Portable solar panel

Moodymike · January 01 2021, 12:49

I want to install a small portable solar panel on my B32. This is purely to keep batteries topped up whilst on a swinging mooring. The idea would be to strap to coach roof with the cable running through hatch to a fixed point and then wire into system. Suggestions please for a suitable panel and wiring into existing electrics.

IslandAlchemy · January 01 2021, 18:51

Something about 50w should do the trick.

Use a PWM controller. I found one on ebay which supports 2 battery banks, so it will charge and monitor starter and house batteries separately.

Lyra · January 02 2021, 17:08

Is it only to compensate for the self discharge, or do you have anything operating while on mooring?
If it is the former than even a small 12V/5-10W panel will do the job and you do not need any controller, just a diode between the panel and the battery (or 2 diodes if connecting both to starting and service batteries). I did this several years ago when my boat was left on shore and I just wanted to keep the batteries alive - see photo.
If there is something operating then you should first determine the consumption, then size the panel accordingly, and in this case a simple controller must be added.

Secret World · January 03 2021, 00:58

Here's what came with our 30C when we bought it in October. I'm not sure of the wattage of the flexible panel but it's a great spot for it. Wiring it permanently looks ugly so we just run the wires down the side of the companionway to the house bank under the port settee. When it's not sunny or we don't need it, we disconnect at the dodger and stow the wires and controller.

JEN-et-ROSS · January 03 2021, 09:52

Hi..Go to https://www.photonicuniverse.com/en/
They have everything you need at low price. We installed a 2x100watt panel set on the aft gantry about 2 years ago, and together with regulator, cables, etc, it cost approx. £250. It runs the fridge and autopilot without issue, even in our Northern climate.....Bill

IslandAlchemy · January 03 2021, 11:18

This is what I bought, which was perfect for keeping the batteries topped up on the mooring:-

https://www.ebay.co.uk/itm/50W-ETFE-Flex-Semi-Flexible-Mono-PV-Solar-Panel-for-Boat-Tent-or-12v-Battery/353264294061?hash=item52403158ad:g:HXoAAOSwAiVfo6pl

https://www.ebay.co.uk/itm/20A-Dual-Battery-Solar-Charge-Controller-Regulator-for-12V-or-24V-Battery-NEW/383870230845?hash=item596072e13d:g:91cAAOSwMXdf4b9B

£65 for the lot.

Moodymike · January 03 2021, 11:32

Appreciate everyone's input thanks. Any contacts to obtain suitable weatherproof connectors to extend cables ?

IslandAlchemy · January 03 2021, 13:16

Again, ebay is your friend.

Yngmar · January 03 2021, 13:18

Quote from: Moodymike on January 03 2021, 11:32
Appreciate everyone's input thanks. Any contacts to obtain suitable weatherproof connectors to extend cables ?

The standard for that is called MC4 and you can buy them for next to nothing on your favorite Chinese online shop, or eBay. https://en.wikipedia.org/wiki/MC4_connector

The same place should also have matching double-sheathed exterior grade solar cable (which is always tinned).

Moodymike · January 15 2021, 12:28

What is the correct procedure for connecting and disconnecting a portable panel to avoid damage to either the panel or controller?

JEN-et-ROSS · January 15 2021, 15:54

Quote from: Moodymike on January 15 2021, 12:28
What is the correct procedure for connecting and disconnecting a portable panel to avoid damage to either the panel or controller?

The instructions I received with the controller suggested disconnecting the Panels first, the controller next, and when reconnecting, connect the Controller first then the Panels. This is to avoid the Controller ever being disconnected from the Batteries while still connected to the Panels as I understand this can do serious mischief to the Controller....Although I suppose if it was dark it wouldn't really matter......Hope it helps......Bill.

Salty · January 15 2021, 22:56

When I installed my two panels, I covered them up throughout the installation so that no current was being generated until all electrical connections had been made.

catlotion · January 21 2021, 10:03

Quote from: Secret World on January 03 2021, 00:58
Here's what came with our 30C when we bought it in October. I'm not sure of the wattage of the flexible panel but it's a great spot for it. Wiring it permanently looks ugly so we just run the wires down the side of the companionway to the house bank under the port settee. When it's not sunny or we don't need it, we disconnect at the dodger and stow the wires and controller.

hi, don't suppose you know the size of your panel please? I'd like to do something similar but can't get to the boat (30c also) to measure...

Moodymike · January 21 2021, 15:51

This is the panel that I bought, dimensions at bottom of page.

https://www.amazon.co.uk/gp/product/B07XF3Z1Q5/ref=ppx_yo_dt_b_asin_title_o02_s01?ie=UTF8&psc=1

catlotion · January 21 2021, 22:05

Thanks. Is it the 50w? Looks rectangular and wider than 56cm...?

Moodymike · January 21 2021, 22:30

It is the 50 Watt version

heywoodp · January 22 2021, 19:03

Island Alchemy, regarding the dual charge controller you got, are the two battery feeds totally independent ?. Are any of the lines commoned ? On my boat I have a shunt which sits between the two negatives so these would need to be separate as well as the positives

Salty · January 23 2021, 12:05

I used a Marlec charge controller, that had two separate charge outputs, one of which I used for the domestic house batteries, the other was used to charge a totally separate bank of batteries used in my case for an electronic antifouling system that was switched on when the boat was launched in the spring, and off when the boat was hauled out in the autumn. The engine start battery looked after itself, though I had a wired in emergency start changeover system that I could use in event of the engine start battery going down. The boat was kept on a swing mooring so no mains power during the season, and it all worked well.

IslandAlchemy · January 23 2021, 12:23

Quote from: heywoodp on January 22 2021, 19:03
Island Alchemy, regarding the dual charge controller you got, are the two battery feeds totally independent ?. Are any of the lines commoned ? On my boat I have a shunt which sits between the two negatives so these would need to be separate as well as the positives

yes, there is a battery bank 1 output, and a separate battery bank 2 output. Bank 1 (house bank) has priority, and you can also change the percentage charge going to each one. So in the winter, I set mine to 30% engine and 70% house, but in the summer when I'm using the boat I have it set to 10% engine and 90% house bank.

Secret World · February 08 2021, 04:26

Will measure it out this week when I'm down at the boat...

Secret World · February 09 2021, 04:11

Quote from: catlotion on January 21 2021, 10:03
Quote from: Secret World on January 03 2021, 00:58
Here's what came with our 30C when we bought it in October. I'm not sure of the wattage of the flexible panel but it's a great spot for it. Wiring it permanently looks ugly so we just run the wires down the side of the companionway to the house bank under the port settee. When it's not sunny or we don't need it, we disconnect at the dodger and stow the wires and controller.

hi, don't suppose you know the size of your panel please? I'd like to do something similar but can't get to the boat (30c also) to measure...

It measures 46"/117 cm x 22"/56cms, with room to spare on top of the dodger. It is flexible so curves with the dodger. I can't see what wattage it is.