12v solar panel system?

[Mike53]

I have a small sailing boat with no charging system.

I wish to fit a couple of 12v units. Namely a Lowrance GPS/fishfinder combination and a marine VHF radio both coupled to a 12v battery.

Rather than having to remove the battery for charging after each use I would like to fit a solar panel and whatever bits and pieces that should be fitted to a system. This to me is new technology and I would like some guidance.

The piece of kit I have least comprehension of is a charging regulator. I do understand the need for the solar panels charge to be diverted once the battery is fully charged.

Any advice appreciated.

Thanks

Mike

 

[BigRobCanUFixIt]

if you are buying a kit for that purpose then all that should be taken care of and installing it as per instructions should be fairly straightforward.

If you are thinking of making it from scratch. Then things like exposure to the salt water should be considered. A regulator will keep the voltage to supply the voltage at a constant level ie if it is a scorching day the voltage will be the same as an average day, 12v batteries often have a charge voltage of about 13.5 volts. If the regulator is required to shut of the supply then a feed back control loop may need designing into the circuit.

 

[ericmark]

The regulator is the main thing. There a number of types. The basic type just sinks the energy once the set voltage is reached normally around 13.8 volt.

But there are two draw backs.
1) Solar cells will produce more power if the output voltage is adjusted to match time of day.
2) When charging a traction battery while flat you want around 14.8 volt and when near to fully charged it needs to drop to 13.2 volt.

So the clever regulator feeds the power from the panel into a capacitor then takes that power and turns it to AC then back to DC to step charge the battery. So it can extract a lot more power from the same solar panel.

As a bonus the same regulator also works with wind chargers.

But these regulators are not cheap so not worth it for very small panels. Sorry don't know point where it's worth getting good regulator.

The cheap regulators do need either a diode or disconnecting before using another form of charging.

Now my VHF radio does take a fair load from battery around 20A on transmit some take even more. But I do a lot of chatting a little below where you transmit 144 to 146 your around the 156 mark I think. So what you need to work out is how big does it need to be.

I don't know if you live on board like my son did with narrow boat or if just part time but if part time then since not using anything when moored up a very small panel may be enough.

He had 400Ah of domestic battery and another 120Ah for engine and with a solar panel giving 1/2 an amp at best it did not need any regulator. However some boats seemed to be covered in panels then it was very different.

So how many AH is the battery and how long will it last? Assuming in good condition this should give you the average use. Sorry all down to maths.

 

[Mike53]

Thanks,

Penny is starting to drop.

I have purchased a Lowrance LMS 480m (new) but the set is supplied without a manual. I am supposed to be able to download it from the internet but the size is 5656kb. I am unable to download this as my internet connection is so poor. Accordingly I have not even been able to determine the power consumption of the Lowrance so am as yet unable to start any calculations.

I anticipate I will use my small sailing boat regularly in the summer and hardly at all in the winter. To calculate power requirement I will assume 4 hours use 4 days a week in the summer.

As I have not purchased the VHF I still have the option to go for hand held but the power consumption of a fixed VHF will depend on actual useage and I would rather have a fixed VHF and generally leave it on standby.

I will post again once I assertain the power consumption of the Lowrance unless some kind soul would download the manual for this purpose.

Mike

 

[ban-all-sheds]

I am supposed to be able to download it from the internet but the size is 5656kb. I am unable to download this as my internet connection is so poor.

It must be unworkably poor if you can't get the 200 bytes per second it would need to download overnight while you sleep.

 

[Mike53]

The situation is we can only receive a broadband signal while our phone line is in use. Whenever we need to use the internet we have to phone someone or get them to phone us. It is a bit inconvenient and expensive to have 2 phone lines engaged all night.

In fact we were better off when we had a dial up internet connection.

Mike

 

[ban-all-sheds]

That's not a "poor internet connection", it's a fault.

http://www.filesaveas.com/jarviser/hubtrouble.html#type9