Run Washing Machine from Battery Bank? Help Please!


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Rod Halling
Rod Halling
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Hi All,

We are in the middle of refitting Oyster 55/36 Magic Dragon (1995) for our upcoming circumnavigation with three young children and have a seized Kohler generator that we are getting rid of. We are trying to find a way of running the washing machine from our Mastervolt 4.5Kw inverter, but it is struggling to cope. The situation is:

1) Our battery bank is 4 new Victron Gel 220 amp/hour 12v beasts - 440 a/h at 24 volts.
2) New Victron Battery Monitor installed
3) At most, the washing machine draws 2Kw for short times whilst heating, spinning etc.
4) Problem - Washing Machine works fine in initial stages, as it draws very little current to fill and initially wash. The inverter seems to "go to sleep" whilst doing this and then not allow the washer to go into the spinning stage. I can "fool" the inverter, by switching the fridge/freezers on (another 40 amps draw), but this involves loading the inverter with a circa 80 amp total draw when the machine is spinning, which quickly drops the battery voltage to as low as 18-20 volts for a short time. This is not really sustainable.

I think that the inverter is working fine - it seems to power everything else OK - fridge/freezer (the original holding plates), toaster, microwave... My current best guess is that either our cables feeding the inverter are too small, or that the "old-tech" batteries can't easily supply the peaks. As we have only recently bought the batteries, I am reluctant to upgrade to Lithium, although I think that may work for us. I believe that Lithium have a much higher capacity to charge and discharge quickly.

We are currently installing 750w of solar on a new aft arch, plus 2 Rutland 1200 wind generators. I feel that this lot should give us enough to run the boat - if not, we'll add some more solar on the bimini.

Washing machine works fine on shorepower! If anyone has any suggestions, we would be most grateful. We really don't want to buy another generator - trying to get the boat into the 21st Century!

All the best to you all, Rod

Dick
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Rod.Halling - 11/19/2020
Hi All,

We are in the middle of refitting Oyster 55/36 Magic Dragon (1995) for our upcoming circumnavigation with three young children and have a seized Kohler generator that we are getting rid of. We are trying to find a way of running the washing machine from our Mastervolt 4.5Kw inverter, but it is struggling to cope. The situation is:

1) Our battery bank is 4 new Victron Gel 220 amp/hour 12v beasts - 440 a/h at 24 volts.
2) New Victron Battery Monitor installed
3) At most, the washing machine draws 2Kw for short times whilst heating, spinning etc.
4) Problem - Washing Machine works fine in initial stages, as it draws very little current to fill and initially wash. The inverter seems to "go to sleep" whilst doing this and then not allow the washer to go into the spinning stage. I can "fool" the inverter, by switching the fridge/freezers on (another 40 amps draw), but this involves loading the inverter with a circa 80 amp total draw when the machine is spinning, which quickly drops the battery voltage to as low as 18-20 volts for a short time. This is not really sustainable.

I think that the inverter is working fine - it seems to power everything else OK - fridge/freezer (the original holding plates), toaster, microwave... My current best guess is that either our cables feeding the inverter are too small, or that the "old-tech" batteries can't easily supply the peaks. As we have only recently bought the batteries, I am reluctant to upgrade to Lithium, although I think that may work for us. I believe that Lithium have a much higher capacity to charge and discharge quickly.

We are currently installing 750w of solar on a new aft arch, plus 2 Rutland 1200 wind generators. I feel that this lot should give us enough to run the boat - if not, we'll add some more solar on the bimini.

Washing machine works fine on shorepower! If anyone has any suggestions, we would be most grateful. We really don't want to buy another generator - trying to get the boat into the 21st Century!

