Batteries vs Generator?

Ironworker · Post by **Ironworker** » Mar 27th, '22, 18:08

First I know that my 31 is a day boat but I want the ability to overnight a couple of days in some measure of comfort. Which means limited cooking, a small freeze on the boat and a air conditioner!

I've weighed the benefits of a diesel generator vs going with a lithium battery bank and at this point I believe the lithium batteries is the way to go. Less weight, no noise and far less maintenance. I believe I can meet my energy needs at roughly half the cost of a generator.

Technology has certainly advanced but I'd like to ask your opinions as well before I launch in this endeavor.

MarkD · Post by **MarkD** » Mar 27th, '22, 18:36

Rick:

I see many people utilizing a small Honda portable on the few occasions they need to have the creature comforts. A lot less of an investment and one less thing to maintain and install. And, they are quiet.

Mark

Yannis · Post by **Yannis** » Mar 27th, '22, 23:03

I have a 28 equipped with 2 X 130 w solar panels and 4X100 Amp lead, car type batteries. Nothing lithium or expensive stuff.
I never use any shore power.
All electric needs are supported by the 3 X 100 Amp battery bank, where the 4th one is NOT connected to the solars and is a start up battery for the port engine, replenished by the port engine alternator.
Most of my electric consumption is for my 70lt plus 30 lt fridge and freezer, roughly 80-90%.

I have endless hot water by using an instant gas water heater and a 2 gas burner range for cooking.

I fail to see how I could run an A/C out of batteries...when I last did the math I came up with Amp shortages that would call for refrigerator cut backs which in our climate is a no no.

So, there you have it, perhaps the li-ion batteries are more powerful but I would like to see a proper calculation of Amp hours, also accounting for surge (starting) elect4ical consumption.

Yes, the little 1000 or 2000w gen could be a logical solution, I just fear the noise.
I installed two fans in the cabins ...they’re ok up until 30-35 C max, after that they just blow hot air!

The biggest heat producer in the cabin are the aluminum window frames. During the day they are simply untouchable. If I could insulate them somehow without it being too ugly, I could improve my comfort significantly.

Ironworker · Post by **Ironworker** » Mar 28th, '22, 08:49

Good thoughts. I had planned on the Honda Generator as a back up but I don't want to haul extra gas. I've seen too many boat fires in the GOM for that.

In regards to the AC, I'm considering one of the new 12V units. There is little to no room for solar panels and I don't think I'll need them. I have two large alternators on the new QSB 5.9s that I'm installing. I only need the AC overnight. The bugs are too bad in some of the anchorages I'll be visiting.

I do need a fair amount of power during the day from my house battery bank. Running a couple of big Kristal electric reels deep dropping eats up some power as does running a 3KW transducer and a bunch of electronics. With the Lithium, I can get 500Ah worth of top quality batteries for roughly 5 K plus another 1.5K for the associated equipment.

I will still use lead acid Group 31 batteries for my starting batteries.

Carl · Post by **Carl** » Mar 28th, '22, 09:25

Rick-

I do not have anything to add, but very curious and will follow this post.

You know it can be done as it has been done. It's just a matter of adding up the power needed to run for so long then finding the right storage capacity with some extra not to overtax the batteries.
I pushed mine to its limits trying to cook in a microwave for an extended time. I set it up for coffee pot, blender charge up my AC fridge when away for extended periods and a quick heat up in the microwave. We decided to make pasta on the hook on an overnight stay. Even with the motor running, I drained the deep cycle battery too low and it never recovered. The good news we had pasta that night and it was only a battery change to get back up to speed. But I learned the batteries take a long time to charge and discharge pretty quickly under a good continuous load. I should have pushed for the reheat...but when the wife wants pasta.

If you can get a good charge on the batteries then get cabin cooled down on your motors before switching over to batteries its not so bad time wise. Lucky too we sleep at night when the brutal sun is down.

