MPP Solar LV2424 kicks butt!!!
- Thread starter erik.calco
- Start date
I'm just realizing I should install a combiner box at the solar panels. I'm planning six 300 watt panels at 24v. Each panel generates 12.5 amps, so six 15 amp breakers in the Midnite Solar MNPV6 combiner box?
whoops. sorry for the duplicate message.
whoops. sorry for the duplicate message.
erik.calco
Solar Badger
These are 12V drop in replacements. Each one has its own BMS. So, with a 2S2P, I have 4 12V batteries or 4 BMS's, combined to create a 24V bank. Each 12V battery has a 5 light LED SoC indicator.
Will has videos tearing it apart if you follow that wiki link I shared earlier.
There's no evidence of this. Each one can have a different LED indication. When the BMS cuts off one of them, it is clear. When I reset it, it still indicates 1 blinking LED despite being a part of the bank, even when the inverter was still connected to it. So this drop from 4 lights to 0 (1 blinking) happens while it is a part of the bank, even with charging and load.
That does not rule out, though, that being in a bank creates some faulty logic in the BMS, though.
Note that when I charge one of the 12V's individually, it is still connected to the bank. But, the inverter is no longer connected, so no charging/discharging of the 24V bank while I do this. For this reason, I try to never do this while it is sunny.
erik.calco
Solar Badger
I was supposed to hook mine up today. BUT, I spent my time dealing with an incident, so didn't put it up. You'll likely need heavier gauge wire from the combiner box to the inverter, depending on how many you are putting in parallel. You'll want to price that and factor that into your plan. I have 10 gauge for PV to combiner, 4 gauge for combiner to the inverter.
erik.calco
Solar Badger
OK, this is my new guidance for the Solar power priority setting if you are trying to avoid using AC to charge the batteries, yet are using AC to augment the load, and want to maintain a high SoC overall as a UPS.
To keep it simple, I'll just state this if you are setting it for the next 24 hours, such as in the morning, since this depends on PV production and factors in overnight consumption.
If you anticipate a higher load than you'll produce from PV, set it to Battery-Load-Utility. If you plan to produce more PV than you'll consume (including overnight), set it to Load-Battery-Utility.
To put it another way, it appears that if you consume more than you produce with PV, despite augmenting with utility power, you are likely to decrease your battery bank SoC over 24 hours.
It took me 3 incidents since December to really conclude this, with the last one being this past week. What was happening was I was losing SoC on the bank. The battery voltage reported by the LV2424 was slowly decreasing giving you an indication. Over time, which can be weeks or months depending on your scenario, your SoC will get critically low. But, you may not know it until you lose utility and try to run an increased load off it, which was the case for me.
I had other variables to sort out in this with the Lion Energy UT 1200s. Long story short, their LED indicator isn't as trustworthy as I hoped, and the LV2424 battery voltage is a better indicator than I thought.
Here are all my settings to give you context:
To keep it simple, I'll just state this if you are setting it for the next 24 hours, such as in the morning, since this depends on PV production and factors in overnight consumption.
If you anticipate a higher load than you'll produce from PV, set it to Battery-Load-Utility. If you plan to produce more PV than you'll consume (including overnight), set it to Load-Battery-Utility.
To put it another way, it appears that if you consume more than you produce with PV, despite augmenting with utility power, you are likely to decrease your battery bank SoC over 24 hours.
It took me 3 incidents since December to really conclude this, with the last one being this past week. What was happening was I was losing SoC on the bank. The battery voltage reported by the LV2424 was slowly decreasing giving you an indication. Over time, which can be weeks or months depending on your scenario, your SoC will get critically low. But, you may not know it until you lose utility and try to run an increased load off it, which was the case for me.
I had other variables to sort out in this with the Lion Energy UT 1200s. Long story short, their LED indicator isn't as trustworthy as I hoped, and the LV2424 battery voltage is a better indicator than I thought.
Here are all my settings to give you context:
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Some interesting info to share. The past few weeks I've been having one of my two inverters faulting with an 06 error. Output voltage is too high. I've been working with Ian and MPP solar to troubleshoot. When Ian looked at my settings he had me change a few things as he had seen this before. I did tweak the settings as he requested and (knock on wood) things appear to have stabilized, however, I'm not ready to call the problem resolved.
