New system needed

[Sooz52]

Hi, I’m in a Hymer and underpowered, working from it with my laptop and only lasting up to 2 days without driving, so I need an emergency refresh. After a reasonable amount of research I’ve found how complex this is - I’m hoping not to have to become an expert on this before I buy as I really need to replace things this weekend! I want to last up to a week year round in Spain starting the engine, do basically want a system which goes up in power not down when the laptop is plugged in.

Solar panels in place = 2x50 (probably) in series. I’d like to add a 300W panel and I have space, aiming for 400W total.

Regulator = NDS SC300M and it says that Maximum peak power for each input is 150WP. Does this mean I can’t stick a panel of more than 150W on it? The other 2 panels are both plugged into input 1. I’ve seen a few makes bandied about, happy to spend more for a good MPPT. Any recommendations?

The batteries are old and having had them tested yesterday one is duff and the other is vaguely ok so I’ll replace both. Should I go for the max Wh that fits in the space or do I need to size them for the panels?

I feel I could make too many mistakes here, is there such thing as an expert to call and pay for advice without having to buy from them?

A little worried and definitely overwhelmed with figures which immediately emerge on this topic!!

 

[Lenny HB]

Solar panels are best connected in parallel on a Motorhome as if connected in series shade on one panel will kill the output from all the panels.
400 watts of solar still may not be quite enough for what you need in December and January but probably the max you can get on the roof.
It would be easier to add 2x 150w panels.
The regulator you mention I can't see it being much good at that price for a 300 watt regulator probably not even a proper MPPT regulator. Much better to go for either a Votronic or Victron regulator twice the price but they work well.

Have you considered fitting a couple of Lithium batteries? They will give you greater capacity and charge a lot quicker but you would need to fit a new mains charger and a B2B and will probably cost you £1500-£2000.

 

[tonyidle]

Simplistically: as much solar and battery as you have room / the budget for. There is no link between battery capacity and solar. Your ideas are sound. A quick scan of the manual for the SC300M suggests that you can connect a maximum of 150W to each input but you would be wise to opt for MPPT. Take a look at the Reviews section on this site for someone to install and advise - any decent trader should be able to offer sound advice without insisting on a sale and no doubt others on here will have recommendations based on experience.

Once battery capacity and solar charging are optimised, no matter how large or efficient your installation, you will still struggle in Winter during a continuous cloudy period. Options then are EHU on a site, use of a generator, or to travel a reasonable distance. Charging from the vehicle alternator when driving can be optimised using a battery-to-battery charger - Sterling is one decent make but you will receive other recommendations. There are at least a couple of Funsters who manage to stay off hook-up for extended periods who can offer more specific advice.

 

[9526]

First thing, try not too panic

It really isn’t half as complicated as you think.

If your batteries are u/s then no amount of solar will cure your issues a cpl of these (or similar) should see you right though

LFD90 Varta Professional Dual Purpose DC Leisure Battery 90Ah (930090080)

LFD90 VARTA Professional Dual Purpose Leisure Battery <i>Innovation with Purpose, Premium Experience, Powerful History</i> VARTA was founded in 1887 Germany, and was established fully in 1904 by delivering the first electric vehicle battery, famously driven by Thomas Edison. Soon after, VARTA...

www.tayna.co.uk

Panels - 2 x 150w @ circa £150 each (photonic universe)

Controller, look for Mttp by Victron or votronic (circa £150)

Amazon product ASIN B00O326R6W
We also carry a flexible panel on a cheap controller which we can point directly at the sun in winter (obviously optional

We have the above setup (similar) and have never struggled in Spanish/Portuguese winters (we even use that setup to charge 2 ebikes.)

Uk winters are a different animal of course

 

[autorouter]

Regulator = NDS SC300M and it says that Maximum peak power for each input is 150WP. Does this mean I can’t stick a panel of more than 150W on it?

Your existing regulator will handle two 150W panels, one on each of the two inputs. It will handle a single panel up to 200W if connected to both inputs. From the manual:
"Is it possible to mount a single 200W panel on a single input (pf1 or pf2)?
you can connect a 200W panel such as pf1, provided the other channel (pf2) is shorted or joined with pf1."

