Lead acid or agm/gel

[Culwatty]

Originally Posted by Reefmagnet

Diesels produce less CO and there's less chance of either an internal exhaust leak or venturi effect filling the cabin with fumes.


If you're using HF get some technical info on the grounding and shielding recommendations for your unit from it's manufacturer. HF (and AC for that matter) can cause problems if there are grounding issues. Some AC inverter TIG machines don't actually use HF in the traditional sense so are relative safe, but forewarned is forearmed!

Ahhh, well I may have stumbled across another idea yet, measurements pending I may be able to run a generator head from my inboard engine, simple clutch and pully setup given the 34hp, most 10kva diesel gens are 10hp ish so I might be able to run a reduction to get the speed!

Yes I will ask the questions, I'm wondering if an "inverter generator" would be better cleaner source....

Also found some people selling alternator driven power sources that can have welding "boxes" attached so there must be a way to make it work. But if I go that way will start a new dedicated thread!

Thank you for all the help so far everyone! I'm getting quite excited

[Culwatty]

Originally Posted by Adelie

Life cycles for regular discharge to 50%:
AGM: 500-700
FLA: 750 or so
Gel: 1200ish
Carbon Foam: 3500
All these are variations of lead acid batteries. Charging from 50% will take 6-8hr regardless of Charing capacity, trying to cram energy back in faster will cost you life cycles.
Fastest charging system will be to run a generator for an hour or so when the battery will accept a lot of current then just solar as charge rate tapers off and solar can handle it all.

Gels are finicky about charging.
AGM really need to be fully recharged regularly, at least 5 times per week. To do that you need a moderate amount of solar change for most of the time. To achieve the fast charging rates you need a really heavy duty charger, $$$$, and it will only shave 30min or so off of charging time.

Since money is an issue, I would go with the FLAs. You can replace them anywhere in the world. If you get golf cart batteries from a name brand you know you e gotten a really deep cycle and not a hybrid battery or worse, mis-labelled starter battery.

If money were less of an issue, I wasn’t going very far and I really didn’t want the hassle of maintenance the I’d get Gel.

Best bang for the buck is probably carbon foam but with big up front costs. If I was going to go electric propulsion I’d get Carbon foam despite the big up front costs.

The only thing I would consider using AGMs for would be the electric motor on the dinghy. Several small batteries easy to load and unload individually, tolerant of jostling and working on their sides if knocked over.

I wouldn’t want LiFePo yet, to much extra electronics in the BMS to go wrong in the marine environment.

As it happens I’m in the middle of adding another FLA golf cart battery to my boat. I got it mounted and ties down today. Next I need to wire it.

This is my main concern, getting to the batteries is going to be an absolute arse, probably involving long pipes mirrors and yoga to top them up. There is a £20 difference a battery to go agm and I am only still considering agm due to the location of the bank (although considering that they are t105 I may still get better bang for my buck in a different size)

I'm going to crawl around under the deck and see if there is anywhere else I can store them with decent space for access, I can see an acid dipped pipe flicking acid at me if I end up where they are now..... rather not!

I'm seeing the logic to fla, just trying to make it safe!

Originally Posted by Dockhead

I will second the suggestion about golf cart batteries. I think that's the sweet spot for lead batteries in terms of cost versus life. They are tough and should last 1000 cycles if you take care of them (don't discharge below 50%, top them off to 100% at least every few days, equalize). In my opinion the only good case for VRLA batts (gel, AGM) is when you don't have accessible storage for your battery bank so need them to be maintenance free. I had AGM's on my last boat for this reason.


I will also second the strong advice against a petrol/gasoline generator in a locker. Some rules about petrol/gasoline on board:


1. CO kills. A lot of boaters every year. How will you get the exhaust reliably out and away from the boat?


2. Petrol/gasoline vapours are heavier than air, collect in bilge, creating a fuel-air bomb. Some boaters are killed every year due to explosion of petrol/gasoline vapours. Therefore, you must EITHER (a) separate an enclosed petrol/gasoline generator from the main hull volume and make sure the enclosure drains directly overboard so that vapours can escape; OR (b) follow the full bilge blowing and purging protocols like a boat with petrol/gasoline propulsion.




The only really good way to generate electricity using petrol/gasoline on board is to put a suitcase generator in the dinghy, or possibly on a swim platform from where exhaust can't blow into the cabin, and even then -- keep your CO detector alarms up to date.


Diesel generator and/or solar is a much better way to do it.

Yep! I have defined decided diesel generator is the way forward. Am looking at options

My plan was to do just so with the enclosed space, but even then I think its a risk not worth taking...

