How do I connect a solar panel to my Sargent EC500 power control unit?

[RustyRuss]

OK boys n girls I’ve been looking into solar panels and the kit needed to make them charge Bob’s (our MoHo!) leisure and vehicle batteries whilst parked up and drinking grape juice! ? I have seen many videos and came across this technical bulletin from Sargent which suggests that all I need is a solar panel and it will wire straight into the back of the EC500 psi at terminals 1&2. Can any of you confirm that this is indeed the case? Also can you recommend the max size of panel I should get and any other hints n tips you’ve encountered. Thanks in advance!

Stay safe!
Russ

 

[tonka]

Yes. 100% did it on my past van Apache 700. Sargent sell the lead that you need.
The ec500 will accept up to a 120watt panel, it also has built in smart charge facility and will do both engine and leisure batteries. Some people will slag it off but it works fine and did me ok for 6 years.
Always recommend to fit a second battery first

Have a read up in the solar section and you will gain a lot of info. Most items you can get off eBay etc.

 

[PhilandMena]

Agree with above. A factory fitted solar regulator was fitted to mine (rated at 10 Amp)and just a case of making the connections. I have since left mine in situ and fitted a 10 Amp MPPT regulator.

 

[RustyRuss]

Thanks guys! Phil you fitted an Mppt? I’m aware of what they are, wiring diagram or a sketch or “connect terminal 2 on the psu to terminal 12 on the mppt with 4mm cable” verbal instructions would be really useful. Also where did you buy your 120w panels from? Are Chinese ones ok? I have to say I would prefer to deal with a uk company (even if the panels do actually come from RPC) from a warranty and fault find/contact point of view. Thanks again for your input and any further replies n posts will be much appreciated!

Cheers!

Russ

 

[Spanner]

Our van has the Sargent EC500 fitted and it never managed to reliably share the solar power between the leisure and vehicle batteries, despite the “Smart” setting within the control panel set to on the vehicle battery was often below 12 volts while the leisure batteries were kept fully charged.

I now have a 160 watt panel feeding a Victron MPPT controller connected to the leisure batteries and a genuine “Battery Master” which keeps the vehicle battery fully charged every day without fail.
As the Sargent EC500 has a 24/7 parasitic drain I leave the EC500 switched off when the van is not in use.

The Sargent EC500 always keeps both sets of batteries topped up when on the mains hookup.

Chris

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[RustyRuss]

Chris thanks for your reply. Any chance you could draw a wiring diagram, photograph it and post it to this thread? Wiring sizes would be very useful too! Hope I’m not being a pain! Thanks in advance,

Russ

 

[PhilandMena]

Thanks guys! Phil you fitted an Mppt? I’m aware of what they are, wiring diagram or a sketch or “connect terminal 2 on the psu to terminal 12 on the mppt with 4mm cable” verbal instructions would be really useful. Also where did you buy your 120w panels from? Are Chinese ones ok? I have to say I would prefer to deal with a uk company (even if the panels do actually come from RPC) from a warranty and fault find/contact point of view. Thanks again for your input and any further replies n posts will be much appreciated!

Cheers!

Russ

If it was me, I would fit a 150 W solar panel. The solar regulator is rated at at 10 Amps and using a 150 or even a 180W solar panel would not exceed 10 Amps regardless of what the maths show. (You will never get the 100% output quoted. (The best I can get from my 125 W S.P. is just over 5 Amps and it needs to be an exceptional day too). Try these guys for both your solar panel and MPPT Regulator. Very good quality with a good reputation. As for wiring instructions its easy peasy. Have a look on U-Tube too.

If your sticking with your 120 W S.P.

https://www.photonicuniverse.com/en...nels-up-to-130W-12V--260W-24V-up-to-100V.html

Otherwise

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

Solar Panels

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

Instruction Manual for Regulator.
<Broken link removed>

 

[Spanner]

Chris thanks for your reply. Any chance you could draw a wiring diagram, photograph it and post it to this thread? Wiring sizes would be very useful too! Hope I’m not being a pain! Thanks in advance,

Russ

You can’t have too much solar power !

In the real world no panel produces the quoted output, for example the highest output I’ve seen from our 160watt panel is around 7.5 amps in clear sunny conditions at midday and in poor conditions less than 1A
If I was in your position I wouldn’t route the solar panel wiring through your Sargent EC500 also you would then be restricted to 10 amps maximum.
Have you measured up the available space on your roof to fit the largest panel or panels? also consider if in the future you may want to leave room to fit a satellite dish etc.