Some background on my setup:
2 inverters LV2424's running split phase
8 Panels 2600 watts with 1300 watts tied to each inverter
6 Lion energy batteries for 285ah
My operating strategy for the system has been to maximize my investment by pushing both the panels and the batteries to use the power generated/stored in each. During the day I run loads higher than my capacity to drive power generation of the panels. If I don't do that they don't produce. As I'm not generating enough power for the loads the batteries pick up the slack and begin to drain. At a certain point, the inverters start to backfill with AC power so all three are feeding power. Once the sun goes down the panels turn off. The batteries continue to drain and then right before low voltage cutoff the AC charger bulk charges the batteries. After a few hours, the charge is complete and I'm running solely off batteries until the sun comes up and the cycle repeats. I don't want my batteries sitting there unused as I have many thousands invested in them.
My low voltage cutoff is 23 Volts
Bulk charge (was) 29.2
Float (was) 27.2
Setting 20 (battery Stop discharging voltage when grid available) was 23
Setting 21 (batter stop charging voltage when grid is available) was 29
1) Bulk charge setting I got from Lion energy
2) low voltage cutoff I got from experimenting and accounting for slight variations in the batteries themselves + a little buffer to ensure my batteries began charging before hitting the BMS cutoff
3) Setting 20 was set similar to Low voltage cutoff thinking that would be the voltage at which the batteries would begin to use the grid to charge
4) Setting 21 was set as close to bulk charge thinking that should be the same or close to bulk charge voltage.
Neither setting 20 or 21 are well documented.
Troubleshooting my issue.
1)Ian first had me lower my bulk and float settings down by .5 volts to 28.7 and 26.7 respectively
2) He then had me change setting 20 to 24 volts and 21 to 26 volts
I asked him to explain the logic behind the changes in settings 20 and 21 and he explained the following. The bulk charge and float voltages (17 & 18) are for the SOLAR charging only. The AC charger is not "designed" to be bulk charging every day and is instead to be used as a top off when the batteries dip down. While the units have two chargers the bulk charging should be handled by solar and the top off should be handled by AC power. I was effectively doing the inverse as my loads were exceeding my solar generation (as explained above) Ian felt having setting 20 set the same as low voltage cutoff was a red flag.
So how it works with the revised setting is as follows: when the batteries get to 24 volts (setting 20) and ac is available, it will begin to supplement with AC charging to bring the batteries back to 26 volts (setting 21).
So far things have been stable the past three days. I should add however that I feel largely unsatisfied in my understanding as to how I could be running for 3 months with my original settings without issue, now have this problem, and how these changes may have fixed it. I really just wanted to relay the details about how the settings are "designed" to interact with one another
Some background on my setup:
2 inverters LV2424's running split phase
8 Panels 2600 watts with 1300 watts tied to each inverter
6 Lion energy batteries for 285ah
My operating strategy for the system has been to maximize my investment by pushing both the panels and the batteries to use the power generated/stored in each. During the day I run loads higher than my capacity to drive power generation of the panels. If I don't do that they don't produce. As I'm not generating enough power for the loads the batteries pick up the slack and begin to drain. At a certain point, the inverters start to backfill with AC power so all three are feeding power. Once the sun goes down the panels turn off. The batteries continue to drain and then right before low voltage cutoff the AC charger bulk charges the batteries. After a few hours, the charge is complete and I'm running solely off batteries until the sun comes up and the cycle repeats. I don't want my batteries sitting there unused as I have many thousands invested in them.
My low voltage cutoff is 23 Volts
Bulk charge (was) 29.2
Float (was) 27.2
Setting 20 (battery Stop discharging voltage when grid available) was 23
Setting 21 (batter stop charging voltage when grid is available) was 29
1) Bulk charge setting I got from Lion energy
2) low voltage cutoff I got from experimenting and accounting for slight variations in the batteries themselves + a little buffer to ensure my batteries began charging before hitting the BMS cutoff
3) Setting 20 was set similar to Low voltage cutoff thinking that would be the voltage at which the batteries would begin to use the grid to charge
4) Setting 21 was set as close to bulk charge thinking that should be the same or close to bulk charge voltage.
