Power requirements sanity check

[prv]

As for backup, I am thinking about some of those battery operated lights.

Do you mean for nav lights? The 1-D-cell-and-a-torch-bulb jobs? I've not tried them myself, but several people have reported them to be complete rubbish.

If you have LED nav lights you should always be able to light them with your main battery, the current drain is so low (from memory, my lights on KS were 80mA each). I reckon an adequate backup for them is the Big Feckoff Torch you want on board anyway - in the unlikely event your lights fail and something big is heading towards you, flashing the torch around (initially at your sail, at their bridge if necessary) will let them know you exist.

Oil nav lights is an interesting idea. Probably not the most practical answer, but for nostalgia on a classic boat, why not? One of the Pardey books (I think it's Self Sufficient Sailor) has lots of tips about how to do this.

Pete

 

[Tranona]

Thanks all,

Looks like there are a few things I can do to get the most range.

It looks like the order of cost is:
Change to LED tri-light
Add a 2nd 110 amp leisure battery
Battery monitor
Smart charger

As for motoring, it sounds like we need to run the battery for a couple of hours a day. Do it at night and it will cut my consumption because the lights will be run directly from the engine for some of the time.

Suggest you also order your engine with the optional 55amp alternator if you are increasing your battery capacity - or get a Nanni where it is standard.

 

[Westerly Jetstream]

Suggest you also order your engine with the optional 55amp alternator if you are increasing your battery capacity - or get a Nanni where it is standard.

Just remember three things, 1 never discharge your domestic bank more than 50%.2 your alternator will be at max 55 to 60% efficient and 3 your smart regulator can trip with an over voltage situation if its too small for the battery bank.
Beta engines come with a 60 amp alternator as std, but a 110 as a cruising option much more sensible if your swinging to your own hook and avoiding marinas Remember your actual alternator output which will be the 60% figure should be at least 25% of battery bank size and at best 40%. We all have yachts to go sailing not to spend hrs motoring to charge batteries.

 

[Tranona]

Just remember three things, 1 never discharge your domestic bank more than 50%.2 your alternator will be at max 55 to 60% efficient and 3 your smart regulator can trip with an over voltage situation if its too small for the battery bank.
Beta engines come with a 60 amp alternator as std, but a 110 as a cruising option much more sensible if your swinging to your own hook and avoiding marinas Remember your actual alternator output which will be the 60% figure should be at least 25% of battery bank size and at best 40%. We all have yachts to go sailing not to spend hrs motoring to charge batteries.

Correction. The Beta 14 comes with 40 amp as standard and 70 (not 55 as I quoted earlier) as an option.

 

[pvb]

Just remember three things, 1 never discharge your domestic bank more than 50%.2 your alternator will be at max 55 to 60% efficient and 3 your smart regulator can trip with an over voltage situation if its too small for the battery bank.
Beta engines come with a 60 amp alternator as std, but a 110 as a cruising option much more sensible if your swinging to your own hook and avoiding marinas Remember your actual alternator output which will be the 60% figure should be at least 25% of battery bank size and at best 40%. We all have yachts to go sailing not to spend hrs motoring to charge batteries.

I'd agree with (1), discharging batteries below 50% is a killer.

But I don't know where you got (2) from, alternators are rated according to their max output, so why should you think they'll only give 55-60% of that? My 90A alternator certainly pumps out close to 90A if the batteries can take it.

And point (3), that a smart regulator can trip with over-voltage? The smart regulator determines the alternator voltage.

As Tranona says, the OP's Beta 14 has a 40A alternator as standard and the higher output option is a 70A alternator.

As for the relationship between alternator output and battery bank size, there's a lot of myth about this. The reality is that a smallish alternator can happily work with a large battery bank. Using your figures, I'd need something like a 400A alternator for my battery bank, but I can assure you my 90A alternator works fine.

 

[Westerly Jetstream]

I'd agree with (1), discharging batteries below 50% is a killer.

But I don't know where you got (2) from, alternators are rated according to their max output, so why should you think they'll only give 55-60% of that? My 90A alternator certainly pumps out close to 90A if the batteries can take it.

And point (3), that a smart regulator can trip with over-voltage? The smart regulator determines the alternator voltage.

As Tranona says, the OP's Beta 14 has a 40A alternator as standard and the higher output option is a 70A alternator.

As for the relationship between alternator output and battery bank size, there's a lot of myth about this. The reality is that a smallish alternator can happily work with a large battery bank. Using your figures, I'd need something like a 400A alternator for my battery bank, but I can assure you my 90A alternator works fine.

