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Solar Regulator


SJWBallistic

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Good Morning

I am seeking some advice on a topic of which i have little or no knowledge.

I own a 2011 Autotrail Savannah on the 3.0 Fiat Ducato cab.

We purchased the vehicle in January of this year.

We have had an on-going issue with the Sargent EC500 unit switching itself off intermittently. The panel was returned to Sargent for investigation and they replaced the two PCB and this was re-fitted on Friday. Upon returning home the same problem occurred so I contacted Sargent. They were extremely helpful and when advising them of the issue the 1st question was "do you have a solar panel fitted?" The suggestion was made that the panel was over folding and that the Sargent unit shuts itself down if a voltage in excess of 15 volts is seen.

 

I have disconnected the panel and all is now working correctly. I presume that the solar charge controller is at fault. It is a Chinese C1210 which looks to be cheap and cheerful.

 

My question is what type of replacement should I be seeking?

 

Thanks in advance of your replies.

Stuart

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It is not an uncommon issue for the budget Solar regulators to not regulate the voltage at all well.

 

We saw one in May that was putting out 16.9v and the cause of several issues.

 

We think the best is the Votronic MPPT range, see here for details :

http://www.aandncaravanservices.co.uk/solar-power.php

 

I would guess that a MPPT 165 installed correctly will harvest twice the power your old one delivered.

 

 

 

 

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I can second the advice Allan has given above regarding the Votronic 165 MPPT regulator. Took that advice myself to replace a Vision Plus standard regulator and what a difference. I also took the opportunity to fit the temperature sensor which may have proved a wise move during these recent weeks........

 

David

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The Votronic MPP 165 is a MPPT solar regulator which 'loads up' the Solar Panel to draw maximum power from it, as all Solar regulators do.

However, on some regulators this can result in the Solar Panel voltage dropping below 12.7v and so no charge will take place, even if the Solar panel has 2 amps available it won't charge the battery.

Obviously the charging voltage must be higher than the battery voltage and, ideally about 2 volts above the battery voltage.

So if a solar regulator has loaded up a solar panel so much that the voltage drops below 13.0v then the charge rate will be either non existant or very low.

 

The Votronic varies and controls the load on the Solar Panel to ensure the charging voltage is the optimum for the battery, effectively using a 'minimum voltage' to operate.

 

Is this what you mean by 'low voltage cut off'?

 

 

Or are you referring to the Generic Solar regulators (not designed for motorhomes) that have only a single battery output, not the dual battery of a motorhome solar charger, but do have an additional 'Load' output for powering Lights, etc from the battery.

On these regulators, which are usually less capable Solar chargers, a minimum voltage value can be specified upon which it disconnects the load from taking power from the battery?

 

 

If you mean the first then it is a valuable asset that can harvest up to 30% more power in typical UK low light conditions.

 

If you mean the second, then I would suggest any 'Solar regulator' with such a feature should be avoided as they are typically poor quality chargers designed for houses/buildings.

It always makes me chuckle when I see one of these, because the 'Load' output almost always uses a symbol of a 'Light Bulb' to signify the load when the last thing you will want to operate while the Sun is high in the sky is a light bulb.

.

 

 

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The low voltage cut off on the Votronic MPPT controller only operates on the solar panel input voltage (not the battery output voltage). As Allan had said, the solar regulator will regulator the output voltage and provide charge current into the battery only if sufficient solar POWER is available.

 

Even in overcast conditions, a solar panel will generate some VOLTAGE but very little POWER. In complete darkness, the solar panel will produce no usable voltage or power. This matters to the MPPT controller, as the controller will reset its charge sequence when the solar input voltage drops below the battery output voltage. As soon as the voltage rises again, it will start off another Main/Full charge cycle from 30mins up to 6 hours depending on the battery type setting.

In overcast conditions, the controller just stops supplying a charge to the battery. Since there is no load on the solar panel, its output voltage remains high enough to stop the controller restarting a main charge cycle.

