Batteries drained

I was surprised when the chap taking us through the handover in 2019 talked of our van needing to be on EHU when parked at our home. He may have said it needed EHU once a week but I don't remember. I was surprised because the 69W solar panel I fitted in our 2003 Duetto kept both batteries fully charged even in the winter months without the need for EHU.
Before I did any modifications to our Kemerton XL I was disappointed with the relatively low battery voltages at home. Green field camping without EHU, such as being at an ASOC meeting soon showed how limited our TV viewing would need to be.

Forum members have been very helpful in identifying the shortcomings of the Sargent EC700 system, with no modifications a modern A-S van has been designed to need EHU. You should be able to managed 24 hours of camping off-grid, somewhat more if you don't watch TV. Parked at home I think the advice I was given at the dealer was probably about right. Even with an 80W solar panel parked at home it needs a bit of EHU from time to time. When our Sargent EC700 system is on, the standing current is around 250ma, 6 amps used in 24hrs, that's a significant amount required from a solar power each day, without you even living in the van.

I fitted a second 80w solar panel (160W total), both solar panels are independent of our van's Sargent system as is the Votronic Duo Dig solar controller. At home I have the EC700 powered off, so have this potential extra 6amps to charge the batteries if they need it, which is nice.

I haven't read enough reports on here of owners of newer A-S van that have the lithium battery, a start-stop engine with "smart" alternator, and possible B2B arrangement. I wonder how these owners manage camping off-grid.

I agree, A/S do seem to have designed the recent vans assuming that EHU will be used onsite. 
On the other hand are we giving them too much credit in saying they actually thought about the design rather than just creating an electrical Frankenstein monster which sounded great on paper by people who have never tested the system in a real life situation?

Yes carman. I'm not a technophobe but I naively assumed a brand new campervan with PV and modern kit would deal with being off EHU. I note the advice on additional PV but I'm not keen on drilling through the roof. That and the crap LPG "guage" are particularly disappointing. Oh and a decent sound system that only works with the ignition on.

But how many dealers actually know about such technical things?

Like buying a new car, salesmen are salesmen, technicians, but I could be wrong.

On our Duo handover, almost all the time was spent on showing me how to link my mobile to the van, same as when we bought the Fiesta. Still wondering how it links up!
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Richard

 but just had my Grandson round to take his 50 year old VW Beetle out for a spin in the sunshine and it started first time. Has been in our garage since October last and I have not charged the battery or anything else and first time he has looked at it.
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Richard

I had battery drain problems when I first had my W> Duo. Finally traced the drain to a water tank blanket heater which had been left on by the dealer. Keith

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2 x 80 panels with mppt controller wired directly to batteries ref modified .this will keep the batteries fully charge all year round and will help the batteries last a much longer life.when people have to keep putting the batteries on charge to bring them back to full charge and have gone below 12.0 volts make the battery life much 
less .so lots of people post about flat batteries on here but has any person that has done the mod to the ec500 or ec700 had problems after.I have space to put a 3rd 80w panel but the 2x80w has work great for now but I am looking at running my fridge off the 12v as can be done with the mppt controller I have fitted

Looks good glyne, did you fit this yourself? I would rather use a pro who knows what he's doing than mess about with this myself.

glyne lock wrote:[You must be registered and logged in to see this link.]
2 x 80 panels with mppt controller wired directly to batteries ref modified .this will keep the batteries fully charge all year round and will help the batteries last a much longer life.when people have to keep putting the batteries on charge to bring them back to full charge and have gone below 12.0 volts make the battery life much 
less .so lots of people post about flat batteries on here but has any person that has done the mod to the ec500 or ec700 had problems after.I have space to put a 3rd 80w panel but the 2x80w has work great for now but I am looking at running my fridge off the 12v as can be done with the mppt controller I have fitted

I did the mod on Duo some 18 mths ago and never had a battery problem since and no EHU.
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Richard

Victor Johnstone wrote:Looks good glyne, did you fit this yourself? I would rather use a pro who knows what he's doing than mess about with this myself.

Go for it, just research what is required and you will not look back. Votronic, which I used have a good installation guide.

Make sure when drilling the roof, you know where you will come out!! I got it a bit wrong.
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Richard

Victor Johnstone wrote:Looks good glyne, did you fit this yourself? I would rather use a pro who knows what he's doing than mess about with this myself.

Yes that’s my own camper but I do fit lots of solar systems for other people 
My own camper the panel was getting the sun blocked in the winter by the roof light as the panel was not fitted with the correct space below. I could not clean the roof the heat below the panel would have been very hot in the summer  so is the reason it’s fitted as it is to the roof rack .myself I want a solar system that will perform as it should do not just fitted for sales talk.with the mod as lots have now done with new wires from the panel to the mppt controller gives my camper good charge and my alternator will not have to work hard to charge the batteries as the solar system will have done this already.even if I should stay on a site and has ehu I don’t pay for that and the money saved is more then my solar system has cost myself

Victor Johnstone wrote:I would rather use a pro who knows what he's doing than mess about with this myself.

Likewise....I wish that it was easy or even possible to find one.

nice to see a panel fitted as to the space Ian .I use black cable and put red shrink wrap at the cable ends but cable ties are better then red tape .myself I don't like seeing the red cable the all black looks better. people say what size panels they want fitted and I say we will see what roof space you have first

Here's just a distillation and my opinions of some things I've learnt about A-S solar and my suggestions. Modifications of an A-S solar setup involve 2 stages, you choose, replace the solar controller as fitted from new, only after that's been done would I suggest you consider having additional solar panels fitted. If you just go for fitting an extra 40W panel (80W+40W) it's probably poor value.

