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Old 11-05-2020, 11:50   #31
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Re: Lead acid or agm/gel

Around here you can get a good 6v golf cart battery for around $170....
4 of them will set you back about $725 with tax....You'll have 440 amp hours...and based on my own personal experience, get a good 5 years out of them. Engine battery is typically a stand alone 12v bat and these can run from $150 to waaay more, but no fancy charging system required.

For an old geezer like me, I find a single 6v battery to be way more manageable than a behemoth 12v bat being about half the weight.

Its a more or less $1000 investment when you are done. Coupled with a good solar array and windcharger you will likely get more years...so you have to factor in several hundred more dollars for those goodies.

Avoiding discharging below 50% is key to any good battery maintenance.

Keeping your beer cold is not cheap !!
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Old 11-05-2020, 11:58   #32
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Re: Lead acid or agm/gel

I like Gel batteries. For the price difference though, I'd go with lead acid. I can't say for sure there's a ton of difference in life. However, gel do seem to keep on going, I've not owned one more than 4 years though. (not a failure)
Lead acid seem to last 5-6 years with minimal care. (unless they sit unused forever) My failures with lead acid were always; lack of use, or a dead short early in life. Cant say I remember one flat "worn out" from cycles.
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Old 11-05-2020, 12:13   #33
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Re: Lead acid or agm/gel

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Originally Posted by Bill O View Post
Would look at 6V golf cart batteries for the house instead of dual purpose

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.
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Old 11-05-2020, 12:33   #34
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Re: Lead acid or agm/gel

First of all, I think you need to complete that electrical survey/audit of your needs - and keep your finger hovering over that buy button for the thruster ! You don't mention refrigeration/freezer at all - do you have any? I use approx 110Ah daily on those. What's your engine/alternator charge capacity? I run a 110Amp Balmar - detuned for longevity - and an external regulator that allows me to charge effectively when I move with the engine. How much do you plan on moving? 375 watts of solar with a PWM keeps me charged ( at 50deg N lat) most of the time otherwise with a 420Ah FLA battery bank. We're coastal cruisers and not liveaboards. I'm sticking with the FLA's because they're easily accessible to service every 3-4 weeks, and are cost effective for me. Your space requirements/inaccessibilty may rule otherwise. But definitely replace the all-purpose with dedicated deep cycle batteries whatever chemistry you choose.
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Old 11-05-2020, 12:46   #35
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Re: Lead acid or agm/gel

This is the way I see it...

Back in the day, you had to use a little handle to wind your car window up and down....
Nowadays, you push a little tab and an electric motor does the work for you, if you don't have water in it or the battery dies.

Both methods move the window up and down...but my preference is to use the handle. I understand the handle. I know how to fix the handle and if the battery ever dies or a little electric motor quits working, I can still raise and lower the window with a handle.

Today's boats are like today's cars...electric everything. I think a lot of electronics is nothing more than sales gimmicks to get you to buy the car.
Like buying a super duper brand "x" golf ball with the illusion that it will improve your golf game.

I want to be able to fix my stuff when I'm in the middle of nowhere.

I feely admit I'm an old geezer, but I like it that way. I know how to fix stuff that breaks or quits working.

When it comes to batteries...I'm a firm believer in the KISS theory. Try to find your super duper gel, extra special brand "x" lithium battery with triple overhead cams in some outpost island or town. You are gonna hear " say what again.....??"
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Old 12-05-2020, 00:13   #36
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Re: Lead acid or agm/gel

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Originally Posted by Pete7 View Post
I think these two items are your problem. There is a reason for gas on smaller yachts. Its cheap and available the world over, just needs sensible precautions.

The generator inside a locker, hmm I think you should re-think that one.

https://www.bbc.co.uk/news/uk-england-cumbria-34637493

It you cook on gas and heat with diesel, you don't need the big generator and everything becomes so much simpler. After all, why run a petrol generator to enable induction cooking, why not just use gas?

Pete

May I elaborate and stress what Pete and the others are saying about a gasoline generator. The margin between error and imminent death here is so close, you have to step away from it. A gasoline or any other CO2 producing source in a locker, with forced are is where the problem lies. It is not a guaranteed ventilated area.
Let me demonstrate with a factual example:. We had a built in PC server at home and force fed air for cooling only the PC. The only time I knew the fans failed (after years of operation), was when the server malfunctioned due to overheating.