Yannis · Post by **Yannis** » Mar 28th, '22, 09:44

I haul extra gas for the outboard so that is not an issue.

I’d like to know about these new 12v AC’s, btu’s and consumption.
What you’re describing is that you assume the motors will run every day. In my case, I want AC without running the motors at all for several days in a row.

Carl,
These boats are completely uninsulated, with everything closed, the candles still flicker...
The effort to cool the cabin with the engines will probably last 10 minutes...

Edit: I looked up Honda generator 1000w and they are rated 12v/8A, which may mean that the load in 12v devices can be no more than 100w approx. in which case they cannot sustain any 12v AC unit. They could if the AC was 240v or 120v. But then you need no batteries.

Amberjack · Post by **Amberjack** » Mar 28th, '22, 14:11

Carl wrote: ↑Mar 28th, '22, 09:25
I pushed mine to its limits trying to cook in a microwave for an extended time. I set it up for coffee pot, blender charge up my AC fridge when away for extended periods and a quick heat up in the microwave. We decided to make pasta on the hook on an overnight stay. Even with the motor running, I drained the deep cycle battery too low and it never recovered. The good news we had pasta that night and it was only a battery change to get back up to speed. But I learned the batteries take a long time to charge and discharge pretty quickly under a good continuous load. I should have pushed for the reheat...but when the wife wants pasta.

Air conditioning in the US Southeast I understand but cooking is easy to solve. We stay on the hook for 3 days at a time without issues. Morning coffee cooks on an Iwatani butane stove top which can do the job for pasta in the evening if needed. Evening protein cooks on a Magma propane grill which comes out of a deck locker and pops into the stern flag mount. After dinner my wife cleans up while I de-rig the grill which goes back into the deck locker. They also make mounts that work with fish rod holders. So, no big issues with cooking.

There are aggressive mosquitos up here and up in Walsh Cove they're huge--I think they evolved to live on moose or grizzly bears. A few years ago I rigged a screen for both aft cabin bulkhead windows and made a mosquito net for the forward hatch which allows us to leave the hatch up. We get us a nice breeze through the boat most nights. But we're not on the ICW with 95% humidity.

Carl · Post by **Carl** » Mar 28th, '22, 15:49

Doug-
I have the same Magma propane BBQ, mine fits into a pole holder and I have a set of legs for it should I bring it onshore. Works great and may have been able to boil water using that inner plate....that would be "IF" we brought a pot to hold the water. My wife expected to use the Tupperware in the microwave to boil the water, I thought that dinner was going to be done at a marina with shore power. It did work eventually...but not a way I'd advise doing it.

Yes, screens when we go to certain locations. Fire Island at Watch Hill is one very definite place to use screens, especially at certain hours...Its like the flies hear dinner bells and we are the dinner.

Amberjack · Post by **Amberjack** » Mar 28th, '22, 16:18

Bugs, that’s a whole new thread.

ktm_2000 · Post by **ktm_2000** » Mar 29th, '22, 12:17

a question to the folks considering Lithium, how do you charge them?

the reason for my question was that I asked my engine dealer if I could charge lithium batteries and he stated that some of his customers have had issues where it fried regulators and he's dealing with warranty issues and strongly suggested that I stay away.

I have not researched it heavily and purchased out lead-acid batteries for my starting and house loads.

Carl · Post by **Carl** » Mar 29th, '22, 12:47

ktm_2000 wrote: ↑Mar 29th, '22, 12:17 a question to the folks considering Lithium, how do you charge them?

Usually with my Visa card.

ktm_2000 · Post by **ktm_2000** » Mar 29th, '22, 13:01

good one - - I've been abusing mine lately

Ironworker · Post by **Ironworker** » Mar 29th, '22, 13:26

Based on my research it takes a smart charger specially designed for lithium batteries. Here is a resource page scroll down to find charging with alternators.

https://www.victronenergy.com/media/pg/ ... ality.html

ktm_2000 · Post by **ktm_2000** » Mar 29th, '22, 20:14

Rick,

So your thought is that you charge them up at the dock and not recharge underway?

