So... what have we been doing over the winter? Mostly renovating a new workshop for Malu Marine, which will really help with future work on King Malu. And... getting ready for new battery bank for the electric drive.
Since the latest version of the electric drive is now doing all it should and we're really pleased with it, it is now time to upgrade the rest of the system. The first job is the batteries. We have ordered 16 Exide propulsion batteries, which should be with us by the end of February at the latest.
But where to put them. We made cardboard cutouts to check sizing and have been round the boat trying different locations. It's also important to maintain the balance and trim on King Malu, so we cannot suddenly place 500kg of lead on one side of the boat. We do have a significant number of lead 'pigs' to remove or move to adjust the balance and trim so it's quite a complex plan. We also have 8 of the old 12v batteries on the port side we will be removing.
The first two options we looked at were (1) batteries under the seats in the saloon (2) batteries port, centre and under the galley. I didn't like #1 because it moved the weight too far forward for my liking and made the cable runs long and more significantly made the battery banks complex to manage.
When I say complex to manage I mean that there is a legal requirement in USA and EU that battery banks should be isolated both positive and negative since the high voltage propulsion bank must not be connected to ships earth (called an IT system). And they also must be isolatable into 48v battery banks for maintenance. So, taking sixteen 6v batteries and making them into banks of 4, 6 & 6 might work well in balance/trim but would then make a headache for isolating as the isolator would be mid-bank.
It looked like port, centre and galley was the best option so we removed the old galley, allowing us to measure more carefully and renovate the galley at the same time.
Having done so we were less than sure the batteries would now fit! Time to put thinking caps on.
Since the latest version of the electric drive is now doing all it should and we're really pleased with it, it is now time to upgrade the rest of the system. The first job is the batteries. We have ordered 16 Exide propulsion batteries, which should be with us by the end of February at the latest.
But where to put them. We made cardboard cutouts to check sizing and have been round the boat trying different locations. It's also important to maintain the balance and trim on King Malu, so we cannot suddenly place 500kg of lead on one side of the boat. We do have a significant number of lead 'pigs' to remove or move to adjust the balance and trim so it's quite a complex plan. We also have 8 of the old 12v batteries on the port side we will be removing.
The first two options we looked at were (1) batteries under the seats in the saloon (2) batteries port, centre and under the galley. I didn't like #1 because it moved the weight too far forward for my liking and made the cable runs long and more significantly made the battery banks complex to manage.
When I say complex to manage I mean that there is a legal requirement in USA and EU that battery banks should be isolated both positive and negative since the high voltage propulsion bank must not be connected to ships earth (called an IT system). And they also must be isolatable into 48v battery banks for maintenance. So, taking sixteen 6v batteries and making them into banks of 4, 6 & 6 might work well in balance/trim but would then make a headache for isolating as the isolator would be mid-bank.
Having done so we were less than sure the batteries would now fit! Time to put thinking caps on.
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