As usual pvb you and i will have to agree to differ IMHO and from experience No alternator can continually give its rated output Smart regulator or not they are at best 60% efficient when run for along time.
Also from experience running a huge battery bank with a small alternator is asking for trouble
e.g. I rewired a 40ft sail training yacht recently and despite 30mm alternator cable from the 40 amp alternator with smart regulator it would trip out after 30mins. Now the alternator was checked by a marine Specalist and the smart regulator was changed 3 times the boat has electric furling,reefing, and winches and the battery banks where Huge The final solution was a bigger alternator, and the old alternator is working away happily on another vessel with smaller bank, I' ve worked on dozens of boats as have you we just have different ideas.At 66 i'm not likely to change. Each to his own suffice to say that after many years of problems the boat mentioned did ASAB for first time with no electrical problems post rewire.

 

[pvb]

As usual pvb you and i will have to agree to differ IMHO and from experience No alternator can continually give its rated output Smart regulator or not they are at best 60% efficient when run for along time.

Most decent alternator manufacturers quote an output figure which is an average of hot and cold outputs (the sustained output is slightly lower when hot). However, the reduction is nowhere near the 40% you're suggesting. Balmar, for example, quote 95A as the output of a 100A alternator when hot.

 

[Blueboatman]

I sailed for years with a 4amp outboard alternator, one 110 leisure battery... AND a 18w solar panel that measures around 450mm square.. Which I still have. They really are unobtrusive and can be set up temporarily every day outside on the outside of the dodgers or pushpit, using strings in each corner and a stick ' prop'..
Add led masthead replacement bulb as suggested, lose some interest in VHF perhaps, sorted..

 

[Ru88ell]

You haven't allowed for charging phones and iPads. My boat is similar in size to yours and I only have a 60ah which lasts a long time. Change whatever you can to LED and just have stuff on if you really need to. My LED anchor light has a sensor, so isn't burning when I'm asleep and daylight has arrived.

 

[William_H]

I would suggest the OP priorities should be first LED nav lights then an additional battery and amp/volt meter. Then perhaps a smart regulator and if necessary a bigger alternator. However far better to reduce current consumption by switching instruments off.
Certainly don't even think of battery emergency nav lights. Op shopuld also fit interior LED lights being very low current consumption. good luck olewill

 

[Iliade]

LED, LED, LED,

... and turn your radio transmit power down to 1w. Better still, use the handheld for listening watch.

I use a halfords bike headlight as an anchor light. 180 hours from three AA batteries...

My autopilot & plotter/sounder are now responsible for almost all of my power usage.

 

[Iliade]

'Emergency' nav lights: A set of coloured lenses are available to enable Petzl Zipka head torches to be used as such. Zipkas are surprisingly bright, conform to no known marine legislation, are reasonably waterproof and run for days on three AAAs.

 

[onesea]

2 side to this IMHO:
1) Power Usage.
Switch to LED its not expensive order from china, I have some on the way if you want the spares PM me. I could order 5 for the price of one here!
Turn off what you do not need, 1w on VHF will do a surprising amount (if you have to chat on VHF),
Oil lamps below are the way to go.
Have a bright all round white light/ tourch, as your emergency navlight (again led).

2) Power Generation/ storage.
Keep what you have got, forget all the gizmos and money.
Just buy one small trickle charger for when you are not onboard these (20 quid). I have been known to leave mine in the cabin when its going to be wet and frosty still seems to keep battery up.
If your battery falls below 50% occasionally yes it will damage it, but by how much realistically. Then I just consider it as a consumable.

How long should they last anyway even fully maintained, there is much less to go wrong this way.

One I would add I have jump pack with inverter and light and tyre inflator as a backup. Handy for keeping charge on phones laptops etc, can be charged through cigarette lighter. Also if I had no shore power I would take it to the pub to charge it...

 

[charles_reed]

If you have used 40 amp hours .
You will not recharge the battery by runnng the engine with a 40 amp alternator for one hour.
The charge current at first may be high but it will soon drop off.
I have the same capacity of alternator on a motorboat. With one starter and one leisure battery. If we motor three hours it seems sufficient to recharge the battery.

Oh that you were right (about a 40amp alternator) actually putting out 40 amps. You are about right with the 3-4 hours to recharge the batteries, in practice, and to get full charge you will need an external smart controller.
In fact the alternator quoted capacity is the rated maximum an alternator will put out - kept at the maximum for very long most alternators melt.

VicS has it right, though he is understandably coy about the bit extra, which is heavily hostage to the law of diminishing returns.

 

[charles_reed]

<<But I don't know where you got (2) from, alternators are rated according to their max output, so why should you think they'll only give 55-60% of that? My 90A alternator certainly pumps out close to 90A if the batteries can take it.>>

Perhaps "if my charge controller decides my batteries can take it" - in practice alternators operate @ far less than 100% rated output. Which is a good thing as continuous maximum output usually involves overheating and melting.

<<And point (3), that a smart regulator can trip with over-voltage? The smart regulator determines the alternator voltage.>> Some, notably the Balmar and TWC used to as a final safety measure when you had a short in battery. I'd agree not in normal duty.