Originally Posted by Dockhead

With those kind of power needs, you need a proper diesel generator.


You can run a compressor off a generator; there are different tricks to make it work better. For example use a charger/inverter with power boost.


Proper marine diesel generator is costly, but as with so many things it is costly because it's worth it. They are very safe because diesel exhaust contains almost no CO, and exhaust is routed out the transom where it is hard to blow back into the hull volume. They are much longer lasting and more reliable than petrol/gasoline generators provided you avoid light duty ones like Fisher-Panda, Paguro, etc. They are cheaper to run. You can install them inside the hull volume without any special precautions -- leaked diesel fuel is not nearly as dangerous as leaked petrol.

Yes I see all of the pros and cons thank you guys!

So my only unanswered question, gassing from batteries and the vents. How can I stop it eating the boat?

[ranger58sb]

Originally Posted by Adelie

Life cycles for regular discharge to 50%:
AGM: 500-700
FLA: 750 or so
Gel: 1200ish
Carbon Foam: 3500

There are AGMs, and then there are AGMs...

Lifeline AGM specs say 1000 cycles to 50% DOD.

See here, Expected Life Cycles, p40:

https://lifelinebatteries.com/wp-con...al-5-06-19.pdf

Odyssey expresses their expected life cycles slightly differently, or at least they used to. Something like 600 cycles to 80% DoD, IIRC...

-Chris

[Dockhead]

Originally Posted by GrowleyMonster

THIS. Except in the UK they might not be so cheap. If you buy them in the US from a golf cart shop or from Sams Club they are crazy cheap. 6v 215 or 220 AH for around $90 sometimes less. These are very rugged batteries and I used a set for 7 years for electric propulsion with long periods of absolute total neglect due to being away on ships. If I had been home to babysit them, they would have gone 8 or 9 years, I am thinking. So do the math. One pair of these gives you 12v at 215ah for $180 or so. Maybe less. Want 1000ah at 12v? Ten of them will cost under $1k even with core charge. They are a nice handy size to move around, unlike 8D's. BTW I ran them waaaaaay down and it didn't seem to hurt them, not counting deliberate discharge several times to 0 SOC in order to perform a capacity test. True deep cycle batteries you c an do that. "multi-purpose" or "marine" batteries, well, I wouldn't. Sure, LiFePO4 batteries can do all that and more, but they aren't cheap. Multipurpose batteries vs LiFePO4? if you have a good BMS that you don't mind risking your life to, the lithium are probably the better choice. So thay say, anyway. Gel? Meh. AGM? You pay a lot more for not much more performance. The thing with Golf Cart batteries is in most of the world they are expensive. In the US, they can be pretty cheap.

They're more expensive than in the U.S., mostly because of 20% VAT.


Trojan T105's (my choice of golf cart batts -- more expensive but definitely better quality) cost about £140 each (https://www.tayna.co.uk/industrial-b.../trojan/t-105/). That's actually about the same as they cost in the U.S. if you add the VAT. 8 of them for £1120.



LiFePo4 will be cheaper per cycle used and will work much better. But you have to invest into reconfiguring your electrical system and adding control systems. I would have gone that way but with a long list of boat jobs and uncertainty due to the pandemic, I chickened out and went with Trojans.

[Dockhead]

Originally Posted by ranger42c

There are AGMs, and then there are AGMs...

Lifeline AGM specs say 1000 cycles to 50% DOD.

See here, Expected Life Cycles, p40:

https://lifelinebatteries.com/wp-con...al-5-06-19.pdf

Odyssey expresses their expected life cycles slightly differently, or at least they used to. Something like 600 cycles to 80% DoD, IIRC...

-Chris

Trojan claim 1200 cycles @ 50% DOD for the T105's.


But lab cycle life and real life cycle life are very different things in my experience.



I was using 27TMX's before, which Trojan claims will last for 600 cycles @ 50%. I was getting maybe half that in real life, even though I take pretty good care of my batteries.

[ranger58sb]

Originally Posted by Dockhead

But lab cycle life and real life cycle life are very different things in my experience.

Yep.

But it's the only apples-to-apples metric that I know of for comparing initial specs. Aside from weight, I guess... which would be pretty crude.

-Chris

[Reefmagnet]

Originally Posted by Culwatty

Ahhh, well I may have stumbled across another idea yet, measurements pending I may be able to run a generator head from my inboard engine, simple clutch and pully setup given the 34hp, most 10kva diesel gens are 10hp ish so I might be able to run a reduction to get the speed!

