Solar panel charging

[peterjl]

Hi

 

Well we have made our decision to change Moho to a new Globecar. The new one will have a solar panel which I haven’t had before sooooooooooo

 

On my current Globecar, In fact as far as I can recall on all the Moho’s I’ve had since early 2000’s, when I am plugged into mains both engine and habitation batteries charge. So if I have a solar panel will this charge both batteries? Is this What usually happens?

 

Peter

[aandncaravan]

Depends on the electronic charger/control systems already in the vehicle.

Have a read of this web page. It contains lots of advice, hints and tips -

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

 

[Deffheads]

Hi, surely if your buying a new Globecar motorhome the best people to ask about the solar charging is the supplyling dealer. We retro fitted a solar system that charges leisure battery until fully charged and converts to charging engine battery.

[peterjl]

Thank you both.

 

Yes I will ask the dealer but I like to do my homework beforehand as experience tells me dealers, however good, are not always right because of the various options available in the market.

 

Also I had just assumed both were charged then began wondering so came to this forum who have a

Ways been so helpful in the past.

 

I will read the article and be prepared. Thank you for the link Allan.

 

Thankyou

 

Peter

[Robinhood]

...as already answered, much depends on how any system has been implemented and wired.

 

I also wouldn't jump to too many conclusions since I believe you were looking at the "Summit" range, and surprisingly, the manual for these (downloadable from the German side of the Globecar site), implies that these use CBE electrics rather than Schaudt!

[aandncaravan]

Peterjl, the Solar webpages provide generic Solar Info, but if Robin Hood is right you can find lots of info on the CBE kit on the 'Wiring Your Own Camper' webpages. At the bottom of the webpage there are wiring diagrams and photos. http://www.aandncaravanservices.co.uk/wiring-your-camper.php

 

[peterjl]

Thank you Robin.

 

Yes we were looking at Summit range however having spent a couple hours sitting in a fair selection of Globecars we have come back to the Globescout. I have the technical spec brochure but that doesn’t name the charging control unit. I will have a look on line.

 

Thank you

 

Peter

[Robinhood]

..it will be a Schaudt (Probably EBL119)

 

For ease of use, and because I don't habitually use solar (I use a portable, plug-in panel carried only when we expect to be off-grid for extended periods without travelling) I added the Schaudt LR1218 regulator to my EBL99 equipped Campscout, and that does trickle-charge the vehicle battery.

 

If you've got a factory or dealer-fitted option, I'd punt on it being a similar set-up.

[peterjl]

Thank you Robin. It’s a dealer fitted option so that looks promising.

 

Up to now we have relied on two batteries which have done up proud. In the last few months we have spent more time than usual off grid and whilst the batteries lasted several days we were careful in our electric usesge and so now feel solar is way forward. It will be interesting to see how we get on.

 

Peter.

[colin]

I would not assume that's the set up a dealer will fit (from experience), you need to check what they will fit and explain what you want.

[Geeco]

We have a solar panel factory fitted to our Auto-trail. When it is parked up the solar panel keeps both the vehicle & habitation battery charged. This works if you do not shut down the full isolation switch. When one battery is fully charged it changes over & charges the other. It works very well as I always have fully charged batteries when I collect it from our open air storeage location. Cheers, 

[dipsticks]

I have been wondering how people prevent their solar charging systems overcharging their batteries or how it is managed ?

 

Short of disconnecting manually how do the manufacturer fitted system work ?

[aandncaravan]

dipsticks - 2018-05-16 11:58 PM

 

I have been wondering how people prevent their solar charging systems overcharging their batteries or how it is managed ?

 

Short of disconnecting manually how do the manufacturer fitted system work ?

 

 

Swift group use Sargent chargers. Most of the British Sargent Power Controller/chargers either have a built in regulator, or cabling to connect a Sargent Solar regulator. They are mostly quite crude solar chargers that continue to charge the battery at 13.7v, they don't switch off when the battery is full, see - .https://sargentltd.co.uk/shop/product/dual_solar_regulator/125

Few Dealers fitted the factory recommended solution, but that seems to be improving.

