diy solar

diy solar

Epever charge controller dropping out of MPPT mode

It is always running in PWM mode. MPPT just restricts the Max Pulse Width to stay within the panels Max Power Point Voltage. It is a search and trim algorithm. Useful at high current Bulk charging. Not needed for Lower Pulse Width, lower current, Float charging.

BTW: PWM of a DC-DC Buck Switcher (converter). Not PWM FET short of the cheap solar controllers.
 
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have the same problem with a epever
I do too. Especially if there is another active charge source on the circuit.
From time to time I do have to power-cycle the controller - XTRA3210N And yes, it goes back to normal voltage and charging. I don't really get it either. I have a DC switching breaker for the panel input so it's easy to disco the panels and then powercycle the controller.
 
I do too. Especially if there is another active charge source on the circuit.
From time to time I do have to power-cycle the controller - XTRA3210N And yes, it goes back to normal voltage and charging. I don't really get it either. I have a DC switching breaker for the panel input so it's easy to disco the panels and then powercycle the controller.
My old A-Frame camper had a 100W panel, ep2210 SC, 2ea 100AH AGM batteries.
The AGM would not charge at float, and needed about 14.2 volt to charge, so 100w panels needed more bulk time.
So I would restart the Bulk cycle: throw a towel over the panels, pull the SC connection to the batteries, reconnect and remove towel.

No problems on my new camper. 2ea 250w panels, Victron Smart Solar 100v/50a, 480AH LiFePO4.
Victron has a lot of settings to control Bulk (absorption) Charge exit.
Absorption Voltage: V value
Absorption Duration: Adaptive or Fixed; Adaptive reduces time for shallow discharges which protects the batteries.
Max Absorption Time: T value
Tail Current: A value; note: lower Amps ends Absorption
Re-Bulk voltage offset: V value; note: voltage below float restarts Bulk charging.

The LiFePO4 batteries will charge at (my) Float 13.6v and are nearly fully charged at (my) Absorption 14.2v.
 
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My suspicion is that any compatible victron appliance/component is a ready fix for all of it. :love:
Their stuff is generally about twice the price though, but surely worth it for some. I had both in my cart at time of purchase, thought I would try the cheaper alternative, but always thought that if it failed I would come back and get the victron option.

I got one of their dc-to-dc chargers and it's definitely dabomb. I have a renogy scc too, and it's been fine, but it's just for trickle charging the SLA engine starting bank for the old motorhome. As I like to say, friends don't let friends buy renogy stuff. LOL
 
I am fairly new to running DC charge controller. Mine is the newer BougeRV 40 amp MPPT. I never thought of calling it "PWM Mode" but a few times, I have seen it go to where it drags the panel voltage down to close to my 48 volt system. But I neve see it really stuck there unless there is very little sunlight, in which case, that may be the maximum power it can get. The BougeRV MPPT search algorithm sees very aggressive. I have a total of ten 100 watt panels, wires 5S 2P for a VOC of about 110 volts (150 rated on the CC) and the VMP should be about 90 volts with an IMP around 11 amps. When I have good sun with no visible clouds, the panel voltage will move up and down over 5 volts out of the 85 to 90 volt area, while the current swings almost 3 amps out of just 11 amps. That makes the wattage drop and rise over 10%, or even 15% of the maximum. I understand MPPT has to "hunt" a bit to find the peak, but this just seems to move too far.

The other thing I find very odd is that the maximum power for the day and the total energy for the day seem to move in opposite directions. The Charge Controller stores the maximum power it hit each day as well as the total KWHs produced each day. And the numbers always seem to move opposite from each other. My best energy production days always show a lower maximum power for the day. And not by a small amount. On the day it produce 4,018 watt hours, the peak power was only 726 watts from the 1,000 watts of panels. But then a few days later, we had intermittent clouds, and the total production fell to just 3,159 watt hours, while the peak power was up to 832 watts. And on another cloudy bad production day, I even saw the peak watts hit 997 out of the STC panel rating of 1,000, but production for the whole day was bad at just 1,886 watt hours. Do others see this happening?

What I think is going on is the panels are cooling when the clouds are out, and then the cloud clears, AND the panels is getting both direct light from the sun, and extra scattered light from the surrounding clouds. So it hits a nice peak power, but it does not last. But the BougeRV charge controller does not graph the energy over a day, so I can't see if this is the case.