Ironworker · Post by **Ironworker** » Mar 30th, '22, 06:06

Unfortunately, I made a couple of post that somehow didn't get on the forum. Likely on my end and I'll add the info back this evening after my outboard stringers are installed.

I'll be charging both the lithium (House) and the AGM starting batteries at the dock and underway My plan is to install an Invertor/Charger.

Ironworker · Post by **Ironworker** » Mar 30th, '22, 06:08

This is the AC unit I'm considering

https://mabrustore.com/collections/mari ... nditioning

Carl · Post by **Carl** » Mar 30th, '22, 09:18

I haven't researched it to any degree, but charging these batteries is a common practice. The Toyota Prius only charges its batteries when underway from both the lil gas motor and regeneration. I'm sure its like the AMG's you need to supply the juice the way the battery needs it supplied at whatever voltage and amount of time and I'm sure isolating them is important too.
I think the trick is to find what works best to meet the needs.

I was under the impression that DC power was not as efficient as AC.

Yannis · Post by **Yannis** » Mar 30th, '22, 12:50

The AC description doesn't say anything about 12volt operation.
Also, it doesn't say anything about watts.
Im curious to see how you will make it work and what amp consumption you estimate.
Thanx.

Ironworker · Post by **Ironworker** » Mar 30th, '22, 15:46

Yannis wrote: ↑Mar 30th, '22, 12:50 The AC description doesn't say anything about 12volt operation.
Also, it doesn't say anything about watts.
Im curious to see how you will make it work and what amp consumption you estimate.
Thanx.

Yannis,

Check out this page. They are all 12 volt. If I was starting from scratch with my electric reels, I'd wire my boat for 24V but I'm too heavily invested in 12 volt to turn around.

https://mabrustore.com/collections/mps-dc-units

Ironworker · Post by **Ironworker** » Mar 30th, '22, 15:50

Carl wrote: ↑Mar 30th, '22, 09:18 I haven't researched it to any degree, but charging these batteries is a common practice. The Toyota Prius only charges its batteries when underway from both the lil gas motor and regeneration. I'm sure its like the AMG's you need to supply the juice the way the battery needs it supplied at whatever voltage and amount of time and I'm sure isolating them is important too.
I think the trick is to find what works best to meet the needs.

I was under the impression that DC power was not as efficient as AC.

Carl,

The trick is charging two types of batteries at the same time. In my case it would be Lithium (house) and AGM (starting). My current plan is to use each alternator to charge both the respective starting battery and add to the house charge. Its also my understanding although I have not verified this that using Lithium batteries with a Cummins Engine is not approved.

Tony Meola · Post by **Tony Meola** » Mar 30th, '22, 21:49

Carl wrote: ↑Mar 28th, '22, 15:49 Doug-
I have the same Magma propane BBQ, mine fits into a pole holder and I have a set of legs for it should I bring it onshore. Works great and may have been able to boil water using that inner plate....that would be "IF" we brought a pot to hold the water. My wife expected to use the Tupperware in the microwave to boil the water, I thought that dinner was going to be done at a marina with shore power. It did work eventually...but not a way I'd advise doing it.

Yes, screens when we go to certain locations. Fire Island at Watch Hill is one very definite place to use screens, especially at certain hours...Its like the flies hear dinner bells and we are the dinner.

Carl

We have used a Coleman propane stove in the past, when staying offshore overnight. Made coffee and heated up Beef Stew. I am sure it would easily boil water and make pasta. Use to set it up on the deck. Not elegant but it works.

Carl · Post by **Carl** » Apr 1st, '22, 06:13

Ironworker wrote: ↑Mar 30th, '22, 15:50 Carl,

The trick is charging two types of batteries at the same time. In my case it would be Lithium (house) and AGM (starting). My current plan is to use each alternator to charge both the respective starting battery and add to the house charge. Its also my understanding although I have not verified this that using Lithium batteries with a Cummins Engine is not approved.

