warwicksail
Well-Known Member
Have spotted these tday at maplin I have two 110 amp hour batterys http://www.maplin.co.uk/Module.aspx?ModuleNo=217850&source=1&DOY=8m3
SOLAR PANNELS
- Thread starter warwicksail
- Start date
VicS
Well-Known Member
[ QUOTE ]
Have spotted these tday at maplin I have two 110 amp hour batterys
[/ QUOTE ] 12 watts not big enough.
Two of them, one for each battery, would just about keep them charged, and recharge between fortnightly weekend outings if you were cautious with your power use and were able to mount them permanently in good positions.
Not many are even going to agree with me about that!
Have spotted these tday at maplin I have two 110 amp hour batterys
[/ QUOTE ] 12 watts not big enough.
Two of them, one for each battery, would just about keep them charged, and recharge between fortnightly weekend outings if you were cautious with your power use and were able to mount them permanently in good positions.
Not many are even going to agree with me about that!
Relax
Well-Known Member
I was 'given' a Chrissy prezzy (from SWMBO) of a tiny 1.5W 'Maplins' solar panel - and promptly stuck it in the garage and forgot about it.
The other day tho I came across it and attached it to one (only) of my 85AHr batteries. It works!! After several days (4-5) on charge it has pulled the voltage up from 12.6 to 13 volts indicated.
I've bought another ...... see how we go!
The other day tho I came across it and attached it to one (only) of my 85AHr batteries. It works!! After several days (4-5) on charge it has pulled the voltage up from 12.6 to 13 volts indicated.
I've bought another ...... see how we go!
VicS
Well-Known Member
[ QUOTE ]
After several days (4-5) on charge it has pulled the voltage up from 12.6 to 13 volts indicated.
[/ QUOTE ] If and when you get up to 14.4 V is the time to consider that you have got the battery anywhere fully charged. Then if you disconnect the panel and still have 12.7 volts or better 24 hours later you'll know it's fully charged. You'll get there eventually provided the battery is not duff.
If you put Warwicksail's 220Ah of battery on it you'd be lucky if it kept pace with the self discharge rate.
After several days (4-5) on charge it has pulled the voltage up from 12.6 to 13 volts indicated.
[/ QUOTE ] If and when you get up to 14.4 V is the time to consider that you have got the battery anywhere fully charged. Then if you disconnect the panel and still have 12.7 volts or better 24 hours later you'll know it's fully charged. You'll get there eventually provided the battery is not duff.
If you put Warwicksail's 220Ah of battery on it you'd be lucky if it kept pace with the self discharge rate.
Rabbie
Well-Known Member
So how would the Maplins jobbie working at 12W work on a, say, 85AH battery?. Is this good value for money or a waste of time. No deep tech stuff please Vic as I am electrophobic.
Relax
Well-Known Member
Thats 13 volts with the panel off for 24 hours - its now on the other battery.
Going to wire them both through the battery switch to avoid all the croc clip stuff.
Going to wire them both through the battery switch to avoid all the croc clip stuff.
VicS
Well-Known Member
[ QUOTE ]
12W work on a, say, 85AH battery
[/ QUOTE ] I would expect a 12W panel to keep a 85Ah battery charged OK. I have for several years had a 5 watt panel charging a 40 or 45 Ah battery. Its has done what I wanted which was basically to avoid the need to take the battery home once or twice during the season for charging. But it all depends on how much power you use. If you use more in a weekend than the panel can produce in 7 days then the battery will not be recharged by next weekend. Remember also that batteries don't like being left partly discharged, the sooner they are recharged the better.
I do have modest electrical demands. I seldom sail at night I manage with just one fluorescent lamp in the cabin, although there are three altogether. I have a hurricane lantern as an anchor light, the VHF is hardly ever used for transmitting. I have no pumps or power hungry electronics, but I do use an Autohelm most of the time. Also I get no where close to using the boat every weekend.
