Portable solar and / or B2B

[Cush]

After reading some posts by Richard and Ann and AdamB I am seriously considering portable solar to recharge our needs when wild.

Just wondering where the mppt goes? On the panel or near batteries? I fancy one of those bluetooth ones!
Are there any recommended brands / kits?

I have an 03 Cheyenne with easy access to the leisure batteries in the rear. Would approx 6 m be too far to run a battery to battery charge system or does that go via the Sargent?

Thanks, in anticipation
Cush

 

[Raul]

Controller should be as close as possible to the battery.

 

[The Wino]

Why portable solar do you mean a fold up panel?. I would fit one on the roof over where the battery is and the solar controller next to the battery.

 

[Cush]

Why portable solar do you mean a fold up panel?. I would fit one on the roof over where the battery is and the solar controller next to the battery.

Sorry, yes, fold up. I will have another use for it when not being used in the van so foldable will kill 2 birds etc etc. I also understand that as it is angled when set up it doesn't need to be as physically large as roof mounted ones. A Bluetooth mppt would let me monitor it like the fixed systems do. I think.

Thanks to both of you for advice re the controller.

 

[rosalan]

Although you may have dual use for the folding panels, the inconvenience of setting up each time you stop, with trailing wires, to say nothing about it getting 'borrowed' by others when you are not in attendance.

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

 

[Cush]

Although you may have dual use for the folding panels, the inconvenience of setting up each time you stop, with trailing wires, to say nothing about it getting 'borrowed' by others when you are not in attendance.

thanks for the words of advice. The plan would be, if the controller has got to be close to the control unit then I'd mount this permanently in the rear locker and have a quick release plug between the controller and panel, probably close to the controller. I could always climb the ladder and put it on the roof out of the way or only have the panels out when were in. I don't mind the faffing around, I quite like it.

Appreciate you making me think about security. Thanks again

 

[TerryL]

To answer the thread title if you tend to stay put in one place then solar. But if you move around then a B2B will recharge your batteries in an hour's driving. Personally I've got both, plus 2 leisure batteries and a battery master which keeps engine battery topped up if we don't move for a bit. Never have to think about it now.

NB don't use the B2B to recharge by just running the engine at a standstill - not good for the motor.

 

[nicholsong]

I agree with TerryL's comment about B2B.

As regards angling solar panels vertically, that is only efficient if you also are around to follow the sun horizontally. I have seen studies that show that flat panels which receive the rays from whichever direction the sun is horizontally are as efficient as vertically angled panels fixed facing south which will receive nothing at sunrise and sunset, wheras a flat panel will receive some, albeit reduced, input.

Geoff

 

[Cush]

Hi TerryL and nicholsong
Thanks for your guidance and experience. It's much appreciated.

Take care

 

[Cush]

For anyone interested in the effect of tilt, or lack of it. Thanks Nicholsong for the pointer.
Most issues with being flat are that they get dirtier quicker, although not such a problem with a temporary set up or easily accessed one

http://www.silverspray.co.uk/wp-content/uploads/2012/03/Solar-PV-tilt-effect.jpg

It's just one source but other sites seem to pretty much agree. Tilt makes less than 10% improvement. Facing due south is the most important thing. Curious as to how you get a panel with 0 tilt (flat) to "face" any direction

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

 

[Richard n Ann]

Our panel output more than doubles when tilted, It depends what time of year though, massive difference in October - 2 amps flat shoots up to 8+ amps at 40° tilt South.

Edit: Just looked up the photo album. 9.2 amps on the 28th October from our150w panel tilted

 

[Raul]

Also, the latitude you are at that moment, makes a big difference. That graph looks at a very low latitude, you will never gonna get that, at 50 deg plus north latitude.

 

[Lenny HB]

No problem with fitting a B2B with the batteries 6m you just have to make sure you use large enough cables to keep the volt drop to a minimum.

 

[Off da Grid]

From about April to September it doesn’t really make much difference whether your panel is flat or tilted, as the sun is higher in the sky. My batteries are pretty much recharged by 10am (255 watt panel mppt Votronic charger) during this period. Generally we find our power usage drops during the summer as we’re outside more.
Outside these months it does improve the output of solar if you match the angle to the average sun angle on the day.
I use an iOS app called simply solar, it gives the best angle and where to point your panel.

 

[The Green's]

To try and answer a couple of your other questions -

The MPPT is better closer to the battery, than the panel. My understanding is that there is normally a higher voltage and lower current on the run from the panel to MPPT, than from MPPT to battery, and therefore any loss of current due to resistance will be less.

For your quick disconnect, you could probably use MC4 connectors, the standard connector used in Solar setups. They are cheap enough, easy to fit and crimp yourself, and pretty easy to disconnect especially if you have the little tool.

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

 

[DBK]

Your MH has lots of roof space so I think you will find for the price of a folding panel you could get twice or even three times the capacity with fixed panels on the roof. Fit and forget, they will just work and when it's cloudy a flat panel will gather more power than one pointed to the invisible sun.

If you need a portable panel for another use then buy a second one, whatever is best, for that specific application.