I don't think it's a trick but just finding out what works best for your application. We know Lithium batteries can be charged with AC chargers and we know we can use regular house batteries to run an inverter for AC, so that is one way to charge them. IS it the best way...I'd think every time you convert the juice you're losing some in the process making it less efficient. Then comes the game of how efficient can you make it and at what cost in terms of complexity, space, and cost. Also if it's only once in a while you going to be doing this overnight Air conditioning...do you really care if you burn an extra gallon or two of diesel to get the required charge.

Carl · Post by **Carl** » Apr 1st, '22, 06:29

Tony Meola wrote: ↑Mar 30th, '22, 21:49 Carl

We have used a Coleman propane stove in the past, when staying offshore overnight. Made coffee and heated up Beef Stew. I am sure it would easily boil water and make pasta. Use to set it up on the deck. Not elegant but it works.

Thanks Tony. With the magma grill I can take the grate off and there is a diffuser plate under which can be used to heat pans and pots. I use it for breakfast when on the hook overnight. Works well if there is no wind and if I had said pan or pot. We did not.

The inverter works fine for everything including the microwave to a point. The point was about 10 minutes on full power when the house battery cried help. Till that time we were making popcorn or heating up something for a couple minutes at most...not a problem for my single house battery. HAd I known this was what we were going to do I'd have brought a pot for the propane grill as microwaving water to a boil takes awhile with a relatively small microwave. Then the 10-15 minutes for pasta to cook, heat sauce etc. Had I known or if it was my intention to cook with the microwave I'd have doubled the house batteries and or gone bigger with batteries. That night was outside our normal needs. It worked though.

CamB25 · Post by **CamB25** » Apr 1st, '22, 07:01

10k BTU is roughly 3kwh. 3000 watt-hours. If 12 volts, that's a 250 amp-hour battery system, so 2 or 3 regular 100 amp-hour batteries for each hour of operation. I think it's going to take a large battery bank to power an AC for any length of time.

Carl · Post by **Carl** » Apr 1st, '22, 07:22

https://battlebornbatteries.com/run-rv- ... batteries/

Hmm DC AC units are more efficient...who knew.

...I was thinking of AC in terms of sleeping comfort, reducing the humidity and just cooling off the V-berth area with a curtain to contain cool air. 10K BTU was much more than I was thinking on a hook. I'm still sure it could be done, but that becomes how many batteries do you want to carry for once in a while, at what cost. Its weighing the options easy simple for some AC power, more complex and expensive for more. Generator, expensive upfront, but lots of power...noisy, upkeep and its only once in awhile.

CamB25 · Post by **CamB25** » Apr 1st, '22, 12:46

Marketing math. I'm not convinced there is a winning energy density trade off that points to battery-power AC over diesel generator. However, if you were looking for a silent way to recharge a battery bank while on the hook, consider a methanol fuel cell (https://www.my-efoy.com/en/efoy-fuell-cells/). They are basically silent and the fuel is stable. The downside is capacity...rated around 200 ah/day. Not enough for AC, but would be a clean, no noise, no maintenance on board charger.

I used one of these EFOYs in the design of an autonomous rail boxcar power system some years ago. Large battery bank to power the systems, solar cells as the primary recharging method, and the EFOY as a back up to the solar. Worked, and continues to work, very well. many units running around.

Amberjack · Post by **Amberjack** » Apr 1st, '22, 13:34

Carl, take a look at this butane stove top cooker to supplement your Magma grill. About $100 on Amazon for a top of the line stainless steel unit. Less expensive ones are $30-40. They all work the same.

We use ours for coffee in the morning and occasional other cooking but mostly the Magma grill in the evenings.

Half the college kids living in dorms have them in their rooms so if you're near a college town buy your fuel canisters there. $1.60 ea at H Mart in the U District near me, $6.50 at Fisheries Supply a mile away.

