Electrical (DC)

During the summer of 1999 as we concentrated on getting Maringret ready for extended touring in Scandinavia we realised that the existing electrical system needed both to be partially replaced/upgraded and also some extensions to be made. The replacements were mainly perished cabling and the 25 year old switch panel (which included many modifications whose purpose was no longer clear). Approximately 45 meters of cable was removed and replaced with much less as it turned out that many of the cables were not connected to anything. The improvements were mainly fourfold:

  • a wind generator to help the batteries maintain their charge whilst away from marinas;
  • an intelligent charge splitter between the engine alternator and the two batteries;
  • a power management system that enabled battery status, charging and consumption to be managed digitally from a centrally located panel;
  • low current consumption reading lights.

This is the new electrical schematic versus the original electrical schematic (as the boat was supplied).

Breaker Panel

The switch panel with 8 switches was replaced with a breaker panel with 12 breakers. Of the 12 breakers (i.e. circuits) two are presently unused and reserved for future use. In addition there are an additional two places on the panel which can be utilised for two more breakers in the future (this would give a total of 16 breaker or circuits). We decided to get away from switches with in line fuses and move to breakers. If a short circuit occurs with a breaker then the breaker may be reset once the circuit problem is cleared, no fuses are consumed yet the solution provides electrical safety. ETA 1110 breakers which are the physically smallest breakers ETA makes were selected as the electrical panel for the Maxi is rather small. The breakers fitted are a combination of 5 and 10 amp breakers. While the electrical panel was being overhauled is was decided to integrate a power management system which is described below.

Wind Generator

Determining what size and make of wind generator took quite a bit of time. For the make we spoke to any boat that came into our marina sporting a wind generator. For sizing we constructed a table totaling our electrical consumption in terms of amp-hours. We then tried to find magazine articles (we couldn’t find any books on this specialty subject) which reviewed wind generators.We finally decided on an Aero4Gen which is the middle of the range wind generator manufactured by LVM Ltd. As a rough estimate, in approximately 20 knots of wind we seem to get on the order of 2 amps from it. Once we purchased the wind generator we mistakenly thought that the hard part was over. It turned out to be equally time consuming to have a support fabricated that would fit our boat. This is the finished product, the generator itself, and the bracing fabricated to support it. For those wondering why there is a cord attached to the wind generator, this is so that the device may be pulled sideways to the wind in case it ever needs to be stopped.

We should mention that we initially looked at using solar panels instead of wind generators as we judged them to be passive and less effort to deal with than wind generators (i.e. no moving parts etc.). After researching this we found that for our present latitudes (55 degrees N) they were not sufficient to meet our needs without ridiculous amounts of deck area being committed (and quite probably coating the sails in solar panels also). Not only would this have been impractical but also extremely expensive. When Maringret moves south to sunnier latitudes we will certainly revisit this matter and most likely supplant our wind generator with appropriate solar panels. We would then have the best of both worlds.

Intelligent Charge Splitter

Our Yanmar engine alternator is rated at 55 amps and was previously wired to the two batteries which were connected in parallel. A simple way to connect up the two batteries but it did not allow each battery to be charged according to its needs and also did nothing to prevent one of the batteries going flat and then draining the remaining good battery. To separate the batteries we purchased a commercially supplied set of isolating diodes. These would prevent a depleted battery from draining the remaining good battery but caused a voltage loss of approximately .7 volts. this meant that the battery were doomed to never be fully charged by the engine. After 1 week of operation we removed the isolating diodes and replaced them with a X-Split Electronic Split Charger. In addition to acting as isolating diodes this unit determines what charging voltage a battery requires and delivers that charging voltage (up to the 14 volts produced by the engine alternator). Each battery charging voltage is produced independently which means a fully charged battery will not be over-charged while a totally depleted battery will receive close to the maximum charge available.

