On board power made easy

[Al]

Greetings,
With good fortune, I recently found and subscribed to a blog site related to boating to and from Southeast Alaska by a couple on a Nordic Tug.
The author is so very descriptive of their adventures I could not but join for the additional knowledge they share on so many boating fronts. Following is but one of the enlightening results of addressing on board battery power.
Thanks for reading. (Trust I am in safe waters transferring this blog information to the Trawler Forum without permission It would be nice if they were members of the forum. Given an opportunity I'd ask them.

Power Made Easy – Airship’s Electrical Upgrades – Riveted

Al-Ketchikan 27' Marben Pocket Cruiser

 

[DavidM]

Power made easy, yes. But not cheap at $8,000 list price for their battery bank.


David

 

[Bruce B]

Lithium batteries...
Not yet, not for me!
All I can think of is the Samsung Galaxy Note 7.
Yes, I understand that there are different technologies out there but I think I will wait on the sidelines for awhile.
Funny, I'm not this conservative about new technology usually but our boatyard (New England Boatworks) has built 2 or 3 very high tech sailboats that have burned to the waterline because of Lithium Ion technology.
Someday...
Bruce

 

[O C Diver]

Hmmm, nothing much new there. I do the same thing with 960 AH of Trojan T105s. Not sure why anyone would want to build the capacity to make hot water off of batteries versus heat from the engine. Let's see I'm going to spend the money for LED lights but have an electric water heater running.

Ted

 

[Trundlebug]

Interesting link, thanks for that.

But I'm really surprised they seem to be trying to heat all their water by electricity, no wonder their consumption is so high. There's no mention whatesoever of a calorifier, which would provide all the hot water they would need for up to 36 hours in a well designed system, without any need for heavy battery consumption.

Even the generator could be piped in to the system to heat the water using free heat.

 

[twistedtree]

It's great to have people ahead of you/us working out the bugs in this stuff.

For boats, I think the compelling benefit of LiFePO4 batteries is the ability to charge them at full rate right up until they are full. This makes recharge via generator much faster and better on the generator, and it reduces the number of underway hours required to recharge from the main engine alternator(s).

Other benefits, like being able to utilize 80-100% of their capacity vs 50% for lead acid, and the reduced weight of LiFePO4 per ah of capacity, are nice but not compelling. For a trawler, the weight difference is such a small % of the boat's weight that it makes essentially no difference. And the reduced space consumed by fewer batteries with the same usable capacity is nice, but again not game-changing.

On the down side is the cost, and the immaturity of charging technology that can lead to damaged batteries. As for fire hazard, my understanding is that it's Lion batteries that can be a fire hazard, not LiFePO4. It's important to distinguish when assessing the risks. Just because boats sink, doesn't mean cars sink, even though they are both means of transportation.

My house (as in solar off-grid dirt house) batteries are nearing the end of their life, and my loose plan is to build up a LiFePO4 battery system in parallel and as an intended replacement, and test it out before the existing bank craps out. Then, assuming success, I'll build a similar system for the boat as its batteries reach EOL 5 years or so from now. But this is probably like my cruising plans - highly subject to change.

 

[folivier]

Not to be condescending but if someone doesn't understand the difference between LiFePO4 and LiON they need to do a lot of research before considering lithium batteries. I had a 1000AH LiFePO4 system in my motorhome. And only installed it after tons of research. What I found out about the system is it is actually simple but requires a different mindset on charge/discharge profiles. I used an older Freedom inverter and after much experimenting found a charge profile that worked but I always shut it off after charging. There are newer inverter/chargers out there that are programmable to keep the float down below the resting voltage of LiFePO4's.
I sold the system to a friend who is enjoying the batteries. IMO if you do the requisite research they are an excellent system for a boater who anchors out.
And the LiFePO4 will not burn or explode. One of the 1000AH cells came in leaking electrolyte. So being curious I poured some on a concrete floor and used a small butane torch to try and ignite it. It smoked but did not burn. The recommended thing for leaks is to dilute with water. There is a video from Australia that shows someone directly shorting a LiFePO4 cell to see if it will catch fire or explode. It did neither but smoked quite a bit.

