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All Electric?


Mike1951

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Been looking at the possibility of dispensing with gas - electric oven and induction hob. We will only be living aboard weekends for the next few years as we are still working and we have shore power at the marina, so only one or 2 nights crusing away from the marina. We have a 3KW inverter/charger and 4 x 150AH lead-carbon deep cycle batteries. Any experience/thoughts?

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9 minutes ago, Mike1951 said:

Been looking at the possibility of dispensing with gas - electric oven and induction hob. We will only be living aboard weekends for the next few years as we are still working and we have shore power at the marina, so only one or 2 nights crusing away from the marina. We have a 3KW inverter/charger and 4 x 150AH lead-carbon deep cycle batteries. Any experience/thoughts?

So you have 600Ah of lead carbon batteries. Assuming discharge to 60% DoD that is about 3.6kwh at fast discharge. Things other than cooking are likely use at least 1kwh per day so I guess it depends on how long, when you are away from the Marina, you are moored vs cruising. If away for 2 nights, how much cruising you do on the second day. And whether you are planning to roast the Christmas turkey or just heat up some beans on toast!

 

And perhaps most importantly, what charging devices / capabilities you have other than shore power.

 

I expect you could make it work if you have a modern engine with decent alternator, but you would just end up burning diesel instead of gas. Which brings me to the main question, why do you want to get rid of the gas?

 

It is always a bit dangerous to tailor your boat to a very specific usage regime, not only because your personal circumstances might change, but also because you might reduce its saleability.

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20 minutes ago, Mike1951 said:

Been looking at the possibility of dispensing with gas - electric oven and induction hob. We will only be living aboard weekends for the next few years as we are still working and we have shore power at the marina, so only one or 2 nights crusing away from the marina. We have a 3KW inverter/charger and 4 x 150AH lead-carbon deep cycle batteries. Any experience/thoughts?

 

If you want to get rid of gas and go all-electric you'll have not only an electric oven and induction hob but also kettle and presumably toaster (uses a lot less power than a grill), and perhaps a microwave.

 

You need to do a realistic power budget, but I can see two problems. The first is that even though you're unlikely to turn everything on at once, a 3kW inverter (6kW for short peaks) is probably not big enough when you're cooking. The second is that you don't have anything like enough battery capacity either in Ah or current to support an inverter that can draw 250A continuous or 500A peak.

 

I'll be going all-electric but on a series hybrid boat with a 10kW inverter and 35kWh of LiFePO4 batteries (and a 9kW diesel generator) where this is no problem...

Edited by IanD
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A diesel generator running on HVO would be required to power the Hob, oven and all the extra stuff.

Unless you have a widebeam covered in solar and a huge battery bank thats about your only choice.

 

Edited by Loddon
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17 minutes ago, nicknorman said:

"And perhaps most importantly, what charging devices / capabilities you have other than shore power.

 

I expect you could make it work if you have a modern engine with decent alternator, but you would just end up burning diesel instead of gas. Which brings me to the main question, why do you want to get rid of the gas?

 

It is always a bit dangerous to tailor your boat to a very specific usage regime, not only because your personal circumstances might change, but also because you might reduce its saleability."

We are speccing a new boat for next spring. The engine is a Beta Marine 38 with 2 alternators. We won't do a lot of cooking onboard to be honest. Something from M&S in the oven and some spuds on the hob. We will have a toaster and microwave anyway for the beans on toast! The gas install is getting on for £1300 without appliances so that gives us a bit of extra budget. When cruising we normally eat at a pub on 2nd night.

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3 minutes ago, Mike1951 said:

We are speccing a new boat for next spring. The engine is a Beta Marine 38 with 2 alternators. We won't do a lot of cooking onboard to be honest. Something from M&S in the oven and some spuds on the hob. We will have a toaster and microwave anyway for the beans on toast! The gas install is getting on for £1300 without appliances so that gives us a bit of extra budget. When cruising we normally eat at a pub on 2nd night.

You might just be OK with that. If you can afford it (and it's not too big for the boat) a Beta 43 can be fitted with more and bigger alternators than a Beta 38, and at fairly low cost. Don't forget that you'll never get the rated alternator current for any length of time, especially with lead-acid batteries...

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43 minutes ago, Jen-in-Wellies said:

What are your reasons for getting rid of gas? Perceived safety, global warming, moving heavy bottles, cost? What is important to you that you want to change?

Heaving heavy gas bottles as we get older. Safety is a concern. We are used to gas on boats and are very careful, but if family are using the boat, they may forget to turn the gas off when leaving the boat and we are too far away to go and check. 

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19 minutes ago, Mike1951 said:

Heaving heavy gas bottles as we get older. Safety is a concern. We are used to gas on boats and are very careful, but if family are using the boat, they may forget to turn the gas off when leaving the boat and we are too far away to go and check. 