In your case, if the fans forcing the air fail, the fumes may overpower you and soon afterwards kill everyone inside your vessel, without you ever even knowing it. You will be constructing your own gas chamber. CO2 leads to muscle dystrophy, which means there is a period where you will realize that there is a problem , when you become hazzy and finds that you unexpectedly can't move even a finger. It is a period before unconscious sets in, upon which death follows.

In that period you will be in those nightmares where you know you have to wake up or die, where you try to scream but nothing comes out, you can't move a single muscle. Active people in such toxic environments, feels tired at goes to sit down or to relax. Then they start to ponder what is the problem. If they realise what the problem could be, they suddenly finds they can do nothing to stop it.

Then they stay put in their last positions, all whilst the fumes from the generator's muted doef-doef-doef sounds, silently pumps more death in the air and they eventually die.

The muscles around your chest that enables your breathing , fails and you stop inhaling altogether.

Then you die of CO2 poisoning. Yet, Not the CO2 coming from the source, but the build up of you bodies own CO2 which you cannot exhale. That is what kills you. It is called The silent death.

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Old 12-05-2020, 01:21   #37
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Re: Lead acid or agm/gel

Cold Cranking Amp batteries for starting an optiion to lead acid and agm is a Calcium battery. For house batteries deep cycle such as Trojan.


A Calcium battery is a still a lead acid battery; they are usually sealed maintenance free. Calcium replaces antimony in the plates of the battery to give it some advantages including improved resistance to corrosion, no excessive gassing, less water usage and lower self discharge.
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Old 12-05-2020, 01:59   #38
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Re: Lead acid or agm/gel

We use golf cart batteries to make 12 volt and 24 volt banks. Total amp hours at 12 volt is about 1100 ah's. We also have 4 solar panels, 500 Watts. We typically lose 5-7% every evening. The 12 volt bank recovers to 100% by mid afternoon, the 24 volt bank holds steady through the day, after 4 days it is down to ~80%. We then run the generator to top up the 24 volt bank and make water, usually 100~130 gallons over 3-4 hours. Our discharge depth is very shallow because the bank is large. We will add more solar panels this year so the 24 volt bank can recover to 100%, solar and good controllers are fairly inexpensive. The bank is about 5 years old and seems fine for it's age, I've not load tested them though. Golf cart batteries at Sam's Club are about $100~125 each. We replace the ten batteries every 5-6 years. We also use dewatering caps to minimize water loss, we water the banks about every two months.

On passage we run the generator daily because our amp hour usage increases.

We have all the regular cruising gear, fridge freezer, lights, iPads, phones, computers... Cooking is by propane, we don't have a microwave.

The key items as we see them are:

Golf cart batteries are cheap and long lived if the depth of discharge is shallow. Make sure your battery bank is big enough so the discharge level is shallow.

Solar is a wonderful charge method for golf cart batteries because it can charge them slowly through the day. Add enough solar to bring the bank back to 100% by days end.

We don't count or care about amp hour usage, we only look at state of charge, we use the Smart Gage bought from Maine Sail.

We don't have a high amperage alternator on the propulsion engine because we rarely run it. We use the generator for any charging when solar can't keep up. We use Sterling chargers for both banks, again bought from Maine Sail.

Replacing ten golf cart batteries every six years is an annual cost of $200. We replace them before they fail.

So in a nutshell; big golf cart bank, shallow discharge, enough solar to bring the bank to 100% daily makes for a tough long lasting inexpensive battery solution.
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Old 12-05-2020, 18:37   #39
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Re: Lead acid or agm/gel

Thanks guys!

I hear you on the generator. Will stay outside!

What about marine generators? Just as a question more than anything else! The welder is not an option but a necessity for me, same as a compressor will be. Mobile workshop!

OK so my battery tray is behind the engine, the aft of the boat is not sealed from the saloon at all. So any gas produced will be in the living space, now can any of the discharged liquids gases speed up corrosion in metal? Metal boat?.. I'm guessing I cam use a long vent pipe and have it go through the stern with a good loop to stop sea getting in?

The batteries are going to be a pain to get to for the top ups, if I relocate them To the saloon there is nowhere Central to put them they will be just below the waterline, tad over maybe assuming that will effect handling of the boat.

