As others have duly noted the subject has probably been done to death but here is my two cents worth on changing the house bank to
Lithium.
My first comment would be to say that along with lots of reading on the subject as to how to wire up your setup and what components you need/want - it would be wise to check pricing in detail as well. Something I very much neglected and consequently blew my
budget out of the
water, so to speak. Foolishly I figured the cost of the
Lithium Batteries and the cost of an
Alternator regulator suitable would be the bulk of it. And they were of course the biggest items, but it ended up all the ancillary stuff that compounded the
price.
I also failed to recognize that the system I envisaged and what I would end up with were two quite different things.
I already had a
Victron Multiplus Compact 12/1600/70- 16
Inverter Charger that would handle a Lithium
charging profile, a
Victron MPPT 100/15 and a little 80 watt
solar panel to keep
battery topped up while on a swing
mooring.
Quite by chance on another forum I got to know a
marine electrician offering
advice who I eventually worked together with on installing the system, and without whom I would have made a complete hash of. So my
advice is seriously consider working with a professional installer. I usually do most of my own maintenance/upgrades on the
boat - but in this case, though expensive - I'm glad I had a professional because the system is complicated - there being so many options modern
equipment provides.
Here are the initial components to the system: I installed an Arco Zeus external
regulator controller (the previous one had given up and is what prompted the whole exercise including the lithium change over), and a positive side shunt with slow blow fuse (actually a fuse designed for
electric motor). And also an
alternator protector which absorbs an energy spike/dump from the alternator if the Lithium
batteries suddenly decide to not accept any charge.
With the Arco Zeus I have a couple of points which people may consider.
Given that in most installations the Zeus
wiring harness will require either an extension to the
battery harness or the alternator harness. As I'd chosen to mount the regulator near the alternator the battery harness needed extending by around 5 meters. It's a good thing that instead of just having terminals on the regulator they provide ready made looms for the alternator and batteries with appropriate connectors. This means on the regulator side one cannot connect the wrong wires to the wrong terminals. However once the extensions are made to the 14 wires comprising the battery harness unless you have 14 different coloured wires that match the original it's easy to mismatch the connections. This could easily have been checked by having a connector Pin to colour code diagram so that a continuity test would be easy to ensure correct correlation - however no such diagram existed. Once the wires are extended all the joints are insulated and so there is no means to check each wire is going to be used for the correct purpose.(My installer got back to Arco and has since been given this information which I hope becomes part of their
documentation as an extra check)
As it turned out, after
installation the regulator showed a fault - "internal
sensor error" which meant the regulator would only operate in "Limp Mode" providing a very low amount of field
current in order to limp home on severely limited charge output. As we had no clue as to its cause after all the checks we could make, Arco agreed to send out a completely new unit without hassle, to
New Zealand at no charge and very promptly considering how far it had to come which I thought was excellent
service. I'm not sure if this would have been the case had I not employed a professional installer. This is perhaps another reason to consider a professional who puts a lot of business their way and has a reputation as an installer to oversee that it is no fault in the
installation process.
I was very impressed watching the app show how the regulator was doing a balancing act between alternator temperature, the
engine revs and
charging requirements of the Lithium batteries, getting nearly 70 amps charge at around 1100rpm, cutting back if the alt temp got too high. As our alternator is rated at 120 amps, but a Chinese built Bosch knock off, we decided to be conservative in the settings with a max temp of 80C and I think a max output of 80 amps (which is probably close to its max continuous duty cycle). Either way with the temp. control - the Zeus pampers your alternator - because those Lithiums can really gulp charge.
Here's another little point with the Zeus harness. The recommendation is to have a shunt for the alternator and for the battery. But why are the alternator shunt wires included in the battery harness rather than in the alt. harness? Anyone who wasn't focusing would perhaps have extended the battery harness, pulled it all through a conduit, threaded that all the way to the battery, only to find out those two wires go to the alternator shunt and probably didn't need extending anyway.
One more thing, and these are only minor in the grand scheme of things, but those putting in Lithium batteries, especially if Victron components are used which are common, will no doubt see the value of a Victron smart shunt for accuracy and communication of data. However as others have duly noted, using the smart shunt to communicate to the Arco Zeus means either putting the sense wires directly on the same terminals as the main
cables, or tapping new threads in it for connection of the sense wires which is going to void the warranty on the shunt, and possibly affect accuracy. In our case I already had a negative side shunt near the batteries for my BEP battery
monitor so I just added the Zeus sense wires to that which means I keep the little BEP
monitor, the Zeus gets its info and all is sweet. The values of this shunt were a little different than the standard 500A/50mV, so the Zeus programming needs to reflect the actual shunt used which in my case was 450A/50mV. I also added the smart shunt in the same line, because we needed that information for the Victron Cerbo GX. The functions of the GX in our case were primarily to manage and prioritize the three charge inputs, (alternator, shore, solar) through DVCC, (Distributed Voltage and
Current Control) and to communicate with our apps via
wifi or bluetooth whichever it is.