However it would be at its limit, with no scope for future expansion. If you're intending to fit two 150W panels, this will handle it, and you could upgrade later if necessary. This controller is already an MPPT type, which is better than the cheaper PWM type.

This controller can also be set up for charging standard wet, AGM or Gel batteries, as well as lithium. There are 'jumpers' (think of them as switches) that can be set for whatever battery you choose.

You don't seem to have a requirement for short bursts of heavy current, for powering a 2000 watt inverter for example, so Gel batteries would be a good choice. They are more expensive than standard wet (flooded) batteries, but can be discharged to a lower level, down to 20%, without damage. Most standard wet batteries are best restricted to 50% discharge. If you want the best, Lithium (LiFePO4) batteries will do it all - high currents, low discharge levels, half the size and weight etc - but they are expensive.

^{_{Subscribers  do not see these advertisements}}

 

[Minxy]

Consider going for gel rather than AGM batteries as gel can be discharged lower (to 20% rather than 30%) without damage and appear to have a longer life overall. A couple of the below batteries should fit under your cab seat (assuming that's where the others are) and will give you 156ah - they for some silly reason are numbered '65' and say they're 75ah but are in fact 78ah, giving 125ah usable power (compared to 2 x 90ah AGMs giving 126hg).

GF12065Y Sonnenschein Battery (GF1265Y / GF 12 65 Y)

GF 12 65 Y Sonnenschein GEL/VRLA Battery Sonnenschein is owned by the battery manufacturing giant Exide. With over 130 years in the battery business, Exide are known for their quality in the industry. Sonnenschein were one of the first companies to develop VRLA GEL batteries and to this day they...

www.tayna.co.uk

In our previous camper I installed a Votronic Duo 250 controller but in our new Carthago the dealer fitted one of the below NDS 300 ones which has proved just as good and costs half the price (haven't checked to see if you can get a NDS display to link to it as we don't need it as it's linked to our existing control panel). We did 2 months in Spain over Dec/Jan/Feb and often stopped for up to 4 days and didn't have any issues at all with power even on cloudy days.

Accessories - Cables, Adapters, and Installation Supplies

You can order accessories for your solar panels, portable power stations, charge controllers and more at Solar Power Supply.

www.solarpowersupply.co.uk

 

[hilldweller]

A 50W panel is a waste of space. Scrap those and see how much you can fit starting from scratch.

The more the merrier.

 

[Sooz52]

I have an MPPT regulator now but tbh my assumption is I need to upgrade. Can’t figure out how to edit my post to add this. However I’m now thinking scrap the 2x50w (sell them on) and replace with 2 x 250-350. My very technical mate says put the batteries in series to produce 24V. Maybe they are in series already... not sure (I remember the difference from school). Does this seem normal in a Hymer - to decide between 12v and 24v?
I’ve decided that panic is bad (mickyc ?) and I’m staying put for 1 or 2 weeks - with all the lockdowns here movement may be impossible soon anyway!
So now I’m pottering, learning about my MH and contemplating power. Schematic later of my thoughts ?

 

[9526]

I certainly wouldn’t contemplate wiring my leisure batteries to produce 24 volts.

That would cause you countless issues IMO

KISS principle wins every time

 

[peterc10]

There is no link between battery capacity and solar.

Not sure I would agree with you from a practical point of view. There is no point in having lots of solar if you do not have enough battery capacity to store it. Equally there is no point in having lots of battery capacity if you do not have enough solar panels to fill that capacity.

So there is a balance to be made between the two, especially when you are on a limited budget.

^{_{Subscribers  do not see these advertisements}}

 

[Minxy]

I have an MPPT regulator now but tbh my assumption is I need to upgrade. Can’t figure out how to edit my post to add this. However I’m now thinking scrap the 2x50w (sell them on) and replace with 2 x 250-350. My very technical mate says put the batteries in series to produce 24V. Maybe they are in series already... not sure (I remember the difference from school). Does this seem normal in a Hymer - to decide between 12v and 24v?
I’ve decided that panic is bad (mickyc ?) and I’m staying put for 1 or 2 weeks - with all the lockdowns here movement may be impossible soon anyway!
So now I’m pottering, learning about my MH and contemplating power. Schematic later of my thoughts ?

