Solar panels

Dbvwt & Glyne - thanks for the advice.  I am very happy to fit a 250 but it's also not in stock.  Our off-grid aspirations are limited to the occasional use of a site in the late spring and summer that doesn't have an EHU  - noting that most sites do have EHUs.  We are never going to so called 'wild camp'.  If I decide to increase the solar wattage, I favour re-rolling the cigar lighter socket on the outside of the van to accept the unregulated output from an 80W folding solar panel wired in parallel with the 80W panel on the roof.  I would only carry this additional panel if I know I'm going to use it.  Yes - I agree that Marconi's work recorded in his long EC700 thread is invaluable.

Yeah I have to say I'm really happy with my final setup.  The 250 MPPT controller with twin 80W panels has been perfect for my use.

I would say for Caraman's use though that a single 80W will suffice.  When I had just the one it only struggled due to the Sargent system messing the charge up.

With that bypassed everything simply gets on with charging as it should.  It's nice to have the ability to upgrade if you want with the 250, but solar is very usage specific and can see there's no point spending money on big setup's if you never need the additional wattage .

In terms of the Votronic being out of stock, isn't there another version of it - I'm sure after I got mine someone highlighted the exact same controllers are for sale for cheaper but it's just re-branded under another name?  Also, isn't the Victron well regarded too?  Possibly another one to look at.

Greyhound wrote:Yeah I have to say I'm really happy with my final setup.  The 250 MPPT controller with twin 80W panels has been perfect for my use.

I would say for Caraman's use though that a single 80W will suffice.  When I had just the one it only struggled due to the Sargent system messing the charge up.

With that bypassed everything simply gets on with charging as it should.  It's nice to have the ability to upgrade if you want with the 250, but solar is very usage specific and can see there's no point spending money on big setup's if you never need the additional wattage .

In terms of the Votronic being out of stock, isn't there another version of it - I'm sure after I got mine someone highlighted the exact same controllers are for sale for cheaper but it's just re-branded under another name?  Also, isn't the Victron well regarded too?  Possibly another one to look at.

Thanks.  I think the only two MPPT dual battery controllers are the Votronic and EPever which I think Glyne has.  I think Victron only does single batteries.  I would be interested to know what different name the Votronic is marketed under.  I am in no rush to do the mod as it won't now be used in anger for a while and the motorhome is still under warranty until May.

Greyhound - I've found a 250 in UK - £132.61 incl. p&p.  This seems a bit steep.  Do you agree?

Still not convinced of the huge advantages I see mooted for MPPT. The Dual batt controller I use from Photonic is a fraction of that cost and, I'm willing to bet, not a lot different in real time practical use? (£34) Have used them on 5 applications now, never had a failure, or a flat battery!!!

Parallel or series?

Further to my stated interest on page 11 to explore connecting our 2 x 80W solar panels in series that feed a Votronic MPP 250 Duo Dig, I decided first to do some voltage checking with the existing parallel arrangement, it was rather revealing.

Yesterday after dark the Leisure Battery was at 12.73V, that's close to 100% charged, the Vehicle battery though was a surprise at 12.32V, that's only about 60% charged. I had believing that with our 160W of solar and a MPPT controller, I took it that we had loads of solar power, enough that I'd not pressed the off button on the EC700 PSU for several weeks. Even with everything off on the LCD panel, from memory something around 200ma could still be consumed by the EC700 system. Over 24 hrs that's about 4.8 amps the solar panels need to keep pumping back into the batteries. Yesterday I turned off the power going to the EC700 PSU with the black isolator button.

Today I continued with some voltage checking. At last around 11am the solar voltage was getting up to 19V, the Victronic display was displaying a solar charge between 0.0 and 0.1 amp, Leisure Battery was at 12.79V, Vehicle battery at 12.4, the slight increase in Vehicle battery voltage more representing the charging from the solar controller which was at last kicking in with rising light levels.

By 1.40pm the solar charge was at 0.3 amps, (an hour earlier it was still 0.1 amp), Leisure battery 13.04, Vehicle battery 12.49V, solar charging ended though at 2.27pm on what is a rather dull day in mid November.
My measurements at 5.10pm by torchlight are, Leisure battery 12.73V, Vehicle battery 12.3V which is what it was at this morning, the only difference is that since yesterday the EC700 is now fully off.

Bottom line, if light levels are low, at the ends of the day in summer, and during the darker days of winter, connecting solar panels in parallel puts a handicap on a solar system because battery charging will only happen once a threshold voltage is reached. This threshold will be reached sooner if the solar panels are connected in series. Whilst there is a disadvantage with series, if only a small part of one solar panel is shaded, from a few fallen leaves for example you might not get any solar charging. I'll report back after the change to series. Currently I suggest that If you've a separate solar controller connected direct to your batteries, keep your Sargent system powered down in winter.

