I completed the testing of my new Lithium install today and thought I'd share the setup and a few photos with the folks here that provided me so much help and guidance.
So this is for my 2011 Lagoon
450. The boat was built for the charter trade
and has extensive dc loads (2 not too well insulated fridges, a freezer
, all electric winches, etc) and a large 13KW generator
along with full air conditioning. In charter
, the mode of operation was sail/motor during the day, run the generator
(and air conditioning) all night which also recharged the 800 AH of AGM
batteries. My wife and I will be living aboard
in the Bahamas
and did not want to be a slave to the generator and are willing to give up air conditioning (or at least cut back it's use to every other week or so). I bought the boat in March not in great shape; two years of charter and three years of utter neglect had taken its toll so Iíve been busy with restoration
and repair since then but converting to a large Lithium bank and upgrading the solar have been high priorities.
So I started with the size and weight of the pre-existing batteries - they weighed about 520 lbs and fit under the berth in the master cabin
along with a really disturbing rats nest of cables
and wires that connected them and connected the master switches for the house batteries and starboard engine
. I considered a 4P4S arrangement with CALB CA400AH (1600AH) cells but they were hard to get and seemed to be getting harder to get rather than easier. The 180AH cells were plentiful and I was told (and have since confirmed) that they actually have at least 200AH capacity. So I opted for an 8P4S configuration (1440AH). I got the cells from Kelly Larsen at the Electric Car Parts
Company in Utah. They actually shipped from CALB USA in California
and arrived at my local freight depot. I picked them up (not easy in a Subaru, but thatís another story) and moved them to my basement for few months to ďget to know them.Ē
I followed Maine
Sailís advice and got a decent bench supply (0-60A, 015V) and top balanced them in groups and ultimately together (32P - takes time to top balance with 50 or so amps spread over 32 cells). I then configured them in the 8P4S setup and, using my new Victron Multi 3K inverter/charger started cycling them - charging and discharging all the while monitoring the stability, behavior, and performance. The Victron was a little tricky to program but I followed the general advice of Rolf Roetter and Rich Boren and tried to set it up for a consistent 13.8v in absorption with no float. BTW, this is also where I learned a valuable lesson - connections matter! (duh) After fooling with jumper cables
and finally replacing them with cheap
but decent automobile battery cables the charging and discharging behavior settled down and I started getting predictable and expected behaviors. I also started being careful in assembly of the configurations, polishing the terminals and using dielectric grease for all the bus bar connections.
I then added the components of a homegrown BMS. I used the Lightobject programmable voltmeter (discussed extensively in this thread) driving a pair of BlueSea 7713 remote
battery switches. Programming the Lightobject was easy and I ultimately wired the on board relays in series with the manual remote
switches that came with the 7713s and (on the boat) used those switches to replace the Battery Master switch. The Lightobject voltmeter has 4 programmable settings that translate to Charger
cutoff (14.1v), Charger
restart (13.6v), Load cutoff (12.6), Load restart (12.8). These are initial settings and may change as I gain more experience. I also purchased a Junsi 8s logger for cell level monitoring but have not yet decided whether I will install that on the boat - the 8P cells are just incredibly stable and with the careful top balancing Iíve done, they never seem to drift more than a couple of millivolts apart.
While still set up in my basement I also wired up (and got to know) a Victron BMV 700 battery monitor
- a marvel of a device that has really helped me understand and anticipate the behavior of the bank. It also drives alarms for high and low voltage (inside the range of the HVC/LVC) as well as for low capacity. It has much more capability that Iím just beginning to explore but I canít say enough good about this product. Peter Kennedy (Peter Kennedy Yacht Services - Marine Electrical Systems
) helped with all the products I wound up buying
- all the Victron and Blusea stuff Iíve mentioned plus busbars, fuses
, remotes, etc.
Once I started moving the setup from my basement to the boat, things got serious and I sought some advice and help. I had all the pieces and parts
(charge bus, load bus, ground bus, remote switches, shunts, etc) but was unsure about where to put everything. Andy and Rouric from Yacht Electronic Systems suggested a layout for all the components and offered to help with the recabling. I installed everything the way Andy suggested and then gladly accepted their help in removing the old batteries and untangling the ratís nest of cables in the existing setup. They did beautiful work and when that was completed I did the actual installation
of the batteries. They are installed carefully inside a frame I designed and built and that also accommodated full length ratcheting hold down straps.
I also reprogrammed the existing Cristec chargers to 13.8 volts and use them primarily as back up to the Victron Multi Charger. When it has external power (shoreside or generator), the Victron will throw 120 Amps non-stop at the new batteries until they reach 13.8v at which point it will switch to absorption and rapidly tail off current
and eventually float (which Iíve programmed to be effectively off).
I also replaced the crappy controller that came with the pre-existing solar panels mounted over the davits
as practice for my upcoming solar upgrade (also another story).
I completely sidestepped the (seemingly endless) debates about the best approach to deal with the alternators. I view the alternators as a backup to the solar (primary) and the Victron (primary when the generator is on or when docked with shore power
and backed up by the Cristecs). We also donít motor
very much - itís a sail boat ya know. Anyway, I didnít have the money
to upgrade the rudimentary hitachi 80 amp alternators so I just left them attached to the starter batteries and ran the house bank connections to a switch that allows me to turn them on as chargers when I need to and have the time to monitor
them and turn them off when I donít.
Finally, I also had to cut back the drawer that fits under the berth to accomodate the Victron. That space is pretty tight now and I'll probably have to add better ventilation but for now am just monitoring the temperature in there.
Anyway, weíre just getting used to the new setup and I still have to tackle the solar upgrade. But Iím pretty proud of the way it turned out and attached some photos of the install for anyone whose interested. Happy to answer any questions or provide more photos if anyone is curious about the details.
And a big thanks to all of you for your help and advice!