Power Management System

There is a saying to the effect that “something that is not measurable can not be controlled; something not controlled can not be managed; something not managed can not be improved”. With a zero sum operation such as electricity on a boat (i.e. a boat not hooked up to the marina power supply) improvement is a constant battle. Either the supply of electricity can be increased or the usage decreased. The previous sections on the wind generator and alternator charge splitter describes what we did to increase our supply, the power management system was what we did to try and control the usage. Once again we prevailed on visitors to our marina and people we met who had such systems. There were a number of systems available. One major factor seemed to be whether the unit would calculate battery levels in amp-hours. We decided to stay away from this as it did not ring true to us. We know that other people use it and depend on it but it did not seem to fit our situation. We purchased a power Management Panel from Sterling Power Products. Features that attracted us were that it was rectangular (some units are based on a round 55mm instrument cutout), it was backlit automatically, it could be switched off (although its power consumption is a miserly 10 mA), it could handle up to 4 channels (we only use three at present), it could be integrated into our electrical control panel. This is one of the shunts which each of the channels uses to measure the voltage and/or current

Low Current Consumption Reading Lights

This project is ongoing. In our analysis of consumption we found that reading lights played a large part. At present the reading lights are 25 watt (which is 2 amps!!!) incandescent lights. Halogen lights generate a similar amount of usable light the current requirement is cut in half. Then there are LED Cluster lights, although expensive each bulb’s usable life is supposedly 100,000 hours and it’s current requirement is 1/12th of an incandescent light bulb.

Davis also makes a very low current anchoring light on a 10 meter lead as well as a version that is intended to be mounted on mast top.

AC Power

We’ve put the AC power description and circuit diagram on a separate page as it really exists in isolation from the DC circuit.

Now that our changes are in place we have realised the following:

  • having a power management system makes one much more aware of power consumption which makes power consumption much easier to control;
  • although dependent on ambient wind levels, our wind generator seems to be keeping our batteries at 13 volts and higher which is certainly better than the 12.3 and 12.4 we used to find after the boat sat unused from Sunday until Friday;
  • the alternator charge splitter brings the battery voltages up much more quickly than the standard system, it also brings the batteries to a higher level than if normal isolating diodes were used (which introduce a 0.7 volt drop);
  • initial use of the LED Cluster lights seems promising in reducing the overall power requirements.
  • For batteries we have a cranking battery, a FIAM 200 amp-hour house battery, and a 60 amp-hour and a 80 amp-hour FIAM battery for refrigeration. Our 200 amp-hour does not seem to deliver 200 amp-hours and we are not sure why. Between our charge splitter and the wind generator it is getting more than ample charging but seems to loose its charge quite quickly. The two FIAM batteries for the fridge (with a total of 150 amp-hours) are exhibiting none of the same characteristics.

Electrical Suppliers

These are some of the manufacturers and suppliers who helped us with this project and that we can recommend:

  • Davis Instruments
    – suppliers of numerous electrical products for marine use, many of which can not be found elsewhere.
  • Driftgate 2000 Limited
    Little End Road, Eaton Socon, Huntingdon, Cambridgeshire, PE19 3JH
    +44/(0)1480 470400
    – manufacturers of the X-Split Electronic Split Charger
  • ETA Power Products
    – manufacturers of industrial grade circuit breakers and other components.
  • Index Marine
    48 Harewood Avenue, Bournemouth, Dorset BH7 6NH
    +44/(0)1202 430149
    – suppliers of numerous electrical products for marine use.
  • LVM Ltd, Aerogen House, Old Oak Close, Arlesey, Bedfordshire, SG15 6XD
    +44/(0)1462 733336
    – manufacturers of wind generators.
  • Nikka Industries Ltd., 611 Powell Street Vancouver B.C. V6A 1H2 Canada
    email: nikka@nikkaindustries.com
    +1/(604) 251-2466
    – have a wide range of stock including the LED Cluster light bulbs made by Davis above.
  • Maplin Electronics
    – very large supplier of electrical components based in the UK
  • Sterling Power Products
    44 Gregory’s Mill Street, Worcester, WR3 8BS
    +44/(0)1905 26166
    – manufacturers of the Sterling Marine Power Management Panel

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