12W work on a, say, 85AH battery
[/ QUOTE ] I would expect a 12W panel to keep a 85Ah battery charged OK. I have for several years had a 5 watt panel charging a 40 or 45 Ah battery. Its has done what I wanted which was basically to avoid the need to take the battery home once or twice during the season for charging. But it all depends on how much power you use. If you use more in a weekend than the panel can produce in 7 days then the battery will not be recharged by next weekend. Remember also that batteries don't like being left partly discharged, the sooner they are recharged the better.
I do have modest electrical demands. I seldom sail at night I manage with just one fluorescent lamp in the cabin, although there are three altogether. I have a hurricane lantern as an anchor light, the VHF is hardly ever used for transmitting. I have no pumps or power hungry electronics, but I do use an Autohelm most of the time. Also I get no where close to using the boat every weekend.
vyv_cox
Well-Known Member
It depends a great deal on what you expect them to do. To restore the power you used at the weekend during the following week, they might just be enough, although a little small. A 12 Watt panel in the UK will give you half an amp at best during the day, even at the height of summer.
In UK for weekend sailing I had a 38 Watt panel to charge two 105 Ah domestic batteries and a 105 Ah starter battery. This was adequate. Now that the boat is in the Med and the fridge runs non-stop May to October, I have the original 38 Watt panel plus 125 Watts on the stern. This will be fine in June and July but only just enough in October.
In UK for weekend sailing I had a 38 Watt panel to charge two 105 Ah domestic batteries and a 105 Ah starter battery. This was adequate. Now that the boat is in the Med and the fridge runs non-stop May to October, I have the original 38 Watt panel plus 125 Watts on the stern. This will be fine in June and July but only just enough in October.
simonfraser
Well-Known Member
i've got 2 12W, it keeps 110A battery & gps/autohelm/eberspacher for a few hours sailing / fidling per week. plus led anchor light 24/7 ! this is for feb in essex.
BUT, you must mount the solars near vertical during the winter, check with the solars on the road side.
BUT, you must mount the solars near vertical during the winter, check with the solars on the road side.
ccscott49
Well-Known Member
Its not going to work, simple as that. You lose more than that in self discharge and in the UK not going to put it back with 12w of solar power for 5 hours a day.
nmelton
Member
After all that has been said I have to say that for the last 5 yrs or so my flexible Unisolar 10W panel has kept my two 110 amp batteries fully charged on a swinging mooring during the summer months!
VicS
Well-Known Member
[ QUOTE ]
10W panel has kept my two 110 amp batteries fully charged on a swinging mooring during the summer months
[/ QUOTE ] Yes but I suspect your Moody has a decent inboard engine with good sized alternator. IIRC Warwicksail does not have an inboard engine, he is just using an outboard which will provide him with b88ger all electrical power.
All you are asking your solar panels to do is to keep the batteries, that will be almost fully charged when you leave the boat, fully topped up while you are away. Its not the same situation as Warwicksail is in at all. He needs a panel that will supply all his electrical power requirements.
10W panel has kept my two 110 amp batteries fully charged on a swinging mooring during the summer months
[/ QUOTE ] Yes but I suspect your Moody has a decent inboard engine with good sized alternator. IIRC Warwicksail does not have an inboard engine, he is just using an outboard which will provide him with b88ger all electrical power.
All you are asking your solar panels to do is to keep the batteries, that will be almost fully charged when you leave the boat, fully topped up while you are away. Its not the same situation as Warwicksail is in at all. He needs a panel that will supply all his electrical power requirements.
simonfraser
Well-Known Member
ok, here is watt one 12W unisolar puts out feb in essex,
100mA total cloud and rain, 700mA suni.
are you realy saying that a 110Av lead acid battery discharges at a rate more than the above ????? mine def does not, & like i said before there is plenty of charge left for the weekend. but you gota mount them nearly upright for winter use.
100mA total cloud and rain, 700mA suni.
are you realy saying that a 110Av lead acid battery discharges at a rate more than the above ????? mine def does not, & like i said before there is plenty of charge left for the weekend. but you gota mount them nearly upright for winter use.
William_H
Well-Known Member
That price is good for 12watts.
