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Generating electricity...

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farmer boy says:

Just to take my mind off scraping the bottom!

I have had a good read through the site and there seem to be a wide variety of different systems in use. I will need some way of re-charging batteries and seem to have a few options....

1. buy a new engine that has a charging circuit - the old one is fine and could be sold on or kept as a spare.

2. Buy a solar panel.

3. Buy a wind generator.

4. Buy a thing that hangs over the back... some sort of turbine?

5. Use paraffin lamps!

They all seem to be quite expensive options (except 4!)- any thoughts as to which is the most suitable? I intend to fit LED's were possible (after talking to Neil R) but I will need power for the GPS, all the lights, phone charger, VHF radio, stereo system, and not forgetting an electric cooker and air conditioning... sorry - dreaming again.

The cheaper Solar panels seem to be just trickle chargers and its not that sunny in Lancashire anyway!

Wind generation looks ok - anyone recommend it?

I guess engine generation will be the most efficient - I assume its just like having an alternator on a car? I am hoping to stay aboard for a few days at a time (occasionally) so I cannot rely on shore power. Hmmm how do you fit shore power... maybe next week!!

oh - just a thought ... can you use caravan type equipment on a boat? I am thinking about gas water heaters - I have one in the caravan - it is tiny - the size of a big shoebox and works a treat...

Appreciate any thoughts..
9:44AM, 10 February 2011 PDT (permalink)

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blueachilles says:

We have two leisure batteries on Blue - 85Ah and 60Ah respectively. Generally speaking, they last a full season, powering speed and depth instruments, VHF, occasional use of a car radio, and lights - not LED.

We spend about 20+ nights on board in a season.

We may top up occasionally mid season if we are in a marina with electric points on the pontoons; we have a battery charger on board, and a camping/caravanning style electric hook up lead. Shore power doesn't have to be any more sophisticated than that, as long as there is a circuit breaker in there somewhere.

I'm not sure about caravan gas water heaters - when I caravanned we used a kettle, and still do on the boat. Caravan gas/12v/240v fridges wouldn't work because boats tip over, caravans don't.

Wind power would be expensive.
103 months ago (permalink)

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songeur2010 says:

I've installed a 10watt solar panel on Songeur, getting plenty of sun this time of year so it's worked well. I've had no problems sailing for 10 hours with the gauges and VHF on the whole time, still starts the yanmar at the end of the day.
LED's are a revolution in power saving so that's a good idea.
In NZ you can run a small marine fridge off an 80 watt solar panel but that is starting to up the ante.
I also have a decent alternator attached to the engine so the battery gets a good charge through motoring in and out of the harbour, I think its a good idea if you have an outboard that it has a charging circuit. As for hot water, just boil the kettle, the boats too small to cram too many accessories on or in.
103 months ago (permalink)

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pjbharrison says:

I have 5 12V 17Ahr batteries in a battery box. Got them for next to nothing out of UPS systems for computers. (I fix computers). I have a small 1.2watt solar panel from Maplin. Lasted all of last season OK. Have depth speed vhf and GPS on board. Didn't use lights at all.
Just got a 98Ahr deep cycle leisure battery for this season (from a bigger UPS system) as I hope to cruise a bit more. Have followed Neil's advice on LEDs. very impressed with how bright and small they are. I'll probably run interior lights off the small batteries and keep the 98Ahr for nav instruments and nav lights.
Outboard has a 3A charging circuit. You can buy a rectifier for an OB for about £40, I believe.
The 17Ahr batteries are small and light enough to bring home and charge, 1 or 2 at a time, if needed.
Single ring gas cooker heats up such a small boat really fast. I use a cool box with ice packs for day trips. Gas heating causes condensation without good ventilation which tends to defeat the purpose!
Argos and others sell wind up led lanterns for camping. I used some while camping for a week last year and found them good.
cgi.ebay.ie/12-LED-WIND-UP-RECHARGEABLE-CAMPING-LANTERN-L...
Originally posted 103 months ago. (permalink)
pjbharrison edited this topic 103 months ago.

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rothwell_neil says:

I have one 85AHr leisure battery, regular sailing with gps, depth and radio on and a good few long weekends never drained this at all using a 13W solar panel and the 5A motor circuit when it was on. Guess that I ran the motor max of 30 hours last year. As the battery is now 4 years old tested the capacity and it is down to 40Amp hours and showing signs of being old, as you should never use more than 50% of capacity this gives me 20Amphours, GPS .5amps, depth .2amps and radio on standby .1amps. max use .8amps, 8 hours sailing and 6.4amp hours used. LEDS don't count as few hours at .1amps. So with no charge even with a duff battery 3 days and then a week of sun will recharge. Rod is right, a full 85Amphour battery will do fine with either solar, motor or occasional top up during the season. A volt meter is all you need as charge it is almost linear <12.8V fully charged, 12.5V, 75%, 12.2V, 40%, 11.6V 25%. That is useful charge so never take below 11.6V to keep it in good nick. Fishfinders have the voltage on them and you can get a battery monitor that does temperature from ebay for £6 from HK.
103 months ago (permalink)

