fitting new solar panels

The Bargee wrote:All good stuff!

..

I have not had the van back yet to take a look but when I do it will be with the intention of seeing whether I can wire a bypass route round the Sargent for essential DC habitation services (lights, water pump etc.) since the last episode caused the cancellation of what should have been our first week away.
I have a pretty thorough professional knowledge of normal electrics (was also a boatbuilder!) but electronics are alien to me and even for an expert they are probably difficult to diagnose in the field (literally!)

There is a very long thread here about the EC700 from 2020 which was initiated by marconi:

https://www.autosleeper-ownersforum.com/t32226-ec700?highlight=EC700

He has done something along the lines you are proposing.  He may have touched on it in a different thread which I can't find.  He doesn't come on the Forum very often these days. You might want to send him a PM.

hi everyone - sorry for late thanks to you all - Dad had a fall and a hospital trip so I'm only just catching back up with things.  This has all been very helpful and clarified many things for me so thank you. 
i have one more dim question - I suspect that there wont be enough space to fit a 175w panel up top - the obvious gap I have is 700mm x 1050mm. the panel the supplier wants to fit is 669 x 1485.  I suspect therefore the biggest panel i could get up there would be a 120w one 
with this in mind - silly question - but would fitting a 100w or 120w panel and a victron smart MPPT with battery master bypassing the EC700 system still be worth doing, given what I want to achieve which is.....leaving EC700 switched off over winter months and being able to leave the van for two months without having to go back and charge up the batteries; go off-grid for up to six or seven nights; fit a 60w inverter to only use when driving between destinations etc. 

steve

Plymouthwelshboy wrote:...would fitting a 100w or 120w panel and a victron smart MPPT with battery master bypassing the EC700 system still be worth doing, given what I want to achieve which is.....leaving EC700 switched off over winter months and being able to leave the van for two months without having to go back and charge up the batteries; go off-grid for up to six or seven nights; fit a 60w inverter to only use when driving between destinations etc. 

steve

No need to do anything if you only want to keep it in storage for up to 2 months.  As for the off-grid - the more solar watts you have the better.   Not sure why you want/need a battery master when you could get a Votronic DuoDig MPPT regulator in stead that charges the LB with a trickle charge going to the VB.  As a bonus this will keep both batteries fully charged indefinitely if you shutdown the EC700.

Plymouthwelshboy wrote:hi everyone - sorry for late thanks to you all - Dad had a fall and a hospital trip so I'm only just catching back up with things.  This has all been very helpful and clarified many things for me so thank you. 
i have one more dim question - I suspect that there wont be enough space to fit a 175w panel up top - the obvious gap I have is 700mm x 1050mm. the panel the supplier wants to fit is 669 x 1485.  I suspect therefore the biggest panel i could get up there would be a 120w one 
with this in mind - silly question - but would fitting a 100w or 120w panel and a victron smart MPPT with battery master bypassing the EC700 system still be worth doing, given what I want to achieve which is.....leaving EC700 switched off over winter months and being able to leave the van for two months without having to go back and charge up the batteries; go off-grid for up to six or seven nights; fit a 60w inverter to only use when driving between destinations etc. 

steve

If you are having this installed by someone else get them to link the 2 solar panels together and then to the MPPT Regulator bypassing the Sargent equipment, this will in effect give you 220w unless you fitted a Victron 140w panel which may just fit  mentioned before you can either fit a duel control Mppt  regulator or a Battery master, Both of these will keep the starter battery trickle charged.

A battery master is usually easier to fit, with the dual controller having to be as close to the Hab battery as possible the distance for running the extra cables sometimes means drilling through the floor and running cable along the chassis and then back up to the starter battery due to fitments been in the way of the cable run. If your starter battery has easy access to your Hab battery it may be simple for wiring in a dual MPPT controller.

A benifit that is often overlooked with the battery master is if the Motorhome is stored in a building or under a carport with no sun or EHU it will still trickle charge the starter battery at the expense of the Hab battery meaning you will always be able to start the van a duel solar controller is no good in this situation

Peter Brown wrote:gpilky, did you re-route the hot air ducting or did your van come like that

It came like that Peter and I just squeezed the batteries into the existing space. Could make more room if needed, but today I was looking at a 230ah lithium that I think would fit (albeit a bit of a squeeze).

G

Spoken to our fitting company. They want to install a standalone system to bypass the EC700. The current panel system would be left alone as is. The standalone system would also be connected to the LB. The 70A battery to battery charger is to future proof the vehicle should we wish to alter switch over to lithium at a later date. They have a short fat 115w panel that would fit the space or they would take a look at moving existing panel. 
I can't do any of this myself. Other local fitters I've approached want to rip out systems and replace whole.lot so I'm sort of stuck here. I'm trying to get the fitter to try and find a larger wattage panel that might fit the space.....but so far he's not playing ball, although if he can move existing panel across he might be able to fit a 140w. But then I'm not sure what that means regarding moving brackets and filling existing holes at old bracket positions 

Caraman wrote:

The Bargee wrote:All good stuff!