Your mate is a pillock - your Hymer, and all it's kit, is meant to use 12v so if you do as he says you could cause major issues!

 

[autorouter]

I'd be wary of going to 24V unless the person installing it knows exactly what they are doing. All your habitation electrics will require 12V, so you will need a 24 to 12V converter on the battery output. Also your alternator/starter battery will be 12V so you will need a 12 to 24V converter to charge the batteries as you drive along. And your EHU charger will need to be 24V, or have a converter on it. That is all perfectly possible - big trucks all have 24V electrics - but it's an extra complication for not very much benefit. The main benefit is if you are running high-power devices like big inverters, which I think you have not mentioned you need (yet).

If you're seriously thinking of going that way, then maybe 48V is even better. Many hybrid vehicles, boats and emergency vehicles have 48V electrics, and the converters are getting cheaper and are more widely available.

 

[tonyidle]

Not sure I would agree with you from a practical point of view. There is no point in having lots of solar if you do not have enough battery capacity to store it. Equally there is no point in having lots of battery capacity if you do not have enough solar panels to fill that capacity.

So there is a balance to be made between the two, especially when you are on a limited budget.

Maybe I should have said that no damage will occur whatever is connected which is what I understood from the question.. I agree with you but when solar capacity really matters (in cloudy conditions) every bit of panel capacity helps. If budget information was available then it would be possible to be more specific. Generally start with maximum battery capacity then max out on solar up to roof space and budget limits.

 

[Raul]

There is a balance in battery storage, charge discharge and solar output.
To be in the Goldilocks you need to supply 12 to 8% with 10% being spot on of charge rate. If you got Lithium, as high as 50% charge rate, no minimum.
That harvest, can vary with location, seasons, tilt and weather. So solar power is a opportunistic charge, you don’t know what you’ll get from one day to the other. Better in the summer.
Flat on the roof you will derate the installed power by 30-50%. A successful system, Tailored to your need starts with your energy requirement. Then storage and then panels. Most folk work this backwards and end up with limitations, that they will work round it.

 

[peterc10]

The idea that you will get better output with sloping panels in impractical unless you are willing to move the motorhome around to follow the sun every couple of hours, and that assumes that you can do that, even if you wanted to. You can get ones that turn with the sun, but they use energy, are expensive and need a lot more roof space in order to make sure they do not shade one another in use.

A static sloped panel will produce more energy when it is pointed to the sun, but less when it isn't.

^{_{Subscribers  do not see these advertisements}}

 

[hilldweller]

My very technical mate says put the batteries in series to produce 24V.

What an idiot.

 

[tonyidle]

To be in the Goldilocks you need to supply 12 to 8% with 10% being spot on of charge rate. If you got Lithium, as high as 50% charge rate, no minimum.

I don't know what any of that means?

Most folk work this backwards and end up with limitations, that they will work round it.

Requirements are simple: as much as can be installed / afforded. The ultimate would be an integrated charging system with all sources working in harmony and a single control centre. The 'limitations' you mention are that one starts with the OEM (and converters) system then progressively improves it as allowed by payload, pocket, space, etc. That seems to be a sensible approach and I understand the OP is attempting to improve things in a balanced manner. One thing is certain - however much improvement is possible I have never heard anyone complain that their battery is too big or that they have too much solar.

 

[autorouter]

However I’m now thinking scrap the 2x50w (sell them on) and replace with 2 x 250-350.

The 250-350W panels are larger than the usual 100W or 150W, obviously, but also the voltage will very likely be higher, about 36V rather than 26V. From reading the manual I think that voltage would be too high for your existing controller. But the power (2 x 250-350W) is too high for it anyway. The suggested Victron or Votronics controllers will be OK with that voltage, but if you look at different brands it's an idea to check they can handle the voltage.

 

[Sooz52]

What an idiot.

She was just trying to be helpful and is researching it for her house.
I gather I need to stay 12v as that’s what MHs take, ok parallel it is then.

 

[Sooz52]

Have you considered fitting a couple of Lithium batteries? They will give you greater capacity and charge a lot quicker but you would need to fit a new mains charger and a B2B and will probably cost you £1500-£2000.