 

[MurrayM]

Thanks for the link, Al.

On the subject of hot water...

The system as described works for someone who pulls their anchor each morning and travels every day, but we like to spend more time in anchorages when there are lots of photo/hiking opportunities. We also don't turn on the electric heating elements in the calorifier, as it would be a major drain on the batteries.

Are there systems available to direct water heated in a calorifier when the engine is running, into a larger insulated water tank that will last significantly longer than the small amount held in the calorifier?

 

[tfmkevin]

Hi all,
I wrote the article in question, so I thought I'd pitch in with a few comments:

First, we understand lithium is well in the "early adopter" stage for boats. I'm an electrical engineer by training and we generally like trying out new technologies, so we decided to be the "canary in the mine" on lithium power. It may not be for you, or for you yet.

Regarding cost: Our 600Ah 12V LiFePO4 battery array cost $5,400 (which was list price) from AM Solar last spring. Since then, they have switched to Victron as their main line, which is more expensive (but apparently very robust.) This included a battery management system (BMS) that automatically prevents the batteries from over charging, over discharging, or failing to balance.

When considering cost, keep in mind that - at least in theory - lithium batteries have a much longer life than lead-acid or AGMs. Estimates are more than 10x the life (both in terms of number and depth of cycles and calendar life). So, where we usually would have to replace conventional batteries that are used heavily every few years, lithiums may just last the life of the boat. All of this is "claimed" so we shall see...

Regarding flammability:
As stated above - Lithium-ion Polymer (LiPo) batteries are flammable. They are the type used in hoverboards, exploding Samsungs, laptops, and Boeing 787s. These batteries are Lithium Iron Phosphate (also a type of Lithium-ion). They are NOT flammable. These have a slightly lower energy density than LiPo batteries, but the safety factor is worth it in a boating application.

Regarding hot water:
We didn't install the batteries so we could leave our water heater on 24/7, that was just a convenient side-effect. Our water heater does heat from engine heat, so we arrive at an anchorage with six gallons of hot water regardless. We could certainly replace the water heater with a better insulated one, and save a lot of cycling of the water heater during the day. It would not help if we have four people showering and a few rounds of dish washing, however.

If we want our power to last longer, we can (and do) turn off the water heater when we don't need it. We just found that our batteries were ending up at 100% after each day of cruising, and we didn't have to worry about conserving as long as we cruised each day.

As someone stated above, a big advantage of lithium is taking it easier on the generator. I'll look up the actual numbers, but I believe comparing this 5-month Alaska trip with the previous year's 4-month Alaska trip, we put about 1/3 the hours on the generator with the lithiums. And, the hours we did run it were under a steady, heavier load recharging the lithium batteries (rather than long runtimes at low-load doing the final 2 stages of recharging AGM batteries). Fewer cycles of the generator, fewer total hours, and running under steady-heavier loads is much better for generator life and maintenance.

Also, as we said in the article, if we were only staying one night, we never had to start the generator at all - or hook up to marina power. That's a nice convenience.

Our boat is a 34' Nordic Tug, and there is VERY little space in the engine room with a 5KW Onan generator in there. The factory house batteries are a total of 220Ah of AGM (2 Lifeline 220Ah 6V GPL-4CTs) This gives about 110 Ah usable (50% discharge max on AGMs). There is practically NO space for additional batteries, but we added a second location so we had double the house battery space, then put as much lithium in the doubled space as we could. That gave us the 600Ah we have now (which is also approx 600Ah usable, so we increased the boat's usable capacity by more than 4x).

Good things about lithium:
- MUCH longer life (10x claimed, but unproven to us - stay tuned)
- MUCH faster charging (full speed right up to "full" rather than 3 stage)
- Larger usable capacity in the same footprint (almost double)
- More efficient charge acceptance (good if you're using solar as a source)
- Lighter weight (1/3 the weight of conventional, but not a big deal in our application).