..

I have not had the van back yet to take a look but when I do it will be with the intention of seeing whether I can wire a bypass route round the Sargent for essential DC habitation services (lights, water pump etc.) since the last episode caused the cancellation of what should have been our first week away.
I have a pretty thorough professional knowledge of normal electrics (was also a boatbuilder!) but electronics are alien to me and even for an expert they are probably difficult to diagnose in the field (literally!)

There is a very long thread here about the EC700 from 2020 which was initiated by marconi:


https://www.autosleeper-ownersforum.com/t32226-ec700?highlight=

He has done something along the lines you are proposing.  He may have touched on it in a different thread which I can't find.  He doesn't come on the Forum very often these days. You might want to send him a PM.

Thanks Caraman. I was actually talking about wiring a bypass around the PSU for the DC hab loads, with new master switches, fuse box etc. Have not got round to thinking about the solar yet! Given that the recent EC700 CP was in fact being caused (apparently) by a faulty solar controller it will be interesting to see what the dealer has fitted. I don’t know a lot about solar but it would seem that Marconi’s thread was coming to the conclusions that a better quality controller is needed, wired direct to the battery (s). Also that the Sargent smart charge facility causes inefficiencies and is best ignored or will be no loss if bypassed. Given these, then the standard solar panel might be adequate.

So bypass the DC and the solar and what are you left with? Just glorified Sargent tank gauges that don’t seem to work either?

Marconi started with the solar regulator from which others followed but went beyond that by making it possible to use his van with the EC700 shutdown which helps when off-grid.

Dbvwt wrote:Bargee, your final sentence did make me smile as that is effectively what my EC480 display now does after all my modifications!!
I don’t want to take this thread off topic but following on from our PM earlier, I would recommend doing the well documented ‘solar mod’ before anything else. If you can also increase the stock 80W panel then also do that. I added a second 80W panel and for my off grid usage, 160W has performed very well.
Here is another of my mods for bedtime reading 

https://www.autosleeper-ownersforum.com/t34440-another-successful-solar-controller-upgrade

So if I can get 115w on top with the 80w.... That would be good and meet my originally stated needs at start? And would it still work if the new system bypassed the EC700 and the old system stay as it is?

As I said my supplier won't do that. See the last post l did above. I have limited people to go to where I am and I can't do it myself....so back to what I said..... He won't interfere with existing system. The only space will accommodate a 115w panel. He will do that as a separate system bypassing the EC 700 leaving the existing one intact. He argues both will work and top up the LB and then the new battery master will take surplus across to VB is I think how he put it. This will give me 195wts across the two systems. Ignoring the inverter issue .... I am assuming that 195w will be ample to go off grid for a week or so and to keep both VB and LB topped up over winter with the EC700 unit switched off...so that I don't have to keep bringing it home every two weeks for charging. 
I know it's not ideal. I know it can be done better but sadly not by me and not by anyone locally.....so cutting my cloth accordingly ......will it work? 

You have a motorhome so are able to travel and stay in your van which enables you to find another fitter in any area that will complete the work you require, do not just accept somthing because its close and its all the fitter is willing to do, it will play on your mind and you will be kicking yourself later

But also a budget, ill parents etc. It is what it is.....we can't travel far for a while and so I need this to be done over a day or two at.most and preferably south of Bristol and west of Dorchester so I can get home rapidly every f need be. 
Thank you everyone for your help. Appreciated as always. It's been really helpful and I wish I could do this myself but it is not within my abilities and after phoning most local suppliers/fitters I will have to go with one that gives me the best compromise.  Not ideal, but for various reasons it is what it is. Thank severyone.

Plymouthwelshboy wrote:But also a budget, ill parents etc. It is what it is.....we can't travel far for a while and so I need this to be done over a day or two at.most and preferably south of Bristol and west of Dorchester so I can get home rapidly every f need be. 
Thank you everyone for your help. Appreciated as always. It's been really helpful and I wish I could do this myself but it is not within my abilities and after phoning most local suppliers/fitters I will have to go with one that gives me the best compromise.  Not ideal, but for various reasons it is what it is. Thank severyone.

See if you can come to some arrangement with Glyne Lock as he does this sort of work and is a respected member on here and I am sure live around your neck of the woods

thanks chris - i will - at the moment I am trying to convince the supplier I'm working with to 
- remove the old regulator
- link the existing 80w and new 115w panels together through a new dual MPPT regulator 
- get the entire solar system bypassing the sargent system completely. 

An alternative I guess is to 
- remove the existing solar panel and regulator 
- fit an entirely new bigger solar panel and new MPPT controller which bypasses the sargent system 

but then this leaves 'filled holes' in the roof and as a boat builder - "filled holes" always fill me with dread and foreboding! 

thanks for your help chris

And it costs more!  Are you going to get enough value replacing the existing panel?  If not, do the former.

thanks caraman - that is my preference absolutely

an update - our supplier is going to fit a new panel alongside the old one and link them via a new MPPT controller and battery master to bypass the sargent system completely. We aren't having a B2b charger fitted at the moment. we will see how we get on with this and then look at fitting two smaller batteries to give us more onboard battery capacity when the current battery needs replacing. 

