Solar chargeing

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Wansworth

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The nature of my sailing means the boat is stored ashore for 9 months of the year in the uk.This year I will be buying new batts and would like to be able to trickle charge them without worry or human interference.What I need is a Janet and John book in colour with simple explanations and neat drawings,thanks.
 
mogy said:
The nature of my sailing means the boat is stored ashore for 9 months of the year in the uk.This year I will be buying new batts and would like to be able to trickle charge them without worry or human interference.What I need is a Janet and John book in colour with simple explanations and neat drawings,thanks.
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Two battery banks?

Two small solar panels, one wired to each.
Simple controllers if the ratio watts to Ah is greater than 1:10 or if the panels are greater than 10 watts . Fuses as close as possible to the connections to the battery positives

OR

One slightly larger panel and a simple two output controller. One output to each battery bank. Fuses as above
 
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Mogy, my boat is ashore near Vigo and I worked out that a 65W panel would just about cope with self-discharge during the worst month (December) in an average year. You'd need to scale your panel based on your own batteries.

Remote measurements taken around 02:00 at night showed that readings remained fairly level at 12.8V between November and March.

I have a 65W panel linked to a Marlec HRDi regulator feeding 2 banks:

450Ah 4xTrojan T105 with a self-discharge rate of around 0.5% / week
100Ah 2xOptima Redtop AGM with a self-discharge rate of around 4% / week

I'll need to look up the exact figures. Optima have a very low self-discharge and T105s are pretty high vs. 12V leisure type batteries. Meant to add that these figures will be at quite high temp. >20C so actual discharge will be much lower in winter months.
 
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Mistroma said:
Mogy, my boat is ashore near Vigo and I worked out that a 65W panel would just about cope with self-discharge during the worst month (December) in an average year. You'd need to scale your panel based on your own batteries.

Remote measurements taken around 02:00 at night showed that readings remained fairly level at 12.8V between November and March.

I have a 65W panel linked to a Marlec HRDi regulator feeding 2 banks:

450Ah 4xTrojan T105 with a self-discharge rate of around .5% / week
100Ah 2xOptima Redtop AGM with a self-discharge rate of around 4% / week

I'll need to look up the exact figures. Optima have a very low self-discharge and T105s are pretty high vs. 12V leisure type batteries.
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So you are doing the reverse leaving your boat in Galicia!The tech bit Iamafraid ent rightbover my head.In theory I ill have a starting batt and a leisure batt.Maybe I illget by ith just a starting batt and use my oillamps.Just seems s shame tohave to buy another batt for the next year.
 
mogy said:
So you are doing the reverse leaving your boat in Galicia!The tech bit Iamafraid ent rightbover my head.In theory I ill have a starting batt and a leisure batt.Maybe I illget by ith just a starting batt and use my oillamps.Just seems s shame tohave to buy another batt for the next year.
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Yes, just heading back in a few weeks time for 6-7 months.

I thought that my figures would be useful if you are leaving the boat over the winter months. To keep it simple, my main batteries lose charge faster than most so your batteries would almost certainly get away with a smaller sized panel. The self-discharge rates I found were at 26C and will be much lower in winter, giving an additional safety factor.

At its simplest, 65W for 450Ah means you only need 13W for a 90Ah battery. Then you need to allow for the fact that a normal cheap leisure battery self-discharges much more slowly than mine. So you are probably looking at a panel in 5W - 10W range (5W should keep a 90-100Ah battery charged up over winter).

More information would help. e.g. Are you leaving it over the winter months or was that an incorrect assumption? Are you buying a cheap leisure battery or something else and what capacity in Ah (for both batteries)? Summer output will probably peak at 4 - 5 times output in December.

I hope that helps.

I am actually trying to get another panel and currently have 2 options in eBay. Someone in Lugo is selling panels and I should be able to drive there on way from Asturias down to Vigo and pick it up. However, his output and panels sizes don't make sense and I'm a bit worried about that aspect. The other option was to buy for a German company and have them shipped.

Do you know of any reliable suppliers near Vigo? I'll have a car for a few days and be able to drive around a bit.
 
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Mistroma said:
Yes, just heading back in a few weeks time for 6-7 months.

