Solar panels

Having travelled a lot with a friend who has an EC500, I've found that whilst camping without hookup, on days with limited light, losing what energy is harvested to the vehicle battery rather than replenishing what has been used by the leisure battery is a concern. As the vehicle battery is perfectly ok if not charged for a week, the solar smart charging is switched off and the solar energy all sent to the leisure battery.

I now have what I find ideal.

The AS install is directable either by Smart or Manual selection to either Battery but is incapable of adequately charging either battery. Not due to its 80W size I am sure but to the charging profile of the Solar Controller or the losses introduced in the installation.

So I have another 100W panel and MPPT controller, engineered correctly and feeding just the Leisure Battery directly. In the morning I direct both Solar Panels to the Leisure Battery. By 11:00 AM the voltgage gets to 13.6 V and the AS install gives up and drops do zero contribution. At this point I manually direct the AS output to the Vehicle Battery which having had hardly any discharge gets to 13.4 V by midday. At which point the AS system soon gives up, right at the peak energy point of the day so wasting all energy.

At midday the MPPT system reaches Float charge conditions and will continue Float Charge for the rest of the day.

This exposes the reason for all the problems being experienced by users.

marconi wrote:So I have another 100W panel and MPPT controller, engineered correctly and feeding just the Leisure Battery directly. In the morning I direct both Solar Panels to the Leisure Battery. 

Genuine question here as this is confusing me a bit.

If I've read you right, you basically have two separate panels, wired through 2 independent controllers to the same battery?  One via the Sargent and one via a MPPT.

So in effect, each controller will see the charge current from the alternate supply?  Wont this 'confuse' the controllers into not being able to detect the status of the battery and therefore cause issues with them determining their charge status e.g. whether to change to float etc?

My thinking is if the Sargent is seeing the MPPT charge, this could be why it's dropping to zero.

As I say, genuine question as I'm still learning the deeper "dark arts" of solar 

Good question  greyhound.

Apparently you have stated one of the myths of Solar. I did wonder about upsetting the EC700 being its dumb smart electronics so I took  the precaution of OK'ing it with Sargent.

Any questions of one sensing the other which of course will happen are explained by my current routine.I want all the power I can get so I use both panels at first and get more than 2 Amps / hour most days from the AS controller. There is no difference in its performance alongside the MPPT until the AS set up gets to its WRONG max point then of course it closes down.
Upon manually selecting the AS charge to go to the Vehicle battery it immediately resumes a 2A charge, then it soon goes through the same routine reaching 12.9V and then into PWM when it is pulsed in a 2 off 1 on ratio with 13.4 volts.

Of course I could leave the AS set up permanently manually selected to Vehicle and the Leisure Battery only would receive the PWM charge. But why waste the power from the AS set for a few hours when it will start to waste power of it's own accord at the maximum power point of the day.

Now then what thread are we on, never mind. The worries of exhausted batteries in storage will be worse than all estimates because neither battery gets a proper charge from the AS Solar set up under any conditions.

Further, I decided on my MPPT set up because it was blatantly obvious that despite copious sun, neither battery was being correctly charged. I looked at one months record of usage and only when on the road did the voltage rise to anything like a charged state. I even questioned Sargent as to whether some sort of equalizing went on over night because both would fall to 12.2V.

My MPPT Controller features battery save. If the Load is connected to the Output terminals and the battery does not receive a good enough charge in the day and is thus in danger of having its life shortened then the load is disconnected so preventing lethal drain.

Initially, for several days after a full days charge with MPPT the Battery Save was activated indicating what I already knew, the AS system is incapable of giving the Leisure battery a sufficient charge.

This is where real intelligent charging comes in with my MPPT, if the profile does not achieve full charge today then the profile is changed for tomorrow untill a full charge is reached. Higher consumption items can be connected to the Load Output and will be disabled under poor charge conditions leaving you with only the essentials run directly from the battery.

marconi wrote:To be fair bolero boy says he is talking of fairly short periods of winter non use.

The 80W panel Nuevo system problem is that it doesn't even come up to a 60W panel performance, which brings me to the point I forgot. 6) The Nevo can select charging for Leisure or Vehicle battery. The charge profile cannot be right for both the performance fits an AGM battery best, a Sealed Lead Acid charge profile would damage the AGM Vehicle battery.

In practice the terminal Voltage goes no higher than 12.9V then the PWM starts a very short duty cycle of 13.5V pulses, shortly after that it will stop charging completely despite full sun at the peak charging period of the day. Hence neither battery will reach full charge, particularly the Leisure.

i would agree with this last para...
both batteries showing 'full' just after lunch and i measured the terminal voltages from the PWM ...vehicle 
battery (sealed lead acid, i assume) was at 14.4v and the AGM leisure batteries were at 12.9v which i take to be a prematurely cut off level?
ive been thinking about adding another panel so i think i may get a 2nd 100w panel, with MPPT controller and just connect to the AGMs. the existing system easily maintains the cab battery and supplies a 'reasonably healthy' charge to the AGMs, so a flexible system??