Relaxez-Vous wrote:Parallel or series?

Further to my stated interest on page 11 to explore connecting our 2 x 80W solar panels in series that feed a Votronic MPP 250 Duo Dig, I decided first to do some voltage checking with the existing parallel arrangement, it was rather revealing.

Yesterday after dark the Leisure Battery was at 12.73V, that's close to 100% charged, the Vehicle battery though was a surprise at 12.32V, that's only about 60% charged. I had believing that with our 160W of solar and a MPPT controller, I took it that we had loads of solar power, enough that I'd not pressed the off button on the EC700 PSU for several weeks. Even with everything off on the LCD panel, from memory something around 200ma could still be consumed by the EC700 system. Over 24 hrs that's about 4.8 amps the solar panels need to keep pumping back into the batteries. Yesterday I turned off the power going to the EC700 PSU with the black isolator button.

Today I continued with some voltage checking. At last around 11am the solar voltage was getting up to 19V, the Victronic display was displaying a solar charge between 0.0 and 0.1 amp, Leisure Battery was at 12.79V, Vehicle  battery at 12.4, the slight increase in Vehicle battery voltage more representing the charging from the solar controller which was at last kicking in with rising light levels.

By 1.40pm the solar charge was at 0.3 amps, (an hour earlier it was still 0.1 amp), Leisure battery 13.04, Vehicle battery 12.49V, solar charging ended though at 2.27pm on what is a rather dull day in mid November.
My measurements at 5.10pm by torchlight are, Leisure battery 12.73V, Vehicle battery 12.3V which is what it was at this morning, the only difference is that since yesterday the EC700 is now fully off.

Bottom line, if light levels are low, at the ends of the day in summer, and during the darker days of winter, connecting solar panels in parallel puts a handicap on a solar system because battery charging will only happen once a threshold voltage is reached. This threshold will be reached sooner if the solar panels are connected in series. Whilst there is a disadvantage with series, if only a small part of one solar panel is shaded, from a few fallen leaves for example you might not get any solar charging. I'll report back after the change to series. Currently I suggest that If you've a separate solar controller connected direct to your batteries, keep your Sargent system powered down in winter.

Is the current shown on the Votronic's display the total charging current or just the charging current going to the LB?

glyne lock wrote:
.. it was myself posted the mppt that is the same as the votronic there are 3 units all the same but different names. ....

Glyne - can you remember what the different names are?

That's quite a web site.  I couldn't see a Votronic lookalike at least not in UK but thanks all the same.  The best price for Votronics at the moment is in NZ and there is stock in the EU but reluctant to buy from these locations due to possible customs issues, if there is a problem with it and the increased p&p.  I'm sure things will improve over the next few months.

IanH wrote:Still not convinced of the huge advantages I see mooted for MPPT. The Dual batt controller I use from Photonic is a fraction of that cost and, I'm willing to bet, not a lot different in real time practical use? (£34) Have used them on 5 applications now, never had a failure, or a flat battery!!!

There's a thread where some of us were having the Sargent system cutout?

A couple of us fitted a PWM controller and were puzzled why the system was cutting out periodically.  The cause was the spikes caused by the PWM controller making the Sargent cut out as it saw the spike as a issue and 'protected' itself.

Since fitting the MPPT it has never had the issue and works seamlessly.

For a simply solar setup without the Sargent electronics in the way, then yes a PWM will indeed work as intended, but doing the bypass that a lot of us have done, you must use a MPPT to avoid this exact issue.

Perhaps, but was the solar controller connected directly to the battery(s)?
If so the Sargent would have been unaware??
Dont know, have neither!!!

As described in another thread, I've done the transplant of PWM --> Votronic MPP, but kept the wiring and location exactly the same (actually had to cut a hole in the face of my EC328 so that it would go in and still provide access to the fuse on the Votronic unit).

As a result, I no longer get the occasional over-voltage alert from the EC328 - though in my case it wasn't a great inconvenience because with the latest firmware all you get is a flashing display - mine never cut out having updated it to latest firmware.

I should add that in terms of charging performance, the Votronic is a little better than the Sargent-fitted PWM controller, but there is not a massive difference in my experience. I think it's likely that providing direct, large-gauge cabling to the battery for the charging current has as much, if not more, beneficial effect as going from PWM --> MPPT.

As far as I know, I don't have a problem. As I said, it was a straight like-for-like swap. No changes to the wiring or location.

I don't think realistically I should expect to see anywhere near 20-30% gain. MPPT may be better, but it's not that much better!

