SOLAR PANELS
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After installing the new Life Line batteries, I installed new Solar Panels.  The new generation panels produce more energy per sqm, compared with the earlier generation.  They are also more efficient and convert 21.5 % of the solar energy to electricity instead of 17-18%.  But best of all, weight is only 1.8 kg /100W which makes it possible to install them on the Bimini.

After installation we now have five solar panels, (total 444 W).  A sunny day in the Mediterranean they produce 25 A/h.  Morning and evenings we get less, as the sun is at an angle and less intense.  After the installation our batteries have never been under 75 %.  Keeping in mind we did not plug-in to shore power for 8 weeks in Greece, that is pretty good.

24 A on a Sunny day

23.9 A on a Sunny day!

If you read my article about batteries, you might remember that battery manufacturers recommend that you charge the batteries full every 10 days to avoid sulphatation.  Without Solar panels it would not have been possible to charge the batteries to 100%  just by motoring.  With the panels it was not unusual that the batteries were fully charged already after 4-5 engine hours, as we started at 85-90 %.

Installation

So how do you install that many solar panels on a boat whiteout making it look terrible?  I was not allowed by Vickie to install a tower across the stern.  Last year in Malta I did see some boats with solar panels on the Bimini.  I contacted the supplier, and got a price that was crazy expensive.

Back in Sweden I did find a company that sold panels with the same specification to a lower price.  I contacted Viktor on Teknikhamstern.  It was a delight to correspond with Viktor as he did know his product.  All the questions I had, were answered.  When he did not have an answer, he got back after some reserch.  It did not take long until I had signed up for four panels.

Two panels are installed on top of the Hardtop, and two more on top of the Bimini.  We also  had an existing 44 W panel in front of the Hardtop.  The two panels on the Bimini was the challenge as they had to be installed on top.

2 x 100W on Hardtop

2 x 100W on Hardtop

2 x 100 W on Bimini

2 x 100 W on Bimini

The solar panels on the Bimini were installed with velcro and Tenax buttons.  I glued 50 mm velcro to the edges of the panel and had velcro stitched to the Bimini.  Under each panel there are two long battens in the same length as the panels. This was necessarily as the standard model did not have a reinforced backside and could be damaged by vibrations.

The new Sunzip models have a reinforced backside to stabilize the panel.  The Sunzip model has  velcro attached to the backside as standard.

It takes in total about 3-5 minutes to take down the bimini including the panels and battens.  The panels have quick MC4 contacts.  We had 40 knots whirlwinds in Monemvasi and did not experienced  any problems.  Some boats took down their sun protections as the wind was gusting so hard.

So far we are really happy with the amount of energy the panels are producing.  It is better than expected.  With this setup I would consider to reduce the battery bank next time we have to buy new batteries.  Off course we are in a very good area for Solar Panels!!  Take a look at this weather forecast for the Athens area.  This is the weather we have had most of the summer.

Sunshine in Athens

Sunshine in Athens

Sun hours in Athens

Sun hours in Athens i August

Shadows

Avoid any shadows if possible!  Building a tower over the stern with antennas on one side, and a wind generator on the other is not a good solution as there will be shadows covering parts of the panels.  Even the smallest shadow reduces the charge a lot!!!  In fact a cloudy day with indirect lightning, can be better than a sunny day with a small shadow.  If you install a tower make sure that antennas etc, are under the solar panels.

When we are at anchor we pull out the main boom to one side.  As the sun in the Med is almost straight up, it is unusual with shadows from the mast itself.

Position of regulator

The voltage out from the solar panels are around 19 V.  Higher voltage means less voltage drop.  The “out” voltage from the regulator is 14.4 V.  On this side a voltage drop will be more significant as the voltage is lower.   I installed the regulator in the locker behind the electrical panel.  Our  batteries are in the aft cabin, and you might think that is not so close to the batteries.  The distance is about 3 m, but the cabling  is massive (350 mm2 ) as it is made to support the charger, inverter and alternators. Take advantage of the existing cabling!

Regulator

Regulator

I improved the ventilation in the locker with ventilation holes in the bottom and a ventilation louver above the panel.

New holes for air circulation

New holes in the bottom for improved  air circulation

Extra ventilation louver

Extra ventilation louver above the electrical panel

 


Comments

SOLAR PANELS — 2 Comments

  1. hallo from sarah jane
    i met the italian dealer of my battery, i have the 6 volt deka. he told me that leaving the solar pannel plug in when you are away ( when there is no consume of amper) will damege them, because the charger work alwys at the max power. i have a mptt regulator . what do you think ?

    • Hi,
      I do agree with the dealer. Would not consider to leave the charge on for extended periods, if I´m not on the boat. If it is solar or a 220V battery charger does not really matter. To many things can go wrong. It only takes that one batter cell goes bad, and you will overcharge the rest of the cells which can cause serious damage. In worse case it can set the boat on fire. A way to reduce the risk is to limit the time that the charger is on, to let´s say 8 hours/every 2 weeks, which could be done with a timer. As there is no consumption, it does not take long to replace what has been lost due to self discharge.

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