diy solar

diy solar

MPP Solar LV2424 kicks butt!!!

thealaskan said:
I gave up on settings, and after looking things over, Installed a separate Tracer solar charge controller in parallel the other day. Works great.

Solar does what it can, and if the batteries get to far down the grid brings them back.

Settings: charge source (solar and utility), solar power priority (battery-load-utility), output source priority (solar-battery-utility)

Wasn't what I had planed, but it works as a whole house UPS/grid backup, and solar assist/power.
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Wondering why are you charging from Utility?.... IMHO its kind of a wasted power, wouldnt be better to just use that energy to directly feed from Utility to your loads without the conversion from AC - DC - AC?.

In my case im using charge source (Only Solar), and then programmed option 20 to (25.5V), in that way im not discharging the battery too much for normal use.... and still have some "reserve" power for outages, where the inverter goes directly to battery mode. Or dont know if you have an special reason for this?

Batteries never go too far down if you program the inverter to just use them to certain voltage, so not necesary to help them with AC.
erik.calco said:
The only "easy" DIY options I can think of is to put it in a sound insulated box. But, then you'd have to address air circulation for the box, which might require fans.

The other you learn building computers. Bigger fans are quieter. Tiny fans are loud and have a high pitch. So, replacing the fans with something that circulates the air with bigger fans will make it quieter. This is why some computer cases have a big 12" fan on the side. Those things are virtually dead silent.

I'd like to create software that hacks the LV2424. I just don't have time to make that a priority anytime soon. In that scenario, I'd turn the fans on/off with the software I wrote.

There is one youtube of a guy hacking his LV2424 to turn it on/off via software. He cut into the switch wire to put in an additional relay controlled switch to a $3 chip with built in wi-fi that connects to his software. It is on my TODO list to one day catch up to where he is. I have kept the browser tab to order the chip open for months.

https://www.aliexpress.com/item/32529101036.html
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The EV forum has some guys hacking the firmware of the MPP Solars, i think they have now custom firmware's for the LV5048.... lost the link but should be googleable.

The guy that hacked the inverter switch its saving around 400W per night with that simple mod, so its a great and cheap idea!

--

About the LV2424, yeah they are loud!... at some point of the day i have my 2 units working at top speed (2KW Solar PV input + 60A charging), so just imagine that turbine working!. As you mention, i think the only solution its moving them to an utility room or putting them in an enclosure with a big extraction / inyection fan. Altough this complicate things a bit and could be troublesome if the big fan fails.
 
mrdavvv said:
Wondering why are you charging from Utility?
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Not trying to go 100% off grid, just trying to have constant reliable power as in a whole house UPS, heat, water, and lift station sewage. 3 separate little UPS's have cooked on snaps or outages, and without lift station there is no water use for going to work.

mrdavvv said:
using charge source (Only Solar), and then programmed option 20 to (25.5V), in that way im not discharging the battery too much for normal use.... and still have some "reserve" power for outages,
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Using a product called Sence which see's items on the grid (electric signature's). Some items that where on the inverter circuit only where showing up. I believe because the Lv2424 was in a partial sensing power state, it seemed that those items where showing up on the grid meter through the power wiring, that where being run off the battery bank.

Not doing this to save a buck yet, just need serious reliability
 
thealaskan said:
Not trying to go 100% off grid, just trying to have constant reliable power as in a whole house UPS, heat, water, and lift station sewage. 3 separate little UPS's have cooked on snaps or outages, and without lift station there is no water use for going to work.


Using a product called Sence which see's items on the grid (electric signature's). Some items that where on the inverter circuit only where showing up. I believe because the Lv2424 was in a partial sensing power state, it seemed that those items where showing up on the grid meter through the power wiring, that where being run off the battery bank.

Not doing this to save a buck yet, just need serious reliability
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Gotcha, in raining season i might do the same as outages are usual... and my dream is having a battery bank large enough to not worry about the lack of utility and solar for a couple of days!.

Btw, pretty nice looking setup!. I also have a parallel connection... how its working for you?, happy with them?, any issues?. How much PV power do you have for each inverter?. Mines have 2200W of solar, and i tough they were goin to self limit at 2000W, but ive seen them running the full 2.2kw from time to time... so kind of worried for them!
 
