Seachange

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  • in reply to: Lithium Batteries #1708

    Seachange
    Participant

    Hi Ross, as you can see its been a while since I have been back to review these posts and have therefore been remiss in responding to you. I would still encourage you to consider Lithium over AGM for all the reasons that have been stated so far. My experience with them has been fantastic and their performance is life changing with respect to operating the boat.

    With respect to redundancy I can offer you the following information as it pertains to my system. I have 7 x 12V batteries configured as 3 x 24V and 1 x 12V banks, each of the 24V banks is paralleled to the charging circuits and also to the discharge circuits (each one can be isolated from either charge or discharge via relays). Each bank has its own BMS and each can be isolated individually if any fault is detected, this then reduces available capacity without losing it completely. I also carry a spare BMS to swap one out if I had a failure with the hardware.

    I guess I am pretty confident with it as I did the installation myself with assistance from Dan and the product supplier. My only “fault” experience to date has been a cell over temp alarm that settled down shortly after it was raised.

    The longest we has spent at sea with them so far has been 4 weeks and they have have run the boat every day with a 3 to 4 hour evening charge to top them back up……..sensational!

    Ross, please feel free to look me up next time you are passing through Darwin and i can give you the tour and I trust R&R II is progressing well.

    Greg

  • in reply to: Lithium Batteries #1312

    Seachange
    Participant

    Hi Ross, the short answer is the Litium Batteries are awesome, I am still getting used to them and have done 3 trips of approximately one week each since they were commissioned.

    Trip 1 (Mini Mini) – I went very easy on them and just monitored things like hourly consumptions, recharging characteristics etc as I didn’t really know what to expect.

    Trip 2 (Mini Mini) – The weather was warming up and I was more confident to push them with some Air Conditioner use and settled into a pattern for charging etc.

    Trip 3 (Lyndoch Bank) – Even though this is a long way out to sea the conditions were still and the boat quite warm. AC ran for the entire 30 hour run to the shoal, ran AC most afternoons for a couple of hours and again at crash time to cool the rooms down for an hour or so.

    The boat typically draws 30 amps at 24V under “normal” load (no AC or Hot Water) and at this rate uses 3% of capacity per hour. With a usesable capacity of 80% this is a theoretical run time of 26 hours before the Battery Monitoring System would isolate the load. The pattern has become to charge each afternoon/evening which usually starts from high 30’s to low 40’s State of Charge and the system charges at about 17% per hour until full (no trickle charging required). This results in approximately a 4 hour run time for the Generator using about 10 litres of Diesel during this time (confirmed via the recently added Maretron Fuel Flow system) which about a 20 litre per day saving compared to the previous configuration. During the Generator run time we heat water and run AC, if needed, to cool the boat plus I would make water if I had a RO plant (another project?). We could probably halve our typical load under extended cruising conditions with two or three on board but I would sure miss my ice machine.

    A new boat sounds very exciting as there are many gadgets that would make life simpler (but the boat more complex) but it is unlikely that we will undertake such a build ourselves. In the meantime Seachange has had her Davit rebuilt and is awaiting the arrival of a Cross Country 4.3m Tender as well as some ZF Electronic Throttle Controls to help me with docking as vision is limited and reversing gets interesting sometimes!

    Greg

  • in reply to: Lithium Batteries #1306

    Seachange
    Participant

    Hi Ross, you raise an interesting point and to answer it accurately requires a slight technical answer.

    The short version is that lithium batteries can accept full charge current all the way to 100% whereas a lead acid must be trickle charged from about 80% thus resulting in excessive generator run times.

    With the new system in Seachange the new inverter can supply 200A at 24V so I can recharge from flat (20%) to 100% in four hours of Genny run time. Additional 24v alternators take care of charging whilst underway.

    With a bit of management I suspect we will minimise generator running to a couple of hours per day depending on air conditioning requirements.

    Greg

  • in reply to: Introduction – Seachange #1305

    Seachange
    Participant

    Sounds like a great trip Ross, I am sure you had a fabulous time. I look forward to absorbing the info you post in the future and would be keen to hear any recommendations you may have for tides to visit the Berkely region.

    Greg

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