I have an arduino uno R3 sitting around that I could try to use to connect but that is rapidly taking me down a rabbit hole different from the problem I'm looking to solve.
MPP LV-2424 uses only a fraction of available power to charge
- Thread starter jailcee
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labeeman
Solar Enthusiast
It is an all in one so the charger will not lose load due to the inverter running.
First off I've set my two charge voltages (float and bulk) to 28.4v as suggested here and recommended by Steve from Overkill in emails. At minimum that should allow more energy to go to the battery in this low current limp mode.
Second I got access to an Ipad, got the paid app, and connected to the BMS. The BMS was very slow to respond (like it took 35 seconds to show me current status once I connected) and when I tried to look at the parameters the iOS app gave me an error after many cycles of trying to read the parameters.
Third I set up an Arduino Uno R3 in USB to TTL mode and tried to connect to the BMS with the JBDTools app from the Overkill website. No joy there either.
I'm now moderately convinced I have a bad BMS. I *was* able to see parameters initially in the android app but not anymore, in any way, and I suspect something in it is preventing my LV2424 from pushing more current to charge the battery.
Second I got access to an Ipad, got the paid app, and connected to the BMS. The BMS was very slow to respond (like it took 35 seconds to show me current status once I connected) and when I tried to look at the parameters the iOS app gave me an error after many cycles of trying to read the parameters.
Third I set up an Arduino Uno R3 in USB to TTL mode and tried to connect to the BMS with the JBDTools app from the Overkill website. No joy there either.
I'm now moderately convinced I have a bad BMS. I *was* able to see parameters initially in the android app but not anymore, in any way, and I suspect something in it is preventing my LV2424 from pushing more current to charge the battery.
labeeman
Solar Enthusiast
You can check if it is the BMS limiting current to the battery by bypassing the BMS. Do not keep it bypassed only long enough just to see if it is limiting the charge current but do check to see if the bat voltage is not high before you do this.
This morning my battery was at 25.1v. I flipped the breaker, disconnected the BMS and connected the battery directly to the all in one. It is currently set at 28.4v bulk and float. I'm seeing it push from 950w up to 1.1kw to the battery. It will go into bulk mode for a few minutes (10-15) then the battery voltage it sees will exceed 28.4v at which point it goes into float mode with around 230w. When that happens the reported battery voltage at the all in one is around 26.9v. It runs in float for a while then switches back to bulk.
Note that I've never seen this unit push that many watts into the battery with the BMS connected, it would always trip some shutdown while ramping up the current.
Note that I've never seen this unit push that many watts into the battery with the BMS connected, it would always trip some shutdown while ramping up the current.
labeeman
Solar Enthusiast
You could ruin a cell if the cell is out of balance and is at the knee it will overcharge that cell and bloat it.
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Following seeing the LV2424 charge the battery when the BMS was disconnected I decided to take a longshot and redo the BMS installation onto the battery. This time I also changed the bolts that came with the cells and used m6x1 12mm studs and locking flanged nuts. I reconnected everything and the first thing I noticed is I was able to get into BMS settings when there was no current (charge or discharge) to the battery. Seems like to get into settings I need to disconnect the battery from the system. I don't know if this is a known thing but that's how mine is working
More importantly after reassembly the battery will now accept the same kind of charging power with the BMS as without (about 1kw max). I have the balancing leads attached exactly the same, and the connections as snugly torqued as before. So either the reassembly somehow reset something with the BMS or, more likely, there is something weird that was happening with the included hardware that replacing it fixed.
More importantly after reassembly the battery will now accept the same kind of charging power with the BMS as without (about 1kw max). I have the balancing leads attached exactly the same, and the connections as snugly torqued as before. So either the reassembly somehow reset something with the BMS or, more likely, there is something weird that was happening with the included hardware that replacing it fixed.