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Red Marlin says:

Our requirements are maybe different as we have a 9 metre and live aboard many months a year in Turkey/Greece. But in our experience. Forget about oil lamps you would never use them. Towed chargers likewise. We have smart charger on the engine but never use the engine to charge the batteriies. So it is between wind and sun, out here sun. UK maybe wind. Because we have a fridge and an electric anchor winch we need big batteries (200amp leisure plus 85 amp engine). We use LED lights - Magic. The oversize solar panel (130) means we rarely need to think about power requirements. Need the big batteries for night sailing if we do not use the engine we need to store enough to carry us through the night.
103 months ago (permalink)

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pjbharrison says:

Hi Neil
How did you test the capacity of your battery?
103 months ago (permalink)

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rothwell_neil says:

Battery testing is pretty easy with a normal 60W car headlight bulb or similar. They are 60W and at 12V pull 5amps (hence don't leave your lights on the car for long). I just connect on a day that I am around and measure voltage and time. You can start and stop if you have a big capacity battery and this doesn't affect the results. So start for a fully charged battery will be 12.6-12.8 volts and then record time and voltage. Normally volatge decay is linear so pretty soon you can get an idea of jow long it will take to drop to 11.6 volts. Otherwise and I tend to do this leave it running and take periodic voltage readings. After 10 hours this is 50Amp hours power etc. If you use a car battery then you should only ever use about 30% of the stated capacity and don't discharge below 12V. Leisure batteries are designed for deep discharge which for many is still only 50% of stated capacity. they will however recover from a few deep discharges. Once a car battery goes right down they tend to be basket cases.

Having said that I have just ordered the electronics to build me a desulphator, batteries suffer from sulphation if stored at low charge or if charge cycles not ideal. Most batteries suffer from this as the main failure mode. I should get this next week and will report in due course. It supposedly pulses the battery to remove the sulphate. Lead acids lose charge quite quickly so if not on solar top up they need to be taken off the boat and charged over winter or they will auto discharge.

Voltage values (no load) against % charge below:

100% = 12.73
90% = 12.62
80% = 12.50
70% = 12.37
60% = 12.24
50% = 12.10
40% = 11.96
30% = 11.81
20% = 11.66
10% = 11.51
Originally posted 103 months ago. (permalink)
rothwell_neil edited this topic 103 months ago.

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songeur2010 says:

I have one deep cycle Battery on Songeur which was thrown out due to not holding a charge. I took it to an outfit which specializes in reconditioning dead batteries (desulphating) and although the battery does not quite have its new capacity it still works fine. This cost $25 instead of $200 for a new one. Desulphating is definitely worth a shot to extend a batteries life. Hopefully with the solar panel keeping it up I will get another couple of years out of it.
103 months ago (permalink)

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rothwell_neil says:

As I am sad I have looked into this sulphating business and actually believe that my battery has reduced capacity due to leaving it on trickle charge over the winter on the solar panel. There is plenty of information I found that shows that if trickled at a low rate then this could establish conditions sub fully charged and encourage sulphation. Maintaining a battery at partial charge develops sulphation and limits capacity. In other words the battery self discharges at a rate greater than the trickle so you see a slow decay over the winter. with the battery maintained over the bleak winter months at partial charge.

I will try to recover this battery and then use the solar charger through the summer as this definitely keeps it full and then disconnect and keep at home over winter. It is also important to periodically charge over winter as lead acid does auto discharge and loses 10-40%+ per month depending on type, gell being the best and wet the worst. This suggests that should charge over winter at least every 2-3 months. If I have to get a new one then I will be monitoring voltage and still bringing it off the boat over winter and charging in the garage.
103 months ago (permalink)

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rothwell_neil says:

Built my pulse desulphator and it is currently doing its thing. Seems to be working as can see minute bubbles coming off plates from the pulses. Works at 1Khz and just the right frequency to give you a ringing in the ears.

One thing that I read and had never considered, freezing batteries. now this may not sound like an issue as cars do not seem to suffer but the fact is that fully charged the battery is 35% sulphuric acid and has a very low freezing point, as it discharges it sulphates the plates and the acid loses strength so that at low levels of charge very dilute acid and higher freezing temperature as in closer to zero. that is why you can test charge by a hydrometer. Moral of the story is that fully charged unlikely to freeze, low charge due to being left on trickle or flat and the battery can freeze which will knacker the plates.
103 months ago (permalink)

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songeur2010 says:

Very interesting, one thing is for sure, I wont have a problem with freezing.
103 months ago (permalink)

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