 

Bailey mostly use BCA kit which isn't sophisticated.

 

 

Arsilicii (used by CI, Rimor,SEA, etc) provide a built in Solar charger which dropped to a high'ish 13.8 float when the battery was full. It never shuts down altogether.

 

 

CBE (used by several converters) have a range of units. Typical is the PRS240 which has a good, low'ish 13.5v Float Lead Acid rate which should reduce overcharging. However, it also has a low 14.1v 'boost' charge rate which won't maximise the power available.

It will 'wake up' each day and charge a Lead acid battery at 'boost' voltage for 90 minutes, regardless of whether the battery is full or not, before dropping to 13.5v.

It doesn't shutdown altogether when the battery is full.

 

 

Hymer, Burstner, Pilote, Adria, etc often use Schaudt equipment. such as the LRM1218 and the older LR1218, the early versions of this were fixed at 14.3v constant.

The LRM1218 drops to a low 13.4v when the battery is full but doesn't shut off altogether.

We rarely see Factory installed Solar, most being done by UK Dealers and rarely done as Hymer/Schaudt recommend.

Although it was nice 6 weeks ago to work on a Hymer where the Solar install was done by Udo Lang himself some years previously, when the owners took the van to Germany.

 

 

The Votronic MPPT range are the units we most rate (also Schaudt compliant) and these have a low 13.4v float rate. Obviously such a low rate won't overcharge, but, once again they do not shut down altogether. always charging the battery when the Sun is up.

 

 

Most generic Solar regulators 'wake up' each day at sunrise and start a period of 'boost' charging even on a full battery. Obviously this is overcharging the battery. The times they stay at Boost vary from 1 hour to 6 hours.

The worst we have seen in this respect is the CBE PRS240 on a Gel setting which charges on boost every day at 14.4v for 6 hours before dropping to a high 13.8v Float.

However, to be fair to CBE, few other manufacturers publish such detailed specs so there are probably many more working the same way.

 

 

We have not come across one installation, either Factory or otherwise, that ceases all Solar charge when the battery is full.

It would be nice if they at least restarted each day with the charge program they were on when they shutdown the previous day at sunset.

Not go straight into 'Boost'/overcharge.

We have heard that Votronic are working on this, but no dates for release yet.

 

 

Manual deactivation is the route to go to preserve battery life.

We always recommend a fuse is fitted in the Solar Panel wiring just after it enters the vehicle, and that this fuse is removed when the batteries are full. This fuse should be installed between the Solar panel and the regulator.

Do not remove any fuses between the regulator and the battery, without removing the other fuse first.

 

 

 

 

[plwsm2000]

aandncaravan - 2018-05-17 1:25 AM

 

....

 

The Votronic MPPT range are the units we most rate (also Schaudt compliant) and these have a low 13.4v float rate. Obviously such a low rate won't overcharge, but, once again they do not shut down altogether. always charging the battery when the Sun is up.

 

 

Most generic Solar regulators 'wake up' each day at sunrise and start a period of 'boost' charging even on a full battery. Obviously this is overcharging the battery. The times they stay at Boost vary from 1 hour to 6 hours.

The worst we have seen in this respect is the CBE PRS240 on a Gel setting which charges on boost every day at 14.4v for 6 hours before dropping to a high 13.8v Float.

However, to be fair to CBE, few other manufacturers publish such detailed specs so there are probably many more working the same way.

 

 

We have not come across one installation, either Factory or otherwise, that ceases all Solar charge when the battery is full.

It would be nice if they at least restarted each day with the charge program they were on when they shutdown the previous day at sunset.

Not go straight into 'Boost'/overcharge.

We have heard that Votronic are working on this, but no dates for release yet.

