Tom and Bex

They might have floating pontoons, but this is what they looked like during the floods last winter😱

And I suspect this is why the straight lithium replacements I mentioned in the other thread work fine with no problems. Yet some suppliers state in reply to questions that is perfectly fine to rely on the bms to control charge, and just rely on the internal bms to shut down charging on high cell voltage trigger. Even though this will shorten the life sightly, I still think LFP treated like this will far outlast LA and with no real increased risk other than slightly shorter lifespan. This is undoubtedly the best simple lowish cost option, particularly for twin alternators. If doing this, I'd wire both alternators to start battery, and run b2b from there to lithium (and know several who have done this).

Kept LA starter, replaced domestic LA with LFP and just rely on bms to manage them and don't worry about limiting charge. 100's of camper and motor homes have this exact setup as well - split charge relay connected direct to lithium as @Peanut mentions in his quote. Yes it might not be the ideal way of managing charge, but seems to work for lots of users. Might not get the maximum lifespan, but does that really matter at around £100 per 100ah battery?

The couple that added b2b connected both alternators to start battery and run the b2b from there to the drop in lithium, so yes slight modifications. The other 2 or 3 boats I know of have a single alternator and split charge relay and just did a straight swap LA to drop in lithium and changed nothing else.

Lithium *can* be fit and forget. I know a handful of boaters now who have done just that - replaced LA with drop in lifepo4 and changed nothing else. A couple have also added a dc to dc charger, but others have just done a straight swap and changed nothing else. Sometimes things can be made over complicated on here! They might not last 8000+ cycles and 20 years, but if they only last 1000 cycles / 3 years, that's still a saving on replacing LA every year or two. These are the cheapest drop in batteries you can find at just over £100 for 100ah with no Bluetooth monitoring. Just relying on the built in bms to cut charging at 100%, and they will often charge til the bms cuts out, and sometimes run them flat til the bms cuts out. They seem very happy with them, but not had them that long. They also abused LA by running them until low voltage alarm on inverter beeps, or lights go dim, followed by only charging for a couple hours or so.

Have you got any dates going back before 2000? I'm sure I went to one on the Neath Canal bank in the 90's. Also helped with the preparation and setting up for one in Taunton when I should have been doing GCSE's so that must have been 90's as well 🤣

Congratulations to Rebellion from all on Tatty Lucy!

I don't think grade B cells would be an problem for typical domestic usage. That deal from Fogstar does look very tempting, and if we hadn't just bought a 100ah for our camper would have been seriously tempted by that offer. Still very tempted to get this to expand our current bank! Our current cells were rejected from diy EV use as the voltage dropped to much under heavy discharge. We're on our 7th winter with them, and no detectable drop in capacity over that time. Rated capacity of 320ah, and when installed we measured 300ah before BMS low voltage cut.

Think Black Prince used these on their hire boats at one time, might be worth asking them if they have any spares lying around.

Something I've not seen mentioned so far, is a lot of lead acid chargers have temperature compensation to raise the charging voltage at lower temperatures. You need to make sure this is disabled for lithium charging. Often this is just a battery temperature sensor that can be left disconnected, but some chargers do have this built into the charger itself.

Love these boats, hope someone buys the moulds and keeps them going!

Haa been for a while - past 2 years we've helped tow non-challenge boats off the mud here, and no chance of getting near the bank on either side.

And a huge thanks for organising the Challenge, and the work you put in to get the winners announced on the night! Definitely a change from the first few challenges we did where the results came out weeks later. Hopefully the increased entries again this year will continue, and the media coverage on Friday evening was mentioned by several people we met along the way. Thanks again.

Thank you! Tatty Lucy won! Very pleased with results and big thanks to the crew including our girls who have to put up with my planning and early starts on the challenge! Lily (our 8 year old) is delighted with the result!

I was thinking as we came down I was glad we didn't have a historic boat to squeeze through the gap on that gate 🤣🤣