Neither setting 20 or 21 are well documented.
Troubleshooting my issue.
1)Ian first had me lower my bulk and float settings down by .5 volts to 28.7 and 26.7 respectively
2) He then had me change setting 20 to 24 volts and 21 to 26 volts
I asked him to explain the logic behind the changes in settings 20 and 21 and he explained the following. The bulk charge and float voltages (17 & 18) are for the SOLAR charging only. The AC charger is not "designed" to be bulk charging every day and is instead to be used as a top off when the batteries dip down. While the units have two chargers the bulk charging should be handled by solar and the top off should be handled by AC power. I was effectively doing the inverse as my loads were exceeding my solar generation (as explained above) Ian felt having setting 20 set the same as low voltage cutoff was a red flag.
So how it works with the revised setting is as follows: when the batteries get to 24 volts (setting 20) and ac is available, it will begin to supplement with AC charging to bring the batteries back to 26 volts (setting 21).
So far things have been stable the past three days. I should add however that I feel largely unsatisfied in my understanding as to how I could be running for 3 months with my original settings without issue, now have this problem, and how these changes may have fixed it. I really just wanted to relay the details about how the settings are "designed" to interact with one another
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erik.calco
Solar Badger
Well, you can see I have setting 20 at 25.5. Honestly, I haven't seen the 20 and 21 settings play a role in any way.
The key here I discovered is the bank SoC can be slowly depleted over months, then finally become a problem. What you'll notice is your battery voltage slowly drop over time when it isn't charging.
What you can do is when you see it getting it too low, give it a good 3-4 hours of AC charging. Calculate it out. In my case, I had 2 batteries cutoff. So, I used the 12V charger to bringing each of those back to where the other two were. Then I put in 3 KWH over 4 hours with the LV2424's AC charging. You just set the amps and the window, and off it goes. Presto! Everything back to where I started, with idle voltage 26.5+ again when not charging.
This is a one off. Normally, I'm set for 2A AC charging for a 1 hour window, primarily so it is easy to change when I need it.
I had my batteries BMS hit low voltage cutoff just one time which made me realize when they are discharging they're even and flat. I could check them and they would all have the exact same voltage. but when they get to the very end they can drop off the cliff at slightly different rates. I had one that hit the BMS cut off out of six. I avoid that now by not allowing the pack to go below 23 volts or 11.5 volts per battery.
erik.calco
Solar Badger
Yeah. Same conclusion. Perhaps the BMS does voltage regulation. When connected to the bank, that can perhaps impact the LED readout too, making it less reliable when the bank has a load or is being charged. I haven't 100% proven this, yet. But, that's my current interpretation based on what I've seen.
That idle bank voltage reported by the LV2424 when there is no charging does definitely drift lower over time. I was hitting 25.5V regularly before the last incident. That's the best indicator. If I could chart it at 4:00am every day, I think you'd see it drifting lower, especially if the Solar power priority was Load-Battery-U.
Solar power priority definitely plays a big role, as I noted above. When you have PV coming in, changing it can have an instant impact on how many amps are directed to the battery. When Load is a priority, it can definitely drain the bank faster as it won't be charging it as much from PV.
Capt Bill
Sailing Options
I just got some more information about my battery charging options when two or more MPP LV2424s are configured for USA spec 240ac split phase. I am not so happy with the options I just learned about from Ian at MPP in USA. I am posting my challenge to MPP in Taiwan for a firmware update that might make their great bang for the $ buck LV2424 even better: (via email dialog posted below with a link to this forum thread: (Hope this is not too long to post here:
To Ian (USA MPP), and MPP headquarters in Taiwan
(Please forward this message to MPP in Taiwan.
cc: DIY Solar Forum Thread: "MPP Solar LV2424 kicks butt!!!"
REQUEST to MPP in Taiwan Re: LV2424 Inverter Generator to Battery Charging Options:
I would like to be able to use a 120vac Inverter Generator to charge my battery bank
when I have two or more of your LV2424 configured for USA standards. 240vac split phase.