 

 

Manual deactivation is the route to go to preserve battery life.

We always recommend a fuse is fitted in the Solar Panel wiring just after it enters the vehicle, and that this fuse is removed when the batteries are full. This fuse should be installed between the Solar panel and the regulator.

Do not remove any fuses between the regulator and the battery, without removing the other fuse first.

 

 

 

The Votronic MMPT will also "restart" if the solar panel voltage drops below about 14V for only 18 seconds. This is likely to happen when driving through a tunnel etc. so it could go through this several times a day.

 

You almost want to switch off solar when driving or when you will be on ehu for more than a day.

 

 

 

[peterjl]

So, as the novice solar panel user who started this thread, does the above mean that most users switch off/take out fuse to switch off, their solar panel charging whe driving or on emu?

 

And the question that must follow is, if users don’t, just leave them charging, are they shortening battery life and if so by how much?

 

Peter

[aandncaravan]

Peterjl, All battery manufacturers say that batteries shouldn't be left on long term charge, Solar or EHU.

For their AGM batteries, Banner say if the vehicle isn't going to be used for over 7 days then turn off the charger.

 

Yuasa say on their website that any Wet Acid battery kept on long term charge should be replaced after 2 years.

 

Victron say that if the Float/trickle charge is a low 13.3v, then the damage to the battery may be minimal, but that 13.8v will shorten life but don't stipulate by how much.

 

 

It depends a lot on battery temperature, the charging voltages (both 'Boost' and Float/trickle), the battery technology (some batteries like Banner Energy Bull use a high Antimony construction which is especially prone), etc.

Having chargers with temperature compensation makes a big difference. Another reason why we like the Votronic as Temp Comp changes the way it works on 'first start-up'.

 

 

So the answer to your question is depends.

 

As a rough guess a High Antimony content battery (the construction favoured by Banner and the mega deep cycle companies like Rolls, etc) in Spain during a hot Summer with less than ideal charging profiles might struggle in little more than 12 months.

 

 

I think, generally, people leave Solar charging on all the time because historically, 30 years ago when chargers were really low power, Dealers were saying to leave the batteries on mains EHU all the time. The combination back then of low power 13.5v chargers and batteries which self discharged fairly quickly meant little damage was done, because the batteries actually did need some small charge.

 

These days quality batteries don't self discharge and chargers are high current and high voltage, compared to 30 years ago.

 

I think it may take a few people reporting premature battery failure before a rethink takes place?

 

 

 

 

 

[plwsm2000]

peterjl - 2018-05-17 3:57 PM

 

So, as the novice solar panel user who started this thread, does the above mean that most users switch off/take out fuse to switch off, their solar panel charging whe driving or on emu?

 

And the question that must follow is, if users don’t, just leave them charging, are they shortening battery life and if so by how much?

 

Peter

 

Peter,

I am not sure if anyone has ever fully characterised the effects of overcharging in this way, and although there will be some detremental effect, I would be surprised if it was significant when you consider the many other factors that affect battery life.

 

The only thing I have done is to trick the controller into thinking the battery is at a higher temperature than it really is. The controller then drops the charge voltage accordingly. I have a switch to put it in this mode when on long term ehu and also when travelling (if I can be bothered). This only works for the Votronic mppt controller. Overall, is this helpful? - yes; essential? - no.

 

 

[peterjl]

Ok. I follow the argument but now comes the silly question.

 

So the solar panel always generates electricity in sunlight. If you remove the fuse so that electricity does not reach the charger where does it go? Does the panel just stop producing if no draw. Will this reduce solar panel life?

 

All of a sudden what I thought was a simple decision to have a solar panel seems extraordinarily complicated. Sorry if my question is silly but my career was not technical so some details go over my head.

 

Peter

[colin]

Have been using solar for 30 odd years now and will continue to use it, our present van is still on it's original 7 y.o. leisure battery, although when in storage it is mainly under cover and gets little light.

