My Settings for MPP Solar PIP-2024LV-MK 24V System

[ender]

It is interesting, and I think important information. But I would not be hasty to go to 60A because I did one day when I was in a rush to top of my batteries before going boondocking and I wound up with melted plugs. In fact, even when I bump my MPP 2424LV up to charge at 30A the plug gets a bit warm. I have found that at 20A everything seems to be just fine. So it amazes me when I see folks saying "40A for every battery" or some such thing. I don't know the technicalities of the process, and I could be wrong, but I think if you start bumping the amperage up to 60, 80 or even 100A you could wind up with some very unpleasant and unexpected results. (My system: MPP 2424LV with 10ga cable handling the AC in and out, SOK 12V 100aH x 6, Renogy 100W panels 3S2P, Honda 2200i.) It's all a learning process and I'm glad to have a forum like this to glean all the info I can and hopefully continue to refine my system.

Melted plugs? Which plugs? 60A on a 24V system would equate to roughly 15A at the 120VAC input to the MPP Solar box which is right at the limit of what a typical 12AWG extension cord is rated to handle (20A at 60C). On the battery side, I'm using 4AWG wire as recommended by the MPP Solar manual which is rated to handle 70A at 60C. In other words, if you use the correct gauge wire as recommended in the MPP Solar manual, you should be fine.

That said, the real reason I wouldn't set it to 60A would be because you'd be charging the batteries at 0.6C which while fine, will probably decrease overall cycle rating of the batteries due to the heat generated in the cells. Not sure what this degradation would be and if it's something even worth worrying about in the grand scheme of things.

 

[B.T.]

Melted plugs? Which plugs? 60A on a 24V system would equate to roughly 15A at the 120VAC input to the MPP Solar box which is right at the limit of what a typical 12AWG extension cord is rated to handle (20A at 60C). On the battery side, I'm using 4AWG wire as recommended by the MPP Solar manual which is rated to handle 70A at 60C. In other words, if you use the correct gauge wire as recommended in the MPP Solar manual, you should be fine.

That said, the real reason I wouldn't set it to 60A would be because you'd be charging the batteries at 0.6C which while fine, will probably decrease overall cycle rating of the batteries due to the heat generated in the cells. Not sure what this degradation would be and if it's something even worth worrying about in the grand scheme of things.

I was using a 12ga extension cord of about 10' in length when this happened. As I stated previously, check your MPP if you choose to charge at say, 40A, and touch the AC connection to see if it's hot or even warm. I have, and it is. In fact the cord going into my MPP 2424LV is 10ga which held up nicely, but the 12ga was toasty (at 60A). I noticed that when I went to the big box store to get a new plug they are rated at 15 and/or 20A which corresponds nicely with the average circuit breaker on a duplex receptacle. I do believe if I remember correctly the MPP manual wanted 8ga wire for the AC in and out, but I found a 6' heavy duty extension cord (copper) of 10ga and it has worked well and gave me the male and female ends needed. As for the battery cable I opted for the biggest I could stuff in the opening MPP provided which turns out to be 2ga, a bit disappointing because I wanted to use 2/0.

I agree with you totally that it is best to charge at a lower current for the sake of the batteries. I try to plan ahead now and will either use strictly solar over a number of days or 120VAC at 10A to charge with. (Shame they don't have 15A, 25A etc. in the settings.) But unfortunately sometimes I forget and 20A seems fine also. Math and manuals are wonderful things. But I'll trust my real world experiences over both. I would be interested to hear from you if you do decide to pump it up to 60A sometime and let it rip. Let me know how it comes out.

 

[B.T.]

Ender, well, my batteries arrived. Just for the heck of it, I checked each one and it read 13.5V. I connected them in parallel and clamped an amp meter to the positive wire and it read 0.03A. So, I was assuming that the batteries were not balanced. I connected them to my battery charger and it indicated 65% full which at 13.5V (as identified in the chart at the beginning of this post) seemed way too low. But, in spite of this, I left them charge. After 2 hours, they were at 75%. After four hours (two additional hours) they were still at 75%. At this point I disconnected them from the charger, checked the voltage again and they both read 13.38V but when I connected the amp meter it was reading zero. So, I assumed that in spite of what the charger was telling me (75% charged), at this voltage and no amps moving between the batteries, they must be fully charged (Maybe a bad assumption?).

So, I connected the batteries in series to my MPP unit, turned it on, inputted the settings as listed in this post, switched on the PV and noticed that the PV was charging the batteries (green light was blinking on unit). The batteries voltage was reading 27.2V (or 13.6V per battery in series). Again, I thought this odd since the voltage is in the 100% fully charged range. So I installed the Watch Power software and, sure enough, it is indicating that the batteries are only 60% charged at 27.2V. Any clue what is going on here? Shouldn't they be fully charged? It's odd that both my battery charger and the MPP Solar unit are essentially showing the same thing, i.e., something way less than 100% when they should be at 100%. Any help would be greatly appreciated. My apologies if I'm missing something basic. Kind of still a newbie at this. Thanks.

