Charging House Batteries From a Honda Portable Gen

[Koeketiene]

As far as I can tell from the graphs, the windcharger isn’t great. Only a narrow band of windspeeds in which useful amounts of current are produced.

That has been my experience too.
Had a Rutland 913 on my previous boat and the solar panels outperformed my windgenny by a considerable margin.
And a windgenny is 'not great' when sailing downwind (like Las Palmas - St Lucia as you are contemplating).

A Watt and Sea would be great if I could afford £3.6k. A hydrovane would solve a lot of problems if I could afford £5.6k. (Equipping for long passages is already costing me north of £24k).

Don't know what boat you have, but if she's tiller steered you might want to have a closer look a 'sheet to tiller' selfsteering.
YouTube would be a good start.
It can take a while to get to grips with it, but once you have the knack it's a sight to behold.
Reliable selfsteering for little more than 100 quid.

 

[KeelsonGraham]

Agreed Paul. You’ve probably convinced me that using it to power the battery charger isn't a good idea.

Working out the power consumption of a Raymarine Type 1 linear drive is pretty hard. It’s downwind sailing so the boat is going to be wallowing when goose winged. So, I’m guessing that power consumption will be on the higher end of the scale.

 

[PaulRainbow]

Taking the figures from Martin of Jambo (see the ‘How is this possible?’ thread) the daily requirement is about 420Ah. My own rough calculations come out very close to this figure assuming you want to run a fridge, chartplotter and AIS all day and radar at night.

750kw of panels operating a latitude of 30N with the boat pointing E/W are going to give you about 180 Ah. The deficit needs to be made up by running the engine. And maybe a little more from the genset whilst it’s powering the watermaker

420ah seems very high, you'd need about 1000w of solar for that, on a good day. There are lots of other long distance cruisers on here, perhaps some would care to comment ?

 

[KeelsonGraham]

420ah seems very high, you'd need about 1000w of solar for that, on a good day. There are lots of other long distance cruisers on here, perhaps some would care to comment ?

I’m assuming worst case. Hot, so the fridge runs a lot. Bright, so the chartplotter is set bright. Shorter days, and half the solar panels not directly facing the sun.

 

[PaulRainbow]

Agreed Paul. You’ve probably convinced me that using it to power the battery charger isn't a good idea.

Working out the power consumption of a Raymarine Type 1 linear drive is pretty hard. It’s downwind sailing so the boat is going to be wallowing when goose winged. So, I’m guessing that power consumption will be on the higher end of the scale.

You're right, it's hard to calculate the consumption on paper. So much depends on the boat, the conditions and how she's set up.

 

[Koeketiene]

I’m assuming worst case. Hot, so the fridge runs a lot. Bright, so the chartplotter is set bright. Shorter days, and half the solar panels not directly facing the sun.

Have a look at a keel cooled fridge - they are not so power hungry in warmer climates (if you haven't already).

 

[Graham376]

Taking the figures from Martin of Jambo (see the ‘How is this possible?’ thread) the daily requirement is about 420Ah. My own rough calculations come out very close to this figure assuming you want to run a fridge, chartplotter and AIS all day and radar at night.

750kw of panels operating a latitude of 30N with the boat pointing E/W are going to give you about 180 Ah. The deficit needs to be made up by running the engine. And maybe a little more from the genset whilst it’s powering the watermaker

Some people must have a hell of a lot of high draw electrical comforts on board. Our summer cruises for several years from N Wales, took us down to France, Spain and Portugal and of course back with many overnights. At that time, we managed (carefully) with 200w solar + Aerogen (which contributed little) and 220AH of domestics. Fridge was running full time, as was autopilot plus radar mainly at night which scanned for a couple of minutes, every 20 mins or so, then put back on standby.

We now have 320W solar, 450AH domestics and a larger fridge compressor on high cycle with below decks temperatures regularly 30+ degrees. Based on Algarve mooring or anchor we haven't had to use anything except solar to charge batteries for the last couple of years.

 

[Mistroma]

That has been my experience too.
Had a Rutland 913 on my previous boat and the solar panels outperformed my windgenny by a considerable margin.
And a windgenny is 'not great' when sailing downwind (like Las Palmas - St Lucia as you are contemplating).

Yes, my experience of a 913 was that it averaged 10Ah per day in a Scottish summer and that fell to 7Ah per day as I went to the med. The newer models claim much better output and are probably a great way to spend almost £1,000 to get 12-14Ah per day.
Solar outperforms it by a huge margin on cost per Ah, unless you live somewhere very windy and sail in winter.