I thought that my figures would be useful if you are leaving the boat over the winter months. To keep it simple, my main batteries lose charge faster than most so your batteries would almost certainly get away with a smaller sized panel. The self-discharge rates I found were at 26C and will be much lower in winter, giving an additional safety factor.

At its simplest, 65W for 450Ah means you only need 13W for a 90Ah battery. Then you need to allow for the fact that a normal cheap leisure battery self-discharges much more slowly than mine. So you are probably looking at a panel in 5W - 10W range (5W should keep a 90-100Ah battery charged up over winter).

More information would help. e.g. Are you leaving it over the winter months or was that an incorrect assumption? Are you buying a cheap leisure battery or something else and what capacity in Ah (for both batteries)? Summer output will probably peak at 4 - 5 times output in December.

I hope that helps.

I am actually trying to get another panel and currently have 2 options in eBay. Someone in Lugo is selling panels and I should be able to drive there on way from Asturias down to Vigo and pick it up. However, his output and panels sizes don't make sense and I'm a bit worried about that aspect. The other option was to buy for a German company and have them shipped.

Do you know of any reliable suppliers near Vigo? I'll have a car for a few days and be able to drive around a bit.
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Yes the boat is laid up in Chichester.The batts came ith the boat are probably useless no.I plan on buying at least a starting battery for the coming season 70ah .So a simple set up hich ould maintain that battery over the next winter.I live near Lugo but I am the least indicated to assist you in solar panels.If you send me an address I can go and visit them.As for Vigo I have no idea .Thanks for your advice.
 
I leave a van parked up for a couple of months at a time. A 20 Watt panel propped up in the windscreen keeps the battery topped up in spite of the immobilizer, radio and central locking receiver remaining connected and operative.

On the boat I have 240 watts of solar panels which stay connected for similar lengths of time to your layups. They are controlled by a top of the range charge controller. When aboard in the Greek summer they make headway against the fridge, radio and sailing instruments.

Rigging solar panels is pretty simple but depends on what sized panels and what controller you use. Most important is to minimise the voltage drop from the panels to the controller and then battery.
 
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mogy said:
Yes the boat is laid up in Chichester.The batts came ith the boat are probably useless no.I plan on buying at least a starting battery for the coming season 70ah .So a simple set up hich ould maintain that battery over the next winter.I live near Lugo but I am the least indicated to assist you in solar panels.If you send me an address I can go and visit them.As for Vigo I have no idea .Thanks for your advice.
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Intially, thought the boat was wintering in Galicia so my estimated output in December would be too high. You'd only expect to get around 40% of the output I was expecting for Galicia. Even so, Chichester will be much colder (hence self-discharge slower) and you are only talking about 70A battery. I still think that a 5W panel would be OK as long as the battery started off fully charged.

Fitting is really simple with a small panel and one option is just to disconnect the battery from the boat's electrics and use decent crocodile clips to connect the panel. If you get a much larger panel you will need to buy a regulator as well but it sounds as if you won't need to do that.

I seem to remember that you'd get away without a regulator on a 70Ah battery as long as the panel was less than 7W. Not much of a risk with a 5W panel in winter as output is going to be pretty small.

Hopefully someone else will provide some additional information based on experience in Chichestr area during winter.
 
My boat is in Chi Hbr and I have 2 x 15W panels that keep my 2 x 110 Ah batts full All winter after a good charge with shore power at the start. I have a single bank 10W Phocos regulator, that is worth having as it is 2-stage - bulk and float.
I also have a Voltage Sensitive Relay (VSR) that prioritises the start battery first, then links the house battery when the start batt reaches 13.8V. Some 2-bank regulators (or charge controllers as they are often called) have a VSR built in.
D
 
Not a huge range in responses with one exception:

1) 5W without a regulator should be OK
2) 8.2W with a regulator (pro-rata 35W with 300Ah bank, Chichester area)
3) 9.5W with a regulator (pro-rata 30W with 220Ah bank)
4)20 Watt panel propped up in the windscreen of a van so battery probably around 60-70Ah.

Simple pro-rata calc. based on battery size isn't completely accurate but probably good enough to indicate approx. panel you need.

