300Ah LiFePO4 upgrade

[Starscream]

More data:

I switched the solar panels from my original 2x50W parallel-wired 12V Amazon panels to the 36V 100W anti-shading BougeRV panel. the two 50W were angled to the sun with zero shade, and the 100W panel was flat on the bimini top with the mast down and shading a portion of it (I have an extension mast carrier pole that allows the cockpit enclosure to be up while the mast is down).

With the fridge ON and running, and all the cabin lights ON, and maybe 30C in the cabin: results according to the DC to DC charger app:
2x50W panels = 16.1V, 0.87A
1x100W panel = 19.7V, 1.53A

Shows how crappy Amazon panels can get after a couple of years. When the mast is up and only the backstay is shading the panel, I'm hoping things will get even better.

[Starscream]

I've left the boat unplugged from shorepower for three days now, with the fridge running and the solar panel up but shaded by the mast. I suppose there are a couple of little loads, like the bilge pump lights and USB lights and the electronics monitoring things, but they can't add up to much.

After the first day with about 4 hours of sun, the battery was at 98.4%, and now after two more cloudy days the battery is at 94.5%. It's cool at night tho, but I'm quite happy with this result.

It does feel like infinte power, for now.

[OverEasy]

Hi StarScream!

That sounds pretty impressive to a novice like me!
That’s a pretty good charge status for what could be considered normal static operations (not using cook plate or coffee maker).

Bravo!

Do you have any plans on doing any further stress testing of your system such as maybe running a coffeemaker in the morning and maybe frying up some eggs and bacon for breakfast in the morning and maybe a couple of nice burgers for supper? It would be interesting to see how it recovers charge with that kind of utilization. (This has been sort of our concern with moving away from any open flame or propane on our boat to a Solar Lithium battery electric system.)

Best Regards,
Over Easy

[Be Free]

I've left the boat unplugged from shorepower for three days now, with the fridge running and the solar panel up but shaded by the mast. I suppose there are a couple of little loads, like the bilge pump lights and USB lights and the electronics monitoring things, but they can't add up to much.

After the first day with about 4 hours of sun, the battery was at 98.4%, and now after two more cloudy days the battery is at 94.5%. It's cool at night tho, but I'm quite happy with this result.

It does feel like infinte power, for now.

Unless you have some significant loads that you've not accounted for I'd say you're in great shape. You are running less than a 3% deficit under less than ideal conditions for your solar. That would work for me. Good job!

[Starscream]

Hi StarScream!

That sounds pretty impressive to a novice like me!
That’s a pretty good charge status for what could be considered normal static operations (not using cook plate or coffee maker).

Bravo!

Do you have any plans on doing any further stress testing of your system such as maybe running a coffeemaker in the morning and maybe frying up some eggs and bacon for breakfast in the morning and maybe a couple of nice burgers for supper? It would be interesting to see how it recovers charge with that kind of utilization. (This has been sort of our concern with moving away from any open flame or propane on our boat to a Solar Lithium battery electric system.)

Best Regards,
Over Easy

Thanks O.E.

I almost went to electric cooking, but made a kind of fundamental mistake. I was thinking about a 2000W inverter, but on the Renogy App a discount code came up that put the 3kW inverter below the price of the 2kW inverter, so I ordered it knowing it was a couple of inches bigger than what I had measured for. Well, yeah... now I don't really have a good mounting plan. It fits but puts sticks out around a corner putting some electronics in range of a water leak.

But yeah, I'll do other tests for sure. Maybe I'll watch the hockey game tonight on the boat and see what that consumes

[OverEasy]

Hi StarScream!

Just as a random thought I had when considering the potentials of an advanced electric approach like you have accomplished was to suspend mount the inverter on standoffs (for cooling air circulation) in the aft berth of our Mac26X under the raised ceiling on on the starboard or port side. That or to the wall on either side or to the aft wall of the head compartment. I too was looking at the basics of inverters capable of handling at least 2kw which pushes one into the larger 3kw units. While the units have come down in size over the years they are still something that needs a good bit of space and air circulation. For our operations these are relatively unused real estate options that could readily fit the 3kw inverter.

The ceiling area is a double wall construction so spreader expanding anchors would work without much concern.
The head wall is easily accessed from both sides.
The upper portion of the aft berth side wall is the hull so that would be a bit more involved with possibly a pair of sealed thru hull carriage bolts or something else.
The lower portion of the aft berth side wall is a double wall so spreader expanding anchors would work without much concern.