All the best to you all, Rod

Hi Rod,
If you did not have 3 children, I would try to talk you into giving up the washing machine. A lot of the introductory “fun” of getting to a new village/town is looking for the resident who does laundry and sitting around, talking with and meeting others in doing so. And if you plan your route well, your clothes will be bathing suits and t shirts.
I would continue to discourage as, in the repertoire of cruising skipper’s headaches, washing machines are not at the top (generators take that prize), but they are not at the bottom either. And support, once you leave home territory, is hard to come by.
That said, three children….
First, A suggestion: wash only in cold water. Heating water is a huge power-sink and the clothes will get clean, but may not be quite as “bright”. It was a cruising mantra when I started out in Central America to not have white underwear and white shirts etc. as they would come back clean, but a bit dingy as the small villages often used recycled water and the water was certainly not heated.
Some invertors have a hard time with fluctuating power demands. When I run my microwave, with its on-off cycles, I need to have an AC night-light (very low power demand, but enough to keep the invertor active) going to keep the invertor from going to sleep. In this way, when the microwave cycles, the invertor stays “on line” and power is available when the microwave calls for it again.
I would be surprised if your invertor cabling was too small a gauge: it is too easy to determine (4.5 kw at 24v for ?? meters = such and such gauge for ex.). It is also easy to check. Now the connections may need cleaning, but your issues sound different from voltage drop.
It sounds like you are depending on your invertor far more than most (frig/freezer, toaster, microwave, washing machine), especially when about to set off on a cn. I would urge you to think about redundancy and back-ups.
It is great to be using power generators such as solar and wind, but I would suggest that diesel generators will have a place well into the 21st century.
And, yes, you do not wish to hammer the batteries into a 18-20v level (24v bank). Gels are pretty robust and accommodating, but they will sulfate and have their life shortened. I would in no way describe them as “old tech” there still remains no proven and safe alternative to the AGMs, Gels, and flooded batteries which have powered us for so long. Lithium batteries have come a long way, but their use is still restricted to those “early adapters” and field reports, much positive, are still rolling in. I would very much discourage, at present, a couple with 3 small children from setting off on a cn with lithium.
The gel cell battery bank should be able to do the work demanded with out any trouble: the crunch will be how long the high load demand is needed. That is one of the benefits of a generator: lots of power for the period you need it. Solar and wind power cover this by big battery banks or the battery banks get hammered when large and sustained demands occur.
Enough for now: Come back with questions/comments etc.
My best, Dick Stevenson, s/v Alchemy
Another random thought: I have seen solar panels on biminis and very seldom have I felt that the job was well done. Two things stand out. One is that to tolerate the loads of weight up high on a bimini, the bimini support structure must be very well engineered and robust (think bashing to wind in a swell and waves for a few days at 15-20 degrees of heel and how that structure will manage. Second is that the bimini and solar panels must be fairly easily field removable to prepare for storms at sea or at anchor.

Rod Halling
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Dick - 11/20/2020
Rod.Halling - 11/19/2020
Hi All,

We are in the middle of refitting Oyster 55/36 Magic Dragon (1995) for our upcoming circumnavigation with three young children and have a seized Kohler generator that we are getting rid of. We are trying to find a way of running the washing machine from our Mastervolt 4.5Kw inverter, but it is struggling to cope. The situation is:

1) Our battery bank is 4 new Victron Gel 220 amp/hour 12v beasts - 440 a/h at 24 volts.
2) New Victron Battery Monitor installed
3) At most, the washing machine draws 2Kw for short times whilst heating, spinning etc.
4) Problem - Washing Machine works fine in initial stages, as it draws very little current to fill and initially wash. The inverter seems to "go to sleep" whilst doing this and then not allow the washer to go into the spinning stage. I can "fool" the inverter, by switching the fridge/freezers on (another 40 amps draw), but this involves loading the inverter with a circa 80 amp total draw when the machine is spinning, which quickly drops the battery voltage to as low as 18-20 volts for a short time. This is not really sustainable.

I think that the inverter is working fine - it seems to power everything else OK - fridge/freezer (the original holding plates), toaster, microwave... My current best guess is that either our cables feeding the inverter are too small, or that the "old-tech" batteries can't easily supply the peaks. As we have only recently bought the batteries, I am reluctant to upgrade to Lithium, although I think that may work for us. I believe that Lithium have a much higher capacity to charge and discharge quickly.

We are currently installing 750w of solar on a new aft arch, plus 2 Rutland 1200 wind generators. I feel that this lot should give us enough to run the boat - if not, we'll add some more solar on the bimini.

