42. Solar charging my Lithium Batteries

Hi, how are you doing? Thanks very much for watching. Well, what a difference a day makes! This time yesterday, there wasn't a cloud in the sky, the day turned out to be the hottest day, April day since 1949. And by this time, which is round about 8 o'clock in the morning, I had 80% full batteries, and that was all because of solar. And that's what today's video is going to be all about. Back in March last year I purchased two Panasonic
solar panels from Midsummer Energy. Each panel has a maximum of 325 watts, 57.6 volts and
5.65 amps. They're quite large at just over a metre in
width and one and a half metres in length.

Even though my narrowboats roof has just over
16 square metres of available space, I needed to take a number of things into consideration
before I decided where to mount the panels. I have a multifuel stove chimney, tv aerial
and mushroom vents all getting in the way. The biggest issue for me was to have the space
from the rope eye in the centre of Alice to the stern free as much as possible, to avoid
my centre line ropes getting tangled up. Also, Photovoltaic panels work most effectively
when the maximum amount of light particles from the sun hit their cells at a perpendicular
(90 degrees) angle.

The difference in output between flat and
angled panels can be as much as 20%. This was the difference at various angles this
evening. I decided to use these angled brackets to
mount my panels. I decided to mount the panels at the bow of
Alice either side of a mushroom vent. I drilled holes on the side of each panel
into the aluminium frame. I added standard M8 bolts, washers and nuts. Forward wind a
year and the fact I didn't use stainless steel is clear to see. So take note and install
stainless steel bolts that don't rust and require extra hassle and work later on. I fitted the brackets to the solar panels
and lifted them onto the roof of Alice to measure up. After positioning and standing
back and checking from the stern, and from the sides I marked where the holes of the brackets would
be and got to work making 8 holes in the roof! Once I had drilled the holes I tapped them
so I could screw the bolts straight into the roof without the need for nuts on the underside.
I added lots of Sikaflex to the underside of each bracket and positioned the brackets
and screwed them on firmly.

I will be taking the panels and brackets off the roof when
it's time to paint Alice. Midsummer Energy were really helpful and supplied
the panels with MC4 connectors. I decided to connect the panels in parallel
to avoid shading on one panel, bringing the whole power output down. I used two 4mm cable
branch connectors. One for the positive and one for the negative.

4mm double insulated
solar cable was then taken in through a mushroom vent to the stern of the boat where my battery
cupboard is located. When I paint the roof, I will feed the cables in via a dedicated
roof cable gland. I have a Victron Smart Solar MPPT 100/50 charge
controller. This has Bluetooth built in and I can see live, the status of what solar is
being produced on my mobile phone. The MPPT monitors the solar voltage and current
and constantly ensures it's getting the most from any available light. Before the MPPT I have added a Blue Sea 300
amp switch, so that I can completely isolate the panels if I need to. It was then time to connect the solar cables
and the battery cables to the MPPT. Although the sockets on the controller were
the screw type that clamps the cables, knowing vibrations can affect these types of connections,
I once again used ferrules on the ends of all the cables to form a solid and secure
connection. I used a Dymo, Rhino 4200 label printer to
identify my wires.

It not only prints onto stick labels like the ones I used on the larger
battery cables, it also prints onto heat shrink. I printed off a series of heat shrink labels
and along with the standard red or black heat shrink, I shrunk them in place. [Heat Gun Fan Noise] This created a neat, labelled and
secure cable ready to connect to the MPPT controller. Using the Victron Connect app on my phone
I connected the MPPT using Bluetooth. The app informed me there were more up to
date firmware and Bluetooth versions available. I simply pressed the update button for both
and they remotely updated the controller.

