Re: Solar panels

by Caraman Tue Nov 23, 2021 12:09 pm

Relaxez-Vous wrote:Here are just my quick impressions.
Well it's another dual battery solar charge controller in the market alongside the Votronics Duo Dig and the Epever DuoRace.

The maximum voltage Voc this controller can accept is 29.5V. Our PV logic's 80W panel A-S fitted to our van has a Voc of 22V, so only parallel connected solar panels can be connected to this controller.
Incidentally if anyone wants a second 80W panel they supplied one to me last year, a special because it's not listed on their website. It was rather expensive and came in a box from PV Logic with Auto-Sleeper printed on the cardboard.

All the references to de-sulphating etc about battery recovery suggests it is designed to appeal to as many customers as possible. With a properly installed solar system you don't need de-sulphating. If I had a flat battery I'd know that it was nearly at the end of its usable life. I'd use a CETEK charger to try a final resurrection, I would not rely on my solar charge controller to do it.

It doesn't have Bluetooth but does have some display unit which I haven't checked out. I'd be half expecting to read that it been made out of recycled plastic and no whales were harmed in its manufacture.

My opinion is that you are far better buying a Votronic or Epever solar controller.

Thanks and I agree the de-sulphating bit. There is a bluetooth version available but not yet in stock in UK and price not known. There is a plug in display which is comprehensive but more expensive than the controller:

https://www.roadpro.co.uk/product/02h05c-solar-power-monitors/touch-screen-display-for-sun-control-2-regulators-c5705/C5705

I've spoken to NDS and RoadPro. Although it is capable of phase charging the vehicle battery including bulk and absorption charges at up 14.4V, it will only do this when the vehicle battery voltage has dropped below 12.5V which is about 80% SOC and then only if the leisure battery is 80% SOC or above. Once the vehicle battery charging cycle has started, it should take it all the way to 100% SOC but normally, if the leisure battery is below 80% SOC or if the vehicle battery is 12.5V or above, all the available charge goes to the the leisure battery. If both batteries are being charged simultaneously, the current will be split between them. NDS said the split is not predicable as it depends on each battery's energy requirement with the most discharged battery taking the most energy, noting that the vehicle battery charging current is capped at 5A and the leisure batteries at 20A or 25A depending on the model.

by Relaxez-Vous Tue Nov 23, 2021 6:55 pm

Considering the NDS 320W Sun Control 2 Dual Regulator MPPT further, I might be generous and add that it may have a place in an installation more where EHU isn't so readably available, say on a boat.

More of a repeat, concerning my findings recently of my LB being fully charged yet the VB was at about 60%, that's despite having 2 x 80W soar panels, I believe there where two reasons, November's dull weather plus I'd left the EC700 PSU switched on. This was perhaps consuming about 4 amps in 24 hrs, a lot for even my solar panels to put back each day. There was little surplus solar power to keep the VB topped up and the design of the Votronic limits the charging current to 1 amp. In our Duetto that we had in the past the Morningstar PWM solar controller in winter I would set charging at LB 50% - VB 50%.

Regarding me taking a measurement of the current my Votronic unit was delivering to my VB, I did take a measurement, it was 0.46 Amps. This was on a sunny day after I'd changed over my panels to series, the LB was fully charged. This may show up a disadvantage of the Votronic unit, if for any reason the VB is in a low charged state, only 1 Amp max will be delivered. It will take even longer to get back up to 100% if the VB has not been isolated from the vehicle's electronics. I have not seen what current is consumed by a 2019 Peugeot Boxer when parked. I don't know either which battery powers the tracker A-S fitted. If I make sure I turn the EC700 off in winter with my solar setup I expect both batteries will remain charged. If this happens again, my VB is low, I may well use a CETEK charger to quickly charge back up the VB.

I've just measure both battery voltages after a moderately sunny November day, LB 12.8V and VB 12.7V, 3amps charging max today and a measurable Watt/hrs went somewhere too.
I have my suspicions, just as the EC700 can be a drain on the LB that's if you forget to turn it off with the black isolation button on the PSU, so too the VB can be drained if you don't isolate the battery on a Boxer at the ignition switch.

I don't want to change to an Epever solar controller because it's big, but in winter in future I'm going to keep a closer eye on the VB voltage.