Roopert wrote:

marconi wrote:By 11:00 AM the voltgage gets to 13.6 V and the AS install gives up and drops do zero contribution. At this point I manually direct the AS output to the Vehicle Battery which having had hardly any discharge gets to 13.4 V by midday. At which point the AS system soon gives up, right at the peak energy point of the day so wasting all energy.

As Greyhound says, I think you are misinterpreting what you are seeing.

If you connect two charge controllers to one battery, one will almost always "win", and the other will back off. That's because, with manufacturing tolerances being what they are for electronic components, one will always have a slightly higher threshold voltage for each of the charging stages. Typically what will happen is that one will see the increasing voltage (caused by the other charge controller) as a sign that the battery is approaching fully charged state, and will shut off its output.

So it is completely normal to see one have its output drop to zero while the other continues to charge.

Sargent will have been quite happy to OK having two chargers connected, because it will do no harm. But that doesn't mean that you can read into it that the controller in the Sargent unit is "giving up". It is shutting off correctly to prevent what it "sees" as the probability that the battery will be overcharged.

I wrote quite a long reply to this and it vanished. Suffice to say, please don't use small quotes out of context, I am not misinterpreting, I am stating what happens and how I use the power available.

glyne lock wrote:Marconi
1 what mppt controller are you using
2 as Greyhound and Roopert have said  the mppt controller is making the cheap pwr controller switch off .the pwr fitted is only 10 amp so is the reason you you can only up grade the panels to 120 w and is a very very cheap pwr only one place for it is in the bin the mppt will give a better float charge than a pwr and is one of many reasons to fit a mppt controller

1) Victron

2) There is an urban myth that you can't run two Solar Controllers to the same battery.
However of course it would be wise to use two which are identical.
I am very well aware that I am using two totally different technologies so the charging profiles will be different.
I myself make the statement that of course the PWM gives up, not only because it has the wrong profile for the Calcium Lead Acid Battery it is attempting to charge.

The facts are which must be all read and understood before commenting.
The AS system is incapable of charging either battery properly.
I am not connecting via the Sargent but direct to the battery so any 120W (or I think that has changed now) any other limits do not apply.
My main intention is to direct the AS system to the Vehicle battery where it can play with its pathetic attempts at charging.
The MPPT system will normally be the only controller on the Leisure Battery.
However I reserve the right to manually switch the PWM in as well to make use of the 2 A plus available until the charge reaches 12.6 / 12.9 V.
I state that the AS system gives up at 12.9V WHEN CONNECTED TO THE VEHICLE BATTERY so giving that an inadequate charge. The PWM does operate with a 9 seconds Off 3 seconds on duty cycle with pulses to 13.4V but that still does not charge to more than 12.6V finally, in a whole day of full sun. Quite pathetic for an 80W panel.
Other owners are finding the AS 80W system inadequate, it is nowhere near the capability of my old 60W panel I had on other vans.
Other users are finding the overwinter Solar capabilities a worry, no wonder.

I have had 80w solar panels in 3 AS Van's charging my batteries adequately via Sargent systems for 13 years. The AS supplied system up to 2014 is fit for purpose with an 80w panel.

The 30w panel supplied to maintain the vehicle battery was also capable of meeting it's intended objective.

The solar smart charging in the EC500 and 700 (whatever size of solar panel) has an Achilles heel and is best switched off.

If unsatisfied with the solar charging of the EC500 or 700 it is best to disconnect solar panel from Sargent psu, replace single channel solar controller with dual channel (cheap basic will do) and connect it to both batteries.

This will give optimum solar solution for both camping and storage.

Peter

Yes abandoning the EC700 connection is becoming the general consensus on this thread.
With my method I also abandon PWM for the Leisure Battery, MPPT is much better at using the power available. It also leaves the van untouched re Warranty in these early days. Also I have complete control and flexibility as to charger selection.

Do you know what the Achilles heel is. I suspect losses in the solid state switching, hence the Battery does not see the Controller voltage output.

I expected to come to the sun as in other years but with a new van with a larger solar panel and be totally self sufficient. 
I should be relaxing, not studying the daily charge characteristics. I must add though that although you can't always go by what owners say, the majority of marques are having problems with poor Solar performance and additional panels are being added all the time. A nice little boost for the local economy.

marconi wrote:Peter

Yes abandoning the EC700 connection is becoming the general consensus on this thread.
With my method I also abandon PWM for the Leisure Battery, MPPT is much better at using the power available. It also leaves the van untouched re Warranty in these early days. Also I have complete control and flexibility as to charger selection.

Do you know what the Achilles heel is. I suspect losses in the solid state switching, hence the Battery does not see the Controller voltage output.