I clicked the cog at the top right to set
up the controller. Next, I clicked the Battery link.
I made sure the battery voltage was set at 12 volts and using the drop-down menu, I changed
the Battery pre-set to Lithium Iron Phosphate (LiFePo4). This set the MPPT with the recommended settings
from Victron. The absorption voltage was set to 14.2 volts, maximum absorption time was
6 hours. Float voltage of 13.5 volts and with no equalisation. If you've watched any of my previous
lithium battery videos, you'll know the system has a
battery management system. When the BMS is happy, it gives a positive
signal via it's charge connection. You can use this to simply turn the MPPT on
or off automatically using the VE.Direct non-inverting remote on/off cable. This is a nice and simple
solution and all it would take is for the connection to the battery bus bars via a fuse
and job done. However, I wanted to use the single VE.Direct
port on the controller to send solar information to a Victron Color GX display that in turn
uploads all the data online. There isn't such a thing as a VE.Direct splitter so I could've
only have one or the other.

This is where the additional time spent testing came in
and hence the delay in this video. I knew I needed to interrupt the supply of
power from the MPPT controller to the batteries bus bars. This needed to be automatic using
the BMS in an over voltage situation. I initially purchased a Victron Cyrix-Li-Charge
relay to automatically stop the charge. It seemed to work exactly as planned. As the
relay has inbuilt intelligent technology, it cut the relay at night or when there was
significant cloud cover. You would think that's fine, however the constant
on/off of the MPPT, caused the Bluetooth to randomly stop working and some days I'd be
able to see the solar information in the Victron Connect app and others I couldn't. So I needed to look for another
disconnection method. I chose a simple on/off 12 volt 100A contact
relay, again with 6mm bolt connectors for the solar cables I'd already made up and spade
connectors for the supply.

I wired it up and nothing happened. The relay just wouldn't
engage. I measured the amperage from the BMS and found although the positive supply for
the load disconnect was 2 amps, the positive supply for the charge disconnect was 100 milliamps.
Not enough to engage my simple relay. Now, finding a relay that had contacts over
50 amps but with a coil of less than 100 milliamps was very difficult. They are available
but boy they are expensive. I wondered if I could use a Victron Battery
Protect but in reverse. On the last page of the Battery Protect data-sheet,
there was the diagram I was looking for. When using the battery protect in Li-ion mode
it acts like a simple relay but with a tiny 1.5 milliamps when operational. So I replaced
the coil relay with the battery protect and connected the positive feed to the screw terminals.
I fed the positive from the battery BMS to the green remote of the two pin connection
and a negative feed to the middle of the green three pin connection.

I then programmed the battery protect, using
the LED display to 8C. This is Li-ion mode. If the remote power is cut as when the BMS
senses an overvoltage, the battery protect stops the connection between
the two screw terminals. This has worked flawlessly
including the problem with Bluetooth. I have my lithium inside my boat in the warm
but if you were to install the batteries in a cold engine bay, Victron have now introduced
a way to stop the charge when the batteries are below their recommended 5 degrees Celsius. When using lithium its recommended to use
a BMV-712 battery monitor, as this uses very little current. This battery monitor has a
connection on its rear to connect a temperature probe to the batteries. Both the battery monitor and the MPPT can
communicate to each other via a recently introduced VE.Smart network.

At the bottom of the settings page, there
is the VE.Smart Networking tab. If you click this tab you can create or join a network. As I've already done this on the battery monitor,
I clicked join existing, chose the already set up network and it connected them together.
I haven't used the temperature connector on my battery monitor but if I had, it would
show up here and communicate it's temperature with the MPPT. The 625 watts of solar has produced just over
325 kW of power during the past year. August being the highest at over 60 kW and January
being the worst at 9.48 kW. Remember these figures aren't what the panels
can do, but what they have generated for use. So when I'm moving, the alternator will be
charging the batteries and so the solar is not required and therefor,
it won't be shown in the stats. Mol, Do you want to go for a swim? In, in, in. Ahh, that's better, isn't it On the whole, I'm really pleased I got them
and it is great being able to look at how the panels generate clean
and efficient energy.

As always I've included links to the items
I've discussed in this video, including links to Midsummer Energy and Onboard Energy. Don't
forget if you buy anything from Onboard energy, you can get 15% off using the promo code JONOPROMO. Until next time, see ya later..

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