Im following this thread as Im experiencing similar MPP 2424 issues. I have 6 240w 3s2p panels and expecting close to 1440w in full sun, Im getting on average about 250w off peak hours and at most 650w at full peak. Each 3 panel serial array puts out 104v open circuit using voltmeter. MPP display shows about 80v occasionally peaking at 88v. I'm concerned I may have misread manual as it says the " PV Array MPPT Voltage range" is 30~80vdc and Maximum PV Array Open Circuit Voltage is 145v. Even if it was clipping the volts, at maximum, 80v is about 90% of maximum (Pmax) I'm expecting from my panels (30.4 x 3 = 91.2v). So Volts seems fine, its the amps I think thats the problem. My panels short circuit current is 8.37a and Current at pmax is 7.89, so the two 3 panel arrays in parallel should put out 15.78a. Im further confused by the meaning of whats on the display in that it says PV "input" is 84v, but next screen it says Amps are 15a but instead of "input" it says "Batt", which appears to mean what the MPP is "outputting" 15a to the 2 SOK 206ah batteries (24v bank), so 26.4 x 15 = 396w. So if my shunt says 26.4v is coming in to battery (or SOC) then it shows amps as 15a then it makes sense that my batteries are getting about 400w from MPP, but again, why 1440w of solar results in 400 into battery. I'm also off grid, but when I run my generator which is attached to MPP, the MPP sends the maximum 40a to the batteries so the batteries are not full and are accepting 1000w from combined solar and AC from Gen. My mind keeps coming back to that "PV Array MPPT Voltage range".. is it not capable of accepting more? I also calculated my cable runs and it just does not make sense the kind of loss im experiencing. My next step is to test individual panels since they are new (but again 104v on voltmeter open circuit). The system is in the Sonoran desert and visibility on one of these days was approximately 90 miles. Some of the clearest solar environment in North America. And although my average load is about 170w, I turned on the whole house and microwave up to1700w and little if any effect on what the shunt read going into battery or Watts coming from Solar. What gives?
cotrailhead
New Member
I’m not entirely sure I understand your description, but I do want to express what many lv2424 owners have noticed. The lv2424 will not bulk charge until the voltage has dropped to some set number. I don’t know this number off the top of my head. So let’s say you are fully charged and over night your battery drops to 26.9 volts. The next day, you’d like to see all available solar being used to charge the battery at the fastest possible pace, but the lv2424 will not do that. You have an option of turning the whole system including the panels off, waiting a minute before restarting. Then the lv2424 will begin a bulk cycle. Otherwise, you’ll just have to deal with slow charging. Some people adjust the float voltage to match their bulk voltage to force faster charging, but I think that is frowned upon. HTH
nicorellius
Troubleshooter
I've been using this for a few months and it's been great:
AiLi Battery Monitor Voltmeter... https://www.amazon.com/dp/B07CTKYFTG?ref=ppx_pop_mob_ap_share
Very affordable and easy to set up. I also have an LV2424 and it's been a interesting experience getting it configured just right. This battery monitor has helped me a lot.
Once you get your BMS issues sorted, I'd suggest bulk at around 28.4 V and float around 27.2 V. You'll notice that your battery bank will likely show 100% SOC around 27 or a bit more volts.
Bud Martin
Solar Wizard
- Joined
- Aug 27, 2020
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- 4,844
Can you show us the 2424 parameter settings?
nicorellius
Troubleshooter
What is your solar charge max current? I've got my "total max" set to 80 A and utility max set to 40 A, so solar max by the difference is 40 A. I had these set wrong for a while and saw similar issues. Lots of sun but low incoming watts. Except when load was high, then the panels would deliver close to max output (1.4 kW in my case). After changing the maxes to what they are now, when the sun shines my batteries charge at 20-30 A.