I think I’d steer clear as they’re so expensive. Do they have a shorter life too.
Now I’m trying to understand the difference between gel and AGM

^{_{Subscribers  do not see these advertisements}}

 

[Sooz52]

A 50W panel is a waste of space. Scrap those and see how much you can fit starting from scratch.

The more the merrier.

This is what I’ve pretty much decided now

 

[Sooz52]

A couple of the below batteries should fit under your cab seat (assuming that's where the others are) and will give you 156ah - they for some silly reason are numbered '65' and say they're 75ah but are in fact 78ah, giving 125ah usable power (compared to 2 x 90ah AGMs giving 126hg).

GF12065Y Sonnenschein Battery (GF1265Y / GF 12 65 Y)

GF 12 65 Y Sonnenschein GEL/VRLA Battery Sonnenschein is owned by the battery manufacturing giant Exide. With over 130 years in the battery business, Exide are known for their quality in the industry. Sonnenschein were one of the first companies to develop VRLA GEL batteries and to this day they...

www.tayna.co.uk

I’m going to go bigger I think...

 

[Sooz52]

400 watts of solar still may not be quite enough for what you need in December and January but probably the max you can get on the roof.

What would you suggest? I have plenty of roof space and now plan to replace the 2 x 50Ws

 

[Sooz52]

Now I’m confused as I can’t see much in the way of 12v panels over 160w...if I want more than 300w do I need more panels?
So 4x150 12v panels for 600w?

 

[9526]

Now I’m confused as I can’t see much in the way of 12v panels over 160w...if I want more than 300w do I need more panels?
So 4x150 12v panels for 600w?

You are confused because you are overthinking it.

Stick 300w on your roof, get a cpl of decent batteries and a decent quality MPPT and get out and about in your van.

If you need more (most people survive perfectly well on less) then there’s nothing to stop you adding more later (if you have the space). Your original post indicated that your power usage is nothing extraordinary so why not fit a simple system?

Or you could of course study formulas, voltages, sun angles, goldilocks, porridge etc etc etc

And then be even more confused

^{_{Subscribers  do not see these advertisements}}

 

[Sooz52]

You are confused because you are overthinking it.

Stick 300w on your roof, get a cpl of decent batteries and a decent quality MPPT and get out and about in your van.

If you need more (most people survive perfectly well on less) then there’s nothing to stop you adding more later (if you have the space). Your original post indicated that your power usage is nothing extraordinary so why not fit a simple system?

Or you could of course study formulas, voltages, sun angles, goldilocks, porridge etc etc etc

And then be even more confused

Sure but simple question is what panels can I fit if I want 500 or 600w into a 12v system

 

[9526]

Sure but simple question is what panels can I fit if I want 500 or 600w into a 12v system

4 x 150w

 

[Raul]

Sure but simple question is what panels can I fit if I want 500 or 600w into a 12v system

Look at panasonic 295w HIT. They measure 1050mm x 1470mm. I believe you can fit two of these across, if you want lots of power. Of course a controller like victron 100/50 will be needed for these two.
And another big bonus is they are true hybrid cell construction, very efficient compared with other top mono panels, and better in low light.

 

[68c]

I thought a hybrid panel also heated water, probably heavier and bulkier than standard panel.


EDIT: Did a bit more research, seems the term hybrid can either mean electric power and water heating in the same panel, OR, just electric panel using both organic and inorganic cells. Shame they could not come up better names.

 

[autorouter]

Now I’m confused as I can’t see much in the way of 12v panels over 160w.

There are basically two kinds of panels. What you call 12V panels are about 26V and are constructed for controllers charging only 12V batteries. For motorhomes, remote CCTV cameras, unpowered lights, street signs etc. Their power is usually from 20W to 150W. There's a bunch of controllers designed for exactly this type of panel.

Then there's the bigger panels, 250 to 350W, which are constructed for house roof and solar farms. They are usually 36 to 40V, because any higher voltage and they'd be worried about electric shock. There are controllers designed for this higher voltage panel type, with a wide range of voltages and output currents. There's a Victron controller for everything from a 250 watt shed supply to a solar farm of 25000W. These bigger panels are commonly used on motorhomes for more than about 150W of power. Typically the controllers will automatically detect the battery voltage (12, 24, 48V) when they are first connected.

^{_{Subscribers  do not see these advertisements}}