Stage 1. Replace the original solar charge controller associated with the Sargent PSU with a more efficient solar controller that's independent of your Sargent PSU.
Older vans though
I believe that when A-S started to fit solar panels as standard the solar controller was a PWM type (Pulse Width Modulation), it was mounted at the rear of the Sargent PSU. Though older technology a PWM solar controller can do a reasonably good job and charge both batteries simultaneously. A-S initially fitted 40W solar panels, most now would view this size as rather too small. Replacing the 40W with 80W would be a modest upgrade. Perhaps a total wattage of 120W could be accommodated whilst still keeping within wattage and current limits of the PWM controller and Sargent's PSU circuit board. If you want to have more than 120W of solar you will need to have an independent solar control that's separate from the Sargent PSU.

Newer vans
Sargent went backwards I say and fitted instead a basic solar controller in a black or white plastic box that's is mounted close but separate from the Sargent PSU. The solar panel wires go into the basic solar controller and two wires positive and negative go to the Sargent PSU. The clever stuff, the Smart charging stuff uses a Sargent microprocessor to divi up the solar charge between the habitation and vehicle batteries. Perhaps it's a bit like teaming up a basic Robin Reliant to be driven by the smart Lewis Hamilton (on one of his poor days). A modern MPPT controller is more like a Ferrari in comparison to having a Robin Reliant. Also with the Sargent system you have to keep paying Lewis Hamilton's wages to keep him driving the Robin Reliant all the time.

A worthwhile first modification yet still keeping your existing 80W solar panel is to fit (or have fitted) a separate solar controller such as a Votronic Duo Dig or an Epever DuoRacer, each has its individual merits, the Votronic small, the Epever has an App. They are more efficient than a PWM controller, and much more efficient that Sargent's Robin Reliant of a basic solar controller that Auto-Sleepers fit. Both vehicle and habitation / leisure batteries will receive solar power without the need for the current hungry Sargent PSU to be powered up. One unfortunate is the fridge, it needs only 30ma of power to work its electronics, go out for the day when camping on a green field site off-grid and you'll need to keep your Sargent PSU on with its 200ma consumption just to deliver the 30ma the fridge needs. Thank goodness Sargent didn't design the Apollo 13's electronics.

Stage 2. Add solar panels
Mostly fixed on your roof, but you could have a system where you connected a folding solar panel in with your MPPT solar controller based system.
Sargent has a 120W limit on what their circuit board can take. With a standard 80W panel the max of solar you can add is a 40W panel, hence the importance of going for a stage one upgrade and having a solar controller independent of the Sargent PSU. I fitted an extra 80w solar panel which I would not have been able to connect up if I had kept using our EC700 system to control our solar charging. I fitted a Votronic Duo Dig 250 by the way.

Edit: correction Epever DuoRacer

Though I suggested incorporating a folding solar panel in with your existing MPPT, I did come across on the web a RV solar system involving two solar controllers. It is probably OK to connect direct a folding solar panel with it's own built-in solar controller to charge the battery of your choice, vehicle or leisure. This arrangement would probably be no different than having two solar panels wired in parallel. I would not be surprised if there are Forum members who already do this.

Relaxez-Vous wrote:This arrangement would probably be no different than having two solar panels wired in parallel.

The significant difference between wiring two panels in parallel and wiring two solar controllers in parallel is that there is nothing in a solar panel that senses battery voltage.

If you connect two solar controllers to one battery, the output from one controller will inhibit the other - in effect the battery voltage will appear to be too high to one controller because of the output of the other. Exactly how they will behave is hard to predict due to small variations in component values, but it's likely that one will "win" and provide most of the charging power to the battery, and the other will "lose" and do very little.

The only "correct" way to deploy two panels to one battery is to connect both panels to a single controller.

However... there is nothing to stop you connecting one controller to the leisure battery and the other to the vehicle battery - that should work just fine under almost every circumstance (except when the two batteries are connected via a split charge circuit - which isn't very likely in this situation!).

Roopert wrote:

Relaxez-Vous wrote:This arrangement would probably be no different than having two solar panels wired in parallel.

The significant difference between wiring two panels in parallel and wiring two solar controllers in parallel is that there is nothing in a solar panel that senses battery voltage.

If you connect two solar controllers to one battery, the output from one controller will inhibit the other - in effect the battery voltage will appear to be too high to one controller because of the output of the other. Exactly how they will behave is hard to predict due to small variations in component values, but it's likely that one will "win" and provide most of the charging power to the battery, and the other will "lose" and do very little.

The only "correct" way to deploy two panels to one battery is to connect both panels to a single controller.

However... there is nothing to stop you connecting one controller to the leisure battery and the other to the vehicle battery - that should work just fine under almost every circumstance (except when the two batteries are connected via a split charge circuit - which isn't very likely in this situation!).

fitting more then 1 controller to a battery bank does work and is done a lot on large rv with lots of panels .I did check this out with a top brand controller company and they said its ok and will work ok. i did not think it would work so I asked .I fitted 3 controllers and lots of panels and yes I tested the controllers and they all worked. I would say check with the controller manufacturer first that you are going to use

glyne lock wrote:I tested the controllers and they all worked.

Of course they all worked. I didn't say that they would not work. The problem is that they will almost certainly not all be providing equal input to the battery. But externally they will appear to be working just fine.

If you want all of the panels to be providing equal input to the battery, they need to be on the input side to the controller, before voltage regulation.

The core of the problem is this: in order to "understand" the state of charge of a battery, the controller has to be the only device which is raising the battery voltage above its rest state. If multiple controllers are all trying to do it at the same time, they will not measure the state of charge correctly.