How Much Energy?

In September 2020:

We are very comfortable with our energy management. As for the last 2 years, batteries are usually toped of by 10am. We switched to AGM batteries a year ago. So we now have 5 x 125Ah gel batteries that don’t need any maintenance. During our Pacific crossing back in May 2019, we were worried that we would drain the batteries too much in the night, with fridge and autopilot on all night. But it was fine. They would then completely recharge during the day.

In a sunny day, when everything is topped off (batteries and water), we also have the luxury to heat up water if we want to, using the solar panels. This uses a lot of energy so we do it in the middle of the day. After an hour of heating up, we have enough hot water to have hot shower for everybody in the evening 🙂

In December 2018:

After half a year, living on the boat full time, here is where we are:

We left the generator in Portland before we left in July 2018. Our solar panels are still incredible and enough, by far. 95 % of the time, they are enough to have all our batteries completely charge up before 11am. Most of the time, even by 10am. If we spend the whole night under sail (=no motor to charge) and with autopilot, batteries go down quite a bit but it is still ok. We had one stormy day in San Diego, where it took the whole day to recharge the batteries.

So…. solar panels are enough for our needs. Batteries are enough. Life is good, energy-wise 🙂

In February 2018:

Well, we got two 350W solar panels. And… it is heaven. It is enough energy for our needs!!! At around 11am, our batteries are typically completely recharged (after energy has been used in the evening with lights, electronics, etc) and we have the rest of the day to use as much as we want to make water, use the autopilot more if needed, etc! YYEEEPPPEEEE!!!

In November 2017:

A lot probably…

But what I know so far:

Energy storage:

We have 6 12V batteries, but really, one is for the diesel engine, one seems to be an emergency battery (??weird… if it is not used, it would discharge over time…) and we have four for everything else. They are 80Ah batteries. Old model, wet batteries,  that need to have their amount of water monitored. They are not very accessible so it’s a pain, but it’s ok. More importantly, they cannot charge and discharge completely. Only approximately 20% (or 25%? I really need to check that).

What goes out (=consumes energy):

  • Fridge is pretty good and well isolated. It consumes about 4.5A. It is on 12V. So energy consumed is 4.5 x 12 = 54W.
    In terms of Ah, let’s say, with the heat and all, it will need to be on/off 50/50 of the time. So we will need for a 24 hour period,
    4.5A x 12hours = 54 Ah.
  • Autopilot, I know, will consume quite a bit. No idea how much, probably similar to the fridge. I will research it very soon. The autopilot is needed when you don’t want to be at the helm all the time. You are of course still on watch…
  • Water maker, is that device that makes drinkable water out of sea water, thanks to a high pressure pump, and a few filters… We just purchased a highly efficient one: 30L/h (8 Gal/h) with an energy consumption of 200W!!!! Woot woot!!
  • And then, the “house”, which is lights, computer, phones… Hopefully that’s a few watts here and there…

What comes in (=we can generate):

  • we looked at two 200W solar panels. We might even be able to go with 2x 300W panels. It depends on how much room we have on the back structure of the boat…
  • if the solar panels are not enough, we can always run the engine, that will recharge the batteries, thanks to the two alternators we have. But we will try to avoid using the engine for electricity generation. But we will definitely take advantage of it when we are under motor anyways.
  • I saw we also have a portable generator, that needs gas. It says it provides 2000W… I don’t want to use it, but we will see…
  • No plan for a wind turbine so far, but we will see as we go.

Energy balance (in = out??)

It seems like on a sunny day, the solar panels could definitely pull it off… On a rainy day, well, I guess we can shower under the rain, and don’t need the water maker to run as much… More to come when we actually experiment it…