*********************************
Dialog with MPP in USA (attached below.) from Capt Bill / William Self:
I am Sad to get this new lawyer of information; I believe I understand this properly.
If I want to use a 120vac inverter generator on one of my three LV2424 when they are configured for 240 split phase,
to charge my 24v battery bank: ... that is possible if I reconfigure one LV2424 back to Single Mode configuration, (leave two configured for the 240ac split phase); which I would leave all three connected to the same battery bank;
... BUT, I have to wire the solo mode LV2424 120vac OUTPUT to a different separate sub panel.
I am sad to hear that is the way it IS with MPP' LV2424s when configured for 240vac split phase.
I already have my sub panel configured in fine shape. I do not want to re wire a new separate sub panel,
to get a 120ac source battery charging cycle going via the LV2424 internal battery charger; and doubt I will go there.
I might just reconfigure all three of my LV2424 in daisy chain for 30 amp 120ac to be able to use my 120vac Inverter Generator as back up option for battery charging cycle via the LV2424 built in 60 battery chargers; ... and say good bye to MPP' LV2424 240ac split phase. ... I image THAT configuration would give me the option to then take 120vac grid or inverter generator input for a battery bank charging cycle option.
For me, If I reconfigure three LV2424 for 60 amp 120vac, I would have to figure out something else for my one 240ac 1/2 hp water pump. ... I Do NOT want to have to buy a 240v ac inverter generator (when I have two newish 120ac inverter options now), or a separate 60 amp battery charger to be able to be able to initiate a back up battery charging cycle option !!! Personally, it is frustrating for me to learn about this limitation after getting my solar project wired and working. I wish there had been a clue in the promotional information I studies before I purchased. I did not see this limitation coming. Was there any heads up info. about this shortcoming ?
If this is possible: I Request MPP do a Firmware Update Fix for this Significant Handicap. I challenge MPP to make it possible for me to charge my batteries with just 120vac INPUT from the grid, ... or from a 120ac inverter generator; when two or more LV2424 units are configured for 240vac split phase. Is that Possible?
Please let me know if that is a possibility; in the realm of MPPs engineering dept. and its' firmware update options. I want to know what you think of my challenge. I think some other folks on the DIY Solar Forum thread I am involved with (where I posted this same message) would also like to know.
Will MPP take this challenge on, to improve their great bang for the $ buck, LV2424 product, ... to make it an even better?
I am wondering about that with an open mind, while also exploring other options.
Cordially, William Self in Northern California
***********
previous email dialog wit MPP in USA:
> William.
>
> golden rules for AC charging.
>
> If you are configured for split phase ouput , charging will only
> occur with split phase input, etc ( input has to match output, even
> on your third inverter )
>
> Option, have all three inverters on the same battery.
>
> Two as split phase, the third, unaffiliated (use on a separate
> circuit for 120V only) charge your generator via this third unit.
>
> Ian
>
> Ian Roux
> usa-mpp-solar.com / store / manuals / sales
> 801 403 0336
> Utah USA
>
> *****************
> On Mon, Jul 27, 2020 at 2:27 PM -0600, "Bill Self"
> <williamaself@yahoo.com> wrote:
>
>> LV2424 Generator to Battery Charge question:
>>
> I have three LV2424 All In One units I purchase from you on eBay
> (March 2020); now configured for 240vac split phase. I like em with
> a few questions.
>
> I can get the Battery chargers activated and working (only) when I
> apply both legs of 240 vac split phase to INPUT to all 3
> inverters.
>
> 120vac IN to one LV2424 worked great for battery charging only in
> solo mode (by itself) only when wired for one 120ac line in, and
> one 120vac out.
>
> I would like the option to charge my batteries via one of my 120ac
> Inverter generators, on my three LV2424 All In One when configured
> for 240vac split phase, and currently have not figure out how to
> make that work.
>
> I think I may have to reconfigure to parallel daisy change/ three
> LV2424 for 60amps 120vac if I want to charge my battery bank with a
> 120ac inverter generator. or go through the hassle of reconfiguring
> my 240ac split phase to drop one LV2424 out of the config, and put
> it back to solo 120vac mode to get my 120vac Inverter Generator to
> a battery charge option; or purchase a separate battery charger
> (even though I have three 60 amp chargers inside my 3 LV2424 ....