I don't think the MPP is all that accurate, but it seems it certainly would not be reading correctly on your very first charge. I guess you could use a power supply and just let the BMS shut the battery down, but a good quality peak charger seems the best bet to me and then put them in parallel and just be patient. I think after that you could be fairly confident of your voltage readings, i.e. that they are well matched and at (or extremely close) to full SOC.

 

[iamrich]

I am not running AC in or a generator because I don't have grid (yet) and there hasn't been a need for the generator. I am running BYD 24v (~3kwh) battery packs, but my panels charge them so slowly in the morning that by the time there is a big amperage available, they are already topped off. It might be interesting one day to turn the panels off until noon or so and drain the batteries down so I can see how much power my panels actually put out. So far the biggest number I have seen is 1600w (250w panels x9) and half that was going to the AC and lights, so the batteries never saw more than 30a. Nothing gets hot at all on my setup.

 

[Hagrid]

I have a different, more general question for owner/operators of the PIP-2424LV-MSD units out there:
Do the two cooling fans in the chassis run 24/7 while the unit is powered on? I've heard this and wonder if it's really the case, or if there is some sort of thermal cutoff in the fan circuit that turns them on when the temp reaches a certain level. I don't see "fan temp" or anything similar in the programming tables.
Adjunct question: What is the constant idle-rate current usage of the 2424LV-MSD unit when powered on and no loads?

 

[B.T.]

I have a different, more general question for owner/operators of the PIP-2424LV-MSD units out there:
Do the two cooling fans in the chassis run 24/7 while the unit is powered on? I've heard this and wonder if it's really the case, or if there is some sort of thermal cutoff in the fan circuit that turns them on when the temp reaches a certain level. I don't see "fan temp" or anything similar in the programming tables.
Adjunct question: What is the constant idle-rate current usage of the 2424LV-MSD unit when powered on and no loads?

The fans come on as soon as you power up the unit and also, I believe, when the inverter is not on but you are charging with either AC or PV. I have looked at the idle rate but cannot swear to the exact number as I don't usually concern myself with that. I believe it is just a few watts. I wish I could be more precise but I've had my unit for some time and I probably paid attention to those things at first but don't now. I will say that my unit is inside my camper and the fans don't bother me at all. I run a table fan most of the time so it is much louder and makes the MPP unnoticeable. If I use the MPP over the next few days I will take note and come back with more precise info.

 

[Hagrid]

The fans come on as soon as you power up the unit and also, I believe, when the inverter is not on but you are charging with either AC or PV. I have looked at the idle rate but cannot swear to the exact number as I don't usually concern myself with that. I believe it is just a few watts. I wish I could be more precise but I've had my unit for some time and I probably paid attention to those things at first but don't now. I will say that my unit is inside my camper and the fans don't bother me at all. I run a table fan most of the time so it is much louder and makes the MPP unnoticeable. If I use the MPP over the next few days I will take note and come back with more precise info.

Thank you. I would hate to have a couple of fans running in a compartment a few feet away from my bed all night... Looking forward to any info you (or anyone else on this thread) can supply here.

 

[iamrich]

Thank you. I would hate to have a couple of fans running in a compartment a few feet away from my bed all night... Looking forward to any info you (or anyone else on this thread) can supply here.

I have the green hybrid unit and the fans run 24/7 if the inverter is on.

 

[ender]

I have a different, more general question for owner/operators of the PIP-2424LV-MSD units out there:
Do the two cooling fans in the chassis run 24/7 while the unit is powered on? I've heard this and wonder if it's really the case, or if there is some sort of thermal cutoff in the fan circuit that turns them on when the temp reaches a certain level. I don't see "fan temp" or anything similar in the programming tables.
Adjunct question: What is the constant idle-rate current usage of the 2424LV-MSD unit when powered on and no loads?

I don't know about the 2424LV-MSD but the 2024LV-MK idles at ~1.16A from 24V battery setup (the picture below shows 1.26A but 0.1A is from the RPi4 I have connected) when inverter is on.

As for the fans, in the setup pictured below (inverter on but not loaded), the fans are on but at a very low and quiet speed.

 

[Hagrid]

That is awesome info, thank you. It takes a while to find all this stuff out, but I appreciate that you and others are as helpful as you are.

 

[Hagrid]

I have the green hybrid unit and the fans run 24/7 if the inverter is on.

Thank you. From what I have been able to glean from this forum and some YouTube videos, these MPP Solar all-in-one units have a programmable "energy-saver" mode where if the inverter load is low, the fans will either turn off or reduce speed significantly. As soon as the inverter load goes up, the fans go to high speed. Might be an OK sound level if in a compartment and inverter load is small.

 

[iamrich]

Thank you. From what I have been able to glean from this forum and some YouTube videos, these MPP Solar all-in-one units have a programmable "energy-saver" mode where if the inverter load is low, the fans will either turn off or reduce speed significantly. As soon as the inverter load goes up, the fans go to high speed. Might be an OK sound level if in a compartment and inverter load is small.