Yes I will ask the questions, I'm wondering if an "inverter generator" would be better cleaner source....

Also found some people selling alternator driven power sources that can have welding "boxes" attached so there must be a way to make it work. But if I go that way will start a new dedicated thread!

Thank you for all the help so far everyone! I'm getting quite excited

A decent 10kva alternator would require, at a wild guess, around 20 hp. The two things that upset alternators when driving loads are starting surge and power factor that's why a 10kVA alternator will - in theory - run a 10kW resistance heater but can struggle to start a 3kW motor. Some alternators will supply short bursts of up to three times their rated output (to provide motor start capability), but the instantaneous power required from the engine will be proportionally higher for that period.


There's a lot of variation between a cheap and a decent alternator with the same rating. An honest salesman will tell you whether any particular unit will meet your requirements but sometimes you just need to ask for a demo and plug whatever it is you want to run into it to see for yourself.



It's possible that a welding alternator or generator could be driven from the engine. Years ago Lincoln made a 250A DC generator designed to run off PTOs, but if driven directly by an engine it required at least 30Hp (from memory).

[Dockhead]

Originally Posted by Culwatty

. . . So my only unanswered question, gassing from batteries and the vents. How can I stop it eating the boat?

Batteries belong in battery boxes. Vent them. They will keep any spilled or spattered acid from eating your boat or anything else. Hydro caps will cut down on the gases and acid spatters, if you're really concerned.

[Dockhead]

Originally Posted by Culwatty

Ahhh, well I may have stumbled across another idea yet, measurements pending I may be able to run a generator head from my inboard engine, simple clutch and pully setup given the 34hp, most 10kva diesel gens are 10hp ish so I might be able to run a reduction to get the speed!

Yes I will ask the questions, I'm wondering if an "inverter generator" would be better cleaner source....

Also found some people selling alternator driven power sources that can have welding "boxes" attached so there must be a way to make it work. But if I go that way will start a new dedicated thread!

Thank you for all the help so far everyone! I'm getting quite excited

Yes, yes, all of that can work.

And here's yet one more for you --

Since you are carrying a shop with you, I presume you are handy and probably even have reasonable engineering skills.

Why not build your own generator?

A couple of guys on here did that with very good results; search the archives.

They basically took a small Kubota industrial engine, welded up a frame, with belt drive to various devices like air compressors, dive compressors, fridge compressors, and generator heads of whatever type you need. I don't know how much power you need, but if it's within 5kW, you can do this without AC synch problems by using a jumbo alternator (like a HumVee alternator) and a big inverter.



Direct drive compressor will be much more efficient than electric.


If you have the skills and the time, you will save a ton of money and might have some fun. And we'll have fun following your build.

[jimdelane]

FLA vs VRLA vs Lithium is the question

With batteries, you get what you pay for. The cheaper the battery, the worse the performance and the quicker they die. With lead acid (flooded, AGM, Gel, Carbon) they should not be discharged below 50% (12.12v) if you want to get a good service life out of them. Lithiums can be discharged to 80+% without issue. If you are buying lead acid, spend the money on quality brands like Lifeline or Trojan. They cost more for a reason.

6 volt flooded lead acid deep cycle batteries are your best inexpensive battery. The worst 6v golf cart battery is better than the best 12v deep cycle. They require maintenance and are heavy. They need to be maintained which means water, full charging and periodic equalization to last.

Valve regulated lead acid - AGM, Gel and Carbon are nice because they are maintenance free. They suffer from sulfation and should be fully charged daily if possible to burn of sulfation. If a battery sits in a partially charged state long enough, the sulfation will harden into crystals which permanently reduces battery capacity. Most VRLA manufacturers do not recommend equalization because it causes the electrolyte to boil and gas will vent through the valve which will dry out the battery. Not being able to equalize results in shorter life and 20% less capacity than a same flooded battery. The carbon batteries provide better resistance to sulfation but sulfation is a fact of life with lead acid batteries.

Lithiums do not suffer from sulfation but have their own issues. They have a BMS (battery management system) which limits to amp discharge. The smaller batteries commonly are 100 amps. The advantages are longer life (3000-5000 cycles or 4 to 10 times lead acid), higher constant voltage, higher nominal voltage (12.8 vs 12), significantly faster charging, lighter weight (1/2+ of lead acid) and twice the discharge capacity (up to 100%). Lithiums have dropped in price to the point where based on usable watt hours they are not much more expensive that quality lead batteries with significantly higher constant voltage (always 12.8+ and life span)

The biggest issue I see with your set up is you want to go with induction cooking. With what you are proposing for power, it will not work. Large amp draws like hot water heaters and induction cooktops suck so much energy that your batteries will never recover.
Remember that you can only use 50% of the rated amp hours. Also the rated amp hours are based on a 20 hour discharge rate. for a 100Ah battery, that means if you use 5 amps for hour, you have 10 hours (50 amps) before you have only 12.12v and need to stop. Your voltage drops as energy is used. The amp hour rating of the battery drops with higher amp usage. Watts is the true definition of energy. watts = amps x voltage. So if your induction stovetop is 1800 watts = 120v x 15A or 12v x 150A.