<<As for the relationship between alternator output and battery bank size, there's a lot of myth about this. The reality is that a smallish alternator can happily work with a large battery bank. Using your figures, I'd need something like a 400A alternator for my battery bank, but I can assure you my 90A alternator works fine. >>
Like most myth there is a grain of truth. May I explain - if you have a small battery bank it is more likely, in normal service, to become heavily discharged, in those circumstances the rule of thumb, output as 25% of battery capacity is probably valid. With a larger bank, relative discharge is lower and therefore tha alternator needs to put out less charge.
I ran my 90 amp Lucas with 330 ah of capacity for about 5 years before diode bridge burns became too much - the subsequent 110 amp Magnetti Marelli lasted far longer and was much more satisfactory in service.
But then I live on my boat 7/12 and don't stint the electrics.

 

[charles_reed]

2 side to this IMHO:
1) Power Usage.
Switch to LED its not expensive order from china, I have some on the way if you want the spares PM me. I could order 5 for the price of one here!
Turn off what you do not need, 1w on VHF will do a surprising amount (if you have to chat on VHF),
Oil lamps below are the way to go.
Have a bright all round white light/ tourch, as your emergency navlight (again led).

2) Power Generation/ storage.
Keep what you have got, forget all the gizmos and money.
Just buy one small trickle charger for when you are not onboard these (20 quid). I have been known to leave mine in the cabin when its going to be wet and frosty still seems to keep battery up.
If your battery falls below 50% occasionally yes it will damage it, but by how much realistically. Then I just consider it as a consumable.

How long should they last anyway even fully maintained, there is much less to go wrong this way.

One I would add I have jump pack with inverter and light and tyre inflator as a backup. Handy for keeping charge on phones laptops etc, can be charged through cigarette lighter. Also if I had no shore power I would take it to the pub to charge it...

Perhaps, like me his lighting usage is 6% of daily AH usage, in which case LED lighting throughout is a small, expensive, incremental benefit. Certainly I use an LED as riding light but that's totally self-contained.

Oil lamps might be the way to go, but paraffin is curiously unobtainable in most of the European continent, and the lighting, though delightfully romantic is not adequate for any detail work.

Your suggestion about the trickle-charger is both ill-informed and ill-advised - the cost of the damage such a unit if not a switch-mode unit will inflict on the batteries will more than offset any saving on original purchase price.

As to the comment on gizmos, some are definitely worth-while, many I'd agree a waste of time, effort and money - the trick is to know which is which.

 

[charles_reed]

LED, LED, LED,

... and turn your radio transmit power down to 1w. Better still, use the handheld for listening watch.

I use a halfords bike headlight as an anchor light. 180 hours from three AA batteries...

My autopilot & plotter/sounder are now responsible for almost all of my power usage.

Ah! a true amateur who enjoys getting away from the snares of modern life and it's little luxuries!!

Just try living aboard for 6-9 months on end with no fridge, music playback, heating, computer etc.

 

[onesea]

Perhaps, like me his lighting usage is 6% of daily AH usage, in which case LED lighting throughout is a small, expensive, incremental benefit. Certainly I use an LED as riding light but that's totally self-contained.

Oil lamps might be the way to go, but paraffin is curiously unobtainable in most of the European continent, and the lighting, though delightfully romantic is not adequate for any detail work.

Your suggestion about the trickle-charger is both ill-informed and ill-advised - the cost of the damage such a unit if not a switch-mode unit will inflict on the batteries will more than offset any saving on original purchase price.

As to the comment on gizmos, some are definitely worth-while, many I'd agree a waste of time, effort and money - the trick is to know which is which.

With regard to LED lights, as I said to him buy direct from China, I have ordered enough for my boats interior lights twice for 20 quid. No exactly a heart breaker. My light usage is like yours next to nil, with LED lights I will not even wory about the power consumption (now there is a piece of mind).

By trickle charger sorry I did not make myself clear I meant solar jobby like on of these.

As the OP is already using oil lamps I was just offering some moral support, we got our first this winter...

As for the Gizmos to be honest I would rather be sailing than trying to work out which one would work for me. So another days sailing and a year less on my batteries life, I am sorry battery your gona suffer...

Although I do have onboard a little battery charger for when we hook up to shore power just to give a boost to the charging.

Each to there own I guess I like to keep sailing about the wind, not the toys...

 

[prv]

Just try living aboard for 6-9 months on end with no fridge, music playback, heating, computer etc.

What's that got to do with the price of fish? Phill doesn't live on his boat, he uses it at weekends and occasional holidays just like most of us.

Pete

 

[PhillM]

What's that got to do with the price of fish? Phill doesn't live on his boat, he uses it at weekends and occasional holidays just like most of us.

Pete

Very true, the object of this exercise is to be able to set off for a week or so and not have to worry about getting in for power, before I run out of food and water. I'm not planning on crossing oceans, but do fancy a few days away where nobody can find me.