Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 19:37:32 GMT
Be gentle with me please.
Thinking of having a couple of panels fitted (finally ) this summer.
I'll be getting a company in to do the work ... that's not up for discussion.
The thing is we have a starter battery and 3 x 110 ah service batteries at the stern, and additionally 2 x 110ah batteries in the bow, which operate the fridge (and the bow thruster which isn't used).
All the batteries are charged by the twin alternators on a Beta 43.
I assume that two large solar panels on the rear of the roof, will supply power to ALL the batteries ?
Or will the front batteries need their own panel ?
Rog
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 19:44:41 GMT
If the fridge currently works from the batteries up the front of the boat then presumably the answer is yes.
How they are charged is a reasonably interesting question. Are there really long quite thick wires or is it done using an inverter and a AC battery charger at the front of the boat.
The latter would take out the voltage drop problem but the former is more simple while requiring larger cabling.
And I was like "well you did ask".
Isn't it.
|
|
|
Post by Jim on Feb 24, 2021 19:50:49 GMT
I daresay you've researched it, but flat panels are easy to nick with a couple of spanners. I've got a stick down panel, hard to remove in one piece.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 19:57:59 GMT
12 v fridge ... and as it's worked for 16 years I guess the cables are thick enough.
I've been persuaded against stick down panels.
However I do not want tilting panels ... at the moment I'm favouring panels on fixed low legs (no messing needed) leaving an inch or two of ventilation space from the roof.
Rog
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 20:15:57 GMT
Flat and raised slightly is the right thing. Rigid panels last longer.
Do you need to walk on that section of the cabin top?
If not then there are some pretty wicked large panels around like the 365w Canadian solar and the JA 325w panels I recently put on top of the wheelhouse on Dulcinea.
Amazing they arrr.
The bloke I got them from said there are going to be 500w+ panels coming soon.
They might even be here already I have forgotten about it all due to lock down.
These big panels with Victron MPPT do seem remarkable but then the last time I bought solar panels was in about 1997 they were 75w BP panels and cost £350 each.
These 350w panels were less than £100 each a total of 1kw including two MPPT units came out as about £700. The same price as two BP solar 75w panels in the late 90s !!
Amazing really and they will probably last longer.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 20:19:34 GMT
flat panels are easy to nick with a couple of spanners I wonder if the panels could be secured with the sort of security nuts you find on a lot of car wheels. Not sure but I think the common thread size is 13x1.5 coarse thread.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 20:21:14 GMT
I daresay you've researched it, but flat panels are easy to nick with a couple of spanners. I've got a stick down panel, hard to remove in one piece. That's a good point. The scrote who advertised my stolen heater also had a large solar panel on his eBay listings so this does prove your point. Easy to steal but also very expensive to send by post so that could prove interesting.
|
|
|
Post by Telemachus on Feb 24, 2021 20:29:10 GMT
I would expect that your small alternator charges the engine battery and the large alternator charges the domestic and bow batteries. So you can just connect the solar charger to the domestic batteries. No need to charge the engine battery from solar,
Stick down panels seem like a good idea but the perceived wisdom seems to be that they have a very short life.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 20:36:11 GMT
They seem to suffer from inter cell connections breaking thus making the thing useless. The worst thing about it is that you then have to rip them off the boat and make good where they were stuck down.
False economy I reckon.
Plus of course if they don't have a non slip surface they would be a nasty hazard if you did ever try to walk on them.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 21:00:42 GMT
Security torx fixing bolts helps with stopping the panels being nicked. I put my panels down the front to keep them out of the way of the centre rope. Go for the highest voltage panels the controller will deal with as they will be better in low light conditions, plus it reduces volt drop.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 21:38:16 GMT
I would expect that your small alternator charges the engine battery and the large alternator charges the domestic and bow batteries. So you can just connect the solar charger to the domestic batteries. No need to charge the engine battery from solar, Stick down panels seem like a good idea but the perceived wisdom seems to be that they have a very short life. Thank you. Obviously the 'company' I choose will eventually advise on the details of installation in due course ... I was just trying to get my head around it. I think two large 315w panels will fit and do nicely ... we shall see. Rog
|
|
|
Post by Clinton Cool on Feb 24, 2021 22:05:32 GMT
Good on you for finally making the decision to have solar.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 24, 2021 23:09:46 GMT
12 v fridge ... and as it's worked for 16 years I guess the cables are thick enough. I've been persuaded against stick down panels. However I do not want tilting panels ... at the moment I'm favouring panels on fixed low legs (no messing needed) leaving an inch or two of ventilation space from the roof. Rog Don’t get stick down panels, they are utter crap and have a short lifespan. Idealy, you’ll want a panel and mppt nearer the batteries at the front, otherwise long leads will suck up the power. Then a couple of panels nearer the stern with an mppt to charge your main bank. Pissing about with tilt systems is a mugs game, just sit them flat with legs or boxes.
|
|
|
Post by quaysider on Feb 25, 2021 8:36:06 GMT
I am still wondering how the front 2 are currently charged... long thick cables to the alternator, or mains charger? . Assuming the former, (and assumed isolation when not charging from the rear battery bank), I might be inclined to have the panels attached independently - 1 up front to the fridge batteries and 1 down the back for the others. Rather than spending more on expensive mppt controllers, a pair of pwm would probably be fine given you're not live-aboard and don't need to eek the last drop of power out of the batteries in the middle of winter. It's not like you run any big appliances (hair-dryers a side).
Thinking about your mooring habits (to avoid trees anyway) it's not so likely you'll end up with shading causing a problem - and even if it did (from a chimney or whatever) if the panels are independently located and connected to different battery banks, it wouldn't matter.
Do you really need 2 panels? - one for the fridge up front might be enough - I realize, you might be future proofing for when you install a large tv system to run from the other batteries etc.
Questions alas, and not answers . I still can't decide whether to replace my 3 smaller ones with 2 bigger ones... if I do, I'm tempted away from the mppt controller (mine is 50a) cause by the time you get into bigger territory, they are over 200 quid.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 25, 2021 9:00:18 GMT
In truth, I've no idea what I'll need ... I plan to invite someone in to advise me once we're settled back on board. We've managed happily without solar for 16 years as, for us, boating is getting back to basics and more like 'glamping' than home life. We have no intention of getting tv's, coffee makers, micro wave, or any other gadgets ... just hope to garner sufficient power to be able to not run the engine (or at least reduce engine running) on days we choose not to cruise. Basically it's feeding the 12v fridge. I mentioned two large panels as that's basically the only free roof space I have. I understand the latest panels are very efficient, so for our needs, one may well be enough. I have to be honest ... had we not been locked-down last spring for eleven weeks, I probably wouldn't have bothered with solar ... but that period in a sunny spot made me reconsider. It'll be just my luck that finally getting solar fitted this year, C&RT will outlaw it like the dry toilets ! Rog ETA Excellent blog as usual quaysider
|
|