Do your math and good luck.

[Adelie]

Originally Posted by ranger42c

There are AGMs, and then there are AGMs...



Lifeline AGM specs say 1000 cycles to 50% DOD.



See here, Expected Life Cycles, p40:



https://lifelinebatteries.com/wp-con...al-5-06-19.pdf



Odyssey expresses their expected life cycles slightly differently, or at least they used to. Something like 600 cycles to 80% DoD, IIRC...



-Chris

I believe that 1000cycles is dependant on 100% recharge EVERY day.

[Dockhead]

Originally Posted by jimdelane

FLA vs VRLA vs Lithium is the question

With batteries, you get what you pay for. The cheaper the battery, the worse the performance and the quicker they die. With lead acid (flooded, AGM, Gel, Carbon) they should not be discharged below 50% (12.12v) if you want to get a good service life out of them. Lithiums can be discharged to 80+% without issue. If you are buying lead acid, spend the money on quality brands like Lifeline or Trojan. They cost more for a reason.

6 volt flooded lead acid deep cycle batteries are your best inexpensive battery. The worst 6v golf cart battery is better than the best 12v deep cycle. They require maintenance and are heavy. They need to be maintained which means water, full charging and periodic equalization to last.

Valve regulated lead acid - AGM, Gel and Carbon are nice because they are maintenance free. They suffer from sulfation and should be fully charged daily if possible to burn of sulfation. If a battery sits in a partially charged state long enough, the sulfation will harden into crystals which permanently reduces battery capacity. Most VRLA manufacturers do not recommend equalization because it causes the electrolyte to boil and gas will vent through the valve which will dry out the battery. Not being able to equalize results in shorter life and 20% less capacity than a same flooded battery. The carbon batteries provide better resistance to sulfation but sulfation is a fact of life with lead acid batteries.

Lithiums do not suffer from sulfation but have their own issues. They have a BMS (battery management system) which limits to amp discharge. The smaller batteries commonly are 100 amps. The advantages are longer life (3000-5000 cycles or 4 to 10 times lead acid), higher constant voltage, higher nominal voltage (12.8 vs 12), significantly faster charging, lighter weight (1/2+ of lead acid) and twice the discharge capacity (up to 100%). Lithiums have dropped in price to the point where based on usable watt hours they are not much more expensive that quality lead batteries with significantly higher constant voltage (always 12.8+ and life span)

The biggest issue I see with your set up is you want to go with induction cooking. With what you are proposing for power, it will not work. Large amp draws like hot water heaters and induction cooktops suck so much energy that your batteries will never recover.
Remember that you can only use 50% of the rated amp hours. Also the rated amp hours are based on a 20 hour discharge rate. for a 100Ah battery, that means if you use 5 amps for hour, you have 10 hours (50 amps) before you have only 12.12v and need to stop. Your voltage drops as energy is used. The amp hour rating of the battery drops with higher amp usage. Watts is the true definition of energy. watts = amps x voltage. So if your induction stovetop is 1800 watts = 120v x 15A or 12v x 150A.

Do your math and good luck.

These are good comments, but just one word about induction --


I cook almost exclusively with induction on board these days, and it doesn't murder my batteries. 2000 watts for brief periods off the inverter, then 800 watts for normal cooking, generally cycled on and off. 2000 watts is about 80 amps at 25v, so about on the 5 hour discharge curve for a 450 x 24v bank. Where the bank capacity is less due to Mr. Peukert, but not drastically so. Works fine.


I try to cook with gas when sailing without the engine running, or at anchor, but induction is so fantastic that sometimes I can't avoid the temptation.

[Dockhead]

Originally Posted by Adelie

I believe that 1000cycles is dependant on 100% recharge EVERY day.

I think you're right -- lab cycle life and real life cruiser cycle life are two QUITE different things!


Over the years I observe that I get no more than half of the rated cycle life in real life usable, maybe as little as 1/3.