Source priority = SOL
Max charging current = 40a
AC input = apl
Power saving = sds
Battery type = Use
Auto restart on overload= ltd
" " on over temp = ttd
output voltage = 120
" frequency = 60
Max Utility charging current = 40a
Setting voltage point back to utility source when selecting sbu or solar first in setting one = 23v
Setting voltage point back to battery mode when selecting sbu or solar first in program one = full
Charger source priority = SNU
Alarm control = bon
Auto return to def display = tep
backlight control = lof
beeps while primary source interuptted = aon
overload bypass = byd
Report fault code = fen
Bulk charging voltage = 29.2
Float charge = 27.2
Low DC cutoff = 22
Solar Balance = Sbd
There are two items in my menu that I have no reference for in the manual provided for by MPP:
Item #23 is set to = SIG (default)
Item #30 is set to = One (default)
Several of these items I have tried to modify momentarily one by one, then returned them to the ones listed above.
I have 2 12v SOK 206a batteries and the 29.2v charge voltage and 27.2 float are their recommendations. Ive tried raising float as high as 27.8 because I have yet to go above 27.1 in the two weeks since i went off grid. No change. I have a generator that is not auto-start, but when i run it as utility power, I get the full 40a max provided by the above "Max charge current" resulting in a shunt reading of about 1000w incoming into the battery bank. Both batteries at identical SOC according to voltmeter. When I first purchased over a month ago when I capacity tested I got about 5483wh and BMS cutoff was about 21.5v. SOK Recommended charge current = 40a. Maximum listed charging is 50a, although they say BMS can handle more. Six 240w panels 3s2p, soon to be 9 panels in 3s3p. I have 25 foot of 8awg cable to arrays
I may try something like this, but according to my battery specs, 60a would be pushing it. So I may try 40a util and 60a combined (max). My current utility charge and max charge are set to 40a. When I use generator i get the full 40a
I apologize for not explaining my settings and experience more thoroughly. Using your example, Were I able to charge up to and stay at 26.9, what you are appearing to convey as a sub optimal SOC after a night of dropping, I would be satisfied. My bank has yet to charge up to 26.9 and upon terminating sunlight, stay at or above 26.9. I have achieved 27.1 before dusk, but after losing all sun it drops to about 26.8. Waking up to your 26.9 would be a major victory, not a cause for concern. Since my float charge is set to 27.2, frowned upon or not, Im not sure how that would change the existing poor performance. Regarding your recommendation of daily reboots, I'm not sure that provides a permanent solution for me. Again, sorry for my poor explanation. Thank you
Bud Martin
Solar Wizard
- Joined
- Aug 27, 2020
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Try setting the float to the same as Bulk and observe.
I will give that a try. As noted before, Ive set float as high as 27.8 to see what happens. It is now currently off grid, but when i had the unit hooked up to utility company power, I used that 27.8v over night, when I turned off utility power, it settled to 27.11v. I had a 100w freezer as a load and then capacity tested from that 27.11v down to BMS cutoff at 21.5v after 3 days and 5483wh. Those watt hours exceed the WH rating for these new batteries. So it seems as though a couple months ago, when capacity testing, the MPP unit was showing 27.11v (under 100w load) for a fully charged battery bank. Also, as noted before, If the shunt and MPP are showing around 26.8v and I turn on Generator, the shunt shows the battery accepting the full current being offered to it (40a mpp max), so in that range of 26.8+ its not full and not rejecting a charge. So it makes me wonder if resting SOC or under load SOC of 27.11 is near full, then my problem is understanding the relevance of my settings like float etc. But my primary and bigger problem is when the MPP is showing 26.1v in the morning after 1300wh and I have 1440w of solar panels and cant get more than about 40% of that solar power to feed hungry batteries. Thanks for the advice, I think thats my next test, to go above the 27.8 previous high, all the way to 29.2v float
cotrailhead
New Member
26.9 was just an example. I can’t recall what number triggers the lv2424 to begin a bulk cycle. I’m doubt 26.1 will trigger a bulk cycle either. Did the unit charge as expected the time you drained the battery to 21.5?
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