A bit of lecky advice needed please.

[Pete-B]

Hi, I'm a bit of a lecky numpty so I would appreciate any help please.

 

On my new Bessie van I got my dealer to fit a 80w solar panel on the roof which runs into a regulator/charge controller. There are two outputs on this, one to the two 100A leisure batteries and the other to the engine battery with No 1 output having priority. I'm told this one charges whichever battery it goes to until it's full then switches to No2 and so on.

 

Because the van is going to be stood in storage over the winter months, apart from the occasional run out, I asked for the engine battery to be made priority which, they assured me, they'd done. They said I could also press the isolation switch on the Sargent PSU which would prevent any load from the leisure batteries.

 

So, why is it, that, whenever I've checked the voltage of the batteries on the Sargent unit or, the controller over the door, the leisure battery is always higher. A typical reading would be, leisure batteries 12.8v, engine battery 12.3v?

 

When the two cables come out of the regulator/controller they disappear behind the wall so I don't know which one goes where. So, my question is, how can I check, perhaps at the regulator, which cable goes where? I do have a multi meter although I'm not 100% sure how to use it properly, I know how to check battery voltage with it but amps and watts I'm a bit unsure.

 

Thanks in advance for any help.

[Agaric]

The 12.8v shows that the leisure battery is fully charged, but 12.3v shows the engine battery at roughly 60% charged.

 

I'd run the engine for a while to charge the engine battery, then leave it for about 6 hours then test it again if it still reads sub 12.8v in could be a duff battery.

[Tracker]

Pete-B - 2015-11-15 3:49 PM

When the two cables come out of the regulator/controller they disappear behind the wall so I don't know which one goes where. So, my question is, how can I check, perhaps at the regulator, which cable goes where? I do have a multi meter although I'm not 100% sure how to use it properly, I know how to check battery voltage with it but amps and watts I'm a bit unsure.

 

The voltage at the battery will be the it is at the ouput terminals of the regulator so if you can see the terminals check the voltage at each one and that should tell you which output goes where.

 

Be wary of disconecting as some, not all, but some regulators can be damaged if they have an input and no output load so if you need to change the wires over best to disconnect an input lead from the solar panel to the input side of the regulator taking care not to let the loose wire come into contact with anything whilst you work.

 

If you have checked your batteries with your multimeter then you do know how to use it!!

However just in case you got the battery voltages from a fitted voltmeter here is how to use your own multimeter to measure voltage.

To use a multimeter for voltage checks, switch it on, turn the dial to the correct range usualy 0-20 volts DC, plug the colour coded probe leads into their respective colour coded sockets and apply the red lead probe to the red or positive side of what you want to check, the black probe to negative and read off the voltage. Switch off after use to conserve the inbuilt battery, although some will auto switch off if not used for a while.

[bolero boy]

normally on a swift/Bessie van with Sargent ECU there is an input socket up in the roof locker whoch can be connected directly to the output of the solar panel regulator. there should even be a gland already in the roof for the cable to come in.....

this then allows the Sargent box to ',manage the solar power to either engine or habitation batteries.

the PSU panel has a user interface to prioritise the charge routine, or leave as 'smart'.

[Pete-B]

Hi, Yep I do know how to check voltage but I'm not sure how to set multi meter to check amps!

[Tracker]

Pete-B - 2015-11-15 8:16 PM

 

Hi, Yep I do know how to check voltage but I'm not sure how to set multi meter to check amps!

 

Amps is a whole different wee beastie and getting it wrong can give you a wonderful display of flashing lights and smoke!

 

Most multimeters have a range of milliamps or low dc amps in a similar range to volts etc but for anything meatier there is often a separate socket to plug the probe lead into. Do you have instructuions for your meter? If not you may be able to look it up online?

 

To measure amps, unlike volts which is measured across the pos / neg terminals, current is measured inline.

That means, for example, disconnecting a lead from the battery and connecting one probe lead to the battery terminal that is disconnected and the other probe lead to the cable you have just removed from the battery.

The multi meter then forms part of the circuit and as part of the circuit the meter will read the current flowing through it.

Always start with the highest amperage scale available and work down and if in any doubt - don't do it as serious damage can occur if you get it wrong.

[Brian Kirby]

Pete-B - 2015-11-15 3:49 PM........................