On a side issue, when the system was up and running we noticed that with the
engine running, the
solar input (negligible),and
shore power also charging, that the system prioritized the alternator and the Inverter/Charger was idle even though the max Current input was set a 150 Amps. So the alternator was putting out around 70 Amps, yet the
Inverter Charger was idle. We are still wondering why the two main charging inputs weren't working together to get up to say around 130 Amps cumulatively, if any one has any clues for why it behaved that way we would be very interested in hearing from you.
As far as the other components go here they are: As already mentioned a Victron Cerbo GX, Victron Smart Shunt, Victron BMS and Victron Battery Disconnect to manage two 330 Amp Victron Lithium Batteries. I had only envisaged one 330 A at first but later went for two of them. Here's why. Our previous 4 6Volt deep cycle LA batteries connected in series/parallel gave us a nominal 464 Amp capacity, yet to keep within the 50% discharge parameters for battery cycle life, meant we had a working capacity of 232 Amps when the batteries were new. They were 9 years old and failing. Just one Lithium 330 Amp battery discharged to 80% which still gives a very reasonable number of charge cycles and battery life for a lithium, gave us more capacity than the previous setup. (264Ah compared to 232Ah).
Yet two things persuaded me to add another 330Ah battery. First was the added components necessary to control the system and give lots of available information both on the
boat and from anywhere else in the world where
internet connection was possible, meant a greater investment. When I realized where the cost was going, it seemed a waste of
money to put all that effort and expense to manage just one battery. I know it doesn't sound like economic sense, but in for a penny in for a pound.
The other reason is that the one battery looked lonely in the
battery box. Two of them fitted perfectly with still less weight and space requirements than the previous four.
And now I have a system with a capacity of 528 Ah with Victron
Remote Management that also gives me new options for monitoring the
bilge pump,
tanks, location, other alarms,
remote switching of anything like a fridge or
freezer, intrusion
alarm,
camera or whatever your imagination/needs require just about.
Also important to consider is the sometimes bad press, sometimes accurate assessment of Lithium
power,
insurance, local standards requirements for installation. People are adopting "drop in" Lithium batteries as an option. But have they considered beyond the "cheap" option?
Insurance? Legality? In
New Zealand it appears that if we have
shore power provision wired into the boat charging Lithium batteries - then there must be a warning lamp or
alarm in the system for an over charge, or over temperature warning. I'm a bit hazy on this, but apparently it is a condition of installing Lithium batteries properly if your boat is to gain its mains
power certificate of fitness.
I had no idea when embarking on the
project that I'd need a BMS for the Lithium batteries. I considered the "drop in" option and decided I wanted batteries that not only had an internal BMS system, but had Bluetooth built in for communication as well. This led me to the Victron Lithium which are pricey but give that peace of mind. Knowing that they had the internal Battery Management System I gave no consideration for an external BMS until my installer pointed out that the built in BMS only managed what was happening between cells in the one battery and each as an individual battery, but no such management could be exercised over a lithium battery bank (two or more batteries). And therefore the external BMS became yet another "must have" in the system.
Another thing I hadn't reckoned on.
On occasion I'd had to use my house bank to combine with a flat starter battery to get the engine going. A combiner master switch existed between the house and starter main switches for this purpose. Simple.
Not so with Lithium batteries. Apparently with Lithums and a flat starter Lead Acid battery, such is the strength of the current available to flood the starter battery that things could get mighty hot and it wasn't a good idea.
I still like the idea of using if necessary the house bank to get started.
What to do?
If anyone has a better idea I'd like to hear it. But what I came up with is this. The House/Starter system, like most
boats uses a common negative. So if the start battery goes flat, disconnect the Start battery negative, and then use the combiner switch to power all the things the Start battery would normally supply, with the House battery. This protects the Start battery or anything else from blowing up. When the engine has started, (if diesel), it requires no other
electrical input. Don't use high engine revs until the House/Starter combiner switch is again opened, and the negative battery connection replaced on the Starter battery otherwise damage to the Start battery alternator may result. (I should have said we run two alternators dedicated House alternator, and Start alternator).
I may be too pessimistic, but I like to consider what to do before it happens. With all the monitoring
equipment now working will I ever be in a situation where I'm unaware of a flat starter battery?
Another bonus of this new system is with regards to communication on the boat. I now have a router providing
wifi,
internet connectivity, all the Victron components are either using bluetooth or wifi, plus my older
Raymarine electronics only worked using
NMEA 0183 network. However to add functionality to the various components of battery management, we have installed an
NMEA 2000 backbone linking the Arco Zeus and the rest, which means when we need to upgrade our
navigation electronics the basic
network is there and we can add in the Cortex
AIS, all the
Navigation stuff and all the information from the various systems can be observed on the modern Multifunction Displays such as
B&G,
Raymarine or what have you.
Sorry for the eclectic nature of this long and probably boring post, but have just remembered another issue encountered in the commissioning of the system. While the boat was on shore charge, I sat at home watching things on the VRM app. I decided to switch the Inverter/Charger off remotely which worked fine. But on return to the boat when adding in the Zeus and other things we couldn't then get the Inv/Chger working again. It would show some fault. Consult with other knowledgeable people and they seemed to have come across the issue before, but had not been able to reproduce it.
It appears that with the Multiplus C unit a dipswitch option needed changing. My installer Mathew Duckett read up on the manual and altered the offending dip switch - problem
solved.
Good
work Mathew!
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