Carl · Post by **Carl** » Apr 1st, '22, 16:01

Thanks Doug— looks like what I used to use for table side Flambé when working as a waiter. I imagine they work well. I’m fine with what I have. I’m just describing the time I pushed it too far…that was 23 years ago. Damn….it almost seems like yesterday.

Anyway. I put my inverter system together for very basic AC power. Drip coffee pot, 2 cup unit that stays on the boat. Blender, nothing cooler than making a frozen drink on the hook at the beach. The occasional bag of popcorn, platter of pre-made hot wings when chilled with friends on a mooring. I also have a AC fridge….it can stay real cold for a few hours. Long days out offshore, trolling or at beach…start the motor, turn on inverter and let the fridge run to maintain a good chill.

Rick is looking for AC, I used my few times I wish I had to figure out a way. Reduced area to cool, precool with motors charging just before retiring to bed. I wouldn’t care about efficiency as it’s once in awhile.

Tooeez · Post by **Tooeez** » Apr 1st, '22, 16:53

You can run an a/c off of batteries, but it is marginal system and has to be set up just right. I wrote a long answer to a similar question a while back that listed all the trials and tribulations I went through to get it to work, but here's the short version:
I have a 2,000 watt Xantrex inverter and four group 31 lead acid deep cycle batteries. I have a 120v undercounter fridge and a 5200 btu a/c. The normal setup is two batteries, in parallel, on each engine. The inverter is connected to the port bank. I never shut the fridge off; before I leave the dock I switch to inverter, and it is never a problem. We used to do a lot of overnight trips in NY, and the two battery bank was good for at least 24 hours on the hook. I used to have a 1,000 watt microwave, which I used for popcorn and to heat soup and such. That took a lot of juice, so I would switch off the fridge when using the micro.
I had to tweak the a/c to get it to run on the inverter. The inverter couldn't handle the starting load, so I installed a soft-start unit. The water pump uses a lot of amps (almost 1/3 of the total load!), so I replaced it with a smaller pump. That brought the load down to 6.5-7 amps, which translates into about 70 amps dc.
I designed this system so that my wife could take a break from the heat while we fish. While the engine is running there is no problem. I have a selector switch that allows me to change how the batteries are connected together, so if we are drifting or anchored I put three batteries in parallel and we are good for 3-4 hours (with the fridge running also). I tried it overnight once, at the dock: I disconnected the shore power and ran on three batteries. It lasted 6 hours before the inverter gave a low voltage alarm. If I had put all four batteries together I probably would have gotten about 8 hours, but also probably couldn't have started the engines.
Bottom line: it works, but I wouldn't do it again.

Amberjack · Post by **Amberjack** » Apr 2nd, '22, 14:22

Interesting how we configure our boats differently. When we set up Amberjack it was a priority to be able to stay on the hook for up to three days without running the engines or generator. Which is no issue for power, we just start to run out of food. We could add a freezer but that would require a generator, etc so heck with it. In another life I'd put in a freezer and rig with permanent solar panels on a hard top bimini. Then I'd have to figure out additional water and holding tank capacity. Aww, the heck with it.

East coasters rig for longer fishing trips and Southeasters need A/C if they want it to be enjoyable instead of an ordeal. That's probably generator territory until fuel cells or batteries improve. Its fun to think about installing that technology on our 50 year old boats. Says something about the enduring qualities of a Bertram 31.

Tony Meola · Post by **Tony Meola** » Apr 2nd, '22, 22:06

Plan your food right, a couple of coolers and dry ice and you can keep food easily for a week layover.

Ironworker · Post by **Ironworker** » Apr 3rd, '22, 06:21

Food is not my issue. I want to keep an ample supply of bait frozen.

Tony Meola · Post by **Tony Meola** » Apr 3rd, '22, 21:57

Rick

We always used Dry Ice. Might not last a week but you can get at least 4 days out of it. Running a freezer for a week on our boats without dockside power would require a generator, no way around it.

