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Post by IainS on Dec 9, 2016 19:14:03 GMT
The big draw is the proposed 3Kw water heater that dominates the usage. I assumed that during the 1.5 hr lunch stop it would run for half an hour. The other big user would be a combi microwave and grill . As we have volanteer crews we have got to make it foolproof and assume people wont be abstemious with power. I'm starting to come to the conclusion that we will have to wire it so the heater and microwave can only be powered by the travel power unit on the engine. Other suggestions welcome. And yes taking people out on tbe trip boat is the most rewarding boating I have ever done, I have been privelaged to meet some wonderful people. Top Cat I used to drive an electrically powered trip boat where the urn was heated to boiling when on shore power. With the addition of some insulation on the urn, the water was still hot enough for teas and coffees an hour and a bit later. (The boat later had an engine change to a Beta Propgen unit, so no need to pre-heat the urn, and enough power to run a microwave as well). The ones I drive now have separate generators supplying the 240V. In one case, the lighting, cooking, and some heating are 240V. The other has a mixture of 12V and 240V lighting. I'd think travel power or a separate built in generator is more foolproof than using an invertor.
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Post by tonyqj on Dec 9, 2016 20:10:50 GMT
So if we have a 2 hrs run after lunch what's the most we can take out and get the batteries recharged? Top Cat Virtually nothing, unfortunately. The last 10% from 90% SoC to 100% SoC can easily take 3 or 4 hours. Either the charge has to be finished off with solar/shore power or you have to accept that you'll rarely be getting the batteries to 100% and they'll have to be replaced regularly.
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Post by peterboat on Dec 9, 2016 20:37:50 GMT
Top cat when you get back the solar will still be charging in fact it will charge until its dark and turn itself back on in the morning
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Post by Deleted on Dec 9, 2016 20:38:29 GMT
Hmm I thought that might be the case, time for a rethink
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Post by JohnV on Dec 9, 2016 21:22:53 GMT
If you can get the bulk (or the bulk of the bulk ) done before arrival at the berth you of course will not be looking for a lot of power from solar or shore. Just a thought ..... probably totally off the wall and I haven't got a clue if it's practicable but ...... If the berth is secure would it be possible to have a shore base solar charged system at a higher voltage that could finish the re-charging of the boat's system overnight. recharging itself the next day by solar. It would not have to be that high a capacity battery bank as all it would be required to supply is the last 10 or 15% charge to the boat. sounds a bit nutty ...... but it's outside the box. It just depends on how much outside the box you need to be.
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Post by Deleted on Dec 9, 2016 22:03:17 GMT
Interesting thought, our mooring is at a boatyard, it's secure in that access is restricted.
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Post by Deleted on Dec 11, 2016 18:59:41 GMT
Am I right in thinking that to fully recharge a battery after a given amount of energy has been extracted, assuming a large enough alternator the size of the battery is largely irrelevant?
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Post by smileypete on Dec 11, 2016 19:52:17 GMT
Am I right in thinking that to fully recharge a battery after a given amount of energy has been extracted, assuming a large enough alternator the size of the battery is largely irrelevant? Bigger batts will help up to a point, smaller batts will hit absorption charge voltage sooner after which charging is limited to what the batts will absorb rather than what the alt can provide, and the alt current will tail off towards zero. As said above sounds like a travelpower is the way to go for the big AC loads, and conventional alternator/charger/solar/batt bank with smartgauge for the smaller DC loads.
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Post by Deleted on Dec 11, 2016 21:35:08 GMT
Yes I've decided to specify a 5Kva travel power and wire it so the boiler and combi microwave grill will only run from it. That gets the expected maximum drain on the batteries down to about 15 Ah during lunch and I'm hoping that a 2hr run could put that much or most of it back. I'm taking a worst case scenario of a cold grey day late in the season, where the punters don't go to the pub for lunch. So no useful input from solar and they have the heating, lights and stereo on. Now we won't get many days like that but have to handle them.
Also going for a Smartguage and ammeter
T C
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Post by tonyb on Dec 12, 2016 7:36:15 GMT
Not sure if this will be helpful or not.
I understand that although Travelpowers will produce 240V @ 50 Hz across a range of speeds their current output is limited a low speeds. If I am correct would it be wise to specify a 3:1 gearbox or more and deliberately fit an undersized prop so the engine speed is higher when passing moored boats etc.
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Post by JohnV on Dec 12, 2016 8:11:28 GMT
so the engine speed is higher when passing moored boats etc. But, But, But, Won't people be shouting "Slow Down" all the time ?
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Post by phil70 on Dec 12, 2016 8:21:17 GMT
so the engine speed is higher when passing moored boats etc. But, But, But, Won't people be shouting "Slow Down" all the time ? No problem there, change the name of the boat to "NO PROBLEM" and all the punters will think they are being greeted and wave furiously at the boats being passed (which will piss off the shouters) Problem solved. Phil
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Post by Deleted on Dec 12, 2016 15:03:16 GMT
so the engine speed is higher when passing moored boats etc. But, But, But, Won't people be shouting "Slow Down" all the time ? Thanks for the thought Tony, I would have thought a better solution is to select the pulley on the TP so that it spins fast enough at low rpm but doesn't overspeed at max rpm. On Grace we have a 3Kva Travel power and it puts out enough to boil our 2.2Kw kettle at just above tickover what I call "passing sensibly moored boat speed" When the washing machine pulls 3Kw the engine slows noticeably which gave me a start the first time it happened which was in a tunnel. We find that at low speed things just heat more slowly, the only thing that's been a problem with is the breadmaker which the trip boat won't have. On the current trip boat people shout about slowing down no matter how slow we go, it's a case of " It's a trip boat therefore going too fast" regardless of the facts Top Cat
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Post by tonyqj on Dec 12, 2016 16:16:53 GMT
Am I right in thinking that to fully recharge a battery after a given amount of energy has been extracted, assuming a large enough alternator the size of the battery is largely irrelevant? Bigger batts will help up to a point, smaller batts will hit absorption charge voltage sooner after which charging is limited to what the batts will absorb rather than what the alt can provide, and the alt current will tail off towards zero. As said above sounds like a travelpower is the way to go for the big AC loads, and conventional alternator/charger/solar/batt bank with smartgauge for the smaller DC loads. The bit that Pete didn't mention but I think you are already aware of is that the 80% to 100% Absorption bit takes about the same length of time whatever the size of the battery.
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Post by tonyb on Dec 12, 2016 16:27:29 GMT
But, But, But, Won't people be shouting "Slow Down" all the time ? Thanks for the thought Tony, I would have thought a better solution is to select the pulley on the TP so that it spins fast enough at low rpm but doesn't overspeed at max rpm. On Grace we have a 3Kva Travel power and it puts out enough to boil our 2.2Kw kettle at just above tickover what I call "passing sensibly moored boat speed" When the washing machine pulls 3Kw the engine slows noticeably which gave me a start the first time it happened which was in a tunnel. We find that at low speed things just heat more slowly, the only thing that's been a problem with is the breadmaker which the trip boat won't have. On the current trip boat people shout about slowing down no matter how slow we go, it's a case of " It's a trip boat therefore going too fast" regardless of the facts Top Cat If you can I would agree but there is a minimum pulley size that a belt will drive and if you hit that limit you would have to increase the engine pulley diameter and that may not be so easy. Really, as you are doing, it all needs sporting during the design/spec stage. I am a little concerned that the tea urn plus microwave might overload the Travelpower. Too many people think the numbers on the front of a microwave are its electrical consumption when in truth the consumption is not far short of twice the cooking power. I could see a decent size tea urn plus microwave demanding close to 3.5 kW
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