Who needs an alternator? Solar panels on the bonnet?

Yes you're right. Not sure how hot it really gets on a 200series bonnet and how much is due to sun? The bonnet is double skin - so cool air goes between the two skins then into the intercooler and there's a wad of soundproofing - so I'm guessing it may not be a lot warmer than the roof. I'm a bit reluctant to use the roof because we carry a big kayak sometimes.

A flexible 80 watt panel weights 2.5kg so weight is not an issue. Ideally a bit of airflow under the panels ( aided by a few mm of velcro) is desirable. I've used Velcro a lot - it has held most of my rigs together for many years. It would be nice to be able to remove the panels around town and when you sell the car - leave no trace.

Ron, here's a link for a potential panel:
80W flexible solar panel
Just trying to think outside the square this time round!
It might need the backup of a simple Redarc isolator as well in case weather gets too dull...

Phil, I'm thinking like a scumbag thief right about now - and imaging how much I could make in a week, ripping velcro-attached $229 solar panels off the bonnets of 200 series 'Cruisers, as soon as the owners left them unattended, for more than 5 mins. [:-)

Me? - I like to screw stuff down that looks mightily attractive. Perhaps it's because I've lost so much to Hydraulic Jacks over the decades. [:-(

Yep, good point Ron!! Fortunately not too many thieves hang out in the deserts. I'd have to take them off in "civilisation".

You haven't been to Kalumburu? BIL (copper) travelled to aforesaid destination and took his wife along. She went for a ride on a quad bike with one of the "locals" and made the mistake of carrying, and then accidentally dropping her purse, off the quad bike.
It disappeared within minutes - and despite looking for it, and asking all the "locals" if it had been seen, she never saw it again!

Yeah, a simple $100 Redarc might be good backup.

Just on that Redarc subject, I've just had fitted to my car the Redarc smart solenoid/isolator that allows "backflow" to the cranking battery from a charging source in the van, if it detects the cranking battery is a bit low.

Could be relevant to your idea, saves you plastering solar panels all over your bonnet lol

Same here. And I can also parallel the batteries for winching. Wouldn't be without it as we go to some very remote places and solo as well.

Sorry but I can't help with solar stuff. Don't run any.

Phil

Gday Ross,
Yeah I expect glare will be an issue. The other option with mounting is on the roof in front of the roofrails/roofrack, but only useful if no Kayak. With Velcro, it is all movable! Might be able to have it on the bonnet when remote and move it up to the roof for the highway - just thinking it through now. Yeah, it might lift on the highway - at least you'd see it on the bonnet! Its something I'd check.

But don't underestimate the genuine Velcro. Its amazing stuff which I've used for many years to hold all sorts of stuff together. Its also great for electronics because it dampens the vibrations. Buy some and see how strong it is! It holds almost every accessory I have! And I like to be be able to restore a vehicle to original condition when I sell it, so sticky Velcro is removable when the time comes.

TVan has a 100Ah AGM that only runs lights, pump, rechargers and a laptop for the odd movie, so not a lot of Ah. 65W easily copes and keeps the voltage above 13V.

Vehicle has single Engel as the main consumer off a 100Ah marine battery, so thinking an 80W panel will keep it going without too many issues. We travel in winter so engel rarely cycles through the night. You mentioned insulation - I also have an older Engel which I insulated with 10mm high density foam around the front, sides and underneath and added a 12V fan that comes on when it cycles - it's pretty good - still pulls 5A when cycling but doesn't cycle as much. The newer engel is stock standard - no bag but "sort of" insulated in my storage system but only pulls 2.8A when cycling. If I was worried about how much power it was using I'd insulate it as well, but so far haven't seen the need.
Cheers
phil

Forgot to add, solar panels aren't very efficient when covered in dust, so if your intending to mount permanently on a vehicle I suggest you mount them where they can be easily accessed for cleaning.

Gday Leigh,
the 2012+ DMax (unlike the previous model) has the "Variable Voltage Alternator". According to people such as TJM (click link for their description) the voltage can vary from 12.3 up to 15V depending on driving conditions, so upsizing with a diode is not a solution for my mate.

