How to deal with the alternator?!

[Fuss]

Originally Posted by s/v Jedi

So you will post a video showing you starting your diesel from a supercap? The only times I have seen this it turned out to be an LTO battery wrongly labeled supercap.

If there’s nothing to show… there’s nothing to show.

i’ll send a photo later so there’s no confusion what i’m using.
they’re 2 completely different technologies producing similar results.
supercap is smaller, more suitable for providing redundancy when coupled with a lifepo4 that’s also capable of starting.
LTO needs more management and has less redundancy , the cells are bigger, the difference is obvious.

don’t believe the bs on this forum that lifepo4 still starts your engine with 3v cell voltage, it doesn’t.

[Fuss]

This is the maxwell boostcap that starts a 6L diesel and its not LTO technology.

The good thing about it is that it has much more power than Lifepo4 and also much more power than LTO.

The reason I use it is that originally the spec for my motor is 2 paralleled 12v batteries. It would not start on one. Then when I went Lifepo4 I spent a year starting on the eve cells, this worked fine and caused no problems at all. But, I still had the problem that I had no real backup. The supercap needs no charging regime and its big advantage is that a lifepo4 at 10v will charge it enough to start the motor. Something LTO could never do.

So now I can start my motor from a 12v tap on one of the house bank batteries or the boostcap or both. When in both mode, the supercap does all the work and the lifepo4 tap does none.

maxwell boostcap.jpg Views: 18 Size: 202.4 KB ID: 290960" style="margin: 2px" />

[noelex 77]

Originally Posted by Fuss

This is the maxwell boostcap that starts a 6L diesel and its not LTO technology.

Ultracapacitors provide another option for engine starting, but the current offerings don’t have a great lifespan in hot climates or if they are located in the engine bay.

[Fuss]

Originally Posted by noelex 77

Ultracapacitors provide another option for engine starting, but the current offerings don’t have a great lifespan in hot climates or if they are located in the engine bay.

My 600ah 2v flooded lead acid were rated for 30 degrees , they were 16 years old when replaced with lifepo4.
I think agm is about 40 degress, but this really reduces cycle life
Trogan golf cart also
Eve lf280 45 degrees halves cycle life
Maxwell supercap at 45 degrees halves cycle life

So you see that compared to FLA they handle high temp much better and they have a great lifespan…remember, their cycle life is huge.

No one should put any batteries of any technology in the engine room.

[nfbr]

Mine is 48v. The WS and REC does support shutdown, I have not implemented due to trust issues.

I have 2 Li banks / BMS, so a single bank disconnect due to cell balance won't trip things.

A disconnect high on both banks means a controller failure. My WS controller target voltage is set lower than my MPPT's, so really it does bulk but not top off / balancing. Gets to mid 90's %

I have had a hard disconnect. The 200A Class T fuse opened at 150A charge (no one can explain how), taking out the wakespeed. The Alternator rectifier survived with its avalanche diodes. (They don't use Zeners anymore, it's avalanche now). Interesting the fuse failure left the fuse testing ok with a multimeter but unable to conduct more than mA.

Balmar has a APS48 advertised, but not available retail for >12mths
Sterling doesn't do a 48v version and claims "too difficult"

Currently disconnects aren't actually a problem since the Tyco Kilovac solenoid on bank 1 has welded itself closed and my next project is to swap that out this week. Inverter pre-charge needed.

[noelex 77]

Originally Posted by Fuss

Maxwell supercap at 45 degrees halves cycle life

So you see that compared to FLA they handle high temp much better and they have a great lifespan…remember, their cycle life is huge.

As you point out, all the battery options for a sailboat are temperature sensitive. But the expected lifespan of the Maxwell ultracapacitors at 45°C is a rather poor two and half years.

At lower temperatures it is better, but at 35°C (close to our current house battery temperature) it is still only 5 years.

[Fuss]

Originally Posted by noelex 77

As you point out, all the battery options for a sailboat are temperature sensitive. But the expected lifespan of the Maxwell ultracapacitors at 45°C is a rather poor two and half years.

At lower temperatures it is better, but at 35°C (close to our current house battery temperature) it is still only 5 years.

Really, average temperature 35 degrees , when my cabin is running at 35 degrees my batteries are running at 25. I would never have any batteries running an average of 35 degrees.
When hard charging, my batteries run at 31.
Anyway, I expect 10 years, of course I cannot prove this yet as we would have to wait 10 years.

But..
I do have a good track record…I predicted in another thread that EVE LF280 cells could start a 6l diesel with no problems and I would report back 1 year later….. and here we are , more than 1 year later, with perfect Eve cells with a perfect delta…they said, dead in a month, explosions, boat burnt down in the next months, idiot from lala land, LTO is the only solution etc.
When another forum member revived the thread just a few weeks ago , the backpedaling was legendary.

BTW…5 years…a figure most agm users from the past could only dream about….