Carl · Post by **Carl** » Apr 4th, '22, 09:50

Tony Meola wrote: ↑Apr 2nd, '22, 22:06 Plan your food right, a couple of coolers and dry ice and you can keep food easily for a week layover.

We do a week at fire island, two coolers, one for drinks, the other for food. We deep freeze what we can before going, use block ice and have used dry ice. By weeks end the frozen stuff isn't quite frozen, but quite cold.
The drinks...well that chest gets opened alot needing fresh beverages and ice after a few days. We try to chill beverages in the fridge prior to moving to the drink chest. Keeping out of the sun also helps.

Amberjack · Post by **Amberjack** » Apr 4th, '22, 13:37

Tony Meola wrote: ↑Apr 2nd, '22, 22:06 Plan your food right, a couple of coolers and dry ice and you can keep food easily for a week layover.

We start with a week supply of food and pack it in dry ice in Seattle where its available. Then Reid Harbor 60 miles, Ganges 20 miles, Pender Harbor 60 miles, Cortes Bay 40 miles and finally Octopus Islands or Walsh Cove another 40 miles. So, five days travel if pushing along but not killing ourselves. Food resupply options diminish the further north we go so we pick up some where we can but by the time we drop the hook we may have 3 days of decent meals left. One trip we made the decision to stay the extra day even though we knew we'd be eating tuna and crackers for dinner the last day.

Two years ago we pushed further north to Blind Channel Marina and wound up living on frozen marina chicken, frozen steaks, C$10/loaf bread and C$50 box wine. I've had better protein but the bread was great and the wine was OK. Surprisingly as we get further north grocery stores are less available but the marinas have excellent solid block ice, not the crushed, reformed stuff we get in Seattle and the romaine at the marina dock in Pender Harbor was wonderful! Big, clean heads that hadn't been soaked on the grocery store produce shelf.

Yannis · Post by **Yannis** » Apr 6th, '22, 08:00

Rick,

Have you looked into the Eurom 2401 caravan AC?
2400 btu, 700watt, no through hulls, I still doubt it can be run from a battery but its the smallest I can find.
And I prefer the no through hull, no water cooled approach.

Ironworker · Post by **Ironworker** » Apr 6th, '22, 10:20

Yannis wrote: ↑Apr 6th, '22, 08:00 Rick,

Have you looked into the Eurom 2401 caravan AC?
2400 btu, 700watt, no through hulls, I still doubt it can be run from a battery but its the smallest I can find.
And I prefer the no through hull, no water cooled approach.

I haven't but will check it out.

Regarding dry ice, its unavailable in the Family Islands as far as I can tell.

Tony Meola · Post by **Tony Meola** » Apr 8th, '22, 22:03

Yannis

A 2400 BTU AC unit probably would leave the cabin on a 31 cooking in our southern sun. In fact, in the summer, even up here in NJ I would do better waiting for a breeze.

Yannis · Post by **Yannis** » Apr 8th, '22, 22:53

Tony,

They put them in caravans the volume of which is way more significant than the 31 cabin.
I don't know, we probably should read comments from owners travelling in the south to get an idea of their efficiency.
I wouldn't expect to freeze like an AC in a supermarket or office, rather, expect it to bring the temp down enough to bearable range, to be able to sleep without sweating.

Ironworker · Post by **Ironworker** » Apr 9th, '22, 07:29

In regards to AC, I'm looking for a temperature in the mid 70's with a little de-humidification. Its mostly to allow us to put up the enclosures to keep the bugs out at night.

Tooeez · Post by **Tooeez** » Apr 18th, '22, 16:08

2400 btu is too small. My 5200 cannot keep up with the Florida sun in the summer--I keep it set at 85 degrees, and it struggles at that. But--it does de-humidify the cabin, and that keeps the mold away and makes the cabin feel cool and comfortable, regardless of what the thermostat says. At night it will drop the temp to the mid-seventies with no problem.