Washing machine works fine on shorepower! If anyone has any suggestions, we would be most grateful. We really don't want to buy another generator - trying to get the boat into the 21st Century!

All the best to you all, Rod

Hi Rod,
If you did not have 3 children, I would try to talk you into giving up the washing machine. A lot of the introductory “fun” of getting to a new village/town is looking for the resident who does laundry and sitting around, talking with and meeting others in doing so. And if you plan your route well, your clothes will be bathing suits and t shirts.
I would continue to discourage as, in the repertoire of cruising skipper’s headaches, washing machines are not at the top (generators take that prize), but they are not at the bottom either. And support, once you leave home territory, is hard to come by.
That said, three children….
First, A suggestion: wash only in cold water. Heating water is a huge power-sink and the clothes will get clean, but may not be quite as “bright”. It was a cruising mantra when I started out in Central America to not have white underwear and white shirts etc. as they would come back clean, but a bit dingy as the small villages often used recycled water and the water was certainly not heated.
Some invertors have a hard time with fluctuating power demands. When I run my microwave, with its on-off cycles, I need to have an AC night-light (very low power demand, but enough to keep the invertor active) going to keep the invertor from going to sleep. In this way, when the microwave cycles, the invertor stays “on line” and power is available when the microwave calls for it again.
I would be surprised if your invertor cabling was too small a gauge: it is too easy to determine (4.5 kw at 24v for ?? meters = such and such gauge for ex.). It is also easy to check. Now the connections may need cleaning, but your issues sound different from voltage drop.
It sounds like you are depending on your invertor far more than most (frig/freezer, toaster, microwave, washing machine), especially when about to set off on a cn. I would urge you to think about redundancy and back-ups.
It is great to be using power generators such as solar and wind, but I would suggest that diesel generators will have a place well into the 21st century.
And, yes, you do not wish to hammer the batteries into a 18-20v level (24v bank). Gels are pretty robust and accommodating, but they will sulfate and have their life shortened. I would in no way describe them as “old tech” there still remains no proven and safe alternative to the AGMs, Gels, and flooded batteries which have powered us for so long. Lithium batteries have come a long way, but their use is still restricted to those “early adapters” and field reports, much positive, are still rolling in. I would very much discourage, at present, a couple with 3 small children from setting off on a cn with lithium.
The gel cell battery bank should be able to do the work demanded with out any trouble: the crunch will be how long the high load demand is needed. That is one of the benefits of a generator: lots of power for the period you need it. Solar and wind power cover this by big battery banks or the battery banks get hammered when large and sustained demands occur.
Enough for now: Come back with questions/comments etc.
My best, Dick Stevenson, s/v Alchemy
Another random thought: I have seen solar panels on biminis and very seldom have I felt that the job was well done. Two things stand out. One is that to tolerate the loads of weight up high on a bimini, the bimini support structure must be very well engineered and robust (think bashing to wind in a swell and waves for a few days at 15-20 degrees of heel and how that structure will manage. Second is that the bimini and solar panels must be fairly easily field removable to prepare for storms at sea or at anchor.

Hi Dick,

MANY thanks for your detailed and thoughtful reply! Your point is very good about "needing" a washing machine... However, with the three small ones, we would like to make it work. Even though Jane, my wife, is a pretty experienced offshore sailor, with the children it is one of her few "red lines"! On the usage front, we are happy to stick with cold washes - no problem there. I suspect that the water temp from the boat tanks in the tropics will be around 30 degrees C anyway.

I have just looked at recommended cable sizes for inverters and without actually measuring, I'm pretty sure that it's all fine although I will check next time I'm on board. Connections were all renewed when we changed the batteries. I am intrigued that your inverter suffers from the same "going to sleep" problem with your microwave. I will try a much smaller load with the washer next time, as I feel that it was probably too much running the old fridge/freezer AND the washer at the same time - especially against a background of the battery bank only being 92% charged at the start (we had overnighted on anchor in the St. Germans River near Plymouth. I take your point about generators being designed for this situation, but I also wholeheartedly agree that the generator is the thing that will probably let one down in mid-Pacific. On balance, I think we'll try and avoid purchasing another! I believe that we should be able to generate enough with the solar and wind to cover the fridge/freezer, occasional wash, watermaker (small 30l per hour 24v one) and the rest of the boat. Obviously, we will motor at times - then we have a 100 amp alternator on the motor for the house bank. I am thinking of adding a "Watt & Sea" to our new Hydrovane, if the funds will stretch - that will add huge generating power whilst under way. We seem to average 7.5-8 knots in a reasonable wind. 