Other option is to go further astern, cut out the cockpit floor and add an access hatch under the wooden grating that's if the steering gear isn't in the way. not to keen on that as if it leaks that will be straight into the boat where as at the moment I have 2x 2" drains

Lazy question but does anyone have a rough size of their bank in 6v @ whatever ah you have?

I do not have any refrigeration at the moment, and am managing mosty ok but I am in the uk! I'm looking at the cheaper end of compressor fridges, either a small chest freezer with a new stat to make it a fridge 240v or a 12v chest but it works out dam expensive! £300 almost for 30L vs the 90L chest freezer @ £250 its a matter of where to put it as well. Pros and cons!

Will look at some battery prices now!
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Old 12-05-2020, 19:06   #40
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Re: Lead acid or agm/gel

My suggestion, if it is affordable to you, is to go with a suitably sized marine diesel generator. If you want to cook with electricity, you will fire it up at least once per day and it will also charge batteries in the process. No big battery capacity required and no risk gassing yourself with CO.



Your TIG and (presumably) induction stove will also likely run much better and you have the opportunity to make sure whatever you get will run it during the buying phase.

It's not a HF TIG by chance, is it?


Edit. Missed the compressor mention. Compressors are the absolute worse things to try and run off a genset. They take a massive surge of power to start as they start under a not insignificant load. Definitely make sure your compressor can be powered by whatever you plan to set up.
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Old 12-05-2020, 19:43   #41
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Re: Lead acid or agm/gel

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My suggestion, if it is affordable to you, is to go with a suitably sized marine diesel generator. If you want to cook with electricity, you will fire it up at least once per day and it will also charge batteries in the process. No big battery capacity required and no risk gassing yourself with CO.



Your TIG and (presumably) induction stove will also likely run much better and you have the opportunity to make sure whatever you get will run it during the buying phase.

It's not a HF TIG by chance, is it?


Edit. Missed the compressor mention. Compressors are the absolute worse things to try and run off a genset. They take a massive surge of power to start as they start under a not insignificant load. Definitely make sure your compressor can be powered by whatever you plan to set up.
I will see what they look like price wise. Would probably take up just as much room as the batteries

So what makes a marine diesel safe? Obviously properly fitted and silenced, exhaust running through a water muffler. I have made custom exhausts etc, just thinking out loud as it would still be fitted inside meaning if it leaked I'm still getting co!

Yup ac/dc 180a (hardly ever have to get it past 100a with the correct gas mix I love that welder!

Compressor will be belt driven, don't it before with a bug York head. Mount the tank remotely and hey presto! Given the price of V twin heads these days I should get a good cfm at idle with the right pulleys

So batteries

T105 generic no label ones £103 each on ebay no cycles listed
T105 trojan ones £139 don't list cycles on the site
T105 agm £159 advertised as 1000@50% DOD

Then there is this. Must be a typo!
https://www.countybattery.co.uk/indu...BoCH0cQAvD_BwE
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Old 12-05-2020, 21:08   #42
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Re: Lead acid or agm/gel

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Originally Posted by Culwatty View Post
I will see what they look like price wise. Would probably take up just as much room as the batteries

So what makes a marine diesel safe? Obviously properly fitted and silenced, exhaust running through a water muffler. I have made custom exhausts etc, just thinking out loud as it would still be fitted inside meaning if it leaked I'm still getting co!

Yup ac/dc 180a (hardly ever have to get it past 100a with the correct gas mix I love that welder!

Compressor will be belt driven, don't it before with a bug York head. Mount the tank remotely and hey presto! Given the price of V twin heads these days I should get a good cfm at idle with the right pulleys

So batteries

T105 generic no label ones £103 each on ebay no cycles listed
T105 trojan ones £139 don't list cycles on the site
T105 agm £159 advertised as 1000@50% DOD

Then there is this. Must be a typo!
https://www.countybattery.co.uk/indu...BoCH0cQAvD_BwE

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!
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Old 13-05-2020, 00:00   #43
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Re: Lead acid or agm/gel

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.
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Old 13-05-2020, 02:03   #44
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Re: Lead acid or agm/gel

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.
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Old 13-05-2020, 02:12   #45
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Re: Lead acid or agm/gel

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. . . What about marine generators? Just as a question more than anything else! The welder is not an option but a necessity for me, same as a compressor will be. Mobile workshop! . . !

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.
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