 

[RustyRuss]

Well boys n girls I’ve fitted the solar panel. I got it from a supplier in Blackburn, Lancashire. The 120w panel, plastic brackets, grommet box and 4mm 5metre long cables cost £125.

I opened up the Sargent EC500 Power Supply Unit and found that it already had a separate black plastic control box in it for the solar panel. (See black box in upper part of the photo) This had a lit orange LED by a picture indicating a half full battery. There was also a picture for a full/charging battery with an unlit orange LED by it, of which more later.

I attached the panel to the roof with a tube of polyurethane glue/sealant, drilled a 40mm hole in the roof by the T.V. Antenna which is immediately above the EC500 and dropped the wiring through the grommets and sealed the grommet box to the roof with the polyurethane glue. I didn’t connect the extra cables to the terminated flying leads on the solar panel at this stage as I didn’t want to get a shock from the panel whilst wiring it into the EC500.

The black plastic control box on the EC500 had pictorial terminals marked on it for the solar panel + & -, it also had a flimsy pre-wired connector with a red & a black wire attached to the two terminals. The other two terminals were pictorially marked as a battery with + & - signs, these were/are factory connected to terminals on the main EC500 using orange/white trace and white/orange trace wiring and a factory fitted plug/socket marked “solar reg”

I removed the flimsy red & black wiring from the black control box and connected up the, suitably shortened, +ve & -ve wires from the solar panel to the black control box.

I covered the solar panel with the cardboard box it came in, then connected the flying leads from the solar panel to the leads I’d just connected to the black control box in the EC500. (I checked the voltage from the panel using a multimeter before doing this and I was getting 22volts DC with strong sunshine. Hence my earlier caution!!)

I removed the box and went back to the EC500. The orange LED, indicating battery charging, was now the one that was lit. I had previously noted at the EC300 control unit above the habitation door on our Autotrail Apache 632 that the leisure and vehicle batteries were both “good” with 12.7v and 12.5v respectively. They were now showing voltages fluctuating between 13.4v & 13.9v and 12.8v & 13.3v respectively. The weather yesterday was a mix of bright direct sunshine & clouds, the voltages varied up and down for each battery, but never dropped below 12.8v for the leisure and 12.6v for the vehicle battery.

I am sure that the black plastic control box is a PMU type controller and could be replaced by an MPPT type, which is/are allegedly more efficient, but room inside the EC500 is at a premium!

So it looks like job jobbed!

Hope this helps others! You carry out any and alterations to your vehicle completely at your own risk, I won’t take responsibility for your own cockups!!

Cheers! Russ

 

[PhilandMena]

That's it ! Job done!

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[autorouter]

I didn’t connect the extra cables to the terminated flying leads on the solar panel at this stage as I didn’t want to get a shock from the panel whilst wiring it into the EC500.

You won't get a shock from a single solar panel. Every panel I've seen has been below 50V, which is the point where it starts to become dangerous.

Multiple panels in series is a different matter. House solar arrays usually have panels in series, maybe half a dozen in each string, so the voltage can be 200V or more. Now that is dangerous, especially working on a roof.

 

[Revolvor]

Multiple panels in series is a different matter. House solar arrays usually have panels in series, maybe half a dozen in each string, so the voltage can be 200V or more. Now that is dangerous, especially working on a roof.

The input to the inverter from the panels on my roof is 380 VDC. As you say VERY dangerous. That is 14 panels in series.

 

[pengy]

Hi folks

Just found this old thread and hope someone will notice a new message! A guy has fitted a100w solar panel onto my Autosleeper Kingham, and fed the wire into the EC500. But - nothing is getting to the battery, and nothing is registering on the EC480 panel; he's baffled. Any thoughts? I'm wondering if there's a common problem encountered when connecting? Thanks!

 

[tonka]

Hi folks

Just found this old thread and hope someone will notice a new message! A guy has fitted a100w solar panel onto my Autosleeper Kingham, and fed the wire into the EC500. But - nothing is getting to the battery, and nothing is registering on the EC480 panel; he's baffled. Any thoughts? I'm wondering if there's a common problem encountered when connecting? Thanks!

Has he enabled the solar on the panel. ?? It may be set for EHU only and solar turned off. You want it on smart charge.
Did mine DIY worked fine in all the time I had it.