My "solar on the bimini" remark was a little throwaway! We went through all the machinations of trying to design something decent, but failed, so resorted to a stern arch, which isn't ideal on a lovely looking boat. However, there is a deal of deck space that could be utilized to accommodate perhaps 250-500w more, if we need it. I have since seen a reasonable bimini solar design on the Oyster Owners site, but it still looks like a real effort to derig when the going gets rough. Also, we hate having the bimini up outside the tropics, so that probably wouldn't suit us. 

Your comment about redundancy is thought provoking. We should perhaps look at fitting a second inverter?

MANY thanks for all your thoughts - I really appreciate you taking the time to reply in such detail.

With kindest regards, all the best,

Rod
Dick
Dick
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Rod.Halling - 11/23/2020
Dick - 11/20/2020
Rod.Halling - 11/19/2020
Hi All,

We are in the middle of refitting Oyster 55/36 Magic Dragon (1995) for our upcoming circumnavigation with three young children and have a seized Kohler generator that we are getting rid of. We are trying to find a way of running the washing machine from our Mastervolt 4.5Kw inverter, but it is struggling to cope. The situation is:

1) Our battery bank is 4 new Victron Gel 220 amp/hour 12v beasts - 440 a/h at 24 volts.
2) New Victron Battery Monitor installed
3) At most, the washing machine draws 2Kw for short times whilst heating, spinning etc.
4) Problem - Washing Machine works fine in initial stages, as it draws very little current to fill and initially wash. The inverter seems to "go to sleep" whilst doing this and then not allow the washer to go into the spinning stage. I can "fool" the inverter, by switching the fridge/freezers on (another 40 amps draw), but this involves loading the inverter with a circa 80 amp total draw when the machine is spinning, which quickly drops the battery voltage to as low as 18-20 volts for a short time. This is not really sustainable.

I think that the inverter is working fine - it seems to power everything else OK - fridge/freezer (the original holding plates), toaster, microwave... My current best guess is that either our cables feeding the inverter are too small, or that the "old-tech" batteries can't easily supply the peaks. As we have only recently bought the batteries, I am reluctant to upgrade to Lithium, although I think that may work for us. I believe that Lithium have a much higher capacity to charge and discharge quickly.

We are currently installing 750w of solar on a new aft arch, plus 2 Rutland 1200 wind generators. I feel that this lot should give us enough to run the boat - if not, we'll add some more solar on the bimini.

Washing machine works fine on shorepower! If anyone has any suggestions, we would be most grateful. We really don't want to buy another generator - trying to get the boat into the 21st Century!