I've kept mine as it does help on stormy cloudy days. I've managed 140Ah per day but usually once once every couple of years. People see them spinning away in a light breeze and assume they are putting a lot into the battery. The voltage often doesn't get high enough in light wind to actually charge a battery but will offset a small drain and reduce loss of charge slightly.

 

[Momac]

Yes he has! 15 litres for a passage from Las Palmas to St Lucia, either stored in the anchor locker or on the sugar scoop transom.

Does that work out at about 2hrs generator running per day?
I don't understand the thinking and why you wouldn't run the main diesel propulsion engine for the same amount of time at probably similar volume of fuel consumed but probably greater Ah put into the batteries.

 

[KeelsonGraham]

Does that work out at about 2hrs generator running per day?
I don't understand the thinking and why you wouldn't run the main diesel propulsion engine for the same amount of time at probably similar volume of fuel consumed but probably greater Ah put into the batteries.

By my calculations 15 litres gives 13 hours running time (spread over a 25 day passage) Because I don’t have an inverter and need AC for the water maker!

 

[dunedin]

Taking the figures from Martin of Jambo (see the ‘How is this possible?’ thread) the daily requirement is about 420Ah. My own rough calculations come out very close to this figure assuming you want to run a fridge, chartplotter and AIS all day and radar at night.

That might be the norm for coastal sailing, but may be more than needed for an Atlantic crossing (which seemed to be suggested elsewhere).
Zero geographic navigation hazards from the Canaries to St Lucia so why need the plotter on. Should be able to see any other boats by day or night, they are so infrequent. Perhaps plotter on at night for AIS (could do every half hour), and only radar if needed to spot squalls - and again only need to press transmit every 15 mins or so.
Very different if night sailing in busy coastal routes, of course

 

[KeelsonGraham]

Some people must have a hell of a lot of high draw electrical comforts on board. Our summer cruises for several years from N Wales, took us down to France, Spain and Portugal and of course back with many overnights. At that time, we managed (carefully) with 200w solar + Aerogen (which contributed little) and 220AH of domestics. Fridge was running full time, as was autopilot plus radar mainly at night which scanned for a couple of minutes, every 20 mins or so, then put back on standby.

We now have 320W solar, 450AH domestics and a larger fridge compressor on high cycle with below decks temperatures regularly 30+ degrees. Based on Algarve mooring or anchor we haven't had to use anything except solar to charge batteries for the last couple of years.

Maybe I’m wrong in my calculations. I’ve simply taken estimates, based on declared wattages of each item, fudging that for likely percentage of maximum power and then multiplied by likely number of hours of use per day. I have no ’electrical comforts‘ on board unless you consider nav equipment autopilot and fridges to be in that category.

I would personally not like to turn a radar unit on and off every 20 minutes. It’ll likely seriously reduce its lifespan.

Mooring and anchoring doesn’t require an autopilot or chartplotter or AIS or radar, which in my calcs knocks off about 300 Ah per day.

 

[KeelsonGraham]

That might be the norm for coastal sailing, but may be more than needed for an Atlantic crossing (which seemed to be suggested elsewhere).
Zero geographic navigation hazards from the Canaries to St Lucia so why need the plotter on. Should be able to see any other boats by day or night, they are so infrequent. Perhaps plotter on at night for AIS (could do every half hour), and only radar if needed to spot squalls - and again only need to press transmit every 15 mins or so.
Very different if night sailing in busy coastal routes, of course

I’m at a loss to figure out how to use AIS without a chartplotter. AIS is mandatory for the Arc Atlantic.

Anyway, these are my safety choices which don’t have much to do with my original question about adding charge to domestic batteries using a Honda portable gen!

 

[Graham376]

I would personally not like to turn a radar unit on and off every 20 minutes. It’ll likely seriously reduce its lifespan.

What radar do you have? Our old Furuno 1712 has standby mode so can be manually switched to scan as needed or "watchman" mode where it scans at set periods, checks for new targets automatically then either sounds an alarm or, goes back to sleep if nothing found. As it's about 18 years old now and still working fine, no worries about life span.

 

[KeelsonGraham]

Q24. It has a standby mode of course. A watchman mode would be great. I’ll check the manual!

EDIT

The Quantum has a similar function called ‘Timed Transmission Mode’. That’ll save a few Ah!