Thank you everyone for your support. this should now be as everyone has suggested i think and should be ample for our needs. We are 'sitting' on the fence on the inverter issue and will see how we get on next trip out. if charging the e bike batteries becomes a limiting issue on how many days we go off grid, then we will come back and discuss options on that one at that time. 
thanks everyone for your help, patience and encouragement

Also remember it does not matter how many solar panels on the roof you have, they need sun, if no sun then no volts from them that’s worth having, the sun in the winter months in uk is hitting your panels at such sun angle that even in full winter sun don’t expect much volts from them, I use a fold out 300 watt panel, at least you can prop it up at the right angle against the van to get as much as you can from the sun

Snowwolf wrote:Also remember it does not matter how many solar panels on the roof you have, they need sun, if no sun then no volts from them that’s worth having, the sun in the winter months in uk is hitting your panels at such sun angle that even in full winter sun don’t expect much volts from them, I use a fold out 300 watt panel, at least you can prop it up at the right angle against the van to get as much as you can from the sun

This is why it is advisable to use MPPT Regulator has they start harvesting power sooner in the morning and later later in the evening than PWM Regulators, MPPT Regulators are Dawn to Dusk which on winter days and overcast days make all the difference , it’s 6.40 now the sun is not up but it light and my MPPT Regulator is already producing between 0.5 and 1 amp.  They cost a little more than PWM Regulators but the cost outweighs the performance benifits

Some basic (very) maths re solar potential

Max solar energy on earth is at equator and is 1000w/square meter at local noon

Average efficiency of "normal " monocrystalline solar panels 20% +/-, so 200w/sq metre at equator noon.

Averaged, from several sites, area of a 100w monocrystalline panel is 0.5m2 (.48 to .52 from various sources)

That is the quoted figure for Uk, midsummer noon, panel horizontal as most of ours are.
My experience is that is about right.

Winter noon clear sky solar radiation per UK sq m is 23% of summer noon. 

So a 100w panel in summer noon will generate 100w
A 100w panel in midwinter noon will generate circa 23w depending only on latitude, all else being equal.

This is independent of the type of solar controller, this is simply the panel output. MPPT will be better per day, but not much instantaneously.

Figures I have seen quote 95% efficiency for MPPT and 92% for PWM, these are instantaneous efficiencies.

Any thoughts re this, be interested? My new toy, 3d printer is currently printing away on a linear actuator and a rotary table on which I will mount a 23w panel but angled constantly to follow the sun both horizontally and vertically throughout the year. Just for fun and all been done before but it'll interest me, at least!!

IanH wrote:Some basic (very) maths re solar potential

Max solar energy on earth is at equator and is 1000w/square meter at local noon

Average efficiency of "normal " monocrystalline solar panels 20% +/-, so 200w/sq metre at equator noon.

Averaged, from several sites, area of a 100w monocrystalline panel is 0.5m2 (.48 to .52 from various sources)

That is the quoted figure for Uk, midsummer noon, panel horizontal as most of ours are.
My experience is that is about right.

Winter noon clear sky solar radiation per UK sq m is 23% of summer noon. 

So a 100w panel in summer noon will generate 100w
A 100w panel in midwinter noon will generate circa 23w depending only on latitude, all else being equal.

This is independent of the type of solar controller, this is simply the panel output. MPPT will be better per day, but not much instantaneously.

Figures I have seen quote 95% efficiency for MPPT and 92% for PWM, these are instantaneous efficiencies.

Any thoughts re this, be interested? My new toy, 3d printer is currently printing away on a linear actuator and a rotary table on which I will mount a 23w panel but angled constantly to follow the sun both horizontally and vertically throughout the year. Just for fun and all been done before but it'll interest me, at least!!

When we had the Autotrail which had a 150w panel and a PWM regulator I monitored the input for a week on the drive, I used to go out at night and turn on the lights and leave on all night,in the morning I would turn off, I did this for a week and noted how much had been produced power wise, the following week I replaced the PWM regulator with my first Victron 15amp MPPT regulator and did the same with the lights, at the end of the week I compared the power readings and the MPPT was up by about 38% overall, I know each day is different and some days produce more than others but it was enfor me to replace the 150w with a 300w and my second Victron MPPT Regulator,  my mate bought the 150w panel and 15amp regulator and installed it on his shed , it’s still producing and that 12 years ago , the PWM regulator went in the bin

Agreed Chris. However the real point of the post was in response to Snowwolf, in that the energy available is very limited in. Northern hemisphere winter.
BUT not so limited to make winter solar not worthwhile, as both of know well, all of our batteries and assorted toys are 100% happy all winter long, and, up to now, I've only ever had 100w and pwm.
Hope house mods work, they will, and finish quick so you can get back on there!!

..I would  get -more  quotes and advice ,  try a mobile fitter.