Im sure someone will come up with some sort of controller board for the AC grid side. I have heard the tesla power wall can do over the air demand updates so that it knows to charge up before a storm, etc. But until I get my hands on that sort of thing, I figured my needs based upon this:

1KW for every fridge for every day of storage. For me that would be roughly 2kw per 24 hours
2kw for emergency lighting, mechanical room/backup electronics for 24 hours.
4kw of critical reserves, going in is 1kw every 6 hours- assuming 12 hrs of darkness, I need to have 2kw of reserve above my usual 2kw it normally consumes over night.

I think roughly 150% of your 24hr critical load consumption as "storage" is probably adequate. Anymore than that and battery costs start looking pretty high.
 
@thealaskan why not "Solar first" for charging? I've been using that and been happy with it. It still allows the timed AC charging if you have it enabled.
 
erik.calco said:
@thealaskan why not "Solar first" for charging? I've been using that and been happy with it. It still allows the timed AC charging if you have it enabled.
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I don't do solar first for charging, as technically moving from solar->battery -> load is less efficient than solar->load.
I do want to play with my configs some more- I think the Solar first/grid suppliment is the way to go to minimize battery wear. I will have to re-read the manuals again.. (and again.. and again..)
 
erik.calco said:
@thealaskan why not "Solar first" for charging? I've been using that and been happy with it. It still allows the timed AC charging if you have it enabled.
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I cant quite figure out a good time to "charge"- I don't have a time of use plan anways.
I had turned it off, and then during the winter, somehow the battery charge got so low (charge from solar only) that the batteries became toast.
 
erik.calco said:
why not "Solar first" for charging?
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At this time we have light 24/7, it gets so low that the Solar panels make voltage with no amperage, the lv's see this and never go into a grid charge mode.

Tried time start stop, didn't work. I can say I didn't try float.
 
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madmax said:
I cant quite figure out a good time to "charge"- I don't have a time of use plan anways.
I had turned it off, and then during the winter, somehow the battery charge got so low (charge from solar only) that the batteries became toast.
Click to expand...
I leave it to one hour at 2A by default. But, if I see voltage drifting down due to not having enough sun, I might kick it up to compensate. I can VNC to the laptop connected to it to view and change it from the same couch I'm typing on now. That helps tremendously.

I can see right now the battery voltage is a bit unusually low at 25.7V. I'll check the bank to see if it needs balancing. If the bank appears balanced, I might turn up the AC charging a bit tonight, especially if I see it go below 25.5V.
 
thealaskan said:
At this time we have light 24/7, it gets so low that the Solar panels make voltage with no amperage, the lv's see this and never go into a grid charge mode.

Tried time start stop, didn't work. I can say I didn't try float.
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That's interesting and makes sense. Good to know. Thanks!
 
erik.calco said:
Battery re-charge voltage when utility is available is 25.5V. This is as high as you can set it. And, it's fine. I haven't figured it out, but I suspect the SoC of the bank is over 80% there, well within my requirements. This is the key that ensures my batteries stay high when I have no PV input.
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Btw Erik, do you have EVE 280AH cells?. at 25.5V the bank its around 10 -20% according to my shunt:

1595267064204.png
 
thealaskan said:
Nice battery's. Being they are wired in series, no issues with topping them off? Any maintenance like rotating lead and lag?
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Hard to say. I've had the BMS cut out twice since Dec. Both times the bank was out of balance so it was premature.

The one big plus on them is that LED indicator because voltage is useless for measuring SoC, whereas the LED indicator seems reliable. I'd be very much in the dark w/o it. I can check the LED indicator on all the batteries to know right away if things are out of balance.

You can easily top off an individual battery with a 12V charger. You simply disconnect the bank via the circuit breaker to isolate it from loads and charging. You don't have to disconnect the battery from the bank.
 
erik.calco said:
Hard to say. I've had the BMS cut out twice since Dec. Both times the bank was out of balance so it was premature.

The one big plus on them is that LED indicator because voltage is useless for measuring SoC, whereas the LED indicator seems reliable. I'd be very much in the dark w/o it. I can check the LED indicator on all the batteries to know right away if things are out of balance.