The (minor) problem that I have found with the Votronic MPPT is that if you say drive through a tunnel and you are more than about 18 seconds in darkness, the controller restarts another main charge when you return into sun light.

 

Virtually all chargers and power supplies are design to only supply (or source) current. Very few are design to draw current if the output gets too high (they cannot sink current). This means that when two or more chargers are connected together (i.e EBL charger, Solar reg, alternator), the one that can supply the highest voltage will "win" and control the battery voltage.

This is probably what is happening in your case.

 

I am still surprised that you can get an excess of 15V on the battery unless the battery is not connected/faulty. Generally, you should not operate chargers with no battery connected to them.

 

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Thanks very much for your very interesting replies Allan and plwsn2000, I find all and every post regarding batteries and solar power most interesting.

 

Sadly though my own question was in relation to low voltage load cut off as mentioned in the second part of Allans response. So, embarassingly, my regulator does actually show a lamp on these terminals and Allan thinks it likely to be a poor quality charge controller for a motorhome and a bit of a laugh. I thought it was considered to be a good quality and versatile regulator when I bought it about 10 years ago when the choice was not as great as today and MPPT seemed to be in it's infancy. It was camparatively expensive at the time and still works very well in my opinion though it does only accomodate one battery bank. Fortunately that is all I want at the moment. The cab battery has never needed any additional charge above that provided by the alternator.

 

In order to prevent an accidental huge discharge likely to wreck a leisure battery by accidentally leaving something on or even a power hungry alarm, this function seems to me to be a very sensible feature. I just wondered if this facility was included on the Votronic MPP165. I have asked Votronic directly but have not received a reply.

 

The reason for my question is because I have considered replacing my current controller in the light of all the glowing comments regarding the Votronic but am still struggling to justify doing so considering the continuing seemingly impeccable operation of my existing one.

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dipsticks - 2018-07-31 7:56 PM

....

In order to prevent an accidental huge discharge likely to wreck a leisure battery by accidentally leaving something on or even a power hungry alarm, this function seems to me to be a very sensible feature. I just wondered if this facility was included on the Votronic MPP165. I have asked Votronic directly but have not received a reply.

....

 

No. The Votronic MPP165 will not disconnect your battery from the consumer loads as the battery is not wired THROUGH the regulator. You need some sort of switch between the battery and the loads to do this (the MPP165 is just wired to the battery and everything else that is connected to it).

 

I have an EBL223 that (sort of!) performs the function you require (this is called "Battery monitor with automatic disconnection" in the manual). Basically, the EBL223 will automatically disconnect the consumer loads if the battery voltage drops below 10.5V. The reason I said "sort of" is because at 10.5V, the battery is likely to be damaged if left for too long. It would be nice to be able to adjust the 10.5V trip threshold closer to 11.5V but this is not possible on the EBL.

Obviously the battery "switch" will need to be rated to withstand the full worse case battery current so will have to be a substantial relay/contactor.

 

 

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Dipsticks, we used to see many Solar set ups that the owners thought were working well, until they had them 'updated'.

On the Solar page is a genuine extract from an email -

" I have had the new Solar Regulator installed from early September and am amazed by the improvement in performance over the previous 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".

 

 

Typically, installing a decent, motorhome specific Solar charger following the manufacturers instructions can double the power harvested over older Solar regulators.

The MPPT 165 is advertised from £65, that isn't a huge sum.

 

That isn't me trying to 'get work' because we stopped doing Solar work a while ago.

 

Rather than try and find a compromised Solar charger with power shut off, you might be better investing in a specific Battery guard product like - Kemo M148A Battery Monitor Battery Guard Discharge Protection at around £17.

 

You can adjust the voltage at which you shut off the Alarm, or whatever it is draining the power, so it doesn't damage the battery.

 

Such a device, because it is independent of the Solar Charger, can be used on either battery.

 

 

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aandncaravan - 2018-07-31 9:13 PM

 

...

