We recently caught up with Rean Snyman, a keen yachtsman with a huge interest in new technologies and energy management… Here’s how he’s making the most out of his twin Integrel system that he’s recently installed on his catamaran.
Rean, what sort of vessel is S/Y Top Secret?
Top Secret is a 2003 voyage 580 catamaran, it is converted for world cruising and it weighs around 25,000 KG. We live aboard her for nine months of the year and cruise globally.
Historically, what was your generation, storage, distribution set-up onboard S/Y Top Secret?
The vessel was originally set up to use 24v. It had 600ah of lead-acid batteries, so about 8kwh of useable capacity. The batteries lasted about 3-4 years at best.
All of Top Secret’s winches are electric and so is the windlass, so I stuck to the 24v house bank to keep the equipment, which was perfect and still works a treat.
We had 2 x Northern Lights 6kva Generators fitted that were putting out 115v. These were capable of charging the batteries slowly and running the 4 air conditioners and other onboard appliances. One was not sufficient to run all the air conditioners only.
What have you changed about your set-up and why?
We upgraded the boat completely and re-wired everything. We still have a 24v house bank consisting of 4 x super-B 160ah batteries with a useable capacity of 8kwh, so the same as before. We added a bank of 12 x super-B 160ah batteries, wired in 48v configuration with a useable capacity of 24kwh. This acts as the propulsion bank for the electric motors.
The electric motors are Oceanvolt SD15 sail drives. They consume around 12kw continuous each at max throttle. We initially installed 4 electric motors but were struck by lightning and realised that when this kind of thing happens, all power is lost and there is no going anywhere under power, so removed and replaced 2 of them with 55hp Volvo Diesel engines with no electronics, for safety. We now have 2 x electric motors and 2 x diesels (Volvo Penta D2-55). We also initially installed 2 x polar power DC generators delivering 14kw each to charge the batteries and run the electric drives for extended motoring, as the batteries only last around 2 hours when motoring. After the removal of the 2 electric drives, we also removed one diesel Genset and added an Integrel generator to each Volvo – Allowing us to generate up to 18kw of the main propulsion engines. The only reason we did not remove the other Genset was the fact that it can be started and charge the batteries automatically when they are almost depleted, which cannot be done with the Integrel generators.
What are your initial thoughts on your new configuration?
The change has proved very successful and the benefits are:
1. The motors give us hot water for free every time we charge the batteries from the Integrel generators. We previously relied upon electrically heated water before the change.
2. Extended motoring (which we do regularly in no wind and headwind conditions) is no problem and we now charge batteries at the same time.
3. The charge rate from the Integrel generators is fantastic, and I can charge the batteries running both Volvo’s in just over an hour from empty to full. They charge better than the Genset.
4. The Integrel battery monitor is more accurate than the Victron monitor with my batteries.
How long can your vessel be autonomous for and how often/when do you charge with Integrel?
We have 3 modes of power usage on the vessel:
1. No air conditioners on
2. Nighttime air conditioning only
3. All-day and all night air conditioning
1. We use electricity to cook food. We have an induction hob with 5 plates and 2 x combination ovens. This happens every day and uses about 2.5kw of power.
2. We use electricity to wash and dry clothing, bedding, etc… this also happens every day and uses about 2kw of power.
3. We use electric for refrigeration and we have a household freezer and a household fridge, using about 3.5kw of power every day.
4. We have a kettle, coffee machine and a dishwasher, all used everyday and these use around 1kw of power.
All these items are run off a 5kva Victron inverter attached to the 48v bank.
The 48v bank is charged during the day by 2kw of solar panels. These produce 8.5kw in the summer and 6.6kw in the winter each day. The 24v bank is charged by 1.2kw of solar panels, delivering around 4kw in summer and 3kw in winter each day. The 24v and 48v feed each other by means of an MPPT Charger, and we can continue indefinitely as long as we don’t use the air conditioners.
2. We always sleep with the Air conditioning on at night, which uses around 4kw each day. So in summer, solar is enough but in winter it is not quite sufficient.
We will need to run the Integrel generators every 5 days for 1.5 hours, or the Genset for 1.75 hours. This is our default modus operandi, but because we want hot water, I will run one of the Integrel generators on a Volvo engine for a few minutes each day and top up the batteries at the same time.
3. When we have guests or it is just too hot, we turn on all the air conditioners and stay sane. This costs us an extra 20kw each day, so we run both Integrel generators for 40 minutes in the morning for hot water and a top-up and then the Genset runs for about 40 minutes just before bed to make sure we have enough power for the air conditioning during the night. This is max power mode, but is not intrusive in noise, as a bit of engine in the mid-morning and again after dinner is fine when you are getting an entire day and night of quiet air conditioning.
Of course, we do move the boat, and when we up anchor, the engines are started and when we drop anchor the engines are started. When this happens the Integrel generators pump in the power and thus no extra runtime is needed that day. We move the boat at least once every 3 days and so get propulsion as well as charge. Electric drives are great, but for my wife’s sanity, diesels have made a big difference and we have more options.