Fixed Solar Installation

[poiu]

If the pump is ok and nothing else is connected 30% capacity loss in a month is abnormal notwithstanding the tests that were done that say the batteries are OK. I had a similar problem on an industrial battery installation once and got advice from the technical director at Enersys batteries. I was told there was no battery analyser (a few years ago) that could detect and diagnose capacity problems, though many devices claim to do this. The best test of health is a full charge, a short equalising charge if sulphation suspected, a few days at float and then a full slow measured discharge. As yours are new I suspect that all you need to do is to do an equalisation charge and keep them on float with your new panels and their health will get back to normal.

[sailorboy1]

Would seem that to just keep the batteries charged at mooring with nothing other that that mystery load on that you wouldn't need a very big panel. You could get a small panel with a removal mount and just take it down when you leave.

But really your resistance to a better panel mounted to the davits due to windage I think is misplaced. It isn't like the panel is sitting up sideways and the windage across the dinghy makes anything the panel would have a non-issue.

[Dockhead]

Originally Posted by poiu

If the pump is ok and nothing else is connected 30% capacity loss in a month is abnormal notwithstanding the tests that were done that say the batteries are OK. I had a similar problem on an industrial battery installation once and got advice from the technical director at Enersys batteries. I was told there was no battery analyser (a few years ago) that could detect and diagnose capacity problems, though many devices claim to do this. The best test of health is a full charge, a short equalising charge if sulphation suspected, a few days at float and then a full slow measured discharge. As yours are new I suspect that all you need to do is to do an equalisation charge and keep them on float with your new panels and their health will get back to normal.

Well, I'm really not having capacity problems -- capacity of the bank as experienced on board improved for a couple of months after new, and have remained at that level ever since. In other words, they are still better than they were when new (and the Argus tester readings correspond exactly). We have complex systems on board with quite a bit of consumption, and without particularly economizing and with 5 or 6 people on board, we get through a whole day and night on 40% or so of the bank's capacity, at which point I run the generator for a couple of hours. That's with dual refrigeration, central heat (which uses a lot of power), quite a bit of inverter use for microwave, electric kettle, toaster, vacuum cleaner, power tools, AV equipment, etc., and with constant charging of many laptops, phones, etc.

I am away from the boat for a month at a time, and will go especially into a marina or port with shore power for at least one day, everytime I am on board, to give a good overnight charge. I equalize at least every other month.

So I really don't have any complaints about battery capacity or power use, except only that I don't like to have to run the generator all day on my last day on board, and I really don't like the batteries sitting partially discharged for a month at a time. These are really the only problems I am trying to solve here, and some kind of solar installation seems just about perfect as a solution.

[ullar]

Originally Posted by sailorboy1

Would seem that to just keep the batteries charged at mooring with nothing other that that mystery load on that you wouldn't need a very big panel. You could get a small panel with a removal mount and just take it down when you leave.

Quite true. However, thinking of it, convenience of fixed panel (the bigger the better) has been a big bonus in my eyes. Nothing to plug in or out, always working, even when one leaves a boat in bit of a hurry. It's really fit and forget installation. There is already quite a number of things to take care of when going out with a boat.

[Dockhead]

Originally Posted by sailorboy1

Would seem that to just keep the batteries charged at mooring with nothing other that that mystery load on that you wouldn't need a very big panel. You could get a small panel with a removal mount and just take it down when you leave.

But really your resistance to a better panel mounted to the davits due to windage I think is misplaced. It isn't like the panel is sitting up sideways and the windage across the dinghy makes anything the panel would have a non-issue.

Yes, it could be that I am exaggerating all of this.

It's not just the windage, it's the appearance of adding still more carp back there.

Also another 20 or 30kg of weight back there.

Still, there are many advantages, so this approach has not been ruled out.

[sailorboy1]

Originally Posted by Dockhead

Yes, it could be that I am exaggerating all of this.

It's not just the windage, it's the appearance of adding still more carp back there.

Also another 20 or 30kg of weight back there.

Still, there are many advantages, so this approach has not been ruled out.

20-30 kg on a 54' boat, not really anything to even consider in my mind

You know you are going to end up regretting it if you don't just put the panels on the boat. Mount them above your bimini like everyone else and you wouldn't even notice them.

[captain58sailin]

I am a little further north of you and what I have witnessed here, at least in the winter the Airex variety wind generators are keeping various types of vessel's batteries charged that are sitting at the dock for long periods of times, I can't give you specific performance specs. just the anecdotal "Does that unit keep your batteries up in the winter?" The answers have all been yes. I use a 42 Watt fixed panel to keep my (4) 8 D batteries up and not frozen. That is a 12 volt system and I have the batteries completely isolated during the storage phase of the year. I intend to go with a much larger panel when I get ready for the full time cruising in the spring. I am also considering a wind generator as an augment, but haven't found one that wasn't quiet enough to suit me.

[Dockhead]

Originally Posted by sailorboy1

20-30 kg on a 54' boat, not really anything to even consider in my mind

You know you are going to end up regretting it if you don't just put the panels on the boat. Mount them above your bimini like everyone else and you wouldn't even notice them.

I don't have a Bimini! Davits is the only place.

[poiu]

Originally Posted by Dockhead

Well, I'm really not having capacity problems -- capacity of the bank as experienced on board improved for a couple of months after new, and have remained at that level ever since. In other words, they are still better than they were when new.

Sorry for being confused. If the + wire is disconnected there can't be any explanation for capacity loss except for internal losses in the battery and I thought you were saying they were completely disconnected, but if capacity is down and the batteries are perfect something has to be connected to do it as you do say. Good luck with your investigations.

Another thought, I find my clamp meter is not great for small currents and unless you have a mega sensitive current clamp you won't be able to measure the single digit milliamp draw. You may find it works better to use a decent multimeter wired in series to find the small current losses.

[downunder]

If you have davits already the damage is done to the lines of the vessel.

Put as much solar as possible with a well designed structure over the davits.

At least 2 if not 3 x 250 w panels.

The solar frame can have other practical uses such as to hold fishing rods/boat hooks.

[downunder]

This picture should have been in my previous post. 750W

Cheers

[IdoraKeeper]

Originally Posted by Dockhead

Yes, it could be that I am exaggerating all of this.

It's not just the windage, it's the appearance of adding still more carp back there.

Also another 20 or 30kg of weight back there.

Still, there are many advantages, so this approach has not been ruled out.

Do not put carp on the back of the boat. Seagulls will know and the mess will be horrible. Put carp on the pontoon, dead carp are fine on the pontoon...seagulls will stay with the pontoon. Continue to run genset when underway. Just say no to carp.

[senormechanico]

Dockhead,

You have batteries in good shape, but when replacement is in the picture, I hope you will look at Lithiums.

No mess, no leaks, don't care if they are charged or not, nearly NO taper to the charge curve, actually prefer NOT being fully charged, depth to 80 % discharge, half the weight etc. Peukert exponent (put in 120% of charge to get 100% as with LA) is near unity (1.01). In other words, almost 99% efficient.

I'd never go back even if LA's were FREE. Really!

Oh yeah, and I agree about no Carp.

[darylat8750]

Check out MaineSails How to on flexible panels on a bimini if you are worried about looks. I'm a "form follows function" guy myself and would put as much solar as I could on the davits.

[senormechanico]

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