go through the wall and I'll have a door to access behind the wall. I will heavily insulate the batteries to ensure they stay at least 65F year round. Doing it this way allows for shorter cable runs from the front of the batteries to the other components. So hopefully the insulated batteries inside an insulated culvert underground will ensure 65F even when it's -4F outside. If that doesn't work, I'll look into heating pads.

And after going through all this effort and spending the money on the PV and the SCC to harness as much as I can during that four hours, I'm going to be very bummed if the Pylontech BMS throttles me. I guess we'll see.

This will be fun to see in the middle of a forest in Alaska in the middle of nowhere. A helicopter will deliver the panels up there once the snow melts.

Edit: Actually it looks like I'll only get 3 hours of sun on 21 December. So very important that these batteries take whatever charge they are given.

Hi, how'd you overlap the stuff in the last picture?

 

[onobeka]

Guys, I need a bit of help. Currently I have a 6s 2370Wp solar, feeding a grid-tied 5600 VA hybrid inverter (Easun iGrid IV) with the injection turned off. I would like to purchase a Pylontech us5000. However, I hear that the recommended charging current for these batteries is 80A. With the solar power I have, I believe I cannot reach that current, not even close doing a simple math of 2370W/48V(roughly) = 50A. I know that I should be lucky to see that power from the solar, typically it will be much lower, especially in winter and the same would go for a bigger solar.

Do you think that my system would work? According to the loads calculation I've made, I should not exceed 3000Wh/day, so that battery if fully charged could be OK for 1.5d, yet, will I able to charge it with that low amount of solar? I appreciate a fast answer as I am about to choose between an us3000 or us5000. Thank you!

 

[wattmatters]

The battery will charge with whatever the charge controller can supply it with (subject to all the parameter settings such as voltage and current limits). If a low current is all that is available, then the battery will just take longer to charge.

You have ~2.4 kW of solar PV. How much energy / day it can generate is obviously going to depend on your location and orientation of the array relative to the sun, seasonality (length of day) and day to day weather variances.

No idea where you are but I guess you are looking at something like a potential generation capacity of 7 - 10 kWh/day, on average. That might be much lower if you are in a rainy location, have shading, are a long way from the equator etc etc.

So if daily loads are 3 kWh/day, then, on average you should have sufficient energy to operate. The solar PV on normal days will power loads and charge the battery, which will supply power through the night.

But on poor solar days then the PV will struggle to power loads and so you may still be drawing from the battery as well. Get a run of poor days any you may run low. So you need to account for that and have a strategy to deal with such occasions. That might be an alternative/supplemental charging option (grid power, generator) or it might be some form of dynamic load control (e.g. not using some appliances for a while, or using an alternative interim energy source).

 

[onobeka]

Thank you! I know the calculation for autonomy, thus I am aiming for the bigger battery. However I was intrigued that the us5000 requires 80A of charge current. While the us3000 47A. Maybe that’s the max bulk. I am in Romania, not great for winter time and also the solar has some shading these days. Not optimal.

 

[Don B. Cilly]

I was intrigued that the us5000 requires 80A of charge current.

That is probably meant as the maximum current it will take.
I've never heard of a minimum one.
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[wattmatters]

However I was intrigued that the us5000 requires 80A of charge current.

It doesn't "require" 80 A. That's just a suggested charge current. If charging at 40 A, it will just take twice as long as at 80 A. Four times as long at 20 A. You get the idea. The battery will just suck up whatever you supply (assuming it is not at a very high state of charge), be it a handful of milliamps, or up to the charge current limit of 100 A.

Frankly I think 80 A is too high for a 100 Ah battery, at least if done consistently day in day out.

For longevity charging at a lower rate is most probably better. With 2.4 kW of PV, the most you are capable of pushing into the battery is going to be ~50 A, and that's more than plenty.

 

[wattmatters]

That is probably meant as the maximum current it will take.
I've never heard of a minimum one.

Max charge current specification is 100 A.

But yes, stipulating it as a recommended charge current of 0.8C is curious, and high.

And yes, there is no minimum.

 

[onobeka]

Thank you!