The original engine battery has suffered from not having solar on it at first, now rectified by having a little 40w panel just for this.

 

It strikes me that people may be having problems on newer systems due to having large panels with MPPT over cooking the batteries.

[aandncaravan]

peterjl - 2018-05-17 6:20 PM

 

Ok. I follow the argument but now comes the silly question.

 

So the solar panel always generates electricity in sunlight. If you remove the fuse so that electricity does not reach the charger where does it go? Does the panel just stop producing if no draw. Will this reduce solar panel life?

 

All of a sudden what I thought was a simple decision to have a solar panel seems extraordinarily complicated. Sorry if my question is silly but my career was not technical so some details go over my head.

 

Peter

 

 

No such thing as a silly question, wanting to know but not asking would be silly.

 

 

The panel just doesn't generate the power if it isn't asked for.

 

If a battery is 'flat', the Solar Regulator puts a load on the Solar panel relative to the charge required, so the Solar panel generates max electricity.

 

When a battery is full, the regulator drops to it's Float/trickle voltage and the Solar Panel generates only a small amount of electricity.

When removing the fuse the Solar Panel goes from generating little electricity to zero electricity, so no harm at all to the panel.

 

 

 

[peterjl]

Thank you

 

Peter

[Ocsid]

I have fitted a Morningstar Duo along with its associated meter to my Hymer; doing this way back from 2008/9 when I purchased it on a trip to the States.

 

The meter readout of current [from the panel?] drops frequently to 00.000. With my limited knowledge in electronics I am assuming means it has ceased to charge because it believes both batteries it serves need no more?

 

I say frequently as it occurs most of the outings going into that mode in the present bright condition by about 09:30 to 10:00 hrs onwards; again I am assuming this occurring when the last evenings takings from the batteries have been replenished?

 

The panel is a freestanding 85 Watt one, deployed when away which is almost invariably off EHU and typically is 4 to 28 nights a time. The disconnection plug and socket is on the panel feed, the connections to the primary battery have never been disconnected.

 

The van's battery an Exide GEL 90 is during storage always “charged” by the built in Schaudt CSV 409, as the van is left on our EHU 24 x 356 and now for 10.4 years. Throughout with the same factory fit battery that continues to meet our off EHU camping.

So, I suspect any damage being done is quite minimal compared to using another technique.

 

Edit: the second battery involved is a Varta LFD 60. This is taken as and when needed to serve specifically and only the TV and the Alde circulating pump.

At home where the mover needs to do a lot of work that duty is done not by the van's GEL but a Banner Energy Bull left at home 356 days a year on a CTEK 3.6 or more recently a MS5 charger.

[aandncaravan]

Ocsid - 2018-05-18 6:44 AM

 

I have fitted a Morningstar Duo along with its associated meter to my Hymer; doing this way back from 2008/9 when I purchased it on a trip to the States.

 

The meter readout of current [from the panel?] drops frequently to 00.000. With my limited knowledge in electronics I am assuming means it has ceased to charge because it believes both batteries it serves need no more?

 

I say frequently as it occurs most of the outings going into that mode in the present bright condition by about 09:30 to 10:00 hrs onwards; again I am assuming this occurring when the last evenings takings from the batteries have been replenished?

 

The panel is a freestanding 85 Watt one, deployed when away which is almost invariably off EHU and typically is 4 to 28 nights a time. The disconnection plug and socket is on the panel feed, the connections to the primary battery have never been disconnected.

 

The van's battery an Exide GEL 90 is during storage always “charged” by the built in Schaudt CSV 409, as the van is left on our EHU 24 x 356 and now for 10.4 years. Throughout with the same factory fit battery that continues to meet our off EHU camping.

So, I suspect any damage being done is quite minimal compared to using another technique.

 

Edit: the second battery involved is a Varta LFD 60. This is taken as and when needed to serve specifically and only the TV and the Alde circulating pump.

