Immersion and Solar

[Paul C]

Wouldn't it be a bit of a nightmare to plumb in, given that you'd need a header tank above the panel, and a way of completely draining it in the winter (yet still keeping the regular eg calorifier hot water working)?

[smileypete]

Navitron have a smaller solar hot water panel that looks like it'll perform at low angles:

 

http://www.navitron.org.uk/product_detail.php?proID=709&catID=117

 

I'd expect it'd be used with non toxic antifreeze and to heat the water indirectly.

 

ETA: Seems it can be had more cheaply from other suppliers:

 

http://www.swithenbanks.co.uk/Solar_Hot_Water/1130512/Navitron_Fino_Flat_Plate_Solar_Hot_Water_Panel.html

 

cheers, Pete.

~smpt~

Edited April 26, 2013 by smileypete

[Jambo]

Wouldn't it be a bit of a nightmare to plumb in, given that you'd need a header tank above the panel, and a way of completely draining it in the winter (yet still keeping the regular eg calorifier hot water working)?

 

I'm particularly clueless when it comes to plumbing so I don't know how tricky it would be but as far as I know most domestic installations don't have a header tank above the panel. The system is usually sealed and the fluid is pumped between the panel and the tank.

[Paul C]

I'm particularly clueless when it comes to plumbing so I don't know how tricky it would be but as far as I know most domestic installations don't have a header tank above the panel. The system is usually sealed and the fluid is pumped between the panel and the tank.

 

Yeah I think that would be easier, you'd just need to make sure it could self-bleed. Using antifreeze and a heat exchanger sounds sensible too but would obviously lose a little efficiency over the direct solution. I wonder why we don't see any solar heating panels on narrowboats though, I've never seen or heard of one? Seen plenty of electrical solar panels though. Maybe its simply not cost effective to do?

[Grace and Favour]

Yeah I think that would be easier, you'd just need to make sure it could self-bleed. Using antifreeze and a heat exchanger sounds sensible too but would obviously lose a little efficiency over the direct solution. I wonder why we don't see any solar heating panels on narrowboats though, I've never seen or heard of one? Seen plenty of electrical solar panels though. Maybe its simply not cost effective to do?

There are a few about, in fact, there'll be a couple of old threads on CWDF on the subject.

[lewisericeric]

Cheers for the comments guys but still quite in the dark about it all. Will let you know how I get on

[Jambo]

Navitron have a smaller solar hot water panel that looks like it'll perform at low angles:

 

http://www.navitron.org.uk/product_detail.php?proID=709&catID=117

 

I'd expect it'd be used with non toxic antifreeze and to heat the water indirectly.

 

ETA: Seems it can be had more cheaply from other suppliers:

 

http://www.swithenbanks.co.uk/Solar_Hot_Water/1130512/Navitron_Fino_Flat_Plate_Solar_Hot_Water_Panel.html

 

cheers, Pete.

~smpt~

 

Navitron's curtained panels also look very interesting:

 

http://www.navitron.org.uk/product.php?proID=153

 

The curtain means you can shut them down if you're away / the tank is full, the glass box would be nice for protecting the tubes.

[Guest]

Hi there as a footnote to this topic my 12 volt immersion heater has burned out it is less than a year old and was allegedly made in this country the warranty to be honest isnt worth the paper it is printed on as is with most ebay items! So its back to the 240 volt item and use it as a dump load and see how that works

 

 

Peter

[smileypete]

Hi there as a footnote to this topic my 12 volt immersion heater has burned out it is less than a year old and was allegedly made in this country the warranty to be honest isnt worth the paper it is printed on as is with most ebay items! So its back to the 240 volt item and use it as a dump load and see how that works

 

 

Peter

What's the MPPT voltage of your solar array, and the wattage of the immersion?

 

cheers, Pete.

~smpt~

[Guest]

It had 300 watts on it . I will now add those panels to my main array which will take me up to about 1400 - 1500 watts in two banks connected in series to two separate mppt controllers about 90 volts on each.The immersion is one kilowatt at 240 volt my friendly panel builder electrician says it should be ok? but we will see?

 

 

Peter

[DeanS]

Wouldnt the "right thing to do" in the case of one boater having too much electricity, be for him/her to put up a sign saying..."recharge your batts here"...with a shoreline connector available so another boat could moor alongside, and connect up..

