Solar panel without regulator?

[ianc1200]

Is there any issues to be considered using a 30W solar panel, without a regulator, purely whilst at anchor/on a mooring buoy & being able to monitor what's going on via my Smartguage? The leisure battery is 85AH, and used for cabin lights/VHF/chartplotter/radio etc only, and in the marina is charged by it's battery charger on shorepower. A days use of various domestics will use about 30% of the power according to the Smartguage, so I'm just trying to mitigate that whilst away from the marina. Boat is east coast based.

 

[Champagne Murphy]

I can't recall the rule of thumb but there is a feeling in my water that you will need a regulator to avoid boiling the batteries. These guys have always been very helpful. They'll tell you the real deal

http://www.marlec.co.uk/contact/

 

[JumbleDuck]

Is there any issues to be considered using a 30W solar panel, without a regulator, purely whilst at anchor/on a mooring buoy & being able to monitor what's going on via my Smartguage?

You can get a perfectly satisfactory regulator for a shade over a fiver (e.g. http://www.ebay.co.uk/itm/Solar-Cha...lator-Safe-10A-12V-24V-UK-STOCK-/360684563165 for £6.61 including postage) and at that price I can't see any good reason not to fit one.

 

[ianc1200]

I could, but it's something else to find a place to screw down. I assume I won't get anywhere near boiling the batteries - I have a regulator & used previously on the EC and very rarely seen more than 1 amp being produced, so assume the (say) 15AH produced per day would be useful in trying not to run the batteries down too much, whilst at anchor for a couple of days, without having to resort to running the engine for a couple of hours.

 

[Robin]

On our Uk boats where we had largish solar panels for cruising, we had a very simple regulator set up involving adigital voltmeter and either a plug/socket connection that could be disconnected or a simple push/pullswitch that could be turned 'off'. ON our Sun Legende we had a 75W fixed panel on a stern gantry that we switched off when we left the boat, or if the volts climbed a bit too high. WE ran a largish fridge 24/7. WE also had a 120W 'roving' panel on that boat that we laid out on deck when at anchor for long periods as well as a wind generator (big Aerogen 6 type) that was rather less efficient but did have a regulator and charge splitter to divide it's output between our then 3 battery banks. When at anchor for several days it was often necessary to unplug the larger 'roving' solar panel and/or switch off the fixed one. We also switched off the solar panels when motoring so that any voltage 'seen' from those by the smart regulators on the alternators (we had 2 of those as well) would not confuse them into producing less amps. We had a smart 220VAC charger for when connected to shorepower so naturally never left either wind or solar charging operating when we were in harbour and plugged in.

 

[Rigger Mortice]

If you are just using the panel when you are on the boat it doesn't really matter so long as you do monitor the battery reasonably well. A regulator would make it "fit and forget" but will also use a little of the power that you are hoping to get into the battery. Not having a regulator just means you need to keep an eye on things and you need to be careful if you want to leave the panel on whilst going ashore for a few hours. However, the occasional bit of overcharging won't instantly destroy the battery.

 

[ianj99]

Luckily in the UK we have nature's regulator - plenty of cloud!

 

[Stemar]

Someone gave me a rule of thumb that the number of AH a day to expect is 25% of the panel wattage, so 15AH a day is probably optimistic for a 30w panel as an average, but you could get more on a sunny June/July day.

I think you could get away without a controller, provided you never forget to unplug the panel, but it's enough to damage your battery if it gets left on for a week or two between visits. I have a couple of 20w panels with a charger that sends nearly all their output to the starter battery until it's fully chaged then turns its attention to the domestic one. It was a bit of a faff installing everything (I feel your pain about finding somewhere to screw it down!) but now it's done, I'd say it's one of the best upgrades I ever gave the boat. She lives on a swing mooring, but both batteries are always fully charged when I come down, even in the middle of winter. I'd bite the bullet and do it properly.

 

[elton]

Given the low cost of a regulator, the ease of installation, and the possible consequence of doing without, I don't understand why anyone would choose not to fit one.

 

[Davegriff]

I used a 30w panel without a regulator for a couple of years - just kept an eye on the battery voltage with a voltmeter. Bit daft really, as I actually had a regulator that I just never seemed to get round to fitting. Didn't seem to do any harm, and at least I always had full confidence in the state of the batteries!

 

[ianfr]

I have a 20W panel mounted permanently. It is connected via a regulator. Battery us kept fully charged while nothing is being used.
Previous boat had a 10W panel directly wired to the battery. (previous owners) After I bought the boat, I discovered that the battery would not hold a charge.

Draw your own conclusions.

Ian

 

[Rigger Mortice]

I have a 20W panel mounted permanently. It is connected via a regulator. Battery us kept fully charged while nothing is being used.
Previous boat had a 10W panel directly wired to the battery. (previous owners) After I bought the boat, I discovered that the battery would not hold a charge.