So, why is it, that, whenever I've checked the voltage of the batteries on the Sargent unit or, the controller over the door, the leisure battery is always higher. A typical reading would be, leisure batteries 12.8v, engine battery 12.3v?.................................

If you are checking the battery state during daylight hours, you are probably seeing the output voltages from the solar controller and not the true battery state. Why one should be higher than the other I don't know, but might the solar controller have a maintenance output to the starter battery, and a higher output to the leisure battery? Do you have manuals for panel and controller?

[Pete-B]

Hi, Brian,

 

No I don't have any manuals but I did ring Solar technology today and asked their advice and basically the answer was, apart from a load scientific mumbo jumbo, if both lights are showing green don't worry but ring back if things change.

[aandncaravan]

Not sure how you have the Solar Panel and regulator wired but the manufacturer recommends it goes through the Sargent controller, such as an EC500?

 

If it is wired thus the drain on good habitation batteries in storage will be minimal.

 

The drain on the Starter battery will be higher because of the Engine ECU and Alarm always in part operation mode, so drawing power.

Under these conditions, the Sargent will detect that the Habitation battery is full and put a decent charge to the Starter battery.

It shouldn't charge the habitation batteries if they need none.

 

I am therefore puzzled as to why the Sargent seems to have been bypassed, with the Solar Regulator deciding the charging priority and, according to your description, it's 'two outputs' going directly to the two different battery banks?

This is against the power distribution manufacturers guidelines and may confuse the Sargent power unit. Potentially affecting its ability to work out the percentage of power left based upon the charging/discharging algorithms. It may also compromise it's ability to 'see' the real battery voltage as opposed to the voltage at the battery of the Solar regulator? It may not, I don't know, but isn't it safer to have it wired as recommended by the people who do know?

 

If the Sargent EC doesn't 'know' about the charge going into the battery directly from the Solar regulator will it give false readings? What will it do when it sees the battery voltage rising as a result of the charge directly to the battery when it 'knows' that the charging systems it controls are inactive?

 

Maybe I have misunderstood how it is wired up, but the Sargent has a Solar icon that tells you the amount of Solar charge, I don't understand why anyone would bypass this?

 

A point worthy of note is that the Dealer advice on operation might be flawed?

 

If a Solar system IS installed as advised by the manufacturer, you should leave the 'shutdown' button ON for the system to operate intelligently. Otherwise the system will not charge the Starter battery.

 

Maybe there has been a misunderstanding and it has been wired as designed, and does go through the Sargent, all you need to do is ignore the Dealer advice?

 

 

The Sargent manual says :

 

The EC500 PSU incorporates a built-in solar charge management feature, which will control the input from a solar panel (when fitted, maximum rating 120W). Depending on the charge state of the batteries, the solar power will be directed to the required battery, and continuously monitored to ensure optimum operation. For this system to operate intelligently, the shutdown button should be left

switched on.

If the shutdown button is turned off then the solar panel will charge the leisure battery only.

 

 

 

[aandncaravan]

Just in case it isn't wired as recommended (either for you or other readers of the post) and you want to change it on an Ec500. Then you only need a single battery output Solar Regulator connected to FX 1 (Solar Reg positive +) and FX 2 (Solar Reg negative -).

 

As already stated above the Sargent default setting will be the SMART option which decides the battery bank charging itself.

However, you can use the display to manually set it to charge only the Starter battery, or the Habitation battery only.

 

The manual states :

SMART – This turns on the solar smart charging feature. When a solar panel is fitted the

energy from the panel is automatically directed to the vehicle or leisure battery according to

the charge state of each battery and the operation of the mains battery charger.

SMART is the default setting.

LEISURE – This setting will cause the energy from the solar panel to be directed to the

Leisure battery only.

VEHICLE – This setting will cause the energy from the solar panel to be directed to the

Vehicle battery only.

 

[Pete-B]

Not being a techy I become more and more confused on reading these posts?

 

Perhaps I didn't explain the layout properly. The cable from the solar panel goes directly into a regulator/charge controller unit, this item is supplied by the manufacturer who supplied the panel. From this, one cable runs to the two leisure batteries and the other to the engine battery with No1 output (engine battery) having priority until this battery is charged. Once charged the power will then switch to the leisure batteries and when they are full will monitor both lots and float charge as necessary (or so I'm told). This unit does exactly the same job as the Sargent one which my dealer and also the panel provider were not very complimentary about. But when I'm on EHU the power reverts to going through the Sargent unit.