The one thing I do certainly see is that the solar panel voltage is pulled a bit lower when there is the best solar energy being harvested. I guess this makes sense. As the panel can produce more current, a loss of a couple volts is easily covered by a lot more amps. When I saw 650 watts today, it was down to just 83 volts. As the sun was going down, and the power was at just 300 watts the voltage was up to 89 volts.

I am tempted to get a Victron, but this cheap charge controller ($149 USD) can accept 150 Volts, put out 40 amps into a 48 volt system, and has Blue Tooth setup and monitoring. A close matching Victron is about $400. I did find a Victron 150/35 for $323.85 USD. That's close enough for my power level. Anything smaller does not support 48 volt systems. Will it actually produce enough extra power to justify the extra cost? Admittedly I spent $880 on the solar panels. So if this does make them worth more too, I can see it. I wish I knew someone who could lend me a Victron to do a direct comparison. This cheapy did manage to pull 4.02 sun hours in January in So Cal. So it is not doing bad. It only lagged a bit behind the 4.33 sun hours of my Enphase microinverter system on the same day. And I truly believe these cheap 100 watt solar panels could easily be 8% less output than their ratings compared to my big 300 watt SilFab panels.
 
I am fairly new to running DC charge controller. Mine is the newer BougeRV 40 amp MPPT.
I am tempted to get a Victron, but this cheap charge controller ($149 USD) can accept 150 Volts, put out 40 amps into a 48 volt system, and has Blue Tooth setup and monitoring. A close matching Victron is about $400.
Your system seems to be performing fine. The two parallel strings might be the cause of extra MPPT hunting.
Amazon Reviews 10% 1 Star, enjoy it while it lasts. Make sure the heat sink has some ventilation, and it's in a ventilated space.

4.0 out of 5 stars Well built but inaccurate.
Reviewed in the United States on April 28, 2022
Style: 40A MPPT YellowVerified Purchase
If you can have just one charge controller and don't care about accuracy this is a reasonable one at price point. It has a great fit and finish. It handles 2.5 more power than the Victron at the same price and it has built in Bluetooth. You may be able to squeeze 6 gauge wire into the solid feeling termination lugs. It easily takes 8 gauge wire.
The app is usable but basic. It reads .2volt high and can be generous up to 2 amps, showing up to 20% more power from panels that is measured by my clamp meter. I hope the app and firmware are upgradable. The app does allow for changing basic parameters for Lithium batteries.

BTW: I had BougeRV MC4 connectors and they were junk, did not hold up to repeated connect/disconnect cycles.
 
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I just noticed the same thing with an EPEVER 4210 on test. I changed from 2 panels in series to 4, so the PV input increased from ~40V to ~80V, and it dropped the panels to just above the battery voltage (25V in this case, 6S Li-ion). I've designed MPPT charge controller code, and I think it's a common error in the software. The perturb and observe algorithm, used by most low-cost MPPTs, has a nasty habit of getting stuck at the bottom of the charge range in low light conditions. Low-quality ADCs and noise in the current and voltage sampling paths are usually to blame. Also, using the microcontroller's own ADC rather than an external dedicated device lowers the sampling resolution, and it can mean that the controller is not able to detect small variations in current/voltage in order to progress in its power point search.
 
As an ugly work-around (for those of us who don't want to monitor the system frequently), would it work to just have the PV's disconnect every hour or so for 30 seconds, then go back online? All on a timer? Disconnecting the PV apparently always works in causing the Epevers to exit their torpor and to get busy recalculating the proper max power point using existing true panel output. Sure, none of this should be necessary. But would disconnecting and reconnecting the PV cause a lot of wear-and-tear on the SCC or other components? Would we lose a significant amount of collection while it gets going after each disconnect? The problem doesn't seem to occur all the time (so there would presumably be lost collection when eveything was working fine and we disconnect for 30 seconds), but it would sure be better than finding at the end of a sunny day that your batteries are still mostly discharged because the SCC took a 6 hour siesta.

It seems very strange that Epepver doesn't have a firmware fix for this.
 
I have the same issue. SCC pulls panel voltage down to just above battery voltage. See it more on cloudy days but sometimes on sunny days. I have 4 epever (1-30A, 2-40A, 1-50A) in parallel. The panel voltages range from 30-70V. I do not know what is causing it. But would love to solve it. Seems like a common problem.

Some things I know:
Started when I switched from AGM to LifePO4
Effects all 4 SCC the same
Can correct by disconnecting panels
Can correct by increasing the the expected voltage by a couple of tenths
It is irritating

Some things I think I know:
It happens more when the batteries are near full
It happens more when their is low inverter load
Dropping below boost reconnect fixes it (May be because the boost voltage is a couple of tenths higher)
It is a system issue because it happens to all 4
This would be fine if there was no load (maybe preferred), my loads come off the battery, so SCC thinks no load condition.