With the solar panel I was thinking of having the best of both worlds - a simple Redarc isolator under the bonnet to give the big amps when the battery is down, and the regulated solar panel to top it up to 14.4V. If I mount the solar panel permanently, then it requires zero input from me - don't have to pack/unpack or turn anything on or off. Like you say, just have to clean it off occasionally.

Hi Phil G',
What TJM is saying is incorrect. My late 2012 DMax consistently charges at 14.2v, it does not vary between 12.3 and 15V.
This is measured by my Scangauge 2.
Regards
Scooby

Hi Phil,

As you can see above opinions differ but have had similar feedback to what your saying for models 2012 on. The mazda BT50 was similar when they first came out I seem to recall reading somewhere that the dealer has the ability to turn of the smart management function in them.

Might be worth seeing if the new DMAX has a similar setting in the engine management system?

Leigh

Gday Penchy,
Good thought that I may yet go with. My roofrack is very low to the roof - Its a mesh platform that I built that slots into the roofrails. I could stick a panel to the roof under the rack - might not work much with the kayak on though. The mesh is 100x100x5 so wouldn't be an issue.

If the panel is obstructed (something over the top of it) it may not work...might be worth checking.

Thanks Wicket - good point.

Hey...It was a $90k car :-)) And I can assure you this is an excuse to spend more money :-)
I'll skip the middle bit.
I've installed and used a heap of aux battery systems over the past 35 years. Just tossing up something a bit different after my mate told me what he was doing with his Dmax. I like to be unconventional.

Phil,

Don't know if you remember back in the early days of EO, well early 2000's anyway.

Couple of members had roof rack mounted panels, one bloke had 2 at front of his rack, one on top of the other, and when parked the lower one was extended out over the bonnet, providing some extra shade, and being supported by a brace off the bullbar.

The second bloke also had 2 panels, side by side, and secured to the rack with lockable window locks. When parked, he could unlock either side and tilt the panels for optimum performance. Seem to recall they both posted photos of the set-ups, so they may be hidden deep in the archives?

Bob

Gday Bob,
Yeah - rings some bells!!
I have a set of folding panels - that you have to carry in the car, have to be setup, moved around and are very easily flogged. I was just thinking of using the flexible ones instead and mounting them somewhere where I didn't have to lift a finger - just set and forget, like the panel on the roof of the Tvan. My mate with the DMax might want to do the tilting trick though, so good thought.

Cheers
Phil

Gday Bantam,
Yeah...not deadly serious - just thinking of other options with the flexible alternatives.
I bought my first solar panel last year - was an alternator diehard until then! I like it its just set and forget, so moving portable panels around to follow the sun is a pain.

Cheers
Phil

Phill mate things that would have seemed rediculous only a few years ago and now either practical or on the verge of being practical.


On the matter of hook and loop tape.......there is no such thing as "Velcro" according to the companie's intelectual property document.

Not too long ago I was a Velcro distributor......I no longer have a commercial interest.

The right grade of good quality hook/loop tape for the application and the amount of hold can be incredible.

many people would not realise the modern aircraft have kilometers of Velcro products holding stuff together...and not just upholstery.
Velcro make hook loop products in combinations of stanless steel, brass and nomex for the aerospace industry.....expensive and not available to the general retail client...but it does exist.

One of the big advantages of hook and loop fasteners is they are uneffected by vibration.....in fact under certain circumstances vibration actually increses the bond...because the hooks wiggle deeper into the loop.


BTW

Anybody serioulsy looking at velcro type attachment methods, should consult their local cpmpany rep.....Velcro or alternative

When I was in the game, Velcro alone used to manufacture at least 5 grades of adhesive that was factory applied to their product.
In addition to their general purpose adhesive, they had products that where more tolerant to water and heat.

One of the things we where drummed on by the reps was getting the right adhesive for the substrate and correct surface preparation methods.

The original patents on the basic hook and loop products have lapsed some time ago and there are many other companiies making hook and loop fasteners.....in a wide variety of quality and performance....
This is why the Velcro companies are so red hot on trademark issues....
Velcro themselves make a down grade budjet product under another name.