 

[pengy]

Thanks for your quick reply! He's tried it with solar set to 'smart' and also with solar set to 'leisure'. Nothing on either. The overall setting is for smart charging, so I'm guessing it's not that? He did mention a green flashing light, but I'm not sure where that actually is.

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[autorouter]

He did mention a green flashing light, but I'm not sure where that actually is.

Looking at the photo in post #9 of this thread, the solar controller is hidden inside the EC500 box and is not visible when everything is fully installed. The solar controller has LEDs on it, so I guess one of those is the green flashing light.

 

[pengy]

Maybe... he did mention that he'd installed a new regular, so I'm wondering if that could be part of the problem? Maybe if no connections are made to the one in the EC500 it won't work?

 

[RustyRuss]

You need to connect the solar panel +ve & -ve to the mppt regulator/ solar charge controller and then connect the mppt regulator/solar charge controller to the EC500, follow my “how to” in post #9 above for the exact terminal connections. Then go to the control panel above the door of your MoHo and check how to programme how much % charge each battery gets before the the “brain” in the EC500 swaps over to the other battery, it will swap continuously until both batteries are fully charged and then it will maintain them until there is a significant drain on one of them, and of they’ll go again. My Autotrail Apache already had the solar charge controller installed within the EC500, but it may have been installed by the previous owner.....

Hope that helps!

Cheers!


Russ

 

[pengy]

Hi - thanks for your reply. I had found your description and photo, they are very helpful, and I'm sure have helped a lot of people!

Thankfully I had a phone call about half an hour ago to say that it is now working! It is wired into the 'black box' within the unit.

I hope it's now as trouble free as yours seems to be. Collecting the van tomorrow

Yvonne

 

[RustyRuss]

Hi Pengy, "the black box" is the solar panel controller, does everything it says on the tin! Have fun with your new MoHo, Check the control panel above the hab door and you should find, by scrolling through the options using the up and down arrows, that your vehicle and leisure batteries maintain anything from 12.5 ish to 14.5 ish volts, they will fluctuate all over the place, what this means is that the controller is charging one or other of the batteries.

Cheers!

Russ

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[pengy]

Hi Pengy, "the black box" is the solar panel controller, does everything it says on the tin! Have fun with your new MoHo, Check the control panel above the hab door and you should find, by scrolling through the options using the up and down arrows, that your vehicle and leisure batteries maintain anything from 12.5 ish to 14.5 ish volts, they will fluctuate all over the place, what this means is that the controller is charging one or other of the batteries.

Cheers!

Russ

Thanks, I am looking forward to finally getting out and about.

I was pleased this morning to see that even with thick cloud and heavy rain there was still 0.6 amps registering on the panel above the door!

Yvonne

 

[RustyRuss]

Update time....

I wasn’t happy with the 120w solar panel I’d installed, as over the winter of 20/21 whilst in outdoor storage, both vehicle & leisure batteries failed to stay above 12.5v and indeed they both ended up at around 4.5v!! Effectively deep discharged and dead. In the spring I was lucky enough to win a Lithium ion battery in a MoHoFun competition (still cost me £300ish but much better than £700 list price!) I thought I’d better get on top of this so I bought 2 more solar panels. I was careful to ensure that the open circuit and charging voltages were very close to my original panel, this is because the panel with the poorest characteristics becomes the lowest common denominator in terms of output, this is too Techy for me, I took it as read and went with advice from here and from various solar panel suppliers. I installed the new panels to the roof and using the wiring supplied and some extra proprietary waterproof connectors joined them up in parallel.
I had disconnected the terminations at the Sargent EC500 control panel first, I had also bought an Epever dual battery MPPT 20amp controller, cost about £120. I wired from the Epever unit direct to both batteries using 6mm core heavy duty 2 core double insulated flex as per the instructions from the Epever supplier. I also fitted an inline 20amp isolator switch between the solar panels and the Epever unit.
So how does it perform?
Well bloody brilliantly TBH! I have the Epever unit set to 80% charge the leisure battery using the appropriate Li on settings, and 20% to the vehicle battery. Both batteries have consistently stayed at around 13-13.5v during the day even when overcast and howling down with rain. We’ve been off grid pretty regularly during the summer, we’ve just come back from 4 days at Oulton Park for the Gold Cup race meeting and both batteries maintained 13+v at all times.
I guess the proof in the pudding will be during the long dark nights and short days of winter, but all looks very promising so far!

Cheers!

Russ