Goal too, no EHU in winter except to power an oil filled heater when it's sub-zero outside.

by Caraman Tue Nov 23, 2021 8:32 pm

The problem as I see it with the NDS is when the motorhome is out of use. If there is sufficient charge the controller will maintain the LB's SOC but it will allow the vehicle electrics, vehicle alarm if fitted and armed, intermittent use of the central locking and self-discharge to deplete the VB until its voltage has dropped below 12.5V, whereupon the controller will kick in to recharge the VB to 100% SOC. If the motorhome remains out of use for a long time it may repeat this cycle several times.

The constant trickle charge up go 1A that the Votronic can provide to the VB may be sufficient to keep it at 100% SOC. If not as in your case it may struggle to return the VB to 100%. This is not just due to limitations on the charging current but also on its voltage which Votronic has said is about 0.7V below the LB's charging voltage so at best 13.7V and probably less than this for most of the time.

When the EC700 is shutdown, some of the communication module's functionality is also shutdown but it core tracker capability remains active drawing a very small (negligible) current from the LB or the tracker's internal battery if the LB is disconnected or discharged. When not shutdown, the EC700 draws its power from the LB or the VB if the LB is disconnected or discharged.

by Caraman Wed Nov 24, 2021 10:46 am

For completeness I add my understanding of the Epever's VB charging regime taken from its manual:

Like the Votronic it uses a trickle charge for the VB but unlike the Votronic it is fixed at 1A and turns off once the VB is fully charged. It appears that the VB will not be charged if there is less than 1A available and it will only start charging if the LB is fully charged or if there is at least 3A of charge available. It will stop charging if this drops to 2.5A or if the solar panel voltage is less than 2V higher than the LB voltage (I think that’s what it means).

by Caraman Fri Nov 26, 2021 10:07 am

I have just received a communication directly from Votronic in Germany (service@votronic.de) which has given greater clarity to my understanding of the DuoDig's vehicle battery charging.

The DuoDig will only send a charge to the vehicle battery if the leisure battery is in its second and final charging phase (U2). The vehicle battery charge is delivered as a one phase trickle charge of 13.7V resulting in a variable charging current of up to 1A, depending on the vehicle battery SOC and the available solar power. This may mean that if at the end of the day the leisure battery is not fully charged, the vehicle battery may not have been charged that day. If this is repeated day on day, the vehicle battery SOC will drop and won't start to recover until the leisure battery is fully charged again. The speed and degree of vehicle battery recovery will be limited by its trickle charge and duration.

by Relaxez-Vous Fri Nov 26, 2021 5:04 pm

Thanks Caraman your last post explains a lot why our VB had dropped to 60% charge during the dull days we've had in November.
If I had turned off our EC700 PSU when we came home from the Lake District in early October, our LB would have remained fully charged with solar power plus enough spare to keep the VB fully charged too.

At that time with 2 x 80W solar panels then in parallel I am wondering that there was enough solar power to keep the VB fully charged, but the Votronic wasn't able to make full use of all the available power. If I'm correct it points to a minor shortcoming of the Votronic Duo Dig charge controller, the charge current delivered to the VB is limited to 1amp. In winter having a 50% - 50% charging option might produce a better result.

by Caraman Mon Nov 29, 2021 9:15 am

I said before:

The DuoDig will only send a charge to the vehicle battery if the leisure battery is in its second and final charging phase (U2).

The DuoDig in fact delivers up to 5 charging phases to the leisure battery, the last being the float charge U2. As I said before, the vehicle battery won't start to receive its trickle charge until the leisure battery enters its final U2 float charge, at least that is what Votronic has told me.

by Suppersready Tue Nov 30, 2021 10:08 am

I have the Votronic 430w duo with the remote meter. When solar charging is in progress both the leisure cells and starter cell display a positive charge is taking place, this can be observed on the seargent control panel above the hab door and I have confirmed this with a separate meter reading off leisure and starter cells. These readings are different for both sets of cells so I would assume there is no possibility of a equalisation between the two. Additionally the remote Votronic meter displays a current charge of up to 9 amps which I would assume is not the U2 phase.
I’m not about trying to correct any information that has already been posted but thought my own findings may be of interest.

Niall

by Caraman Tue Nov 30, 2021 10:13 am

Suppersready wrote:I have the Votronic 430w duo with the remote meter. When solar charging is in progress both the leisure cells and starter cell display a positive charge is taking place, this can be observed on the seargent control panel above the hab door and I have confirmed this with a separate meter reading off leisure and starter cells. These readings are different for both sets of cells so I would assume there is no possibility of a equalisation between the two. Additionally the remote Votronic meter displays a current charge of up to 9 amps which I would assume is not the U2 phase.
I’m not about trying to correct any information that has already been posted but thought my own findings may be of interest.