[Cheechako]

"With batteries, you get what you pay for. The cheaper the battery, the worse the performance and the quicker they die. With lead acid (flooded, AGM, Gel, Carbon) they should not be discharged below 50% (12.12v) if you want to get a good service life out of them. "

Real life just hasn't proven that out for me. I've always been an engine charging/12V gen type of guy mostly. Lots of reasons and I'm not saying in today's world that is the best way.
But heck, 12.12V would be a luxury for me. Every a.m. In warm climes I would be in the 11.5V range or so. The batteries still seem to last 5 years anyway.

[Adelie]

Originally Posted by jimdelane

FLA vs VRLA vs Lithium is the question



With batteries, you get what you pay for. The cheaper the battery, the worse the performance and the quicker they die. With lead acid (flooded, AGM, Gel, Carbon) they should not be discharged below 50% (12.12v) if you want to get a good service life out of them. Lithiums can be discharged to 80+% without issue. If you are buying lead acid, spend the money on quality brands like Lifeline or Trojan. They cost more for a reason.



6 volt flooded lead acid deep cycle batteries are your best inexpensive battery. The worst 6v golf cart battery is better than the best 12v deep cycle. They require maintenance and are heavy. They need to be maintained which means water, full charging and periodic equalization to last.



Valve regulated lead acid - AGM, Gel and Carbon are nice because they are maintenance free. They suffer from sulfation and should be fully charged daily if possible to burn of sulfation. If a battery sits in a partially charged state long enough, the sulfation will harden into crystals which permanently reduces battery capacity. Most VRLA manufacturers do not recommend equalization because it causes the electrolyte to boil and gas will vent through the valve which will dry out the battery. Not being able to equalize results in shorter life and 20% less capacity than a same flooded battery. The carbon batteries provide better resistance to sulfation but sulfation is a fact of life with lead acid batteries.



Lithiums do not suffer from sulfation but have their own issues. They have a BMS (battery management system) which limits to amp discharge. The smaller batteries commonly are 100 amps. The advantages are longer life (3000-5000 cycles or 4 to 10 times lead acid), higher constant voltage, higher nominal voltage (12.8 vs 12), significantly faster charging, lighter weight (1/2+ of lead acid) and twice the discharge capacity (up to 100%). Lithiums have dropped in price to the point where based on usable watt hours they are not much more expensive that quality lead batteries with significantly higher constant voltage (always 12.8+ and life span)



The biggest issue I see with your set up is you want to go with induction cooking. With what you are proposing for power, it will not work. Large amp draws like hot water heaters and induction cooktops suck so much energy that your batteries will never recover.

Remember that you can only use 50% of the rated amp hours. Also the rated amp hours are based on a 20 hour discharge rate. for a 100Ah battery, that means if you use 5 amps for hour, you have 10 hours (50 amps) before you have only 12.12v and need to stop. Your voltage drops as energy is used. The amp hour rating of the battery drops with higher amp usage. Watts is the true definition of energy. watts = amps x voltage. So if your induction stovetop is 1800 watts = 120v x 15A or 12v x 150A.



Do your math and good luck.

Carbon can be drawn down to 80%DoD and still have 2000ish cycles. That said it’s new enough that there are other issues affecting life that haven’t been definitively worked out. Same as with LiFePo.

Induction cooking is perfectly reasonable to do off of a lead acid battery bank with a couple of provisos.
A. For most cooking you are going to 50-75 amp-hr/day cooking 3 meals. If you are a gourmet cook probably more. This means you need an extra battery (2 if you are using 6v batteries). In order to determine how much energy was involved I bought an induction hob and cooked several meals while measuring energy use.
B. Most induction cookers really prefer a real sine wave so you need to spring for a pure sine wave inverter, a modified sine wave or a square wave won’t cut it. For 2000+W draw you probably need a 3kW inverter.
C. Induction cooking can be a very high draw, 150+amp @ 12v for a full 1800w. This means the inverter should draw from as many batteries as possible to minimise the amp draw on individual batteries. To that end I would have at least 450amp-hr in the bank feeding the induction cooker, better would be to have all the house batteries in one bank.
D. If you are going induction a small convection oven is the next apparent step. Most seem to be 800-1200W so as long as you don’t try running the oven and both burners on high at the same time a 3kW inverter will still probably work fine.
E. There are additional things you can do like using a pot with stainer lid rather than a pot with a strainer insert, this decreases the amount of water needing to be heated for things like noodles. Also saves on wash water since there’s less to clean. You can use pot cozzies while cooking since the burners don’t actually get hot, only the pots and not nearly as hot as a regular burner.