We'll report back how they work out long term. So far we've got a little over 5-months full-time on the boat with them and we love them.

 

[Capt.Bill11]

Power made easy, yes. But not cheap at $8,000 list price for their battery bank.


David

For $8000+ you sure could run that little genset for a long time.

Then there is the odd want to make hot water off the batteries.

They state that they run every other day went they are cruising or they have to run the genset to top off their battery bank.

"So – what if we don’t cruise 3.5-4.5 hours per day with some sunlight to boot? That’s when we need the generator or shore power. If we stay at anchor for more than one night, we need to run the generator to replace what we used each day."

Seems to me if they just heated their water from the engine and learned to use it sparingly, or installed a bit bigger heater, they could go a lot longer between battery charges. Plus the genset could be used to power the hot water heater.

It really seems like a huge up front expense for very little gain.

 

[MurrayM]

Welcome aboard, tfmk

 

[Heron]

All well and good, but:

"We calculated our daily usage while we were cruising around the San Juan Islands in the winter and spring. It looks like we use up to 450Ah of 12V electric in a typical day –"

Zoinks! These folks need to go on an energy diet.
I can go on the hook for 2 days, have hot water, keep the beer cold, run the entertainment, lights etc. for 120 AH/day...all on $500 worth of GC batteries...

 

[HiDHo]

Seems like solar hot water would be the way to go, small collector, circ pump and sun light when anchored.
But I'm with Capt Bill, our 5 kw generator sips fuel and gives us dock side convience when ever the engine heat loop is not in play.

 

[DavidM]

Here is my "ideal" electrical system for full time cruising where you pull the anchor every three days on average and motor for at least 4 hours to your next anchorage:


6 gallon (for a couple, 10 gallons for four) water heater plumbed to engine


600 Ahs of golf cart batteries


200-400 watts of solar- more for NE or PNW, less for Caribbean


High output propulsion engine driven alternator with Balmar regulator


Maybe a small NextGen 3.5KW genset, but maybe not. If you are willing to run the propulsion engine for a half hour to an hour every 2-3 days to heat water, you won't need a genset.


Or use a solar shower, or even a pot of water on the stove that you pour into the solar shower bag for a quick shower.


The water will stay hot for two days if you conserve HW. For the third day, run the propulsion engine for 1/2-1 hr. or the genset for an hour.


If you have a genset, then you also need a big charger, so go with a Magnum or similar 2,000 watt, 100 amp inverter/charger.


The battery bank will give you about 200 effective Ahs (50-85%) and should last three days if you have an efficient refrigerator like the Frigoboat keel cooled system. Such a system with LED lighting will consume about 75 Ah daily. So usually you would not have to run anything. But 200-400 watts of solar will pretty well balance that load on most days. And the batteries will be fully topped up during the cruising day, so they won't sulfate like they will if always left at 85%. The solar panels will also help with this.


Such a system will cost much less than a Lithium battery based system and will work just as well. Sure a 300 Ah Lithium system would be approximately equal to a 600 Ah flooded cell system in so far as useable capacity, but it will cost thousands more.


And as you can see, if you are willing to manage hot water with a solar shower, you don't need to run the propulsion engine or have any real need for a genset. Solar panels, a decent size FLA battery bank and an efficient fridge will make for an economical and eco friendly system.


David

 

[tfmkevin]

All well and good, but:

"We calculated our daily usage while we were cruising around the San Juan Islands in the winter and spring. It looks like we use up to 450Ah of 12V electric in a typical day –"

Zoinks! These folks need to go on an energy diet.
I can go on the hook for 2 days, have hot water, keep the beer cold, run the entertainment, lights etc. for 120 AH/day...all on $500 worth of GC batteries...

As we said, about half of that 450Ah is running the water heater full time (which is really just a convenience - nice to have hot water when you turn on the tap, and not be turning breakers on and off, running the generator for short runs at irregular times, etc.