Niall

Thanks. A problem is the lack of detailed information given in the Votronic manual about the VB charging regime. This is why I went to Votronic in Germany for answers as the UK supplies don't know. It would be worth contacting Votronic to see what they say to you.

by Relaxez-Vous Wed Dec 01, 2021 12:22 am

Suppersready, from my measurements it appeared that equalisation of our LB and VB happened after i took the van for a run out recently, for our walk and pub meal, Total driving time was around 2 hours. I assume this happened when the alternator delivers up enough energy to energise the split charging relay. Before we went out the LB was fully charged, the VB on 60%, perhaps rather than just equalisation from LB Battery to VB Battery, I suppose during our journey equalisation came from the alternator putting most of its charging into the vehicle battery.

by Caraman Wed Dec 01, 2021 8:07 am

I've just been reading about a 4th dual battery MPPT controller - Schaudt LRM1218. It explains that the VB charging won't start until the LB "has passed through the main charging phase". This seems to be common to all them. The Schaudt doesn't define "main charging phase". Votronic has told me for their DuoDig it's when the LB enters its U2 float charging phase. NDS has told me for its Sun Controller its when the LB is up to 80% SOC and the Epever manual explains its when the LB is fully charged (or if there is at least 3A of charge available).

by Suppersready Wed Dec 01, 2021 12:25 pm

I wonder if there is a reason why the MPPT controllers do not have a adjustable charge/split of available power to each set of cells like some PWM have, the benefits would be obvious based on the vehicles particular mode of use at any given time …

Niall

by Suppersready Wed Dec 01, 2021 12:39 pm

Relaxez-Vous wrote:Suppersready, from my measurements it appeared that equalisation of our LB and VB happened after i took the van for a run out recently, for our walk and pub meal, Total driving time was around 2 hours. I assume this happened when the alternator delivers up enough energy to energise the split charging relay. Before we went out the LB was fully charged, the VB on 60%, perhaps rather than just equalisation from LB Battery to VB Battery, I suppose during our journey equalisation came from the alternator putting most of its charging into the vehicle battery.

I have not read the whole thread but I think it’s possible that two 80w panels wired in parallel may not be able to generate enough voltage to deliver what would be enough current into your cells, this would of course be dependant on their actual state if charge. In winter conditions I would expect both panels wired in series to give a better result, albeit the current generated would be less but it would/should be able to generate the voltage to supply that current.

Niall

by Roopert Wed Dec 01, 2021 12:48 pm

Suppersready wrote:I wonder if there is a reason why the MPPT controllers do not have a adjustable charge/split of available power to each set of cells like some PWM have, the benefits would be obvious based on the vehicles particular mode of use at any given time …

I believe that the reason is that it's easy to do with a PWM-based system. In effect the system "time slices" the output into fixed-duration pulses anyway. So it's relatively easy to simply change the proportion of pulses that go to each output. In simplistic terms, that changes the proportion of the solar power, distributed across the two outputs.

by Suppersready Wed Dec 01, 2021 12:57 pm

Roopert wrote:
Suppersready wrote:I wonder if there is a reason why the MPPT controllers do not have a adjustable charge/split of available power to each set of cells like some PWM have, the benefits would be obvious based on the vehicles particular mode of use at any given time …

I believe that the reason is that it's easy to do with a PWM-based system. In effect the system "time slices" the output into fixed-duration pulses anyway. So it's relatively easy to simply change the proportion of pulses that go to each output. In simplistic terms, that changes the proportion of the solar power, distributed across the two outputs.

You have explained that well … even I can understand ! Thank you …
With reference to the MPPT unit I may follow this up with Votronic in Germany.

Niall

by Relaxez-Vous Thu Dec 02, 2021 12:42 am

I came across a website which showed that it was doable to have two solar controllers, one solar panel into a PWM controller, another into a MPPT controller. "Merlin's Beard" as Professor Slughorn would be heard saying.

by Alwaysurfing Wed Dec 15, 2021 2:23 pm

Caraman wrote:
Alwaysurfing wrote:Unbelievable - when i first got the van I complained the solar didn't seem to work - was fobbed off with weather, ehu etc by the dealer. Recently had reason to put in a written complaint about something else and threw in the solar just to add weight - turns out the solar was indeed not working as I suspected. They feebly explained that the fuse - which is hidden inside the enclosure so not viewable - was blown. My personal feeling is the solar was never commissioned as I had never until this point ever seen the amps fluctuate on the EC700 panel. Even on dull days I now have a reading and the batteries have in turn not lost their capacity even this far into the end of year..... absolutely amazing...... its taken me over two years of complaining to get this sorted out.
This is indeed surprising as it is relatively easy to see if there is solar charge by looking at the EC700's CP or using a multimeter. You said "They feebly explained that the fuse - which is hidden inside the enclosure so not viewable - was blown." Where exactly is this fuse as I have not seen it? Has anyone else seen it?