I would not use this inverter in the same room I sleep in. The fans are going to be as silent as they can be at night since there is zero charging, but it is still nosier than I would be happy with. In my workshop it is no issue. I know there are quieter fans in this size that could be used and kind of wish MPP would have done so.

 

[JRUD]

Assuming MPP Solar is basically the same as my GROWATT (2x100aH batteries, 800w solar). Thanx guys for posting so many answers to what has been puzzling me. SOME QUESTIONS: (#1) If I accidentally run down my batteries at night when unplugged from utility one battery shuts down on low voltage. How can I get system going when the sun comes up or is there a way to avoid the problem? (#2) Is there an easy way to monitor things? The app that came on a CD with my unit is too quirky. The updated version isn't much better. The Solar-Assistant mentioned above looks good. Can it be run without me having to learn Raspberry?

 

[JohnT]

Assuming MPP Solar is basically the same as my GROWATT (2x100aH batteries, 800w solar). Thanx guys for posting so many answers to what has been puzzling me. SOME QUESTIONS: (#1) If I accidentally run down my batteries at night when unplugged from utility one battery shuts down on low voltage. How can I get system going when the sun comes up or is there a way to avoid the problem? (#2) Is there an easy way to monitor things? The app that came on a CD with my unit is too quirky. The updated version isn't much better. The Solar-Assistant mentioned above looks good. Can it be run without me having to learn Raspberry?

I'm absolutely no expert here but if only one battery shuts down it sounds like the battery is the problem. If both batteries were balanced properly this should not be happening but maybe someone else on this thread is better informed. As far as the Solar Assistant, while it does appear to be a great package i ended up not buying it. It is produced in South Africa and me being in the States made it a bit pricey to have the full system mailed. The download option is much cheaper (obviously) but then I'd have to buy the raspberry Pi, etc. So, instead i just used the Watch Power software that came with the inverter. Yes, it is quirky but you can export the graph data as an Excel friendly file. I have MS Office so i imported it into Excel and then was able to evaluate the data.

 

[JRUD]

I'm absolutely no expert here but if only one battery shuts down it sounds like the battery is the problem. If both batteries were balanced properly this should not be happening but maybe someone else on this thread is better informed. As far as the Solar Assistant, while it does appear to be a great package i ended up not buying it. It is produced in South Africa and me being in the States made it a bit pricey to have the full system mailed. The download option is much cheaper (obviously) but then I'd have to buy the raspberry Pi, etc. So, instead i just used the Watch Power software that came with the inverter. Yes, it is quirky but you can export the graph data as an Excel friendly file. I have MS Office so i imported it into Excel and then was able to evaluate the data.

Thanx. The batteries are SOK. A quality brand, fairly new. They say the battery is operating normally. The batteries started out fully charged and balanced. Since they are connected in series to get 24v it is impractical to check individual voltages regularly I got PVKeeper (then 2.0) with my GROWATT. They work Ok for changing settings and a quick status check but crash a lot so they are not too useful for data logging. I played around with unit's settings and it seems to be working. Best guess is the settings didn't work with the reduced winter sunshine.

 

[GrumpyOldRetiree]

For you folks putting 2 12v batteries in series to get 24v (nominal) and having power shutting down to the inverter because 1 battery went low, have you considered using this item?:

EQ-24/2 24V Battery Balancer, balances 2 x 12V batteries in series. – Watts247 Wholesale

watts247.com

 

[WYtreasure]

For you folks putting 2 12v batteries in series to get 24v (nominal) and having power shutting down to the inverter because 1 battery went low, have you considered using this item?:

EQ-24/2 24V Battery Balancer, balances 2 x 12V batteries in series. – Watts247 Wholesale

watts247.com

Hey GOR,
Have you used that particular product.
As my build progresses I will probably be scratching my head over similar issues. It would be great to know how to deal with the problem when it arises.
Thanks for the link.

 

[GrumpyOldRetiree]

Hey GOR,
Have you used that particular product.
As my build progresses I will probably be scratching my head over similar issues. It would be great to know how to deal with the problem when it arises.
Thanks for the link.

No, I haven't. I'm still operating with 12V components (batteries & inverters). I brought it up because, I too am still in the "head scratching" phase of upgrading to higher voltage components. This device seems to address the issue of one BMS shutting down the output of both batteries (or input in the case of charging), but does not work to equalize SOC of the 2 batteries in series because voltage is a poor analog for SOC in LFP batteries (except at the extremes).

 

[JRUD]

For you folks putting 2 12v batteries in series to get 24v (nominal) and having power shutting down to the inverter because 1 battery went low, have you considered using this item?:

EQ-24/2 24V Battery Balancer, balances 2 x 12V batteries in series. – Watts247 Wholesale

watts247.com

That sounds perfect. Have you actually used one?

 

[GrumpyOldRetiree]

That sounds perfect. Have you actually used one?

See post #38.