From what I've read, the difference should be a few percent for a simple single-panel system, when averaged over a typical day's charging cycle. My understanding is that low-light performance is better, and reaction to changing light conditions is better (because it is adaptive) but the peak charging rate when the panel is saturated should be about the same - and that is (obviously) what does most of the work.

Thanks, but I don't need any "training". I know how to connect up an MPPT controller, and I know what I'm seeing in terms of charge back to the battery.

The system is behaving in pretty much exactly the same way as when I installed it almost 8 years ago, so I don't have a problem.

Unfortunately the manufacturers have a habit of over-hyping "new technology" to try to make people upgrade to it. Anyone expecting to see 20-30% gain in a like-for-like installation is probably just falling for that hype.

Caraman, in my post above the charging current displayed on my Votronic's LCD display was the instantaneous current. I didn't look but I expect the total Ahs for the day would have been around zero, or possibly less then 1 Ah. From what I could see there were only 2.5hrs in the middle of the day when any charge was being delivered to the batteries sufficient to be recorded on the meter.

I rewired my two solar panels to series yesterday and I'm collecting now some readings which I will post later.

Relaxez-Vous wrote:Caraman, in my post above the charging current displayed on my Votronic's LCD display was the instantaneous current. I didn't look but I expect the total Ahs for the day would have been around zero, or possibly less then 1 Ah. From what I could see there were only 2.5hrs in the middle of the day when any charge was being delivered to the batteries sufficient to be recorded on the meter.

I rewired my two solar panels to series yesterday and I'm collecting now some readings which I will post later.

Thanks.  I'm destined to get a dual battery MPPT Votronic controller hence my interest.  The optional LCD display seems to show the voltage of the leisure battery only.  I was wondering if the current shown is also for the leisure battery only.  The Votronic trickle charges the vehicle battery up to a maximum of 1A but this appears not be shown on the display.  What is not clear is how the trickle charge is managed.  For example, if 5A of solar charge is available and both batteries are depleted, will 1A go to the vehicle battery and 4A to the leisure battery.  If 2A of charge is available, will 1A go to each of the batteries.  If 1A or less is available, will it all go to the vehicle battery or will none of it go to the vehicle battery which would account for your depleted vehicle battery.

Caraman wrote:

Relaxez-Vous wrote:Caraman, in my post above the charging current displayed on my Votronic's LCD display was the instantaneous current. I didn't look but I expect the total Ahs for the day would have been around zero, or possibly less then 1 Ah. From what I could see there were only 2.5hrs in the middle of the day when any charge was being delivered to the batteries sufficient to be recorded on the meter.

I rewired my two solar panels to series yesterday and I'm collecting now some readings which I will post later.

Thanks.  I'm destined to get a dual battery MPPT Votronic controller hence my interest.  The optional LCD display seems to show the voltage of the leisure battery only.  I was wondering if the current shown is also for the leisure battery only.  The Votronic trickle charges the vehicle battery up to a maximum of 1A but this appears not be shown on the display.  What is not clear is how the trickle charge is managed.  For example, if 5A of solar charge is available and both batteries are depleted, will 1A go to the vehicle battery and 4A to the leisure battery.  If 2A of charge is available, will 1A go to each of the batteries.  If 1A or less is available, will it all go to the vehicle battery or will none of it go to the vehicle battery which would account for your depleted vehicle battery.

I contacted Votronic Universe and asked them this very question, they replied they did not have the technical information to be able to answer.



Niall

IanH wrote:Perhaps, but was the solar controller connected directly to the battery(s)?
If so the Sargent would have been unaware??
Dont know, have neither!!!

Yes the solar system was setup directly to the batteries and bypass the Sargent system (which is the main culprit for poor performance).

The Sargent system still runs off and monitors the 12V system however, so it still 'sees' a voltage in the 12V system regardless of whether it's controlling the solar or not.

A sudden spike from the PWM when the sun comes out from behind a cloud (for example) meant the entire 12V system had a brief spike which the Sargent interpreted as a fault and shut itself down as a protection.

With MPPT that doesn't occur.

If you have an older van with the straightforward connection and 12V supply, you can fit whatever you like (within reason), but a lot of these threads are now covering the Sargent system issues which is why the MPPT are being stated as so necessary.

Caraman, I wouldn’t bother with the optional LCD display, just fit the controller to begin with and see how you get on.
I’ve been where you are now and was all set to get the - expensive- display but I’m glad I didn’t. I religiously checked the vehicle and leisure batteries every day with a meter for about 3 weeks after fitting my controller (Nov last year) and everything was fine. I’ve never needed to check things since as it just does it’s job with no fuss, it just works!
I will add that over winter my EC500 is powered down completely but not having to plug into the EHU once a week since has been a joy!