Upgrading your Battery Banks and Alternator in 2014 is a Waste of Money.

[sailorboy1]

Originally Posted by Ex-Calif

Sailiorboy has a few thousand posts, he's hard as nails.

Wait a second, what did I do on this thread?

My feelings are all hurt now

[noelex 77]

Originally Posted by kmacdonald

Another thing to consider when sizing a battery bank is recharge time and efficiency. A large bank discharged to 90% SOC will take a long time to fully recharge. A bank one quarter the the size would be at 60% SOC and recharge more efficiently and faster.

Are you sure?
I have never done the sums.

One simple way of looking at the problem (which avoids integrating the constantly varying charge acceptance) is that given unlimited power the time taken to completely recharge a battery is reasonably independent of the battery size.
It is dependent on the starting SOC (among many other factors) so a battery at 60% SOC will take longer to reach 100% SOC than one that starts at 90%. This is the opposite of what you are concluding in terms of charge time.

Battery efficiency is more complex. It does drop off with a higher voltage and with a higher SOC. The larger bank would be at a higher SOC, but an overall lower voltage (because it will spend more time at a float voltage). I suspect there would be very little difference. Perhaps the smaller bank might have a slight edge here, but it would be a difficult problem to quantify. The high absorption voltages used by many cruisers would swing the efficiency more in favour of the larger bank.

[DeepFrz]

kmacdonald, maybe you could site some sources and other valid information to back up your statement. I'm sure you could find lots of information on battery manufacturers web sites. It might also help if you could specify the battery types and also recharge equipment that you are talking about. Type and size, etc.

[Ex-Calif]

Originally Posted by sailorboy1

Wait a second, what did I do on this thread?

My feelings are all hurt now

Where the hell is the Hug icon...

[exMaggieDrum]

Originally Posted by Fuss

Comment does not apply to batteries...Battery technology has not always been moving like other technologies. It has not moved at all ... for at least 50 years. Lithium is a huge change.

I guess we will have to see how important industrial, heavier duty alternators end up being when coupled with Lithium. Time will tell.
But first of course, we will have a few threads titled....This is my 3rd alternator replacement... Why can't they make alternators like they used to. To which knowledgable people on here will reply... Lithium batteries will always kill old style alternators. These older alternators were made for slow charging old style batteries. You cannot expect them with withstand the stresses of charging these modern Lithium batteries with their high acceptance rates.

10 years from now, the majority of sailing boats will not have FLA, GEL or AGM batteries. It will make no sense when you can have something 4 times as efficient for a 3rd of the weight.

5 years from now Dave, the majority of cruising sailing boats will not have FLA, Gel or AGM batteries.

Lead acid around for decades to come 4arch.... are you really trying to convince me that in 2025, you would consider putting flooded lead acid batteries in your boat.... amazing.

How about a bet - say $200 - that AGMs are still around in 10 years? Alternator technology is evolving too but there is no free lunch. If you need 100aH's daily you will only need to recharge 100aH's. Ditto for 200 or whatever. You still have to convert some kind of energy - solar, wind, motor - in to electricity with some kind of efficiency loss, at least if the laws of physics still apply.

Fast recharging is always great, and if lithium technology improves that it's a good thing. But it's going to be an expensive while until the technology is safer and proven enough to bet your life on it. I am an early adopter of much technology but too often you have to put up with it breaking or finding out that snake oil is still snake oil I am glad there will be folks out there, like you and Nigel Calder, who have the money, time, and backup systems to help evolve it. But to delay important upgrades to normal folks systems that will last them 10 years at a reasonable cost is very bad advice.

My last AGM's lasted that long and my current ones will too. My large solar panels are paid for and are now free and actually provide most of our daily requirements with only occasional topping off with the motor and it's state of the art alternator. It was pricy but not nearly as pricy as the new, not-yet-invented charging devices you imagine will kill everything else. If I waited for what-might-be and also might-not-be-ever I would not be able to go-cruising-now and might-not-ever. Good luck with your waiting and experimenting. Please let us know how expensive it was, how many times you replaced it, and how soon you went back to the old useable technology. After you're done, I will jump right in.

You should read some of the articles in "Professional Boatbuilding" where Nigel Calder bemoans how far away these new technologies are from where he predicted they would be by now. He has been experimenting with these new technologies with huge investments by companies like Mastervolt who would dearly love to have these systems out and working. He discusses the various lithium chemistries that are available and the problems with each of them and the tradeoffs from the electrical systems that they support and that support them.

[OceanPlanet]

For sure Pb is here to stay for the foreseeable future. Even those of us who sell Li systems recognize that. If the sulfation issue with Pb is sorted out, then aside from weight then they can much more efficient when used in extended PSOC (Partial State Of Charge) operation. If you can cycle primarily between 20% and 80% SOC (without the need for frequent topping off) then charging can be faster and more efficient (much energy is lost when charging the last 20%).

There are carbon-Pb technologies that have been around and not fully recognized for marine use, which we are investigating. Maine Sail happens to be doing some testing for us...when the time comes will put out more info.

[hellosailor]

OK, everyone who remembers when the USCG used to change the batteries on buoys by pulling the old ones out and dropping them overboard raise your hands.