You can easily top off an individual battery with a 12V charger. You simply disconnect the bank via the circuit breaker to isolate it from loads and charging. You don't have to disconnect the battery from the bank.
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I was wondweing, Like I said, they look good, looked at them earlier, wondered if a 12v bms would affect the next battery in series for charging?

I'm going to post in the battery section questions of problems that came up with of my charging of my BYD's as I have now found, and just realized I was loosing capacitance over the last 4 months with the 27.5/23.5 30a settings. Battery's are not liking to go over 26.5v, Lithium's are not in the LV2424 settings, and this is probably not the thread.
 
@thealaskan an update today. Had issue #3 since Dec today when utility cut off and it was cloudy.

First, the BMS in one of the four batteries in 2P2S cut off. The LV2424 continued to run off the batteries, and was able to charge when the clouds permitted a tiny trickle because of the 3 batteries. But, it cut off the load per the 23V setting I had, though was registering near 24V without external load. This is progress in that I'm able to achieve a state where it can recharge on its own. But, note that it continues to run off the batteries, so in this state you're in a race to get PV or run out of juice.

I had minimal load. But when I tried to increase it, it pushed it over the edge. Now, another battery tripped its BMS.

Here's the thing. When utility power died, I checked the battery levels before there was an issue, and via the LED the two batteries that cut off reported 4 of 5 LED lights, indicating near 80% capacity. When the first BMS cut off, I had significant load, as I tried to keep my servers going. But, not enough to justify entirely draining one of the batteries in under 30 minutes. It would of had to of pulled all current from just that battery, and even if that was happening, should of taken longer, perhaps 60 minutes.

I then dramatically lowered the load, taking my servers offline. The next one died shortly as well, prolly within the next 30 minutes.

When I reset them, they reported around 10.5V. The other two that still held a decent charge and had 3-4 LED lights read near 12.75V. I put the two dead batteries on a low AC 12V charger. Over time, they slowly built up a charge. In other words. EVERYTHING suggested that they really were dead and that they needed a charge, and took a charge without a problem, and appeared normal in their rate of return to a higher SoC.

So, this leaves these questions?

- Did they somehow very quickly lose a lot of their SoC? How can this happen? That's how it appears if you trust everything else.
- Is the LED meter correct? I've had no reason to believe it isn't. It certainly goes up about the pace you'd expect when charging. But, going from 80% to 0% with the load I had just made no sense.
- Why weren't they near full before this incident? Note that I was not running my servers off them until after the utility cut power. The servers have their own UPS, so this was just to prevent their small UPS systems from failing. In other words, it's hard to imagine that they weren't at least 75% full when utility cut off, leaving me with at least 3 KWH of storage, or 4 hours with my servers running in addition to the other loads.

Long story short, in a 2S2P configuration, I've yet to be able to rely on them to provide expected capacity for a significant load. Note that I have stability in all scenarios so far if I have a minimal load. Even, for instance, when I had a minimal load with only 3 batteries operating, the voltage was not dropping on the bank. Only when I added load did it drain it and kill another battery. But, that's quite an investment to maintain a small load.

Obviously, if the sun was out, I might never of experienced this as the PV would of met a good portion of the load even with my servers on, and all the load w/o the servers.
 
erik.calco said:
Now, another battery tripped its BMS.
Click to expand...
I take it that each low battery was on a separate series set?

erik.calco said:
Did they somehow very quickly lose a lot of their SoC
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Could it be that each battery was not at full charge because of in series/balance, and the led's where showing voltage from the series string?

I have seen in my set up which has led meters if I turn 3 battery circuit breakers off all 4 still show voltage, and only stop when the Anderson connector has been seperated.

Ill bet that you will have to rotate lead and lag in the series sets to achieve balance, the question is how often.

Im starting to think 1 BMS 8S4P for my application
 
Here is a problem too. Changed my amperage to 10 amps to see if I could do better on capacitance.
IMG_2895.JPG

Batterys only charged to 26.3 volts, leaving them 25.9 volts
.IMG_2896.JPG
LV's are set to 27.5 volt.
 
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