[Fuss]

Hey, but, I should apologise to Jedi for the massive thread drift that I created.
I always complain and bang on about this when others do it , and now here am I doing the same.
Next time I will try to create a new thread.

[noelex 77]

Originally Posted by Fuss

BTW…5 years…a figure most agm users from the past could only dream about….

Start batteries typically have a long life due to their high average SOC. A five year life is not unusual even when kept in the engine room. Anyway, when they do need to be replaced they are cheap and readily available anywhere cars can be found so their lifespan is not critical.

Ultracapacitors are harder to source and more expensive.

[Fuss]

Originally Posted by noelex 77

Start batteries typically have a long life due to their high average SOC. A five year life is not unusual even when kept in the engine room. Anyway, when they do need to be replaced they are cheap and readily available anywhere cars can be found so their lifespan is not critical.

Ultracapacitors are harder to source and more expensive.

Yes, but here is the advantage for modern lithium technology….
Firstly you need more than one bank so that there is always at least one bank connected in a lvc or hvc situation.
Second, you don’t always have to keep the batteries at a full state of charge. So, take daily what you need and put it back in in the next day or days. Full charge is not needed.
So, an important point….. if a full charge is not needed then with the capacity and power of lifepo4, perhaps a dedicated start battery is also no longer needed.., perhaps the start battery concept can be replaced with an additional house bank battery that can also start your engine.
That’s what I have now done…an even bigger house bank consisting of 3 banks and one that is tapped to start the engine and backed up with a supercap that does all the work.
So are agm really that cheap compared to lifepo4? Well , in Europe at the moment, you can get Eve 280 cells for 80€ each , so 320 for a 12v bank or 640 for a 24v bank. And of course a bit more for the BMS.
So can you really get 280ah of agm for 320??

[Fuss]

I just realised that I made a small mistake.

in Europe at the moment, you can get Eve 280 cells for 68€ each as they can be purchased without tax, so 272 for a 12v bank or 544 for a 24v bank.
This together with the BMS is the same price as AGM. Which makes it half the price when we factor in the only 50% depth of discharge of AGM.

Of course you have to make it yourself. ....but this is an advantage for anyone with a world cruising boat. flexibility, takes less space, maintainable, cheaper, the only downside is not as waterproof.

[noelex 77]

Originally Posted by Fuss

That’s what I have now done…an even bigger house bank consisting of 3 banks and one that is tapped to start the engine and backed up with a supercap that does all the work.
So are agm really that cheap compared to lifepo4? Well , in Europe at the moment, you can get Eve 280 cells for 80€ each , so 320 for a 12v bank or 640 for a 24v bank. And of course a bit more for the BMS.
So can you really get 280ah of agm for 320??

I understand what you have done and I don’t see any reason why it would not work. People prepared to experiment with alternative systems deserve our praise for testing the viability of these and working out the kinks.

However, I still don’t see the advantages. You are replacing a simple, small and cheap AGM battery with a larger, more expensive and complex combination of lithium batteries and an ultracapacitor. At the same time, you are ignoring one of the chief goals required of a starting battery, which is to provide a system that is totally independent from the house bank.

[Fuss]

Yes, all very good points, please give me a day and I will come back and answer these.
BTW…when I first bought my boat, the start battery ran all sorts of things, I changed this immediately. so I was also a proponent of what you wrote above.

[s/v Jedi]

Okay, that boostcap has some merit but you need to understand that this is in fact six capacitors connected in series, which means the capacitance is only 1/6 of the capacitance of the individual capacitors.

Elon Musk sold Maxwell after deciding he was not gonna power Tesla’s with these, but that doesn’t mean anything for this application.

I guess it would be used as follows: installed just by itself, instead of a start battery and charged by a dc-dc converter from the house battery.

Questions:

- would the dc-dc converter be switched off when the engine isn’t needed?

- what would the recharge time be?

- how many starts on one charge?

- how much energy is required to start (larger) marine diesels?

- modern diesels need electric power to power their electronics to be able to start, so it’s not just about cranking the engine. They have a minimum voltage requirement during cranking. Can the boostcap provide that minimum voltage?

- what is the actual lifespan in our engine rooms and how does that translate to cost per year in comparison to top of the line AGM options. And LTO?

I don’t see any possibility for it to outperform an Odyssey battery.

[rslifkin]

In my case the start batteries power no loads (and are independent of the house bank). So AGMs last a very long time as they're almost always full and any time the boat is on shore power they're floating. Currently mine are 6 years old and doing just fine. In similar service I've seen AGMs pushing the 10 year mark.

Other solutions will work fine if implemented well, but to me the reason to stay with lead for engine starting is that replacements are readily available, they're simple, not fussy to charge, etc. So very little effort is required to get and keep everything working well and when one does wear out I can just grab a replacement anywhere and drop it in.

For weight sensitive applications alternative methods might make sense. But for me, carrying 130 lbs of lead around isn't a big deal when we consider that my 2 engines and transmissions total up close to 2400 lbs and the boat weighs a bit over 27k lbs loaded.