Mick here again.

Long time readers of the blog might remember that when Oleanna was being built in Sheffield back in 2016 we decided that we would have a lithium battery bank installed. Finesse, our boat builders, had suggested it to us and we decided it was a good idea. There were many delays in getting them from the supplier but we finally got our three RELiON LiFePO4 24V 50Ah batteries installed giving us 150 amp hours of electrical energy. We were quite happy with them although larger capacity would have been nice.

One day last summer (2023) the voltage of the battery bank wasn’t as it should be. Upon investigation I found that one of the three batteries was faulty. It was showing 23 volts instead of the more usual 26. I tried to revive it by connecting it on its own to our Victron Multiplus charger whilst we were hooked up to shore power in Cropredy Marina. But it didn’t play ball so a replacement was required.

In theory these batteries have a 10 year warranty so I set to with some investigation. I spoke to Ricky at Finnesse who said that they had not used these batteries again after the long delays in supply that we had experienced. I contacted RELiON direct and they explained that the 10 year warranty worked like this:

Legacy Series (Model numbers that begin with RB) – Should the manufacturer deem a valid warranty claim exist and battery(s) are unable to be repaired in year one (1) through three (3) the manufacturer will replace the defective battery free of charge with a similar product. Should the manufacturer deem a valid warranty claim exist and battery(s) are unable to be repaired in years four (4) and five (5) a similar product will be offered at 20% off the retail MSRP listed at the time of the offer. Should the manufacturer deem a valid warranty claim exist and battery(s) are unable to be repaired in years six (6) through 10 a similar product will be offered at 10% off the retail MSRP listed at the time of the offer.

So, not really a 10 year warranty after all. We fell into the last category of getting a 10% discount off the retail price of a new battery. That was really not an option. We toyed with getting a new bigger battery from another supplier to connect in parallel with the two remaining batteries. At first this looked hopeful but in light of the fact that the old batteries have no programmable battery management system (BMS) it would be difficult to get the settings of a new battery to match. So we decided to limp along on 100 amp hours for the rest of the season and sort it out when moored for the winter back in Goole.

I did a lot of research. There is a very useful Facebook group the “12 volt boating group” (https://www.facebook.com/groups/144684286108763 ) which has many knowledgeable members. In the end I decided that we would buy two new self heating 24v 230Ah LiFePO4 batteries from Life Batteries, a nice friendly company in Cornwall https://www.lifebatteries.co.uk/. There will be a very useful big step up in our capacity from 150Ah to 460. I considered getting just one battery, but as Paul Balmer of Waterway Routes fame (https://www.waterwayroutes.co.uk/) pointed out, if that one battery goes faulty then you have no domestic power. The self heating will come in useful if ever we need to charge the batteries when they are below 0 degrees C.

Measuring the battery tray. 53 x 33 cms available.

The new batteries will be connected in parallel with the lead acid bow thruster bank thereby providing the alternator with somewhere to send its electricity when the lithium batteries are full and switch themselves off from charging. Our old batteries were connected up in the same manner. One new battery would go in the old battery tray in the engine bay and the other in The Shed cupboard inside. There will be a shelf over it so the cupboard can still be used as a Shed.

A bit of a rewire was required. The original installation was a bit untidy and in seven years I’ve not been able to find any fuses in the DC supplies to the inverter or the domestic distribution panel.

When the old batteries were removed it was clear that the tray neaded a bit of TLC. Now painting is not usually my reponsibility on Oleanna but in this case I took on the job, mainly because once completed I would be the only person who would see it and Pip was busy with other stuff.

Next came the installation of a new positive bus bar and fuse holder. It is attached to a bit of wood that was glued to the bulkhead with Gorilla Two Pack glue. It’s a bit skewiff, my excuse being that I was working upside down, back to front and left handed. By the time I noticed the skewiffness the glue had gone off so there was no moving it to make it straight. But it does the job. Along the top is the bus bar. The thin red cable on the left goes via an inline fuse to the shunt for the battery monitor. Next is the orange cable to the new inside battery, then a black cable to the bow thruster bank (via a Mega fuse), another black cable to the 24v alternator and then another orange cable to the new outside battery.

The Victron inverter / charger is connected via the blue Mega fuse at the bottom and the 24v DC system to the orange fuse. All is covered by a plastic cover.

The independant 12v starter battery is on the left. A wooden cover will be placed on top of the whole lot to protect it.

The BMS settings in each battery were programmed as advised by the very helpful Mark Cheesman at Life Batteries https://www.lifebatteries.co.uk/. You can connect to each battery via Bluetooth and an app on a phone. There are two important settings to change: the “batt over voltage” is the voltage at which the charging is turned off, set to 28 volts. It turns back on again when it drops to 27 volts. The other setting is the “batt under voltage” which is when the discharging is turned off, set to 24 volts, it comes back on again at 25 volts.

Time to start the engine. A final check of everything then turn the key. The engine fired up and I monitored the charge going to each battery. Just under 30 amps to begin with which was good. The 100% state of charge (soc) is incorrect. The BMS requires a few days of use to work out the correct soc and even then, as with all soc readings it is liable to inaccuracy.

The temperature of the alternator needs to be monitored and after about 30 minutes it was reading a steady 40 degrees C. This is on the cool side, apparently 90 degrees is ok. I think I need to get rid of the surplus length in the battery cables. I reckon I’ve got about a metre too long in each cable. Once this is done the charging current should increase. To do this I need a crimping tool and some new lugs which I don’t have. That can wait for another day.

I’m looking forward to using the electric kettle when making tea in the morning.