> I am kind of frustrated with my perceived options for charging my
> battery bank with my 120ac Inverter generators.
>
> Questions:
>
> Is there a way to charge my batteries with a 120vac Inverter
> Generator when I configure two or more LV2424 for 240vac split
> phase in the USA?
>
> Does configuring 240vac split phase require me to have 240vac
> split phase Inverter Generator if I want the option to charge my
> batteries via generator; when configured to 240vac split phase ???
>
> Cordially, William Self
> in Northern California
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I think you have bigger problems than just ac charging. The correct configuration for a split phase mmp setup is to have two 120volt circuits feeding for not just battery but for any ac input. If you're running a 240 volt appliance and, the inverters and batteries are overloaded how will that appliance continue to operate when it cuts over to ac power and you have just one 120 volt leg?
Capt Bill
Sailing Options
I do not understand how your question and statements are relevant to my desire to get a battery charging cycle going via 120ac IN to just one, or more of my LV2424 All In One Units when they are configured for 240ac split phase. I want this back up battery charging option for when there might be no grid power for a few days on some possible cloudy day cycle. ... Kind of comes from the realm of my "Be Prepared" Thoughts.
Re: your "have bigger problems than just ac charging" (when?) "running a 240 volt appliance". Honestly seem like no issue for me, plus not a problem. ... I would be making sure All my 240vac breakers were switched to OFF at my sub panel, while being absolutely sure Grid power IN to my sub panel would BE Disconnected /also OFF !!! when I input 120ac IN from an inverter generator to get one or more LV2424s charging the 24v battery bank. !!!
In the realm of My Be Prepared Thoughts here in Northern California, where PG&E might turn the grid OFF during high wind, dry hot, late summer wild fire danger weather; ... I think it is super smart to have an option for a battery charging cycle via a gasoline powered generator; for like in the morning when I am using my kitchen. ... If I fire up my gasoline powered 120vac inverter generator to power up part of my house and kitchen needs, and make sure my refrigerator is cold etc. / ... I think it would be smart to be charging the battery bank at the same time, or at least have that option. Run the generator for an hour (instead of all day), and make maximum use of that generator AC output by also charging your batteries !!!
... I DO NOT WANT TO BUY A 240ac inverter generator to make that happen (when I have several newish 120va ac Inverter generator options already), AND I do NOT want to rewire a new separate sub panel (although I appreciate knowing about that options, and might eventually go there). I think the MPP Engineers in Taiwan could possibly make their LV2424 product better by figuring out a firmware update to allow LV2424 configure for 240vac split phase ... to take IN just one leg of 120vac for a battery charge cycle. Maybe what I want and think is possible, maybe that is not possible, or worth MPP's time (to put on their firmware update goals list).
I think Challenging MPP (in my thinking) in a diplomatic semi public way, as user feedback aimed at product improvement, ... might get a favorable response. I bet they will be wondering about their firmware update options, and maybe we will see such an update.
Does that make a little more sense ???
I like this Affirmation (which I think is our most common human being on earth challenge:
I AM Open to Outcome, while Not Attached to Outcomes.
I also seek to: Live in the Present, while making good or best use of my possible options.
(and not be blaming the shortcomings I see on everyone else, especially on family or close friends :+)
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Capt Bill
Sailing Options
missing from dialog to make a little more sense / from Ian, in prompt response to my questions: ... The third inverter (taking one of my three LV2424 configured to 240vac split phase/ & reconfigure one to single use mode on same battery bank/ leave the other two configured for split phase) will be out of synch with the other two in split phase, so it will need to supply its own panel of loads. Does that make sense? You will just remove some loads off the split phase set onto their own panel. ... Ian
While I reacted to this info. with a MPP challenge for a firmware update; I do appreciate understanding this option; and I might eventual go there. If (when) ... I get an answer back from MPP, I will share it.
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Scott Martinez
New Member
- Joined
- May 3, 2020
- Messages
- 55
This was/is the issue:
I'm running the output Solar-Util-Battery and that solved it. When I get more pannels, I'll try bonding the neutrals.
erik.calco
Solar Badger
That's good to know. Thank you.