At home where the mover needs to do a lot of work that duty is done not by the van's GEL but a Banner Energy Bull left at home 356 days a year on a CTEK 3.6 or more recently a MS5 charger.

 

 

Well this is a great example to tackle, to show how varied situations can be.

 

The CSV 409 that Ocsid says is used 24 x 7 was designed specifically for Hymer, in Hymer Caravans and we have normally seen it in the Nova caravan range from around 2008 - 2014.

It is a fantastic charger being both powerful, 25 - 30 amps (depending on version), yet has an exceptionally low Float/trickle current.

As a result this particular charger, despite being double the power of the average Caravan unit, gives the battery a very easy time on long term EHU.

Exactly what you might expect from a quality, tailor made, literally, Caravan charger.

 

 

The early Morningstar Solar regulators, being American, were designed for the American RV market. Most know that American RV's generally have huge V8 engines and a larger than usual battery bank to cope with such big engines. One RV we worked on had a 6 litre V8 and two huge Starter batteries that made a Fiat Ducato's Starter battery look like it came out of a mini.

As a result the early Morningstar products gave the Starter Battery a higher charger rate that can fry a typical UK Starter battery. Not only was the current high but the voltage was typically the same as used on the habitation battery. This meant that if the habitation battery was low and needed 14.4v, the 'full' Starter got the same, when even 13.8v would have been too high.

 

Note that Starter Battery construction is more prone to damage from overcharging than a quality Leisure battery.

The early Morninstar's we have seen also required the charge split between the Habitation area battery and the Starter battery to be set-up manually, like a 80/20 habitation/Starter split.

But a setting that will work on a Starter battery in the Summer (such as 99/1 when the vehicle is used regularly) might be wholly inadequate in Winter when it needs to be more like 20/80 when the vehicle is often not used and the Alarm, Tracker take more from the Starter than is taken from the habitation battery. Obviously such a setting will fry the Starter battery in the Summer and not optimise power to the habitation battery.

These manual adjustment regulators get setup by the professional Installer, and never changed.

 

The best Solar regulators manage the split dynamically, as and where required. Automatically max power to the Starter in Winter (if required) but only a tiny amount in Summer.

 

 

I would guess one of the reasons Ocsid has not encountered this 'Starter' battery issue is because he has a Caravan that obviously won't have a Starter battery.

 

They are not the best motorhome regulators. This thread on overcharging and the customer going through 4 batteries is not unusual :

https://www.solarpaneltalk.com/forum/off-grid-solar/batteries-energy-storage/general-batteries/6159-advice-morning-star-25a-sun-saver-duo-high-charging-voltage

 

 

 

As for the Ctek 3.6amp? As a charger it is feeble beyond belief, managing around 2.7amps when continually charging a big battery (note the 3.6amps is a 'Peak' rating which it will struggle to maintain once it gets hot). It could take 2 full days to bring up a flat habitation battery.

However, those exact characteristics that make it a poor charger, make it a good Trickle/Float unit exactly because it is feeble and the current is low.

The same battery left long term on a Sargent 20amp charger would have a very different outcome.

 

 

 

Roadpro used to market the Banner Energy Bull as a maintenance free battery. We campaigned for years saying it wasn't. That in a typical motorhome it had a big appetite for Water and very short life.

There are 3 year old threads on here with people arguing we were wrong.

But if you now look on the Roadpro website, after many premature failures were encountered by Roadpro customers, you will find text that says if the battery is used on long term EHU or Solar, it will use lots of fluid. One company recommends monthly checks, which gives you an idea of the fluid loss!!

 

Usually, excess fluid loss goes hand in hand with battery degradation. That Roadpro now warn some batteries used on long term EHU or Solar will degrade, backs up exactly what the Battery Manufacturers say.

 

 

So you can see that while someone may try and tell you why you should adopt 'their' solution, there are an unbelievable number of variables.

What works for them, might be a disaster for someone else.