Some things I do not know:
If there are settings that can keep the system from going this direction
If there is some association with the BMS HVD
If it is the battery change or the parameter change when changing batteries that causes it
 
^^ Yup.

Last trip dry camping we woke to super bright and sunny skies, battery at about 55%, put the portable panels out and connected to second SCC - roof-top flat panels just starting to get solar gain - the other SCC. Portables were putting out fine, but the main controller for the rooftop panels would drift from 44V down to about 18V. Reset it, would work for a bit then drift down again. I just figured it was weak solar gain, was doing better later on - but seems the input from the other controller threw off the main one, never did get very good charging amps from it while they were both charging.

I finally pulled the portable panels off and connected them to my Delta Mini to recharge it. Sure works great there.

With direct sun overhead I should really be seeing 25A or more, maybe 350-375 watts, for 12V charging. But generally it's about half that - about 265 watts out of the 430 watts of panels rating - 2@215W in series. A little disappointing. I have a Victron Smart 100/30 in my amazon cart...they're $225 so I'm hedging. :unsure:
 
^^ Yup.

Last trip dry camping we woke to super bright and sunny skies, battery at about 55%, put the portable panels out and connected to second SCC - roof-top flat panels just starting to get solar gain - the other SCC. Portables were putting out fine, but the main controller for the rooftop panels would drift from 44V down to about 18V. Reset it, would work for a bit then drift down again. I just figured it was weak solar gain, was doing better later on - but seems the input from the other controller threw off the main one, never did get very good charging amps from it while they were both charging.

I finally pulled the portable panels off and connected them to my Delta Mini to recharge it. Sure works great there.

With direct sun overhead I should really be seeing 25A or more, maybe 350-375 watts, for 12V charging. But generally it's about half that - about 265 watts out of the 430 watts of panels rating - 2@215W in series. A little disappointing. I have a Victron Smart 100/30 in my amazon cart...they're $225 so I'm hedging. :unsure:
Maybe check your max voltage parameter? When I first switched to LifePO4 I set mine just above the boost since there is no temp compensation. I noticed that one controller would push another over the max, even when the batteries were low, and I thought that might be part of my panel voltage drop problem. After increasing to 14.5V the solar voltage drop seemed to be isolated to when the batteries were closer to full, but I was never sure.

I could only see the voltage spikes on the computer not the controller or monitor.


Now that I am typing this, I think I might try increasing max voltage a bit more to see if the problem goes away. Maybe at high SOC turning loads on and off causes enough voltage change at the controller to confuse it. ?
 
Could be. Mine is set just above boost.
I keep raising both in an effort to keep it charging - it loads the bus with charge voltage then limits current. Battery doesn't get fully charged.
My 120V charger doesn't do that. ?
 
Following up. I increased my max voltage parameter to 14.8. Boost is 14.2 and float is 13.8. Both clouds and sun and none of the 4 SCCs have dropped panels voltages down since making the change.
 
Ive seen my 4215bn's go down to right at battery voltage with 24 volt and 12 battery banks when its VERY cloudy or raining. As soon as the weather improves they go back up to normal. They have never become "stuck" but again they have never messed up ever in all the years they have been running either.

The lowest I have used them with is 800 watts of panels so that might be why. They do very well in cloudy weather. It takes super heavy clouds or rain to have the drag down that low.
 
Ive seen my 4215bn's go down to right at battery voltage with 24 volt and 12 battery banks when its VERY cloudy or raining. As soon as the weather improves they go back up to normal. They have never become "stuck" but again they have never messed up ever in all the years they have been running either.

The lowest I have used them with is 800 watts of panels so that might be why. They do very well in cloudy weather. It takes super heavy clouds or rain to have the drag down that low.
I don't have any BNs. They seem like a good unit. I have AN and XTRA. I recently got a 50A AN. I was surprised when I got it. Although it shares the same model number as the 10-40A AN, it is pretty big improvement, it is much more substantial, has replaceable fuse, voltage sense, dry contact, and parallel connect.

If anyone is looking, I would recommend the 50A-100A AN over any of the other EPEVER SCCs (since no more BN). Even if I did not plan to use the 50A capacity. The only reason I would go with one of the others is if I was short on space.

Who knows maybe you will see four used XTRA up for sale in the future.
 
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