If we take that out, we're at about 225Ah/day. The inverter has about a ~3A overhead, so if we just turn off the inverter most of the day we're down to 150Ah. Since we work full time while we're on the water, we are almost always running or charging laptops, running our WiFi router, etc. That's probably close to 100Ah, which gets us down to 50Ah per day. The rest is our refrigerator and deck-top freezer, which, since we're long-term cruising where there are frequently no stores, are hard to avoid. The tiny remainder is LED lighting which is almost ignorable.

A comment on the solar also. 200-400W of solar doesn't give you anywhere near 200-400W of actual usable output. Our 520W system (as we said) gives us 80-200Ah per day. Average maybe 120Ah? That uses every available square inch of space on the top of our boat.

Regarding solar showers, for our use (long-term cruising in SE Alaska), moving solar bags in and out of the cabin for every shower is just too much hassle. It's easy enough to start up the genset if you need to shower and don't have the available power.

 

[sunchaser]

I think tfm is having fun. Heck if we looked at every boating add on as having to be the cheapest alternative think about how many marine related companies would go out of business. Why have a boat if we can't pi$$ away some coin while actively engaging in our chosen hobby at the same time.

Being an electrical guy he enjoys the hunt. No different than many others are doing and posting about it on TF. Right now I am in the final design stages of adding an additional AP setup. Keep the old hiccupping AP 20 and add a Furuno 711. Silly investment, yes, but why not?

 

[choppywater]

Hi all,
- MUCH faster charging (full speed right up to "full" rather than 3 stage)

What type of regulator do you have on your alternator? Sorry if i missed it.

 

[tfmkevin]

What type of regulator do you have on your alternator? Sorry if i missed it.

Well, this is gonna blow my nerd credentials right out of the water but... I don't know what regulator we have.

(hangs head in shame as propeller beanie spins slowly to a halt)

It's the stock regulator that came with the boat new. Our engine is a Yanmar 6BY3 260 with a 150A alternator.

 

[tfmkevin]

One more note on the "cost" part of the equation...

4 Lifeline GPL-4CT 220Ah 6V AGM batteries (the max that fits in our limited space) would cost $315 each - so $1260 for a set. That would give us 220Ah usable at 50% discharge.

At 50% discharge, those batteries have about a 500 cycle life. It takes us about 2-3 years to spend 500 nights away from marinas (and therefore deep-cycling batteries), so we'd be replacing AGM batteries about every 2-3 years at $1260 a pop. In fact, the reason we were considering replacing batteries in the first place is our 3-year old AGMs were starting to show signs of wear.

That means that lithium batteries would need to last about 4x as long as AGMs to be similar total cost of ownership. And, we're getting 4x the usable storage capacity to boot. (If they really last 10x, awesome, but we're not holding our breath for the marketing claims)

The price of lithiums is bound to drop in the next few years, so this situation should improve further.

If your boat spends most of its time plugged into shore power, this argument doesn't hold, as AGMs will probably last a very long time as well.

 

[Heron]

If your boat spends most of its time plugged into shore power, this argument doesn't hold, as AGMs will probably last a very long time as well.

Or GC batteries at $100 each. Obviously this is pushing the envelope at a VERY high cost.

 

[MurrayM]

(hangs head in shame as propeller beanie spins slowly to a halt)

Good one

That goes in my quiver of stolen quotes, right beside "Well, slap my ass and call me Judy!"

 

[dhays]

I think tfm is having fun. Heck if we looked at every boating add on as having to be the cheapest alternative think about how many marine related companies would go out of business. Why have a boat if we can't pi$$ away some coin while actively engaging in our chosen hobby at the same time.

Being an electrical guy he enjoys the hunt. No different than many others are doing and posting about it on TF. Right now I am in the final design stages of adding an additional AP setup. Keep the old hiccupping AP 20 and add a Furuno 711. Silly investment, yes, but why not?

I agree. More power to Kevin. I look forward to seeing how these work out in the long term. I will need to change out my house bank at some point (original 6 year old sealed LA batteries right now) and wouldn't mind upgrading the performance in the same footprint if I can afford it. I am very happy to have other boaters experiment on the bleeding edge and pave the way for the rest of us.