Routing of the electrical cables could be accomplished via flex tight conduit under the floor or across the aft berth ceiling.

Personally in my thought experiments (… aka: daydreaming ) I was ‘leaning’ toward the idea of basing the new lithium battery(s) and inverter on the port side as with our current setup having the existing dual Lead acid batteries and A/C unit located on the port side along with the modified galley we have a slight ‘list’ to port that needs to be balanced out some. At some point in time I’d also like to add a solar electric head air extractor vent that could potentially be tied into also venting the inverter cooing air rather than simply heating the cabin space.

Just a thought to share if it’s worth anything…. Again these are just my daydreams….

Best Regards,
Over Easy

[Starscream]

I have a few data points now that we're on our first trip of the season.


The battery was last connected to shore power last Monday morning, it's currently Friday. Mast is down, and the mast and the rolled jib are shading the 100W panel. The fridge has been on continuously.

Currently at 71.6%. We watched the Vegas Knights game and the Habs game on the tv/120V inverter, and charged phones.

I have run the motor for 3.5 hours at 1900 RPM since Monday, at which speed the motor alternator produces 10A. It takes 6A to run all the electronics, fridge and autopilot, so the motor has contributed about 15AH net. The solar produces between 1 and 3A all day.

I'm very happy with the result, I could easily go another 3 or 4 days without running the motor and still have some juice left, if the sun stays consistent (it won't). The fridge isn't working too hard though, last night it was down to 41F outside, so warm weather use remains to be seen. I did use it to freeze two gallons of water for the icebox, and it's remarkable how much work the fridge has to do to achieve that. If I recall my thermodynamics correctly it takes about twice as much energy to freeze water as to boil it, from room temp.

[Be Free]

Thanks for the real-world data points. It's always nice when the calculations line up favorably with reality.

To paraphrase Benjamin Brewster (Yale, 1882), "In theory, there is no difference between theory and practice; in practice there always is."

[Starscream]

Trip 1 completed: battery setup was a resounding success. I wish I had done this years ago. The system is truly set-and-forget: no requirement to do any switching or to remember to do anything. The Lead Acid starter battery never came off of 100% SOC (I installed a shunt on that battery too).

The only thing that went sort-of wrong is that we lost shore power at one point but didn't notice it until the battery was down to 67%. The boat was rocking so much at one point that the extension cord disconnected. I MAY add a better visual indicator for when we are on shore power: currently the panel has a voltage-indicator needle but its location means that its always covered with clothes or gear. I have to think of how that indicator should work: I don't want a light shining all night, but I want something that automatically alerts me if we HAVE shore power then DON'T have shore power.

I was thinking about adding an induction stove and was doing calculations of how many AH it would take to bring a pot of water to a boil using an inverter, and now I'm realizing that it takes more energy to keep our cooler fed with ice every day than to boil a gallon of water every day. We had six on board this past week, so a single fridge just doesn't cut it for us. We have a Bodega cooler that lives under the table, and an Igloo cooler that lives in the tub under the aft dinette seat. I modified the tub with 1" of foam insulation on the bottom covered with fiberglass. We use half the Bodega cooler to keep critical stuff like meat and dairy cold on the fridge side, and the freezer side for smoothie fruit and frozen meat, and to freeze a gallon jug of ice for the Igloo cooler, which is then exchanged for a melted gallon jug of ice from the cooler.

Our setup for F1 weekend in downtown MTL: Was awesome except for the rave at the end of the pier that blasted the loudest bass I've ever heard for 36 hours straight

[OverEasy]

Hi StarScream!

Glad things are working out so well!
Congratulations!

One of the scenarios that we’ve been contemplating for when/if we ever get clear of family obligations and get onto an extended cruise with our new single compartment compressor cooler/freezer would be to do something similar to what you describe. In our case we’d be using the compressor cooler in freezer mode with two or three skinny cold blocks to swap into the olde fashioned insulated Coleman cooler. The thinking is that the skinny cold blocks would by (virtue of their larger relative surface area) would cool faster and allow us to better distribute the cold in the Coleman cooler than a single large block…. At least that’s the thought

Sorry you had to endure the party music… some folks really like to ‘feel’ the beat as it were

Best Regards,
Over Easy