If I were you and speccing a new boat to be all-electric, I'd spend a bit more on an appropriate battery/inverter/charging setup, and maybe go 24V for the domestic circuit to reduce cable sizes and losses and inverter cost and get faster charging -- if you ask them nicely, Beta will supply a Beta 38 with 65A 12V + 24V 100A alternators (24V using the Travelpower polyvee drive pulley), at reasonable cost. Talk to Tim Watts there, he's very helpful 🙂

Edited by IanD
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I'm sure it would be possible to go electric hob and oven with the four batteries - but only if you could constrain your usage to the very limited amount you describe, plus are willing to continually monitor battery level when away from the marina and recharge thoroughly as soon as needed. If you fail on either count it will be a recipe for very short battery life. Realistically I would think you need a bigger battery bank  or lithium batteries to make it work practically.

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18 minutes ago, Awayonmyboat said:

I'm sure it would be possible to go electric hob and oven with the four batteries - but only if you could constrain your usage to the very limited amount you describe, plus are willing to continually monitor battery level when away from the marina and recharge thoroughly as soon as needed. If you fail on either count it will be a recipe for very short battery life. Realistically I would think you need a bigger battery bank  or lithium batteries to make it work practically.

The lead-carbon batteries are supposed to be much more tolerant of partial state of charge operation, but I agree that 600Ah 12V (4 x Leoch PLH+C150FT @ £370 each?) doesn't look like enough for an all-electric boat.

 

Going to bigger lead-carbon is going to put the cost up rapidly and you can't use the full capacity (which also drops off rapidly at higher discharge currents), LiFePO4 might be a better choice but the cost goes up even more...

4 minutes ago, Ex Brummie said:

If you have concerns about family using the boat and forgetting to turn off gas, how can you have the confidence in their respect of the regime required to protect your proposed electrical set up?

 

Configure the inverter to shut down before the battery SoC drops too low? It's a standard feature...

Edited by IanD
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2 hours ago, Mike1951 said:

Heaving heavy gas bottles as we get older. Safety is a concern. We are used to gas on boats and are very careful, but if family are using the boat, they may forget to turn the gas off when leaving the boat and we are too far away to go and check. 

I think of all the ways to kill or injure yourself on a boat, gas is not in the top 100. We had a new boat built in 2010. We turned the gas on. Hmmmm, here we are 11 years later and the gas is still on. Never turned it off (except to change a cylinder). Nothing blown up yet! The BSS and gas installation standards for boats is extremely high so I can’t see why the system would suddenly spring a dangerous leak. We change a gas bottle about once a year - it would probably be every 4 months if we were permanently live aboard. 13kg cylinders are quite heavy but you can always ask a Marina person to install it, surely?

 

I just think you are focussing to much on some (to be honest, imagined) issues at the expense of making the boat a whole lot harder to live with

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2 hours ago, Mike1951 said:

We are speccing a new boat for next spring. The engine is a Beta Marine 38 with 2 alternators. We won't do a lot of cooking onboard to be honest. Something from M&S in the oven and some spuds on the hob. We will have a toaster and microwave anyway for the beans on toast! The gas install is getting on for £1300 without appliances so that gives us a bit of extra budget. When cruising we normally eat at a pub on 2nd night.

If its a new boat why not spec Lithium, charge faster and you can take almost twice as much out of them.

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1 minute ago, ditchcrawler said:

If its a new boat why not spec Lithium, charge faster and you can take almost twice as much out of them.

 

Maybe I've got it wrong, but I thought you should only use ~60% out of Lithiums (ie not taking them below 20% SOC and not charging above 80% SoC) which is not a great deal different to the recommended 50% (100% SoC to 50% SoC) for FLA's.

Certainly not 'twice as much'

 

As with FLA's you can go below the 'recommendations' but the rate of 'damage' increases.

 

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2 minutes ago, nicknorman said:

I think of all the ways to kill or injure yourself on a boat, gas is not in the top 100. We had a new boat built in 2010. We turned the gas on. Hmmmm, here we are 11 years later and the gas is still on. Never turned it off (except to change a cylinder). Nothing blown up yet! The BSS and gas installation standards for boats is extremely high so I can’t see why the system would suddenly spring a dangerous leak. We change a gas bottle about once a year - it would probably be every 4 months if we were permanently live aboard. 13kg cylinders are quite heavy but you can always ask a Marina person to install it, surely?

 

I just think you are focussing to much on some (to be honest, imagined) issues at the expense of making the boat a whole lot harder to live with

 

I agree with the first part of your last paragraph, but I think just "more expensive" is the consequence not "harder to live with"...