Last one is odd man out but it also copes with immobilizer, radio and central locking receiver so might explain it.

So 5W with no regulator or 10W or larger with a regulator. I've never heard anyone say that they have too much solar power so 10W or above might be a worthwhile investment. Otherwise, just use a temporary 5W panel connected via decent clips and wire.
 
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Mistroma said:
Not a huge range in responses with one exception:

1) 5W without a regulator should be OK
2) 8.2W with a regulator (pro-rata 35W with 300Ah bank, Chichester area)
3) 9.5W with a regulator (pro-rata 30W with 220Ah bank)
4)20 Watt panel propped up in the windscreen of a van so battery probably around 60-70Ah.

Simple pro-rata calc. based on battery size isn't completely accurate but probably good enough to indicate approx. panel you need.

Last one is odd man out but it also copes with immobilizer, radio and central locking receiver so might explain it.

So 5W with no regulator or 10W or larger with a regulator. I've never heard anyone say that they have too much solar power so 10W or above might be a worthwhile investment. Otherwise, just use a temporary 5W panel connected via decent clips and wire.
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Thanks!........enjoy your time in Galicia!
 
70w 'shade tolerant' rigid panel seems to keep two house and two engine batteries topped up even thru the current months in uk.
Where you winterise, the trick will be to keep the panel(s) green slime/mold free because that will reduce output!

I have a Rutland controller that regulates the solar input ( as well as the wind generator) and gives at-a-glance battery levels information, for what it's worth..
Dealbreakers with solar are undersized cables, too many/corroded/cheap thrudeck connectors, and poorly made cheap panels that start to fall apart or corrode...
I also have a Solarex 18w semi rigid panel that I bought in 1996, it has 'shone out' to the Windies and resided on 3 boats now, still going strong, but IIRC it cost £180 then! So , quality has gone up and prices down but there are rubbish cheapie around too...
 
Blueboatman said:
70w 'shade tolerant' rigid panel seems to keep two house and two engine batteries topped up even thru the current months in uk.
Where you winterise, the trick will be to keep the panel(s) green slime/mold free because that will reduce output!

I have a Rutland controller that regulates the solar input ( as well as the wind generator) and gives at-a-glance battery levels information, for what it's worth..
Dealbreakers with solar are undersized cables, too many/corroded/cheap thrudeck connectors, and poorly made cheap panels that start to fall apart or corrode...
I also have a Solarex 18w semi rigid panel that I bought in 1996, it has 'shone out' to the Windies and resided on 3 boats now, still going strong, but IIRC it cost £180 then! So , quality has gone up and prices down but there are rubbish cheapie around too...
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Not only slime,bird droppings,obviously bigger panel to tke into account loss of captive area will be needed.Ithink I might go for battery installed in a plstic box on deck with short cble run.For my needs I just need a strting battery.
 
mogy said:
Not only slime,bird droppings,obviously bigger panel to tke into account loss of captive area will be needed.Ithink I might go for battery installed in a plstic box on deck with short cble run.For my needs I just need a strting battery.
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Installing in a plastic box isn't a good idea for most panels. Many, if not all, of the larger rigid panels have a glass coating that's pretty tough and also self-cleaning to some extent. Plastic will probably pick up more dirt and grime and also spread any shadow over a larger area as it will be further away from the surface of the panel. I'd have thought that even a 5W panel would have a glass cover but it would probably stay cleaner than perspex even if it doesn't.

I imagine that a regular dose of heavy rain will keep it clean. Thick snow lying for several weeks would be a problem but not too common.
 
Mistroma said:
Installing in a plastic box isn't a good idea for most panels. Many, if not all, of the larger rigid panels have a glass coating that's pretty tough and also self-cleaning to some extent. Plastic will probably pick up more dirt and grime and also spread any shadow over a larger area as it will be further away from the surface of the panel. I'd have thought that even a 5W panel would have a glass cover but it would probably stay cleaner than perspex even if it doesn't.

I imagine that a regular dose of heavy rain will keep it clean. Thick snow lying for several weeks would be a problem but not too common.
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No the idea is to put the battery in plastic container on deck with solr panel close by.
 
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