Use of a Solar Panel to Keep Batteries Charged

P

Parker

New Member
Joined
Jan 18, 2025
Messages
1
Reaction score
0
Points
1
Age
79
Model
Adventure
I recently acquired a 2021 Adventure 208 which is being kept on a mooring. I am curious to know if anyone has experience using a solar panel system to keep their batteries charged. Any guidance will be appreciated, especially with respect to the selection of components.
 
I have two 140W solar panels in the basement ex owner gave me as he did not installed them and i consider to install them to charge the telectric motor batteries.

Many use a solar panel to keep batteries topped up, from small panels to 100-200W panels depending on space available.
I guess space is very limited on your Adventure 208 so you need to measure what size of panel will fit on the top.
Buy a small Victron solar battery charger, they are high quality and probably most used on boats and on't use cheap ones.

If you use your boat frequently you don't need to charge your batteries if your electrical system is working correctly and no leak is having bilge pumps working frequently.
In 30 years of boating my boats where always 6-10 months moored or in a slip without shore power and i never had a dead battery if battery switches where off and only bilge pump/s connected directly to battery.
If illumination is the problem, my buddy has a similar to 360° anchor light looking blinking light with integrated solar panel and it blinks all night long.

Chris
 
You should easily be able to construct a solar battery maintainer. A charging system is a horse of another color and requires considerable amount of panels. The main problem with maintaining boat batteries is that we have multiple banks of batteries. You can get solar charge controllers that will do multiple banks but they are usually the exception and good ones are expensive.
 
Yes,
but OP has probably not more than 2 batteries so he can connect a small panel using the smallest Victron BlueSolar charger to the engine battery to keep her topped up.
There are also cheapo solar panels with no charger as they produce so low amount they don't need one (they say) to put on the car's dash board but honestly i don't want such thing on my boat.
But again, if the boat is used frequently and electrical system is done correctly there is no need for any kind a solar charger to maintain batteries, without current draw even wet cells will keep their charge for 2 months even in very hot climates they self-discharge about 10-15% per month, in moderate 5-6% per month.

Chris
 
The OP didn't state how long the boat site in between uses but my experience is that in general, the batteries on that model boat will maintain a decent charge for weeks if not months. Of course that depends on whether there is and current draw for directly connected loads like electronic bilge pumps, stereo memory feeds etc. In addition it the bilge gets water from whatever, eventually the battery will run down. If the bilge pump does cycle, the solar maintainer won't make much difference.
Make sure that directly connected loads are connected to only one battery and that the battery switch is set to off when moored. Should the direct connected battery run down, the second batter when selected will be able to start the motor. If really paranoid, carrying a boost charge pack can help start the motor if needed.
 
seasick said:
If really paranoid, carrying a boost charge pack can help start the motor if needed.
Click to expand...
Then i am really paranoid as i carry always a boost charge pack, in my car and in my boat even if i never had to use it on any on my boats.
No, honestly i had to use it once in Costa RIca when my dumb captain left the battery switch on.
But when i was working in the shipyard i have seen boats with dead batteries or sunk because bilge pump drained the battery and owner was not checking his boat after hard rain.
Chris
 
better yet jumper cables for the truly paranoid. when we reduced the auto fleet upon retiring i had a spare set. on the boat they went.
 
i set up my batteries with the house bank and starting isolated from each other. house has simple on/off. starting have 1-2-both. the cables are to feed the house if needed. which i actually did once when my old ox66 engines aux cables did not function and were not charging the house bank. worked ok with charge from the dock power and limited draw while fishing, did not drain the house bank. until i put on an autopilot and first day out after about 5 hours wife said i hear something beeping and the console went dark. autopilot pump drained the house bank. cables turned the lights back on. as for jumping boat to boat i almost did that once as well. 2 guys in a center console dead in the water offshore. one of the guys on my boat said do not tie up to them you don't know who they are, call seatow and give them their position. which we did.
 
I currently have 100W of flexible solar on the roof of my islander. All Renogy stuff. It goes through a charge controller and to the house bank (3x group 31 deep cycles) Keeps the batteries charged, fridge running , pumps, electronics and lights on etc while at anchor. currently my engines charge my house through victron batteries isolators, but I have previously used ACR's too. if I had to do it all again id probably go back to the ACR's. that way the solar would keep every battery charged up. I usually see 5-7A of charging mid day.
 
  • Like
Reactions: Sardinia306Canyon
Fixit said:
I had to do it all again id probably go back to the ACR's.
Click to expand...
Why? Any particular reason for that?