All the best to you all, Rod

Hi Rod,
If you did not have 3 children, I would try to talk you into giving up the washing machine. A lot of the introductory “fun” of getting to a new village/town is looking for the resident who does laundry and sitting around, talking with and meeting others in doing so. And if you plan your route well, your clothes will be bathing suits and t shirts.
I would continue to discourage as, in the repertoire of cruising skipper’s headaches, washing machines are not at the top (generators take that prize), but they are not at the bottom either. And support, once you leave home territory, is hard to come by.
That said, three children….
First, A suggestion: wash only in cold water. Heating water is a huge power-sink and the clothes will get clean, but may not be quite as “bright”. It was a cruising mantra when I started out in Central America to not have white underwear and white shirts etc. as they would come back clean, but a bit dingy as the small villages often used recycled water and the water was certainly not heated.
Some invertors have a hard time with fluctuating power demands. When I run my microwave, with its on-off cycles, I need to have an AC night-light (very low power demand, but enough to keep the invertor active) going to keep the invertor from going to sleep. In this way, when the microwave cycles, the invertor stays “on line” and power is available when the microwave calls for it again.
I would be surprised if your invertor cabling was too small a gauge: it is too easy to determine (4.5 kw at 24v for ?? meters = such and such gauge for ex.). It is also easy to check. Now the connections may need cleaning, but your issues sound different from voltage drop.
It sounds like you are depending on your invertor far more than most (frig/freezer, toaster, microwave, washing machine), especially when about to set off on a cn. I would urge you to think about redundancy and back-ups.
It is great to be using power generators such as solar and wind, but I would suggest that diesel generators will have a place well into the 21st century.
And, yes, you do not wish to hammer the batteries into a 18-20v level (24v bank). Gels are pretty robust and accommodating, but they will sulfate and have their life shortened. I would in no way describe them as “old tech” there still remains no proven and safe alternative to the AGMs, Gels, and flooded batteries which have powered us for so long. Lithium batteries have come a long way, but their use is still restricted to those “early adapters” and field reports, much positive, are still rolling in. I would very much discourage, at present, a couple with 3 small children from setting off on a cn with lithium.
The gel cell battery bank should be able to do the work demanded with out any trouble: the crunch will be how long the high load demand is needed. That is one of the benefits of a generator: lots of power for the period you need it. Solar and wind power cover this by big battery banks or the battery banks get hammered when large and sustained demands occur.
Enough for now: Come back with questions/comments etc.
My best, Dick Stevenson, s/v Alchemy
Another random thought: I have seen solar panels on biminis and very seldom have I felt that the job was well done. Two things stand out. One is that to tolerate the loads of weight up high on a bimini, the bimini support structure must be very well engineered and robust (think bashing to wind in a swell and waves for a few days at 15-20 degrees of heel and how that structure will manage. Second is that the bimini and solar panels must be fairly easily field removable to prepare for storms at sea or at anchor.

Hi Dick,

MANY thanks for your detailed and thoughtful reply! Your point is very good about "needing" a washing machine... However, with the three small ones, we would like to make it work. Even though Jane, my wife, is a pretty experienced offshore sailor, with the children it is one of her few "red lines"! On the usage front, we are happy to stick with cold washes - no problem there. I suspect that the water temp from the boat tanks in the tropics will be around 30 degrees C anyway.

I have just looked at recommended cable sizes for inverters and without actually measuring, I'm pretty sure that it's all fine although I will check next time I'm on board. Connections were all renewed when we changed the batteries. I am intrigued that your inverter suffers from the same "going to sleep" problem with your microwave. I will try a much smaller load with the washer next time, as I feel that it was probably too much running the old fridge/freezer AND the washer at the same time - especially against a background of the battery bank only being 92% charged at the start (we had overnighted on anchor in the St. Germans River near Plymouth. I take your point about generators being designed for this situation, but I also wholeheartedly agree that the generator is the thing that will probably let one down in mid-Pacific. On balance, I think we'll try and avoid purchasing another! I believe that we should be able to generate enough with the solar and wind to cover the fridge/freezer, occasional wash, watermaker (small 30l per hour 24v one) and the rest of the boat. Obviously, we will motor at times - then we have a 100 amp alternator on the motor for the house bank. I am thinking of adding a "Watt & Sea" to our new Hydrovane, if the funds will stretch - that will add huge generating power whilst under way. We seem to average 7.5-8 knots in a reasonable wind. 

My "solar on the bimini" remark was a little throwaway! We went through all the machinations of trying to design something decent, but failed, so resorted to a stern arch, which isn't ideal on a lovely looking boat. However, there is a deal of deck space that could be utilized to accommodate perhaps 250-500w more, if we need it. I have since seen a reasonable bimini solar design on the Oyster Owners site, but it still looks like a real effort to derig when the going gets rough. Also, we hate having the bimini up outside the tropics, so that probably wouldn't suit us. 

Your comment about redundancy is thought provoking. We should perhaps look at fitting a second inverter?

MANY thanks for all your thoughts - I really appreciate you taking the time to reply in such detail.