 

Hope this is clearer!

[aandncaravan]

 

Then I think I did understand it properly and it is not wired how the Motorhome manufacturer recommends?

I am not familiar with the Sargent Solar regulator so can't comment on it's capability, but you don't need to use a Sargent Solar regulator. It can be any Solar regulator.

 

However, it is recommended to connect the regulator so it passes it's power in to the Sargent Controller box which is designed to handle all the power distribution and charging. This Sargent box then decides how the power is distributed, not the Solar regulator.

The Sargent box already controls the Alternator and Mains 240v charging, if it also distributes the Solar charge there is less risk of any issues.

All the Solar charging, amps and volts, will also display on the Motorhomes Sargent display unit so you can track what is happening.

 

It is the way the Motorhome builder/Sargent designed it to work.

 

 

 

[Pete-B]

I don't profess to have a lot of knowledge about this, but, how is it that when Van Bitz fitted a solar panel on my last van they also wouldn't use the Sargent smart charger but instead used a Battery Master they wouldn't even use their cabling saying it wasn't man enough Also when I spoke of the Sargent unit in my last post I was meaning their smart charger not a solar one.

 

By the way my dealer also fitted a heavier cable on this one!

[aandncaravan]

If the Solar Regulator is installed in the correct place, right next to the Power Controller unit or battery with a short cable run of just inches, you don't need heavy duty cable. The skinniest 0.5mm/11amp cable would be sufficient as the voltage drop will be virtually zero over a 12" cable run plus an 80w panel will only deliver a few amps, within the current rating of thin 11amp cable. The cable from the panel to the reg will be carrying about 21v so even a couple of volts drop will result in a very adequate 19v hitting the regulator. We would not recommend 0.5mm cable is used, but it does not need to be heavy duty.

 

The boxes you refer to as 'Sargent smart chargers' are Power Distribution and power Controllers that also charge a battery. They are very capable units that are very sophisticated with functionality often not understood.

 

It seems like maybe you are suggesting that these companies are very accomplished and we know little, which may or may not be true.

However, on the 6th November 2015 Ian Stracey contacted us (like many others) because his Solar Controller was wired direct to the battery, not through the power Controller. He recently wrote,

"I would like to thank you for all your advice regarding solar panels.....

I have had the new controller wired as advised by the manufacturer from early September and am amazed by the improvement in performance from the old unit installed by my Motorhome dealer.

Even in the recent poor weather both leisure and chassis batteries are maintaining full charge and I rarely need to use hook up unless using a lot of electric heating. I am really very grateful and well pleased. The cost of the controller was quite high (at £69) but boy was it worth it".

 

We are just trying to advise you that the way it is wired is not the way the manufacturer of either the Motorhome or the power Distribution system would recommend (which may affect warranty if things go awry?).

 

That it is not working as well as it might, could be a reason to take a step back?

 

For anybody else reading this thread who wants to assess how good their Solar Installation is, have a look at where the solar panel wiring comes into the vehicle? There should be a safety fuse, is there?

 

It is standard UK practise to put a fuse on any cable as soon as practically possible close to the power source before it takes power to any device. The Solar Panel is a power source, with the current potential to melt cables and cause fires.

A Solar Regulator is an electrical device, which if it shorted could cause a fire. Yet we have never seen a professionally fitted Solar Panel with a safety fuse up near the roof where the cables usually enter the vehicle.

 

Mr John Ingle has 4 x 120watt panels. That is the potential to throw over 30amps into his Solar Regulator if it shorted, a real Fire hazard. That many Solar regulators are mounted inside a lovely wooden based cupboard with lots of flammable plastic around doesn't seem to ring any alarm bells.

 

The Solar Installers almost always fit a fuse after the Solar regulator and before the battery, which is clearly designed to protect the regulator from the battery, so they understand the Electrical issues and the practise. But just don't see the Solar Panel as a 'Power source'.

Leaves us astonished every time we see it.

 

I am pleased to say John Ingle, is currently correcting several poor points on his Solar Install. Hopefully at the end of it his Solar gain will increase as well as being a lot safer.