After this and other threads and one attempt at off-grid use in the Summer, I have finally decided to fit a Votronic 165 dual battery MPPT controller but left it too late as their price has escalated and there is now no stock in UK. I am hoping the situation will improve before next Summer.

The fuse is "PF2 10A Polyfuse Solar Panel Input (replaced with fuse 14 on newer units)" according to the dealer manual.

by Caraman Wed Dec 15, 2021 2:53 pm

Thanks. The Harmony manual does refer to a Fuse 14 - 10 Amps - Solar Fuse / Polyfuse (Rear Fitting) but on my EC700 fuse panel it stops at Fuse 13 (11 to 13 being spares). So the fuse must be hidden behind the fuse panel if that's what 'rear fitting' means and your photo shows it. I've had the EC700 top panel off but not inspected the underside of it properly. Next time I have it off I will take a look. The fuse is presumably superfluous when a dual battery solar controller is fitted which will have its own fused connections to each battery.

by Alwaysurfing Wed Dec 15, 2021 3:12 pm

Hi, the fuse is the thing in the middle of pic. The dealer expects me to believe that they removed the circuit board, unsoldered the fuse and put a replacement in its place. I think when they actually bothered to look properly into my complaint they would have found the solar wasn't even connected at its socket e.g. i believe it was never commissioned correctly before they passed the van to me..... still works great now and I will never actually know what took them so long to check properly after i complained so many times. Problem I find is you have not much of a leg to stand on if they don't check things with any care and fob you off rather than just fixing the issues.

I should add my understanding is that these fuses reset themselves so if it was the issue it would fix itself - hence my view they are not being honest with me.

'Polyfuses consist of a matrix of an electrically conductive material embedded in an electrically non conductive polymer binder' - google search !

by Caraman Wed Dec 15, 2021 4:10 pm

I didn't know what a polyfuse was either. Here is my google search:

A "polyfuse" is a fuse made from a polymer. It is a fuse that after it has "blown" will self heal; that is after several days, it will (almost) behave as if nothing has happened.

If the solar regulator was OK one would have to question what made the fuse blow. The 80W Solar panel/regulator output is nowhere near 10A. As you say its more likely the regulator hadn't been plugged in properly in the first place and no check was made that it was working.

by Caraman Wed Jan 12, 2022 11:09 am

I've just changed my solar setup and fitted a dual battery Votronic that bypasses the EC700. It's very early days but I have noticed that when the sun is out as it is today and the green LEDs are all lit indicating a fully charged leisure battery, I get a flickering on the EC700 CP when I turn on the EC700. It doesn't last long but I would rather it didn't do it. It doesn't seem to flicker when the '>80%' and 'fully charged' LEDs are not lit when the solar charge is low or when connected to an EHU with the mains charger on. Has anyone else noticed this?

Addition:

I've just checked it again. The leisure battery solar charge was 14 point something volts when the CP flickered. It's now dropped back to its float charge of about 13.5V and no flickering when the EC700 is turned back on.

by Suppersready Wed Jan 12, 2022 11:59 am

Caraman wrote:I've just changed my solar setup and fitted a dual battery Votronic that bypasses the EC700.

Addition:

I've just checked it again. The leisure battery solar charge was 14 point something volts when the CP flickered. It's now dropped back to its float charge of about 13.5V and no flickering when the EC700 is turned back on.

Mine has done exactly the sae since installation in 2018 …

Niall

by Caraman Wed Jan 12, 2022 12:37 pm

Suppersready wrote:
Caraman wrote:I've just changed my solar setup and fitted a dual battery Votronic that bypasses the EC700.

Addition:

I've just checked it again. The leisure battery solar charge was 14 point something volts when the CP flickered. It's now dropped back to its float charge of about 13.5V and no flickering when the EC700 is turned back on.

Mine has done exactly the sae since installation in 2018 …

Niall

Thanks. That reassures me that I haven't done anything wrong. I don't think it's going to be a problem but time will tell.