 

[choppywater]

(hangs head in shame as propeller beanie spins slowly to a halt)

At this point my next house battery will be a LiFePO4, but who knows what i will settle on next year.

When i was doing research on early this year i was told that my 200 amp alternator that is under spun might not be a good idea and suggested a few 100 to 150 options. There was also a long talk about voltage regulators and how some do not act well to lithium batteries.

 

[Retriever]

I've spent a bunch of time buddy boating with Kevin and Laura, including several weeks in the Alaskan wilderness over the summer. No shore power for a hundred miles. As the owner of a similar boat with a conventional battery bank, I was pretty envious of their battery bank setup.

When they woke up in the morning, they had a full tank of hot water for showers. When I woke up, I started the generator, waited for 20 minutes, and then took a shower.

While I neurotically checked SOC to be sure I never dipped below 50%, they didn't worry, since LiFePO4 batteries aren't damaged by deep discharge.

As their batteries dwindled to 15% SOC, voltage was still above 13. When mine get to 50%, they're near 12 volts. With higher, more stable voltage, motors on the boat should be a lot happier.

I typically ran the generator for 30-60 minutes, both morning and evening. They barely ran their generator at all. Don't get me wrong—I'm not afraid of running the generator (it hardly burns any fuel and is whisper quiet)—but not having to even think about electrical usage is super nice.

Sure, there are lots of ways to cut electrical consumption. But when you're on the boat for five months, mostly in the wilderness, little comforts of home are awfully nice. Turning on the tap and getting hot water or being able to plug in whatever household gadget you want whenever you want makes cruising feel less like camping, which I sure appreciate!

 

[Toolbuddie]

Thanks AL for posting this up, Thanks Kevin for the explanation.
This is the most interesting thing I have read today. Some blaze trails, Some are glad they do!
I can go back to doing nothing now!
Dave.

 

[C lectric]

tfmkevin

KUDOS to you.



Thank you for the write up.

 

[BruceK]

Lithium batteries...
Not yet, not for me!
All I can think of is the Samsung Galaxy Note 7...Bruce

Well yes, but it could be more a Samsung issue than a LI one. I`m hearing even the replacement phones have similar problems.
Here we had numerous house fires from Samsung top load washing machines catching fire. It may not be simply an LI issue.

 

[Al]

tfmkevin- Wow!! So pleased that you have taken the time from your busy boating to contribute to the forum.It was my desire when I posted your blog.
I am so looking forward to meeting the two of you as I have with several of forum members {assuming your adding your name} on your next voyage North.
That we have passed in the night so's to speak, in different harbors during the past year and before not having done so.

Al-Ketchikan 27' Marben Pocket Cruiser

 

[folivier]

When I installed my LiFePO4 system a friend who was a retired CEO of a lithium mining operation preached to me the dangers of lithium. And there are truly dangers with raw lithium. But my system was proven safe before I installed it and remains so. Many, many differences between LION and LiFePO4. Just because they both contain lithium doesn't make them the same. Actually you have a better chance of burning up an alternator than you do with the cells.

 

[Trundlebug]

I'm amazed you only have a 6 gal hot water tank, if I've understood correctly.
No wonder you're constantly having to use supplementary heating. But it's at a cost, and it's inefficient, even if it works for you.

My boat originally had a 9 US gal hw tank, which ran out after 2 people had a shower. As you also found.
So, as I had the space in the engine room I installed an additional 12 gal tank in series with the original, so now we have a total of 21 gallons of hot water, all heated by the waste heat of the engines, and it's enough for 4 showers plus dish washing, plus a wash and shave the next morning without any problem.

Because the second tank is installed in series, it means it doesn't take any longer to heat up that first bit of hot water (eg washing up after getting going, hw is available in just a few minutes) but with more time it heats up the second tank after the first is hot, and we have both hw tanks fully hot after about 2-3 hours running.

Worth considering, as it's much more efficient, although I appreciate the space taken up is probably filled by your generator (which I've always tried to avoid fitting).