Yes of course it wil overcome self discharge and in fact give some usefull charge. The size of the panel is such that it will not be so difficult to mount. But of course 2 panels would be twice as good.
olewill
Yes of course it wil overcome self discharge and in fact give some usefull charge. The size of the panel is such that it will not be so difficult to mount. But of course 2 panels would be twice as good.
olewill
charles_reed
Well-Known Member
Vic
How on earth did you know Warwicksail had such an inadequate means of recharging his batteries?
Dies Sherlock Holmes still practise?
How on earth did you know Warwicksail had such an inadequate means of recharging his batteries?
Dies Sherlock Holmes still practise?
VicS
Well-Known Member
Re: Vic
[ QUOTE ]
How on earth did you know
[/ QUOTE ] Statements like this are a clue, but there are others.
"I have an alternator output on my mariner sailmate 8hp,"
[ QUOTE ]
How on earth did you know
[/ QUOTE ] Statements like this are a clue, but there are others.
"I have an alternator output on my mariner sailmate 8hp,"
ccscott49
Well-Known Member
How long does your solar panel give this output for?
When did you test the output?
What with?
At what time of the day?
What exactly do you mean by "plenty of charge left for the weekend", enough to start your engine?
Do you actually know exactly what state of charge your batteries are at?
How do you know how much your batteries self discharge?
These questions answered will help tell me and others how much the panels are putting into your batteries.
Thanks.
When did you test the output?
What with?
At what time of the day?
What exactly do you mean by "plenty of charge left for the weekend", enough to start your engine?
Do you actually know exactly what state of charge your batteries are at?
How do you know how much your batteries self discharge?
These questions answered will help tell me and others how much the panels are putting into your batteries.
Thanks.
simonfraser
Well-Known Member
sounds like an exam !
When did you test the output? -- feb 08
What with? -- digital multimeter
At what time of the day? -- 9am to 4 pm, yes it varies !
What exactly do you mean by "plenty of charge left for the weekend", enough to start your engine? -- engine starts by pulling it
enough to run the gps/autohelm/eberspacher for 5 hours.
last weekend i started the eber 5x - fuel prob - float V still 12.9
Do you actually know exactly what state of charge your batteries are at? -- pushing them up to 14V during the winter, after starting the eber the float V is 12.9
How do you know how much your batteries self discharge? -- i don't ! but as the float voltage is 12.9 every week i guess i am keeping up
When did you test the output? -- feb 08
What with? -- digital multimeter
At what time of the day? -- 9am to 4 pm, yes it varies !
What exactly do you mean by "plenty of charge left for the weekend", enough to start your engine? -- engine starts by pulling it
enough to run the gps/autohelm/eberspacher for 5 hours.
last weekend i started the eber 5x - fuel prob - float V still 12.9
Do you actually know exactly what state of charge your batteries are at? -- pushing them up to 14V during the winter, after starting the eber the float V is 12.9
How do you know how much your batteries self discharge? -- i don't ! but as the float voltage is 12.9 every week i guess i am keeping up
AngusMcDoon
Well-Known Member
Whether one is enough or whether you need more than one, Maplin's deal is good value for Watts/£.
AngusMcDoon
Well-Known Member
[ QUOTE ]
he is just using an outboard which will provide him with b88ger all electrical power
[/ QUOTE ]
I don't know the specs of the output from the Mariner 8, it may only have a piddly output, but not all small outboards are the same. Modern Yams and Hondas of 10hp have a regulated rectified output of up to 12 Amps, which is usually plenty for the equipment found on boats of the size they are attached to.
My 10hp Yam is like that, and along with a 30W solar panel, it runs a boat with the usual instruments and lights, chartplotter, autopliot, compressor coolbox, and an Eber when the engine is running.
he is just using an outboard which will provide him with b88ger all electrical power
[/ QUOTE ]
I don't know the specs of the output from the Mariner 8, it may only have a piddly output, but not all small outboards are the same. Modern Yams and Hondas of 10hp have a regulated rectified output of up to 12 Amps, which is usually plenty for the equipment found on boats of the size they are attached to.
My 10hp Yam is like that, and along with a 30W solar panel, it runs a boat with the usual instruments and lights, chartplotter, autopliot, compressor coolbox, and an Eber when the engine is running.