With kindest regards, all the best,

Rod

Hi Rod,
Agreed, 3 small ones, and a partner who really wants one, does change the “make sense” ratio for a washing machine. I believe that there exists a wide range of reasonable alternatives when it comes to cruising but, those families that prevail and thrive, find a way to make their boat their home: it is hard to sustain the experience of camping.
I would think a call to Mastervolt might get some answers on why the invertor goes to sleep. I suspect it is a setting designed to protect the invertor.
I support your trying a smaller load next time: as said, a night light is enough to keep my inverter awake. It also must hammer the batteries to have 2 big loads at the same time.

As said in the earlier post, I suspect you will find the cabling adequately sized and the connections ok as well, but checking can’t hurt. It might be a good time to start a paper documentation of the boat’s wiring: such a schematic will be appreciated down the line.
My water maker drew 20a and most of our water making occurred on those days where we needed to motor. This has the benefit of drawing on clean water which many anchorages have a hard time providing. I would suggest doing wash while motoring, but there may be too much of an amp draw for a 100a alternator: one’s motor is mission critical and I tend to not push hard on the PTO, alternator etc.
I think you were likely wise to back off on the solar on bimini project. They are quite hard to do well and as I look around, solar installations, stand out as problematic on many sailboats. Arches are generally much more robustly built.
And, finally, a comment on your observation that your SOC (state of charge) was only 92% as contributory. 92% is actually a very good SOC. I lived for months, probably years, never, or rarely above a 80% SOC. I (with many others) tried to not get below 50% SOC, but it was also very hard to get above 80% (with much better solar and wind, this may be changed some, but only changed dramatically on those with lots of real estate for solar and who cruise in the lower latitudes). To get above 80% one needed many hours of motoring or shore power or long hours of a generator loafing along.
So that meant that roughly 1/3 of your battery bank’s amps were available for use between charging from 50 to 80%. This is clearly changing in recent years, especially with lithium, but is still the case with many/most widely wandering cruising boats.
Let us know what you discover and how things work out.
My best, Dick Stevenson, s/v Alchemy

Rod Halling
Rod Halling
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Dick - 23 Nov 2020
Rod.Halling - 11/23/2020
Dick - 11/20/2020
Rod.Halling - 11/19/2020
Hi All,

We are in the middle of refitting Oyster 55/36 Magic Dragon (1995) for our upcoming circumnavigation with three young children and have a seized Kohler generator that we are getting rid of. We are trying to find a way of running the washing machine from our Mastervolt 4.5Kw inverter, but it is struggling to cope. The situation is:

1) Our battery bank is 4 new Victron Gel 220 amp/hour 12v beasts - 440 a/h at 24 volts.
2) New Victron Battery Monitor installed
3) At most, the washing machine draws 2Kw for short times whilst heating, spinning etc.
4) Problem - Washing Machine works fine in initial stages, as it draws very little current to fill and initially wash. The inverter seems to "go to sleep" whilst doing this and then not allow the washer to go into the spinning stage. I can "fool" the inverter, by switching the fridge/freezers on (another 40 amps draw), but this involves loading the inverter with a circa 80 amp total draw when the machine is spinning, which quickly drops the battery voltage to as low as 18-20 volts for a short time. This is not really sustainable.

I think that the inverter is working fine - it seems to power everything else OK - fridge/freezer (the original holding plates), toaster, microwave... My current best guess is that either our cables feeding the inverter are too small, or that the "old-tech" batteries can't easily supply the peaks. As we have only recently bought the batteries, I am reluctant to upgrade to Lithium, although I think that may work for us. I believe that Lithium have a much higher capacity to charge and discharge quickly.

We are currently installing 750w of solar on a new aft arch, plus 2 Rutland 1200 wind generators. I feel that this lot should give us enough to run the boat - if not, we'll add some more solar on the bimini.

Washing machine works fine on shorepower! If anyone has any suggestions, we would be most grateful. We really don't want to buy another generator - trying to get the boat into the 21st Century!

