wiggy
Well-known member
Any ideas on the largest watttage solar panel size that can be used with 80ah lead acid battery without the need for a regulator, any recomendations on brand ( framed type) or supplier much appreciated.
Solar Panel size
- Thread starter wiggy
- Start date
jonathankent
New member
I wouldn't worry if you need to get a regulator... they are <£20 and will probably keep the battery at its optimum charge.
VicS
Well-known member
[ QUOTE ]
largest watttage solar panel size that can be used with 80ah lead acid battery without the need for a regulator,
[/ QUOTE ] Absolutely no problem with 5 watt. I used one with a 45ah battery permanently connected. Probably no bother with 10 watts either but I would not go any larger if it is to left connected 24/7.
If you need the power and have the deck space and the cash then fit larger with a regulator as JMKENT suggests. If you are not leaving it connected permanently then you can go larger anyway. Maplin do a couple of regulators.
I have found my 5watt panel adequate to top the battery up between weekend excursions with no other charging apart from the meagre output from an outboard.
Be sure you fit a fuse in the circuit as close as reasonably possible to the battery, rated to protect the wiring from the panel (although in the same compartment may not be wise as a blowing fuse might ignite any hydrogen... a ceramic bodied tubular fuse is safe perhaps)
A trawl around the solar panel suppliers websites will find a recommendation for max panel size vs battery capacity but I cannot remember which one.
Sorry I cannot advise on types or sources.
largest watttage solar panel size that can be used with 80ah lead acid battery without the need for a regulator,
[/ QUOTE ] Absolutely no problem with 5 watt. I used one with a 45ah battery permanently connected. Probably no bother with 10 watts either but I would not go any larger if it is to left connected 24/7.
If you need the power and have the deck space and the cash then fit larger with a regulator as JMKENT suggests. If you are not leaving it connected permanently then you can go larger anyway. Maplin do a couple of regulators.
I have found my 5watt panel adequate to top the battery up between weekend excursions with no other charging apart from the meagre output from an outboard.
Be sure you fit a fuse in the circuit as close as reasonably possible to the battery, rated to protect the wiring from the panel (although in the same compartment may not be wise as a blowing fuse might ignite any hydrogen... a ceramic bodied tubular fuse is safe perhaps)
A trawl around the solar panel suppliers websites will find a recommendation for max panel size vs battery capacity but I cannot remember which one.
Sorry I cannot advise on types or sources.
William_H
Well-known member
I agree with Jonathon 10 watts no problem in worst case of panel aligned to the sun and no other drain on battery it should be no problem without regulator. Actually without a regulator you should get more current into the battery so more charge.
However if you have the need for quicker recharge, you have the space to mount it and the cash to buy it the bigger the better. But use a regulator for a big panel. olewill
However if you have the need for quicker recharge, you have the space to mount it and the cash to buy it the bigger the better. But use a regulator for a big panel. olewill
Gunfleet
New member
I have a 32 watt roll up panel which I leave connected all the time. I do actually use a regulator (Fox) however I can tell you that for brief periods on the hottest days with the brightest light it puts out a little over 1 amp (there are losses all round). If you have say a 220 ampH battery bank and the thing puts out 10 amps a day max, you can see you are less than 5% of the battery rating. This is considered safe without a regulator... but I still use one! From this I would calculate back that 10W gets you inside 5% of your battery rating. It's all in Nigel Calder's books.
noelex
Well-known member
I agree with the other posts 5-10w is the maximum solar panel you can leave on an 80AHr battery unattended with no drain, but don't forget if there is a consistent drain on the battery, from say an alarm, the solar panel size could be increased significantly and if you monitor the battery voltage and disconnect the panel you can go as high as you like. I had a 75w panel on a 80AHr battery without a regulator on a trailerable yacht and the battery lasted 17 years !.
Cheers John
see my yacht blog at www.amzerzo.blogspot.com
Cheers John
see my yacht blog at www.amzerzo.blogspot.com
bumblefish
Active member
With our recent weather I would suggest that to get anything useful out of the panel it will need to be bigger than your boat. /forums/images/graemlins/grin.gif
KenMcCulloch
New member
[ QUOTE ]
With our recent weather I would suggest that to get anything useful out of the panel it will need to be bigger than your boat. /forums/images/graemlins/grin.gif
[/ QUOTE ]
Perhaps there's a way to generate electricity from rainfall?
With our recent weather I would suggest that to get anything useful out of the panel it will need to be bigger than your boat. /forums/images/graemlins/grin.gif
[/ QUOTE ]
Perhaps there's a way to generate electricity from rainfall?
jonathankent
New member
Yes.... collect it in your cockpit and as it drains through the outlet put a little paddle wheel, like a water mill, and some techy stuff... and bob's your uncle!! /forums/images/graemlins/smile.gif
jeremyshaw
New member
You have not said what you want it for. As has been suggested, 10% of the battery capacity is generally regarded as the limit for unregulated. As you want the largest possible it suggests you want to get other uses from it than float charging. In that case you might be better off with two panels - you could then cover one to float charge while the boat is unused. Another option would be to put in the largest your budget allows and add a regulator, which is not a big cost compared to the panels. Multiple panels are generally better if you are likely to suffer from partial shade due to booms etc.