I expected to come to the sun as in other years but with a new van with a larger solar panel and be totally self sufficient. 
I should be relaxing, not studying the daily charge characteristics. I must add though that although you can't always go by what owners say, the majority of marques are having problems with poor Solar performance and additional panels are being added all the time. A nice little boost for the local economy.

An update on this subject.

First there are some errors in the above quote due to. 1) Sensible expectations. 2) Lies by the supplying Dealer.

1) Sensibly one would expect a PWM Controller in a 2019 Nuevo not a Two Stage Controller which comes from the age of the Dinosaurs and are notoriously inefficient. The Nuevo uses a Sargent Two Stage Controller.

2) I asked the Dealer and was told that, yes everything is modern digital touch control with Solid State switching. The EC700 uses Relays (not Solid State lossless switching), again ancient technology, to control the 'intelligent' Battery Charging and I suspect to Enable the Lighting circuit, 12Volt circuits, Sockets and Water Pump (Has anyone got a circuit diagram). These Relays will be energised 24/7 whilst the 'van is in use, so consuming precious Solar power.

On return to weak sun and cloudy skies the A-S Solar charging spent more time actually charging the batteries in line with my observations. The Solar charge was as always quite feeble but bizarrely the more sun the less charge the batteries get.

I have disconnected the Sargent Controller and completely bypassed the EC700. I now use an MPPT Controller and although it is early days (still testing), both batteries are seeing charging voltages and charge levels never seen before. The A-S set up merely managed Battery destroying partial charge levels.

I can additionally use my Auxiliary 100W Solar Panel in times of high demand with its MPPT Controller in parallel with total success.

Finally the 80W Solar Panel is quite efficient, something the Sargent controller cannot deal with.

Sorry I missed you post on 18th Feb, I was commuting to the NEC that week and focused on other things.

The 'Achilles Heel' that was introduced with the EC500 and is perpetuated in the EC700 is the Sargent implementation of Solar smart charging.

When on hook up with a constant energy supply 24 hrs a day that smart charge circuitry is capable of keeping both batteries charged whether the van is being used or stored although, in my opinion, the Battery Master solution is more efficient.

When looking to use solar panel whilst camping in the van with either the EC500 or EC700, the Sargent smart system can choose to charge the vehicle battery for the 4 hrs that the most solar efficiency is available to the detriment of charging the leisure battery such that, for example, a leisure battery that could be expected to supply your need for 6 days with solar support can only do so for 3.  Bearing in mind that the vehicle battery will probably last for 3 weeks with no charge even with tracker et al attached its best to switch the solar smart charging off and direct all solar charge to the leisure battery.  If a Battery Master is fitted then the vehicle battery will be charged as well but not to the detriment of the leisure battery.  In storage the scenarios are different and also different between EC500 & 700.

Indeed they are. It would be nice to see a circuit diagram if only for the comedy.

It would be wise to use an de-energized relay to select the battery to charge during storage, I am not sure that it is.
These vans are made to drive from one EHU to another so that charging is available 24/7.

marconi wrote:

It would be wise to use an de-energized relay to select the battery to charge during storage, I am not sure that it is.

For all of the Sargent systems, they recommend switching off the system during storage without EHU and if that advice is followed, all relays are de-energised and no habitation circuits are powered.

Peter Brown wrote:

marconi wrote:

It would be wise to use an de-energized relay to select the battery to charge during storage, I am not sure that it is.

For all of the Sargent systems, they recommend switching off the system during storage without EHU and if that advice is followed, all relays are de-energised and no habitation circuits are powered.

Yes I seem to remember that being what they say. Then the EC700 is still powered and active despite the system being switched off, and with no solar input according to what I observe.

When the system is switched of, the EC700 itself is not active, any solar power is routed to the vehicle battery and a supply is maintained to the Sargent tracker/monitor system.

100mA is reasonable for the tracker/monitor and assuming everything else switched off and a usable capacity of 50AH the battery should last about 20 days that appears to be par for the course on these EC700 vans

Peter Brown wrote:When the system is switched of, the EC700 itself is not active, any solar power is routed to the vehicle battery and a supply is maintained to the Sargent tracker/monitor system.

Peter

That sounds like the statement from Sargent. Have you confirmed that.
 
It doesn't tie in with my experience of a relay pulsing on and off under certain conditions.

Caraman wrote:

3 years = 24,280 hours.  If the tracker is constantly drawing 100mA, the battery must have a capacity of 2,628 Ah!  I think the tracker's consumption is probably negligible and something else in the EC700 is causing the drain even though it is supposed to be switched off.  

Yes indeed.

100mA by coincidence is approximately the energising current of a Relay.

The 'Smart Charging' change over relay contact resistance specification, for a brand new relay, whether energised or not, represents close to the total generally acceptable maximum Voltage drop for a complete Solar installation including all cables connections and fuses.