All the best to you all, Rod

Hi Rod,
If you did not have 3 children, I would try to talk you into giving up the washing machine. A lot of the introductory “fun” of getting to a new village/town is looking for the resident who does laundry and sitting around, talking with and meeting others in doing so. And if you plan your route well, your clothes will be bathing suits and t shirts.
I would continue to discourage as, in the repertoire of cruising skipper’s headaches, washing machines are not at the top (generators take that prize), but they are not at the bottom either. And support, once you leave home territory, is hard to come by.
That said, three children….
First, A suggestion: wash only in cold water. Heating water is a huge power-sink and the clothes will get clean, but may not be quite as “bright”. It was a cruising mantra when I started out in Central America to not have white underwear and white shirts etc. as they would come back clean, but a bit dingy as the small villages often used recycled water and the water was certainly not heated.
Some invertors have a hard time with fluctuating power demands. When I run my microwave, with its on-off cycles, I need to have an AC night-light (very low power demand, but enough to keep the invertor active) going to keep the invertor from going to sleep. In this way, when the microwave cycles, the invertor stays “on line” and power is available when the microwave calls for it again.
I would be surprised if your invertor cabling was too small a gauge: it is too easy to determine (4.5 kw at 24v for ?? meters = such and such gauge for ex.). It is also easy to check. Now the connections may need cleaning, but your issues sound different from voltage drop.
It sounds like you are depending on your invertor far more than most (frig/freezer, toaster, microwave, washing machine), especially when about to set off on a cn. I would urge you to think about redundancy and back-ups.
It is great to be using power generators such as solar and wind, but I would suggest that diesel generators will have a place well into the 21st century.
And, yes, you do not wish to hammer the batteries into a 18-20v level (24v bank). Gels are pretty robust and accommodating, but they will sulfate and have their life shortened. I would in no way describe them as “old tech” there still remains no proven and safe alternative to the AGMs, Gels, and flooded batteries which have powered us for so long. Lithium batteries have come a long way, but their use is still restricted to those “early adapters” and field reports, much positive, are still rolling in. I would very much discourage, at present, a couple with 3 small children from setting off on a cn with lithium.
The gel cell battery bank should be able to do the work demanded with out any trouble: the crunch will be how long the high load demand is needed. That is one of the benefits of a generator: lots of power for the period you need it. Solar and wind power cover this by big battery banks or the battery banks get hammered when large and sustained demands occur.
Enough for now: Come back with questions/comments etc.
My best, Dick Stevenson, s/v Alchemy
Another random thought: I have seen solar panels on biminis and very seldom have I felt that the job was well done. Two things stand out. One is that to tolerate the loads of weight up high on a bimini, the bimini support structure must be very well engineered and robust (think bashing to wind in a swell and waves for a few days at 15-20 degrees of heel and how that structure will manage. Second is that the bimini and solar panels must be fairly easily field removable to prepare for storms at sea or at anchor.

Hi Dick,

MANY thanks for your detailed and thoughtful reply! Your point is very good about "needing" a washing machine... However, with the three small ones, we would like to make it work. Even though Jane, my wife, is a pretty experienced offshore sailor, with the children it is one of her few "red lines"! On the usage front, we are happy to stick with cold washes - no problem there. I suspect that the water temp from the boat tanks in the tropics will be around 30 degrees C anyway.

I have just looked at recommended cable sizes for inverters and without actually measuring, I'm pretty sure that it's all fine although I will check next time I'm on board. Connections were all renewed when we changed the batteries. I am intrigued that your inverter suffers from the same "going to sleep" problem with your microwave. I will try a much smaller load with the washer next time, as I feel that it was probably too much running the old fridge/freezer AND the washer at the same time - especially against a background of the battery bank only being 92% charged at the start (we had overnighted on anchor in the St. Germans River near Plymouth. I take your point about generators being designed for this situation, but I also wholeheartedly agree that the generator is the thing that will probably let one down in mid-Pacific. On balance, I think we'll try and avoid purchasing another! I believe that we should be able to generate enough with the solar and wind to cover the fridge/freezer, occasional wash, watermaker (small 30l per hour 24v one) and the rest of the boat. Obviously, we will motor at times - then we have a 100 amp alternator on the motor for the house bank. I am thinking of adding a "Watt & Sea" to our new Hydrovane, if the funds will stretch - that will add huge generating power whilst under way. We seem to average 7.5-8 knots in a reasonable wind. 