 

There are reasons people want to go gas-free, worries about safety is one -- even if they're unjustified, it doesn't make them less real for the worrier -- and also the need to provide more ventilation (more draughts), not a big concern for many but still real. But unless you already have a massive electric system onboard (e.g. for propulsion) the extra cost doesn't really make sense, especially considering the need for a big expensive pile of batteries that need some TLC and will sooner or later need replacing (because LiFePO4 are too expensive).

5 minutes ago, ditchcrawler said:

If its a new boat why not spec Lithium, charge faster and you can take almost twice as much out of them.

Cost. Worth it if you expect to cruise or live aboard all the time for many years, but not for the kind of use the OP describes.

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1 minute ago, Alan de Enfield said:

 

Maybe I've got it wrong, but I thought you should only use ~60% out of Lithiums (ie not taking them below 20% SOC and not charging above 80% SoC) which is not a great deal different to the recommended 50% (100% SoC to 50% SoC) for FLA's.

Certainly not 'twice as much'

 

As with FLA's you can go below the 'recommendations' but the rate of 'damage' increases.

 

No IMO it’s a myth. It is a good idea to avoid taking LI “up the knee” or “down the knee” but this occurs in the mid to high 90s and below 10%. So you have perhaps 80% of capacity happily available, 90% at a pinch.

3 minutes ago, IanD said:

 

I agree with the first part of your last paragraph, but I think just "more expensive" is the consequence not "harder to live with"...

 

There are reasons people want to go gas-free, worries about safety is one -- even if they're unjustified, it doesn't make them less real for the worrier -- and also the need to provide more ventilation (more draughts), not a big concern for many but still real. But unless you already have a massive electric system onboard (e.g. for propulsion) the extra cost doesn't really make sense, especially considering the need for a big expensive pile of batteries that need some TLC and will sooner or later need replacing (because LiFePO4 are too expensive).

My “harder to live with” related to going all electric with the stated battery capacity and charging capability. Going all-electric with adequate battery capacity (preferably Li) and charging capability is fine.

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3 minutes ago, Alan de Enfield said:

 

Maybe I've got it wrong, but I thought you should only use ~60% out of Lithiums (ie not taking them below 20% SOC and not charging above 80% SoC) which is not a great deal different to the recommended 50% (100% SoC to 50% SoC) for FLA's.

Certainly not 'twice as much'

 

As with FLA's you can go below the 'recommendations' but the rate of 'damage' increases.

 

 

I have the Impression that it is not a problem using Lithiums over the range of 10%=>90%, even 95%, percent. Indeed taking them up to 100% is allowable, though perhaps difficult to gauge, you just don't want to leave them that highly charged for any length of time.

 

Beaten to it by Nick!

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3 minutes ago, Col_T said:

 

I have the Impression that it is not a problem using Lithiums over the range of 10%=>90%, even 95%, percent. Indeed taking them up to 100% is allowable, though perhaps difficult to gauge, you just don't want to leave them that highly charged for any length of time.

 

Beaten to it by Nick!


Yes. A couple of other things to consider:

 

1/ let’s say that using 90% of capacity shortens the life a bit. But the life is 5000 full cycles. If we lose a bit so it’s 4000 full cycles that is still over 10 years of a full cycle every day. And these batteries have a calendar life limitation as well, so no point in treating them with kid gloves if the calendar life then becomes the predominant factor.

 

2/ A lot of life cycle specifications are based on 1C charging and discharging. So for our 600Ah that would be charging at 600A and discharging at 600A. Hmmm, kind of tricky that! Even we can only manage about 200A continuous charge and in reality I leave it on “slow charge” nearly all the time, which is about 95A max. As to discharge, yes occasional short bursts of 200A for the kettle etc, the rest of the time they are dozing.

They really do have an easy life!

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3 hours ago, Mike1951 said:

Heaving heavy gas bottles as we get older. Safety is a concern. We are used to gas on boats and are very careful, but if family are using the boat, they may forget to turn the gas off when leaving the boat and we are too far away to go and check. 

I agree with the weight issue, especialy if the gas locker is situated, as with many boats stupidly in the pointy end, behind a cratch board :banghead:

The safety issue though is a non event. Properly installed its safe as houses. I never turned my gas off in over thirty years liveaboard over 8 boats even when we left for holidays. I have many friends who live aboard full time for many years, non have had any trouble with gas.

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47 minutes ago, Mike1951 said:

£10K of batteries to go Lithium

Well it depends on how much lithium you want, obviously! The OP’s batteries are pretty expensive, my 600Ah cost £1800, but if I’d bought them this year it would have been more like £1400. So £10k gets you about 4200Ah. Which is “quite a lot a”!

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