Help needed solar panel and outboard charging.

Submitted: Wednesday, Feb 04, 2015 at 18:19
ThreadID: 110994 Views:2171 Replies:5 FollowUps:0
This Thread has been Archived
I know these threads generate a lot of white noise, pun intended, but here goes.

I am planning a trip to the cape taking my 5 metre boat, the boat is going on a barge from Cairns to Seisia, I will have a 60 lt fridge in the boat and I need constant power to it.

Question 1 What is the smallest solar panel I would need to charge the battery while the fridge is running, probably in freezer mode under the deck and under a boat cover, so well shaded.

Question 2 will the outboard power keep up charge to the battery with the fridge running as a fridge, under the deck.

My outboard is a 2013 75 Honda it's alternator puts out 44 amps 554 watts and battery charging is 35 amps, does anyone know how effective this would be charging the on board battery ( generic ) and a Gel-Tech 8G31DTM it's specs are 780 MCA 550 CCA 98 AH @ 20 hours, the batteries will be separated.

My thoughts on operation, I would like to mount the solar panel above and to the bait board on the rear of the boat, this is why I would need a small panel, so when the engine is off the battery can charge, is it also possible to use the engine and the panel together once we are on the water or would I have to disconnect the panel.

I hope that's enough info thanks in advance.


Back Expand Un-Read 0 Moderator

Reply By: Member - John - Wednesday, Feb 04, 2015 at 18:57

Wednesday, Feb 04, 2015 at 18:57
Steve, Have you enquired about a 240 volt source on the barge for charging the battery while on-board? The solar panel may not have sun for half the day or more and a small panel may not provide enough to power the 60lt as a fridge let alone a freezer. I would fit the biggest battery I could as a temporary measure. Do you really have to have the fridge in the boat, I presume for on the way back, full of fish? As a logistical exercise, to my mind fraught with possible problems. Is anyone you know going on the barge with the boat, if so, maybe a small generator run for a few hours a day maybe a better option. Good luck.
John and Jan

Lifetime Member
My Profile  Send Message

AnswerID: 545358

Reply By: Bigfish - Wednesday, Feb 04, 2015 at 19:37

Wednesday, Feb 04, 2015 at 19:37
Before you do anything else..check with the boating company. For all you know they might cover your boat completely or have it in such a place that it will not see daylight. I know if it was my boat I would have a cover over it, just as you have done. I have had vehicles sent on barges/boats and have seen some real damage from these boating excursions. Make sure boat/cover and if you do get a panel ...all are secured and tied down safely. I doubt that a boating operator would want a genny running on board his boat. I would be looking at maybe purchasing several large batteries. Is there anyone up in the area you are going to that could look after the batteries until you do the return trip? Maybe sell the batteries off on your return trip. Naturally I am assuming you will need some sort of power for a return trip. If you can get a panel mounted get something that's going to give you say 10amps. 120 watt + but then you must have room to mount on boat and 5 meters is not a large boat. If your going up there in the next few months the fridge will be running 24 hrs a day due to the heat. On freeze I'd reckon you'd be pulling a minimum of 40 amps/day. Probably closer to 60. (Only guessing). I have done a hell of a lot of fishing from boats and have found 12 v fridges a pain to look after when in a sea water environment. One loose wave over the side and the resultant corrosion kills the fridge. Leave the fridge at camp and have esky in boat

Good luck and tight lines.
AnswerID: 545364

Reply By: gbc - Wednesday, Feb 04, 2015 at 21:08

Wednesday, Feb 04, 2015 at 21:08
Sea swift barge? Ring them and have a chat. A couple of long extension leads and a battery charger will sort it whilst on board. My old boy has the same engine on a 4.8 polycraft, they are impressive. Depending on the hours your are doing with the boat running at speed it should easily run the fridge. Driving a few hours a day I'd assume?
Just out of interest I assume you've seen the fuel burn program on the 75 and how it leans out at 4000 odd rpm?
AnswerID: 545373

Reply By: Member - Beatit (QLD) - Thursday, Feb 05, 2015 at 10:22

Thursday, Feb 05, 2015 at 10:22
G'day Steve,

It is a difficult question with lots of qualifications. I just wanted to mention that I ran a 52 ltr Weaco as a freezer in my car (I know it's not a boat) and have two 80 watt panels on the car (1 each side - so both can't face the sun at the same time) and I managed 3 months. I ran the freezer off a 100 amp battery being charged from the car and panels. There was only one or two occasions when I had to top up the battery with a charger because the charge got a little low. By the way this was in NT during October and it was hot and there were several extended stays when we didn't drive.

My guess is that the alternator output may not be enough to keep a battery topped up but that is only a gut feeling. You could run a genny at night to top it up as a thought.

Kind regards
AnswerID: 545395

Reply By: Steve in Kakadu - Thursday, Feb 05, 2015 at 17:50

Thursday, Feb 05, 2015 at 17:50
My mates and I are tossing up as to 1 boat 1 car for 3 of us which means a fair bit of gear in the car when we drive up the top, but we are now thinking 1 extra person and 2 cars with 2 boats.

To put a boat on the barge it is relatively cheap $1665 return, we were thinking about putting most of our gear in the boat for the trip north I have a 150 lt esky that normally resides under the deck, we also have 4 fridges that we run off a gen set and solar panels, we have 2 panels that are 140 watt each but are to big to use on the boat so I was seeing if there was another smaller one that would work.

The more I think about it keeping a fridge on the boat may become a PITA, so I will see the barge mob and ask if we can plug them into the mains on the barge and be done with it.

This trip is for next year from Darwin across to gulf then up the top, so a lot of planing to be done as this will be the biggest off road trip with the boats we have done, we have all the back up gear like extra axle's, hubs, bearings and springs, I also have a very comprehensive tool kit and the know how to use it, so we are well prepared in most ways, but we got to keep the food and beer cold hence the question.

Thanks for the info we will work on it.

AnswerID: 545413

Sponsored Links