If you are looking for performance in a hook loop product make sure you get a quality product that will perform to spec and not just the cheapest thing that comes to hand.

A good hook/ loop product will be fully engineering speced.

Do that and you will be stunned at what can be held by hook and loop fasteners.

So the idea of velcro as a fastener for solar pannels may have been posted in jest......but done right may certainly be viable.

cheers

oops, that Anderson extension lead is 4m Long AND thick. 4 meters thick would be going a little overboard, even for me.

Gday Tony,
I followed your writeup on the Tvan forum. I confess to being inspired by your great use of the flexible panels!

But my Tvan is fine with the 65W panel I put on the roof (no fridge in the Tvan). Really thinking of something that is permanently mounted on the vehicle - so I never have to get it out or set it up. But I still want to be able to carry a double kayak and a bag of lifejackets and seats on the roofrack.

It's great to find another believer in Velcro! But you've got me thinking, that I could just store them away and lay them on the bonnet, roof or wherever as required. Minimal setup required and carrying an extra 4kg of flexible panels is a better option than the 13kgs of bulky folding panels I've got at present.

I've also got a charge lead like yours.
But there's another option is well that I've thought about getting to transfer battery power from the Tvan to the car (or to recharge any flat battery). Its called a Swallow charger and is used by the electric model people. I'd use it as a 6A charger (on the SLA setting) - powered by the Tvan battery to charge the Landcruiser battery. The advantage would be that I could run it overnight, and leave the Tvan solar to do its stuff during the day. But the device itself is one of the best pieces of electric equipment I've ever seen - can use it to recharge any sort of rechargeable battery incl Lipo and also works as a discharger, and can operate off 11-15V or 240V.Link Here. And a disclaimer - my son is the sales manager for the company!

Thanks for the ideas,
Cheers
Phil

Boobook

Just wondering where you got those panels ?

Wicket, I just got them on ebay here

I simply picked these because their dimensions were the largest that would fit on the rear hatch on the Tvan. They seem pretty good and were shipped from Sydney.

Not bad value at $380 plus $40 shipping.

Just found your write up on the Tvan site........these panels are about the only flexible panel that seems to give a decent warranty. So will keep them in mind for a little project that I am planning
thanks

Boobook
Looking at those cables coming from the junction box they look a bit weedy and I'd probably change them so I'm wondering how accessible that junction box is, can it be opened or is it permanently sealed ?

I am not sure which junction box you refer to. I don't have any.

??

If you are talking about the red blocks, they are pairs of red 50A Anderson connectors so I can unplug the panels and use an extension lead when I move the them. The red ones won't fit into standard grey ones and I have standardised on them for all my unregulated solar connections.

Also the 150mm of cables from the panel to the Anderson is what was supplied with the panels on one side, and twin 5mm automotive cable into the hatch roof and to the Regulator, they are covered in white heatshrink. When I use the extension leads, they are 8 B&S.

Am I missing something? The cables are more than up to the task of the 5 Amps available from each panel.

I am referring to the boxe on the panels, the cable that is joined and supplied is 1.5mm2 which I'd like to change , is that feasible?

Kind of changeable wicket.

It opens up easily and you can get access to change over the wires to solder tabs, however it's all covered in silicon to waterproof it. I wanted to put in series Schottky diodes to prevent back flow if shaded but gave up and put them elsewhere.

A bit of hacking and you could get to the solder tabs however if you have concerns I would just limit the length of the supplied cable as I did. The voltage drop at 4A over a short length would be almost immeasurable.

Ok thanks, the ad on the website says the box is customisable so I'm not sure what that meant.
My issue is I'm looking at about 8 or 10 of these panels for the top of a motorhome, from the 1st to last panel in about 3.5 mtrs before I start the cable to the reg so am thinking the supplied cables might be a bit underweight.

oops no need to answer have just realized that these should be ok as the run for each will only be very short but will beef up the cable joining them to the mc y/t types joiners connecting cable