Fortunately, it's not an issue if you are running it to a Reliance Controls transfer panel connected to your main. With that setup, your house wiring continues to use the neutral and ground from your main panel buses, only switching the hot when you transfer. The ground and neutral of your incoming gen (your inverter) gets connected to the main ground and neutral bus in your main.
The result is both your AC in and out ground and neutral of your inverter get connected to your main panel bus bars.
@Bob142
Scott Martinez
New Member
- Joined
- May 3, 2020
- Messages
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Erik, great information. this is how I have my Mpp connected, it goes through my Reliance Control transfer panel and allows me to pick which circuits to use with my inverter . Also lets me use fewer circuits when my panel output is low from cloud, rainy days and my batteries do not get fully charged. I wish more people with use the Reliance transfer panel for connection to their AC panels. When using the Reliance transfer panel there is never a chance to back feed the grid.
erik.calco
Solar Badger
Yeah, I love it! Very happy.
Capt Bill
Sailing Options
I found out from Ian at MPP: If I wanted to use a 120vac inverter generator on one of my three LV2424 when they are configured for 240 split phase, to charge my 24v battery bank: ... that is possible only if I reconfigure one of my LV2424 back to Single Phase 120vac configuration, (leaving my two others configured for the 240ac split phase); and I would/could also leave all three connected to the same battery bank; ... BUT, I would then have to wire the one single phase LV2424 120vac OUTPUT to a different separate sub panel because the input phases would not be matched.
I was sad to hear that is the way it IS with MPP's LV2424s when configured for 240vac split phase. I already have a sub panel configured how I want it. I do no intend to re wire a new separate sub panel, plus take reducing my up to 40 amps input of my current set up to one leg of that sub panel to 20 amps; to get a 120 ac generator sourced battery charging cycle going via one of my LV2424s.
My Best Work Around Idea for Battery Charging with 120 ac Inverter Generator when configured for 240vac Split Phase: NOTE: One does NOT have to consider this idea if you have a 240 ac Inverter Generator. I Do Not Intend to purchase a 240 ac Inverter Generator just for this option of a generator sourced battery charge because I already own two 120 vac Inverter Generators capable of running my house sub panel (when sure Grid Input is locked OFF, plus all 240vac Breakers also locked OFF) along with a LV2424 sourced battery charging cycle.
My best work around idea for my three LV2424s configured for 240ac Split Phase (up to 40 amps on one leg/ & 20 amps on other leg); for Be Prepared Boy Scout in me that wants this option for a possible no grid cloudy period: I would disconnect 2 of the LV2424 from all electrical inputs and output currents/ including battery bank (have marine switches in place for easy battery isolation) after also turning inverter standby mode to off at their LV2424 switches. ... I would then Reconfigure the third LV2424 to function in single phase 120vac mode, and then supply 120 vac from my generator to that 3rd and only functioning LV2424 unit while it is configured for a battery charge cycle. I would be running my house and yard sub panel that my 3 LV2424s previously powered up by my generator at that same time.
I am not sure if I would have to also disconnect the wires on bottom of my one LV2424 reconfigured to 120 vac single phase; those wires connecting to all three of my LV2424 when in 240vac split phase for balance integration. I think not, and hope not.
After charging my battery bank via a 120vac Inverter Generator cycle, I would then have to reconfigure for all three LV2424s back to my previous 240 ac split phase set up for powering up my Isolated Sub Panel via Solar and Battery Power, like it was before.
I wished MPP Solar had a Firmware Update to allow an easy option to power a Battery Charging cycle with a just 120va inverter generator when configuring two of more LV2424s to 240vac Split phase !!! Maybe that is on their list for a possible Firmware Update goal, but I doubt it. This is a backup work around idea I consider doable if I ever needed it, but definitely inconvenient. I have not yet personally tested this idea out. I am 99% certain it would work if ever needed.
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Hedges
I See Electromagnetic Fields!
- Joined
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We wish it was done in software, but software costs more to develop, test, install, repair than hardware. Only production cost per unit is lower.
Get a 120/240V transformer and converter output of your generator to split-phase.
Get a 120/240V transformer and converter output of your generator to split-phase.