 

Rather than try and find a compromised Solar charger with power shut off, you might be better investing in a specific Battery guard product like - Kemo M148A Battery Monitor Battery Guard Discharge Protection at around £17.

 

You can adjust the voltage at which you shut off the Alarm, or whatever it is draining the power, so it doesn't damage the battery.

 

Such a device, because it is independent of the Solar Charger, can be used on either battery.

 

 

That kind of thing would work, but from its datasheet it switches the ground connection and not the +12V line. If any of your consumer loads are separately grounded, you would bypass the switch.

You almost want this device to drive a big relay that switches the battery positive.

 

Do you know of any other protection devices that switch the positive line?

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Many thanks again Allan and plwsm2000 it's kind of you to share your knowledge. After 10 years I have only recently learned of overcharging by solar by reading your posts. I thought constant solar charging just meant a lot of topping up !! I hope to have rectified that already by fitting a 12v, 7 day, programeable timer to disconnect the panels automatically when our PVC is not in use and to override manually at will.

 

Thank you for the information about the function of the EBL223 plwsm2000 something to look out for if we update our vehicle. My current regulator allows for low voltage disconnect at either 11.00 or 11.50v and respectively reconnect at 12.10 or 12.6v though I can change these voltages to whatever I wish and the regulator will switch accordingly.

 

Thanks too Allan I never heard of the Kemo 148A item before, that is worth knowing. I have to say I'm not particularly looking for a specific new regulator but rather to learn of the advantages I would gain (or loose) if I did replace the one I have which, as far as I know works perfectly well as far as its design can allow. I will be keen to update if there are any benefits which I likely don't know about.

 

I must say when I replaced my old PWM regulator with the MPPT I felt just the same as the customer you mention Allan, and I know you are not selling anything, only passing on your valuable knowledge.

 

All I am wondering now is what are the benefits of actual specific motorhome regulators apart from when there is a dual battery function which I feel I don't really need ? I do agree £65 isn't a huge sum but allied with changing it, and a meter, I would want too, at my age and state of health it adds up to quite a bit of work on top of the outlay.

 

I'm sorry if I hi-jacked your thread SJW Ballistic, my posts seemed to fit in and may well be useful to others in future.

 

Kind regards

 

Pete

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I didn't realise your 10 year old regulator was MPPT, that was advanced.

 

While a lot of Starter Batteries hold enough charge to start an engine, many can sit at under 30% charge for extended periods of time without the owner realising.

We have seen an otherwise healthy Starter battery start an engine when as low as 12.3v and down past 50% dicharged.

 

Obviously those situations won't be good for a battery.

 

Think of a high quality dual battery Solar charger ( not one of the overcharging generics, but a Motorhome specific unit) as a way of keeping a Starter battery optimally charged, and as a 'safety valve' for the habitation battery. I don't know if this works in practice, but I like the idea.

 

 

Because you already have an advanced regulator, there probably isn't much advantage in changing. However, if the Solar Panel is the same age it might be worth doing a load test to see how much capacity has been lost?

 

I like your system to prevent overcharging of the habitation battery which would also work for both batteries if you went that route.

 

One of the issues with the often used Victron Single battery Solar Reg paired with a Vanbitz Battery Master is that the Battery Master just passes the same voltage it picks up at the habitation battery, more or less.

This means that whenever the habitation battery gets a Solar14.4v (or 14.8v for an AGM habitation battery) that same voltage goes to the Starter battery, whether it wants it or not.

Along with all the other inefficiencies, that isn't a happy solution yet so often the 'professionals' choice. Shame.

 

 

 

 

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Thanks again for sharing even more useful information Allan and Phil. I have been reluctant to detail my existing equipment as I am aware that you are not a big fan of American equipment Allan. You have said in the past, it may be unlikely to be the most appropriate to use in this country.

 

Well I think it's fair for me describe it all as best I can now.

