Building the lower level of our watertight battery box in the bilge, key to an all electric boat

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Here is the lower level (for 4 x 120Ah batteries) of our watertight battery box, part of our conversion to Vida being a fully electric, zero carbon footprint boat.
The upper layer is also shown roughly in position with 4 x 300Ah batteries.
Two and a half years ago, when we bought Vida, she was in a very tired and damp condition with all original equipment and fittings (much of it not working).
We have removed all the gas, diesel, and paraffin equipment as well as all the plumbing and electrics. We have composting toilets, are installing an electric motor and all electric cooking. We are fitting a huge solar array and probably a wind generator. We have replaced all the windows, removed all the headlining and more. We are replacing all the standing rigging with Dyneema synthetic rigging.
This is the biggest sustainability project of our lives as we prepare for a retirement when we want to cruise the world using zero fossil fuels on a very low budget.
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Lots more detail on our blog at sustainablesailing.net/
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#BoatRefit #sabbatical #forecabin

Опубликовано:

24 май 2022

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Комментарии : 17

@rickytapper9779 2 года назад

Great job!

@SustainableSailing 2 года назад

Thanks

@rickytapper9779 2 года назад

You have opened my eyes on this. I was only thinking 2 dimensionally. Now with three dimensions (2 layers) things are much better!

@SustainableSailing 2 года назад

We are fortunate in having a bilge that is deep enough (and not the place where water drains to in order to be pumped out (the bilge under the electric motor is about 1m deep). I guess that many more modern, shallower hull shapes will not be able to do this (the top of our battery box will still be about 500mm below the waterline). However, when possible it does mean that battery cables can be kept short and it is easier to keep the same cable lengths for multiple battery banks thus keeping the resistance as similar as possible, which I understand is important for equal use, equal charging and equal lifespan of the batteries. We have seen numerous problems with batteries that get flooded and so all electrics are unavailable (Sailing Zingaro nearly sank his Oyster, Rigging Doctor have lost multiple motors and at least one new battery bank). So, for Lithium batteries, we believe that a watertight compartment is essential.

@rickytapper9779 2 года назад

@@SustainableSailing Your boat must be built the same as mine (Pearson 419 Center Cockpit Ketch) cuz I have the same thing. And I saw James' disaster on Zingaro, so I agree with you. It definitely needs to be water tight, My electric engine (Electric Yacht Quiet Torque 20) is over my deep bilge, as well. I will be putting some fiberglass fabricated "straws" to allow for water drainage in my new design (new design thanks to you opening my eyes).

@SustainableSailing 2 года назад

One of our earlier designs included drainage pipes in the bottom. We decided against that as forward of the battery box there won't be any deeper section of central bilge. Immediately forward of the battery box will be a new water tank and that will use the keel top and hull sides coated in food grade epoxy. That will have sides aligned with the battery box to provide the side drainage channels. Forward of that is a raised section with the mast compression post. We plan to provide good electrical connections from this to a new lightning protection plate and it will drain into the side drainage channels. Forward of that is the heads which will have a pump for the shower in it's bilge (with a choice of pump out [if needing to pump out a leak] or pump to grey water tanks when showering). Forward of that we have created multiple watertight bulkheads in our radically revised forecabin so nothing from there will drain into the main bilge. We were a little concerned that the drainage pipes might get blocked and be difficult to clear which was another reason for changing the design.

@ianmckay954 2 года назад

More golden knowledge shared, thank you. I expect you already thought about it, but, some foam sheet or similar between the bigger batteries? I have seen a thin material used within lithiums to separate the internal cells to help with heat dissipation.

@SustainableSailing 2 года назад

Thanks. We haven't put much thought into heat dissipation. That is because in the UK having the batteries below the waterline is going to provide a lot of cooling. So better to have space for the air to circulate around the batteries and inside of hull. Obviously in the tropics things will be a bit different with water temperatures far far higher. I've not seen much in the way of lithium battery cooling in other projects. I guess one option is if we think it is needed later we could add ventilation chimneys which can be capped in rougher weather or when it's cold?

@ianmckay954 2 года назад

@@SustainableSailing I think part of the cooling issue is that the BMS can be made to think the battery interior is too warm and it shuts off charging sooner than is ideal - There is a guy with a channel called Lithiumsolar who breaks apart manufactured battery units to assess the internals. These almost always have something to separate the internal cells (more often than not EVE cells) but I think yours are filled with cylinder cells that may react differently and be less prone to internal heating. It might be worth a word with your unit manufacturer to see if some air gap between your beasts is advisable for optimum charging/discharge. Having said all that your chimney idea would probably work but seems a bit of complication that may be easy to solve at early stage.

@SustainableSailing 2 года назад

@@ianmckay954 technical details of our batteries are at www.ksenergy.co.uk/lithium-iron-lifepo4-technical basically they operate between -20C and +50C I think we are unusual in using them in such big banks so a bit outside their experience. Will continue to think about conducting heat away from the batteries. Initially it sounds like a heat sink would be more effective than anything that would act as insulation. But we need to make sure that we don't over cool them as we do want to go to the Arctic Circle (in summer!).

@daveturner4070 2 месяца назад

How did the heat dissipation work out in the end? Were you able to comparing charging rates with the battery bank open/ventilated compared to in the sealed up box? I wonder if it really makes much of a difference, since it seems like the batteries themselves are not exactly setup to dissipate a lot of heat from inside the battery anyway (no heatsinks or metal cases).

@SustainableSailing 2 месяца назад

Not tested yet. The real challenge won't be until we get to the tropics. Well before then I'll have full temperature logging around the box and batteries so we can see the impact of both charging and discharging then automate appropriate action in plenty of time. If we are concerned we can add a chimney and fan ventilation but I'm pretty confident it won't be necessary.

@russgaulke1364 2 года назад

Obviously you have thought deeply about how you want to design these systems. Do you mind me asking what kind of background you have, for it is obviously you know what you are doing. I wish your videos reached more people.

@SustainableSailing 2 года назад

I (Dave) have been a Methodist Minister for 16 years but before that I was in IT (design, software and networking) for 25 years. My Dad was a very hands on practical architect and my grandpa a joiner. Jane trained as a Civil Engineer and worked for several years at that before we had a family and has had multiple jobs since.

@russgaulke1364 2 года назад

I spent 20 years in the Us Military working on helicopters, after that 11 years as a Baptist Minister and am now enjoying retirement.@@SustainableSailing

@SustainableSailing 2 года назад

We are working towards retirement in 3 years when the refit should be fully complete and tested. Then off around the world. Some of the US is on our wish list, Maine looks beautiful from what we have seen on the Delos and Atticus channels.