My "solar on the bimini" remark was a little throwaway! We went through all the machinations of trying to design something decent, but failed, so resorted to a stern arch, which isn't ideal on a lovely looking boat. However, there is a deal of deck space that could be utilized to accommodate perhaps 250-500w more, if we need it. I have since seen a reasonable bimini solar design on the Oyster Owners site, but it still looks like a real effort to derig when the going gets rough. Also, we hate having the bimini up outside the tropics, so that probably wouldn't suit us. 

Your comment about redundancy is thought provoking. We should perhaps look at fitting a second inverter?

MANY thanks for all your thoughts - I really appreciate you taking the time to reply in such detail.

With kindest regards, all the best,

Rod

Hi Rod,
Agreed, 3 small ones, and a partner who really wants one, does change the “make sense” ratio for a washing machine. I believe that there exists a wide range of reasonable alternatives when it comes to cruising but, those families that prevail and thrive, find a way to make their boat their home: it is hard to sustain the experience of camping.
I would think a call to Mastervolt might get some answers on why the invertor goes to sleep. I suspect it is a setting designed to protect the invertor.
I support your trying a smaller load next time: as said, a night light is enough to keep my inverter awake. It also must hammer the batteries to have 2 big loads at the same time.

As said in the earlier post, I suspect you will find the cabling adequately sized and the connections ok as well, but checking can’t hurt. It might be a good time to start a paper documentation of the boat’s wiring: such a schematic will be appreciated down the line.
My water maker drew 20a and most of our water making occurred on those days where we needed to motor. This has the benefit of drawing on clean water which many anchorages have a hard time providing. I would suggest doing wash while motoring, but there may be too much of an amp draw for a 100a alternator: one’s motor is mission critical and I tend to not push hard on the PTO, alternator etc.
I think you were likely wise to back off on the solar on bimini project. They are quite hard to do well and as I look around, solar installations, stand out as problematic on many sailboats. Arches are generally much more robustly built.
And, finally, a comment on your observation that your SOC (state of charge) was only 92% as contributory. 92% is actually a very good SOC. I lived for months, probably years, never, or rarely above a 80% SOC. I (with many others) tried to not get below 50% SOC, but it was also very hard to get above 80% (with much better solar and wind, this may be changed some, but only changed dramatically on those with lots of real estate for solar and who cruise in the lower latitudes). To get above 80% one needed many hours of motoring or shore power or long hours of a generator loafing along.
So that meant that roughly 1/3 of your battery bank’s amps were available for use between charging from 50 to 80%. This is clearly changing in recent years, especially with lithium, but is still the case with many/most widely wandering cruising boats.
Let us know what you discover and how things work out.
My best, Dick Stevenson, s/v Alchemy

Hi Dick,

Many thanks again for your well considered and detailed response! I have been pretty busy for the last couple of weeks, but in the meantime have been doing a little research on cable sizes etc... All seems to be in order (as you predicted and I suspected) so I reckon that the inverter is going to sleep, as you suggested. At the moment, Magic Dragon is in a shed having her mast, boom and pole refurbished and sprayed, decks sanded and re-caulked, underwater stuff checked and sorted, antifouling applied and the generator removed. Hence, I have been unable to retry the washing machine. We have only ever had a proper battery condition meter for the last few months (never on any previous boats) and being currently marina based are used to looking at a "full" battery bank. Obviously, on previous boats with far less reliance on huge inverters, we have not needed this sort of thing. I'm hoping that the 750w of solar and 2 wind gennies might keep the batteries up to snuff when it is installed in Jan/Feb, but only time will tell!

Our watermaker is a small Eco-Sistems 25-30 litre per hour model that I think we're going to have to run 3-4 hours per day. This shouldn't be more than around 10 amps draw with a little luck...

We can't wait to have all done, get out there and try it!! Nothing is ever perfect, but we will live with whatever we have for a bit before we panic. It may be that a small Honda petrol genny might be the answer for the odd occasion when sun doesn't shine and there is no wind.

All the best to you and yours - hopefully we might meet up somewhere...

Rod 
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