 

We have a Ford Transit based Campervan which was originally supplied to the converters with two batteries, specified as Starter Battery and Auxilliary Battery under the drivers seat. The starter battery is a Ford Silver Calcium and the auxilliary a Varta 90AH Hobby battery. This set up is, I believe mostly required when contractors such as Hydraulic Hose repairers and street lighting companies want to add hydraulic pumps etc to power on site equipment and hoists etc. In our case the converter used the auxilliary battery as the source of power for the Leisure/Habitation system that they added for the living conversion.

 

We wanted to set up the vehicle to operate off grid for as long as possible if not indefinitely in the brighter months. So on the electrics side we added 125W of solar panels, added another matching Varta 90AH Hobby battery under the passenger seat and installed a Morningstar PWM controller directly adjacent to the third battery in order for it to be in the identical temperature environment. I was guided at the time by the kindness of Clive Mott and Frank Bryant on MHF who were always very generous in sharing their extensive knowledge. Whilst I am a capable electrician my knowledge of Solar and Battery systems is close to non existant.

 

In 2007 the new set up worked flawlessly and has done ever since. We are not huge consumers of power but have used all we wanted to over the years and have never given the system a second thought nor worried about running out of power. I simply just topped up the Vartas 3 times a year, the Silver has hardly used any water at all. Surprisingly all three batteries still satisfy ours needs though I am sure that the capacity of the batteries will be quite reduced, hence my latest considerations and trying to make myself aware of the progress of battery and regulator design.

 

I studied the Ford system and made many modifications to the habitation wiring which I considered rather lacking. I found that the Ford system incorporated a bi-stable relay that isolated the 2nd (and third added battery) when the engine was off to ensure at least one battery could not be drained by anything connected to the auxilliary and therefore start reliably. When the ignition is turned on the relay changes and all the batteries (3 in my case) are engaged for starting and during engine running, all are used for other power hungry vehicle functions like heated windscreens etc. So really this is why I'm not too concerned that my regulator only charges one battery/bank.

 

In 2008 there was a lot of talk about the huge advantages of MPPT Regulators so based on the principle of expensive buys the best !! and an unexpected bonus payment I replaced the PWM regulator with a Morningstar Sunsaver MPPT the specification and flexibility of which impressed me. Well I was delighted with the performance and to be honest I still am. All of the parameters in the algorithms are adjustable by linking with a laptop via an interface I pushased with it, using the free Morningstar MS View software. As yet I have changed very little away from the Factory Presets but as I guess I will shortly act prudently and replace the 2 Vartas with LFD 90's or whatever Allan suggests when I do, I will need to alter the Float voltage at least to be in line with Allans suggestions.

 

Have a look at these videos if you are interested

 

 

 

So that's my predicament when I come to replace the batteries as they are surely about to expire; should I stick with the versatile and so far reliable Morningstar Sunsaver MPPT regulator or get a new Voltronic MPP 165 ? also, now as mentioned maybe the panels are getting tired. I used to be indecisive, but now I just can't make up my mind. Is it stupid to leave it all just as it is since it seems to work flawlessly and satisfies all our needs ?

 

I guess everyone is asleep now.

 

Pete

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Crikey can you say 'owt' today, Yorkshire day was yesterday ! (lol)

 

Thanks, that's nice to hear, me knowing little, am extremely impressed with both their products and their customer support which is very important to me.

 

Any question by email gets a number and clear response well within 24 hours and is not dropped until you say so.Very good in my opinion from the other side of the pond and considering the time difference.

 

I enquired by phone to Johnson Controls who make the Varta batteries and they said ask Votronic and when I asked Votronic the same question they said ask the Battery manufacturer. I have never had any such nonsense from Morningstar.

 

Without Allan at A&N I think we will all be doomed.

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  • 3 weeks later...

You're most likely not going to benefit anything going from Morningstar to Votronic. If anything you're possibly losing ability to customize charging parameters and log data. Although if that's the goal I'd go with Victron every time. Far superior in that regard.

 

The problem with Victrons, if you consider it as such, is no direct support for charging HB and EB at the same time.

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