I am checking the state of the 3 95Ah AGM batteries as i have new engines and they need a always hot cable and tech told me that this may drain the battery.
However, after my Victron SmartShunt power drain with battery switches off
port engine battery use about 1% of charge in 24 hours
stbd engine + House battery about 1% too but has double of Ah

I just received my 140Ah LiTime LiFePo and the Victron Orion XS DC-DC charger and as soon it becomes stormy i will change my original GW battery setup to
1 port engine battery (the existing 95Ah AGM)
1 stbd engine battery ((the 2nd existing 95Ah AGM)
1 house battery (the new 140Ah LiFePo charged thru the Victron Orion XS what has a kind of ACR function)

Chris
 
Overkill for the OP's boat. I doubt there is room to mount charge controllers/ battery management system. There is very little space for solar panels. Heck, it's a 20 ft 208:)
 
Sardinia306Canyon said:
but OP has probably not more than 2 batteries so he can connect a small panel using the smallest Victron BlueSolar charger to the engine battery to keep her topped up.
Click to expand...
This is why i wrote this in my first reply, and that OP does not need any solar charger if batteries are good and no draw when battery switch is off.
The other solution i also mentioned would be this very small solar chargers for car dashboard, but i would not trust them.
Chris
 
seasick said:
Overkill for the OP's boat. I doubt there is room to mount charge controllers/ battery management system. There is very little space for solar panels. Heck, it's a 20 ft 208:)
Click to expand...
my charge controller is the size of my wallet. lots of places to mount that IMO.
 
Sardinia306Canyon said:
Why? Any particular reason for that?

I am checking the state of the 3 95Ah AGM batteries as i have new engines and they need a always hot cable and tech told me that this may drain the battery.
However, after my Victron SmartShunt power drain with battery switches off
port engine battery use about 1% of charge in 24 hours
stbd engine + House battery about 1% too but has double of Ah

I just received my 140Ah LiTime LiFePo and the Victron Orion XS DC-DC charger and as soon it becomes stormy i will change my original GW battery setup to
1 port engine battery (the existing 95Ah AGM)
1 stbd engine battery ((the 2nd existing 95Ah AGM)
1 house battery (the new 140Ah LiFePo charged thru the Victron Orion XS what has a kind of ACR function)

Chris
Click to expand...
The victron argo FET charge battery isolators are great. no voltage drop like the old diode block. BUT, with the solar charging the house bank, the two start batteries get nothing from the solar. My batteries are wired different then the idiotic Grady battery layout of: start and start+ house battery. Each engine has its own start battery and there are 3 house batteries. all separate, charged separately but I can parallel both starts together or parallel the house to the starts if needed.
 
  • Like
Reactions: Sardinia306Canyon
Ok, that makes sense.
Well the GW Battery Wiring is not idiotic, it makes some sense as it it easier to wire for GW and owner has 2 x Ah from both batteries but can drain the stbd battery and would need to parallel or start stbd on port engine battery and switch back after a while.
However it's not boating standard and poses problems in several ways i am actually running in after installing the new Hondas.
They have a car type alternator (as most bigger Honda outboards have) so the don't have a Acc Charge Lead and they need to have always hot 12V like the Suzukis with the white wire.
In this moment with the GW battery installation the engines work, but as house and stbd outboard are together most electronics pass out for a second when the stbd outboard cranks.
As written, soon i will change that to standard setup and install the LiTime 140Ah house battery hanging on a Victron XS 12-50 charger to protect the Hondas alternator.
Not sure now where to install the additional battery switch and i have to bring the to the stern battery switch panel connected always hoit cables to the console, or a always hot cable to the stern, not sure now what would be easier to realize.
BEP has this nice battery switch cluster including two VSR's, theat would be a nice setup, but i fear it does not fit my battery selector box.
The rest inside the console should be rather simple and what i already found out, removing the access panel with it's too many screws will make access much more comfortable.
I may write a How-To with photos for others who may be interested to go the same way.
Chris
 
Sardinia306Canyon said:
Ok, that makes sense.
Well the GW Battery Wiring is not idiotic, it makes some sense as it it easier to wire for GW and owner has 2 x Ah from both batteries but can drain the stbd battery and would need to parallel or start stbd on port engine battery and switch back after a while
Click to expand...
pairing up a deep cycle and starting battery is dumb. best way to kill a battery is to expect deep cycle duties from a starting battery and starting current from a deep cycle.
it takes very little extra work to have a dedicated start and house.

I have a bluesea 5511e dual pole switch to turn on both engines at once, and a second 5511e to turn on house bank.
5511e are a direct fit for the factory Grady 1,2,both, off switches fyi

IMO one should be able to drain 100% of the power from their house bank and still start up the engines to drive home
 
Fixit said:
IMO one should be able to drain 100% of the power from their house bank and still start up the engines to drive home
Click to expand...
He can, selecting port battery for stbd engine instead of the low voltage/dead stbd engine and house battery.
Once stbd engine is running switch back to depletetd stbd battery to charge it again, or parallel for same reason.
I would not use parallel for a total depleted battery as it may drain the good port battery so quick that both are too weak.
1° set stbd battery switch to use port engine battery (#2 in my case)
2° start port engine
3° start stbd engine
4° after about 5 minutes switch stbd battery switch back to stbd battery (#1 in my case) to charge stbd engine and house battery to have at least electronics back running
DO NOT TURN THE SWITCH TO OFF OR GO OVER OFF TO OTHER BATTERY! It may damage your charging system

However, 3 or 4 separate batteries are definitively better and less prone to no start conditions or user errors

Chris
 
You must log in or register to reply here.