The rest of you kids can leave the room now.

Given how far the world has come in the last few decades, with outlawing lead from all products and uses, it wouldn't take much thought to say lead based batteries really need to be outlawed, totally, immediately, as soon as there is an alternative. And cost be damned. I'm not saying that's appropriate--just that it is well within the realm of possible.

So as far as lead batteries being around forever....heheh. Sure, just like the MERCURY batteries that were outlawed for watches, what 40? years ago? Don't bet on it.

If that batch of clowns in the lithium battery business ever got organized, they'd be a force to be reckoned with. Fortunately, they're having way too much fun *issing on each other.

[kmacdonald]

Originally Posted by DeepFrz

kmacdonald, maybe you could site some sources and other valid information to back up your statement. I'm sure you could find lots of information on battery manufacturers web sites. It might also help if you could specify the battery types and also recharge equipment that you are talking about. Type and size, etc.

Its common knowledge that filling the last 20% of capacity takes much longer than charging between 60 and 80% SOC. The smaller bank can use smaller, less expensive chargers, alternators, and solar to do the charging.

[socaldmax]

Originally Posted by SV THIRD DAY

I wouldn't call $1700 for a 400AH bank made of gold...but as my wife tells me I spend company R&D money like she spends at a Mexican flea market...way too easily.

If only you could bargain on the price of LiFePo batteries like you can at a Mexican flea market.

[noelex 77]

Originally Posted by kmacdonald

Its common knowledge that filling the last 20% of capacity takes much longer than charging between 60 and 80% SOC. The smaller bank can use smaller, less expensive chargers, alternators, and solar to do the charging.

You are forgetting the battery bank with the higher state of charge is 4 times larger, to use your example. So each battery in larger bank only has to accept 1/4 of the charge current for the overall charge acceptance to be equal between the larger and smaller bank.

For example if we use 100Ahrs for the small bank and 400 AHs (4x100AHrs) for the larger bank. If each 100AHr battery in the larger bank is accepting 10A then the bank is accepting 40A overall. For the smaller bank the single 100Ahr battery has to accept 40A on its own for the battery acceptance and speed of charging to be equal between the smaller and larger bank at that point.

You have removed the same amount of energy from the smaller and larger bank which must be replaced to get them back up to 100% SOC so I don't understand why you feel say the solar panels can be smaller and less expensive for the smaller bank. The energy replaced is identical.

In practice the battery charger and alternator can be made smaller for the smaller bank, but only because the charge acceptance is lower. It will therefore take longer to recharge. The opposite of your contention.

[sailorboy1]

Given that you can only put in the amps a bank can accept, for the same type of batteries wouldn't it take the same amount of time to charge for a given state of charge regardless of bank size as long as the charger can supply that acceptance current?

[boatpoker]

six golf cart batteries, $120ea. inexpensive charger,put some water in them once in a while.

No Boeing explosions, no expensive BMS, no manual charge switching, no concerns about over charging or under charging. no balancing cells, no BS.

For the techie types who must have the latest and greatest, more power to you but my cruising is about inexpensive simplicity and reliability.

[DeepFrz]

Its common knowledge that filling the last 20% of capacity takes much longer than charging between 60 and 80% SOC. The smaller bank can use smaller, less expensive chargers, alternators, and solar to do the charging.

I think your logic is way off here. Of course the last 10% or 15% take longer. On every lead acid battery, not just the big ones. The small one, if you only ever charge to 80%, will die a quick death just the same as the large one if you don't charge it to 100% regularly. Lets compare apples to apples.

[d design]

Originally Posted by boatpoker

six golf cart batteries, $120ea. inexpensive charger,put some water in them once in a while.

No Boeing explosions, no expensive BMS, no manual charge switching, no concerns about over charging or under charging. no balancing cells, no BS.

For the techie types who must have the latest and greatest, more power to you but my cruising is about inexpensive simplicity and reliability.

I find LiFe much easier to understand then F**kn Lead acid (FLA)

[exMaggieDrum]

Originally Posted by OceanPlanet

For sure Pb is here to stay for the foreseeable future. Even those of us who sell Li systems recognize that. If the sulfation issue with Pb is sorted out, then aside from weight then they can much more efficient when used in extended PSOC (Partial State Of Charge) operation. If you can cycle primarily between 20% and 80% SOC (without the need for frequent topping off) then charging can be faster and more efficient (much energy is lost when charging the last 20%).

There are carbon-Pb technologies that have been around and not fully recognized for marine use, which we are investigating. Maine Sail happens to be doing some testing for us...when the time comes will put out more info.

I believe that one of the driving reasons to use AGMs is because the last 20% if much easier to achieve - faster with less loss - than with wet cells. We routinely charged up to 95-100% full with our AGMs. We almost never went more than a day or two at 80% or less. You do have to manage your amp budget (which as several have noted is where you should start), have a large enough bank for what your budget is, and sufficient charging resources. Only charging up to 80% as a practice will reduce the life of the batteries a significant degree.

It will be interesting to follow the C-Pb technology you suggest is in the works.

Noting a few other commenters, lead is dangerously toxic waste, but I believe lithium is far more toxic. Mother nature does not like any of these metals in high concentrations.