 

 

JUST A THOUGHT....LOL

[smileypete]

It had 300 watts on it . I will now add those panels to my main array which will take me up to about 1400 - 1500 watts in two banks connected in series to two separate mppt controllers about 90 volts on each.The immersion is one kilowatt at 240 volt my friendly panel builder electrician says it should be ok? but we will see?

 

 

Peter

OK if you can unplug your 240V 1kW immersion and connect the L and N pins on the plug directly to one of your arrays running at 90V DC, it should give around 140W of heat to the calorifer, better than nothing.

 

If the array is 750W then it it might not affect it all that much, and the controller can still do it's MPPT thing.

 

BTW Dean are you solared up yet? Have you decided to buy 2kW of solar in the end, or thrown the desktop in the cut, or has the long suffering wife has plundered your solar fund, lol!

 

cheers, Pete.

~smpt~

Edited May 10, 2013 by smileypete

[DeanS]

BTW Dean are you solared up yet? Have you decided to buy 2kW of solar in the end, or thrown the desktop in the cut, or has the long suffering wife has plundered your solar fund, lol!

 

cheers, Pete.

~smpt~

 

The panels arrived today and are currently taking up all the living space in the saloon

The controllers arrive next week.

I dont know how to connect it all up yet, so might msg you shortly if thats ok

[smileypete]

The panels arrived today and are currently taking up all the living space in the saloon

The controllers arrive next week.

I dont know how to connect it all up yet, so might msg you shortly if thats ok

 

Sure, feel free to or better still start a thread, would be good to have more input from everybody and might help others planning to get some solar too.

 

cheers, Pete.

~smpt~

Edited May 10, 2013 by smileypete

[Paul C]

The panels arrived today and are currently taking up all the living space in the saloon

The controllers arrive next week.

I dont know how to connect it all up yet, so might msg you shortly if thats ok

 

Actually instead, have a look at "christianonthecut"'s thread - he is in a very similar position to you, having just purchased solar panels and about to wire them up. You should be able to look at this thread and see how they're wired up. Its just a simple addition check to ensure you're not going to go over the input voltage, after all.

[smileypete]

Dean PMed me a little while ago so I replied with the following:

 

Hi,

 

It's better to have the MPPT reasonably near the batts, but somewhere secure and meets the install requirements for ventilation, and also is protected from condensation forming on the steelwork above or inside the MPPT itself.

 

Fixing a plastic drip cover or even a piece of insulation board over it will protect it from drips from above, and fixing it on wood battens to isolate it from and space it away from the steelwork should help prevent condensation forming inside. It won't be a problem in summer of course but come winter....

 

As far as cable size between a 30A MPPT and batts goes, if the MPPT is within say 2m from batts then 10mm² is a reasonable minimum as long as the cables aren't buried in a bundle or in conduit.

 

If the MPPT is up to 3m from batts then 16mm² is better, that said it wouldn't hurt to use that size anyway for lesser distances if it's not much dearer. For a 60A MPPT or 2x30A MPPT just double the cable sizes.

 

Of course dont forget to fit a fuse in the positive near the batts, rated to the output of the MPPTs.

 

For connecting the panels, as you say daisy chain the male and female sockets to connect them in series. For the cable between panels and MPPT, 4mm² will be plenty and is the minimum size for pukka weather resistant solar cable. Smaller cheaper cable might do it but not really worth it unless the budget is really tight.

 

If you have say 3m between MPPT and panels you could get a premade 6m 'extension' cable off Ebay and just cut in half to give two 3m bits with a male or female at one end and then strip the cable at the other cut end to connect to MPPT.

 

I think the MPPT instructions may say to connect the batts first, then the panels. Check the polarity of the voltage coming from the panels as the wires are both black and it's easy to get them mixed up! If you have say 4 panels and 2 MPPTs then you'll need to run 2 cables from each series pair of panels and make sure they're not cross connected in any way.

 

I think that just about covers it on the wiring side, that still leaves some sort of brackets to allow possible tilting and make it easier to lock down and more secure. If you start a thread or search the forum that'll turn up some ideas, maybe something along the lines of fixing the panels securely to a frame of decking timber so that the whole thing is heavier and can be tilted or locked down to hand rails.

 

cheers, Pete.

~smpt~