Draw your own conclusions.

Ian

I draw the conclusion that the old battery was knackered. From what you have told us no other conclusion is realistic.

 

[ianj99]

I have a 20W panel mounted permanently. It is connected via a regulator. Battery us kept fully charged while nothing is being used.
Previous boat had a 10W panel directly wired to the battery. (previous owners) After I bought the boat, I discovered that the battery would not hold a charge.

Draw your own conclusions.

Ian

He's not leaving the boat with it connected or that would be good advice. He's only wanting to use the panel without the reg when he's on board and monitoring the battery manually, so no, a regulator is not needed provided he doesn't forget to unplug it before leaving.

 

[ghostlymoron]

It's difficult to monitor the output when you're not on the boat! And one advantage of solar is that it can generate every day. My advice would be - fit a regulator and forget it. New batteries are expensive.

I used a 30w panel without a regulator for a couple of years - just kept an eye on the battery voltage with a voltmeter. Bit daft really, as I actually had a regulator that I just never seemed to get round to fitting. Didn't seem to do any harm, and at least I always had full confidence in the state of the batteries!

 

[Davegriff]

It's difficult to monitor the output when you're not on the boat! And one advantage of solar is that it can generate every day. My advice would be - fit a regulator and forget it. New batteries are expensive.

Controller is now fitted. As the boat is in use regularly for 10+ months of the year, the panel was not, and still is not, left out when we're not aboard for security (they're expensive too). The OP didn't say he was leaving unattended, but wanted advice re damage to batteries, so I offered real life experience. Presumably your advice is directed to the OP not me!

 

[VicS]

Is there any issues to be considered using a 30W solar panel, without a regulator, purely whilst at anchor/on a mooring buoy & being able to monitor what's going on via my Smartguage? The leisure battery is 85AH, and used for cabin lights/VHF/chartplotter/radio etc only, and in the marina is charged by it's battery charger on shorepower. A days use of various domestics will use about 30% of the power according to the Smartguage, so I'm just trying to mitigate that whilst away from the marina. Boat is east coast based.

A common rule of thumb is to fit a regulator if the panel output exceeds 1 watt per 10Ah of battery capacity or if the panel is larger than 10 watts.

However provided you do monitor the situation there should be no problem without a regualtor. Just dont forget about it for too long.

An inexpensive regulator like the one Jumbleduck suggests will protect the battery from overcharging but it is a simple on/off device which disconnects the charging when the volts reach 14 volts and does not reconnect until they have fallen to a lower unspecified figure.
It will not therefore fully charge the battery

For very little more money you can get a pulse width modulated (PWM) regulator which will control the charging rate as the battery becomes charged, rather than disconnecting it, and should get the battery to a higher state of charge.

To get the most out of the panel you could opt for a maximum power point tracking ( MPPT) controller which by electronic wizardry will control the panel at its maximum output power, usually at about 16 volts or so, converting the output to the correct voltage for charging the battery.

Your choice. PWM probably the best value for money.

 

[ianc1200]

Thanks for all the replies; I have a Marlec HRDX regulator, & as the boat has an overall cover when left at the marina I tested the panel on Saturday under the cover to find only 0.1 amp being produced, and although quite cloudy I was surprised there wasn't something more useful coming through a lightweight cream fairly translucent cover. However the idea isn't to leave the panel out when moored up, only when at anchor/on a buoy when we're staying aboard (ie = using the lights/radio etc and typically using something like 30% of the leisure battery capacity a day).

 

[VicS]

Thanks for all the replies; I have a Marlec HRDX regulator, .

So you can use that. It will accept up to 100watt of solar power as well as the wind turbine. It is in fact a PWM controller so superior to a cheap on/off controller.

 

[JumbleDuck]

An inexpensive regulator like the one Jumbleduck suggests will protect the battery from overcharging but it is a simple on/off device which disconnects the charging when the volts reach 14 volts and does not reconnect until they have fallen to a lower unspecified figure.
It will not therefore fully charge the battery

For very little more money you can get a pulse width modulated (PWM) regulator which will control the charging rate as the battery becomes charged, rather than disconnecting it, and should get the battery to a higher state of charge.

Well spotted. Here, for example, is a PWM regulator for under a tenner: http://www.ebay.co.uk/itm/10A-PWM-S...ntroller-12V-24V-Auto-Switch-UK-/351078233835

 

[GHA]

Is there any issues to be considered using a 30W solar panel, without a regulator, purely whilst at anchor/on a mooring buoy & being able to monitor what's going on via my Smartguage? The leisure battery is 85AH, and used for cabin lights/VHF/chartplotter/radio etc only, and in the marina is charged by it's battery charger on shorepower. A days use of various domestics will use about 30% of the power according to the Smartguage, so I'm just trying to mitigate that whilst away from the marina. Boat is east coast based.

Probably OK if you're on the boat, but it doesn't take much to boil a full charged battery.