 

[Cush]

Also, the latitude you are at that moment, makes a big difference. That graph looks at a very low latitude, you will never gonna get that, at 50 deg plus north latitude.

I thought the figures were % of the max possible at that time? The tables is from the energy saving trust and for our latitudes.

Thanks for all of the input. I'll keep doing the research. Battery to battery is gaining momentum and the solar a close second. Didn't quite understand the b2b in the earlier. Price will win out.

Thanks again to All

 

[Nasher]

One word: Generator

 

[Cush]

One word: Generator

Another word "marmite"

PS. Nice Avatar

 

[autorouter]

Look at the panels of a solar farm next time you see one. They are tilted. If it was even marginally better to lay them flat, that's what they'd all do.

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

 

[Raul]

Indeed. And the angle of incidence, is directly related to the latitude of that location. Or a median for the summer and winter angle, which results in a spring autumn ideal angle. As DBK mentioned, in cloudy weather, best is flat facing the sky. We all fit our panels flat and as much as possible. PV is cheap, with under 200 quid, you could get 500-600w of solar if you know where to shop.

Off-grid PV systems

This part of PVGIS calculates the performance of PV systems that are not connected to the electricity grid but instead rely on battery storage to...

ec.europa.eu

 

[Cush]

Any thoughts on this?
I'm a complete autosparks novice and trying to educate myself

 

[ManTheVan]

Indeed. And the angle of incidence, is directly related to the latitude of that location. Or a median for the summer and winter angle, which results in a spring autumn ideal angle. As DBK mentioned, in cloudy weather, best is flat facing the sky. We all fit our panels flat and as much as possible. PV is cheap, with under 200 quid, you could get 500-600w of solar if you know where to shop.

Off-grid PV systems

This part of PVGIS calculates the performance of PV systems that are not connected to the electricity grid but instead rely on battery storage to...

ec.europa.eu

Can you suggest where that shop might be? Haven’t seen anything remotely close to that amount of capacity for that sort of price, but would love to investigate!

 

[Raul]

Triplesolar ebay shop, 285w for 80 quid. Lots in stock.
CCLComponents, based in Scotland, with nationwide delivery; trina 275w for 90 quid, or 340w for120.
Wind &Sun good deals on inverters, various components and batteries.

 

[autorouter]

Any thoughts on this?
I'm a complete autosparks novice and trying to educate myself

I have the greatest respect for these guys, and if I was going on an expedition into the Australian outback I would listen very carefully to their advice. However kitting out a motorhome in Europe throws up different priorities.

First, a translation of Oz slang into MHFun slang:
continuous solenoid = split charge relay
voltage sensitive solenoid = voltage sensitive relay
thumper = leisure battery/habitation battery
DC-to-DC charger = battery-to-battery charger (B2B)

The issue of 'load-sensitive alternators' has largely disappeared from modern vehicles, but has been replaced by the 'smart alternator' issue which causes similar problems. I'd say all alternators that are not 'smart' are the load-sensitive type.

He is right in that a simple split charge relay is fine for many, and will charge a leisure battery reasonably well, especially if it's a similar type to the lead-acid starter battery. However if you have a big leisure battery bank, or different types like Gel or Lithium, the alternator doesn't really do a good job.

B2B chargers have come a long way from the kind he is describing. They are much more efficient, and can boost voltage and current to supply exactly what the leisure battery requires. Most are settable to the battery type, and do multi-stage intelligent charging for a full charge without overcharging.

Voltage-sensitive relays are fine in simple systems where the only reason the starter battery voltage rises is the alternator when the engine is running. More complicated systems with solar and mains hookup charging will charge the starter battery too, and then a VSR will become a liability.

If you have plenty of solar power and the weather is good, you might not need a B2B. But as the days get shorter you need something more, and a B2B can fill up the batteries with a much shorter drive time than a split charge relay can.

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

 

[Cush]

Thank you so much autorouter I'm sure I won't be the only one that will be wanting to thank you for that info.

 

[Cush]

So ....
Sat in the van in one of our favourite spots overlooking the bay. Got a reply from the good people at Sargent who told me that
"The PSU 2007 does come with a built in split charge relay which links your leisure battery to the vehicle one so while you are driving the van the two batteries will be charged up by the alternator of the vehicle."

How did I never notice. Anyway, before I set off the LB read 12.8 on the panel (not been on EHU before setting off). At the end of a 40 minute B road journey it read 13.3.

Guessing no need for a bat 2 bat now?

Happy to be schooled on the tech side ( autorouter )

Currently pondering why the ultrashort won't do the right thing and yes, the cover is off and bass is on and it is full of water.
When you buy a lemon buy gin too ( van isn't really a lemon incase the seller is reading )

Cush

 

[Cush]

Edit of the above. Must wear glasses and proof read

Ultrastore not ultrashort and gas not bass

 

[Silvabac]

Very interesting..

 

[Cush]

Currently pondering why the ultrashort won't do the right thing and yes, the cover is off and bass is on and it is full of water.

Appears sorted now. Think before t was wind direction and strength

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