LITHIUM BATTERIES FOR DUMMIES!

[john61ct]

Originally Posted by kmacdonald

A simple method of storing multiple charge profiles and then only having to select a charge profile would be nice. 3 or 4 would be nice but might as well allow for 10 or 12 just because.
Does anyone use IOTA chargers?

Yes good brand. Called "converters" in the US RV industry.

[john61ct]

Originally Posted by evm1024

You could pick up one of Bill Thomason's VSR Alt Regulators and have a go at making some code changes. That regulator does have an input for charge current. Heck, that may already be in the code and just need to have a way to toggle it off and on.

yes excellent project, can pretty much do whatever you want.

> So one plan would be to set the belt manager to whatever level (if any) that you want full output to be and use the small engine mode to derate output for everyday charging.

Interesting idea, if you or anyone else tests that please post results

> I've not even entertained changing the voltage set point as a way to get more output.

No, bank wants what it wants.

> Placing a diode in series with the voltage sense and having a relay to short (and thus to take the diode out of circuit) would be one way to fake the regulator into thinking the battery was a diode drop less in voltage than it was.

No, the difference is not constant, you have a fine VR, can set V for any chemistry, don't mess with jury rigs, magnet isn't **that** fiddly

[john61ct]

Originally Posted by hzcruiser

Well, I thought that's what the regulator in the alternator is for, changing the output current based on the input parameters.

Temperature compensation yes, otherwise just regulates voltage, puts out the max amps or a derated setting if fancy adjustable.

But a very simple switch at the helm disables alt output entirely when you need every horse for propulsion.

Works for the cheapest stock alt or the $5000 custom setup.

[evm1024]

Originally Posted by kmacdonald

A simple method of storing multiple charge profiles and then only having to select a charge profile would be nice. 3 or 4 would be nice but might as well allow for 10 or 12 just because.
Does anyone use IOTA chargers?

Many regulators and the VSR do store multiple charge profiles. Switching between them on the fly is currently lacking.

It has been a long time since I was a code warrior (hey I've been writing some perl scripts the last few days...). but a mod to the VSR regulator to allow this is possible.

[a64pilot]

Originally Posted by john61ct

To drive a large alt, say 570A @24V, it seems going with gasoline you need more horses than with diesel engines.

I assume related to the difference in torque?

No a horsepower is a horsepower, regardless of the source.
As was stated torque is a force applied, but there is not necessarily any work done, cause no movement.
Horsepower is force applied and resulting movement, therefore work is done.
Gasoline motors can be at least as torquey as Diesels, just mechanical injection Diesels are very RPM limited due to the amount of time required to inject the fuel, higher RPM is less time and that means higher pressures, that old design mechanical Diesels just could do. So they are relatively low RPM motors, common rail is a game changer to that of course, if it weren’t for emissions, I bet you would see some real hot rod Diesels in the automotive world.
Gasoline motors as they inhale the fuel with the air can run much, much higher RPM and usually higher power motors come from high RPM so they are tuned for higher RPM, but look at old farm gas motors like the “Popping John” two cylinder John Deere tractor in gas, it was very high torque, meaning made its power at low RPM.
That statement is technically incorrect saying that motor is high torque, but its common usage. What would be correct is to say it made its power at low RPM.
The opposite is of course high performance bikes, they make way more than 100 HP per Liter, and do so largely by turning way more than 10,000 RPM, likely up to 14,000 or so.

Also the most efficient RPM for any motor is not necessarily the torque max, it’s wherever the BSFC is highest, Brake Specific Horsepower. Which is a measure of how much power is made per unit of fuel, however this may well not correspond with hull speed or any other desirable trait, so it’s interesting, but not much else.
All Yanmars I believe have a chart that shows it, the chart looks like a gentle U .

5252 is a Magic number, look at the Horsepower formula to determine why.

This link gives a little explanation and some history and doesn’t just state the formula
https://formulas.tutorvista.com/phys...ml?view=simple

[jmh2002]

For interests sake, we had a Balmar DC genset in the past. Some people didn't like them but we were very happy. It was a small 2 cylinder yanmar, with a shaft driven big alternator on the back (about 300amp I think).

We moved our existing water maker HP pump from the main engine to sit on a platform at the back and be belt driven, and we ran a dive compressor from the front PTO too. Both with clutches, and the whole setup was variable speed.

We went this route because we didn't want/need AC, and we were trying to move towards an all DC boat, at least how it was possible back then. It all worked very well for us.

It was quite amazing to sit somewhere at anchor, make water, charge the batteries, and fill our dive bottles.

This was around 20 years ago when this all DC type of thinking was still quite new at the time.

[Q Xopa]

Originally Posted by a64pilot

No a horsepower is a horsepower, regardless of the source.
As was stated torque is a force applied, but there is not necessarily any work done, cause no movement.
Horsepower is force applied and resulting movement, therefore work is done.
Gasoline motors can be at least as torquey as Diesels, just mechanical injection Diesels are very RPM limited due to the amount of time required to inject the fuel, higher RPM is less time and that means higher pressures, that old design mechanical Diesels just could do. So they are relatively low RPM motors, common rail is a game changer to that of course, if it weren’t for emissions, I bet you would see some real hot rod Diesels in the automotive world.
Gasoline motors as they inhale the fuel with the air can run much, much higher RPM and usually higher power motors come from high RPM so they are tuned for higher RPM, but look at old farm gas motors like the “Popping John” two cylinder John Deere tractor in gas, it was very high torque, meaning made its power at low RPM.
That statement is technically incorrect saying that motor is high torque, but its common usage. What would be correct is to say it made its power at low RPM.
The opposite is of course high performance bikes, they make way more than 100 HP per Liter, and do so largely by turning way more than 10,000 RPM, likely up to 14,000 or so.

Also the most efficient RPM for any motor is not necessarily the torque max, it’s wherever the BSFC is highest, Brake Specific Horsepower. Which is a measure of how much power is made per unit of fuel, however this may well not correspond with hull speed or any other desirable trait, so it’s interesting, but not much else.
All Yanmars I believe have a chart that shows it, the chart looks like a gentle U .

5252 is a Magic number, look at the Horsepower formula to determine why.

This link gives a little explanation and some history and doesn’t just state the formula
https://formulas.tutorvista.com/phys...ml?view=simple

Yes a BMSFC (Brake Mean Specific Fuel Consumption) chart would be interesting. I'd be curious to see it, if you could post it. Always handy to have that stuff to refer to.

I have got a set of 2 'Performance' graphs on a 2 page Yanmar 4JH4-TE series brochure. These graphs are Power, Torque and Fuel Consumption.

However it's only HP vs RPM, TQ vs RPM and Ltrs/Hr vs RPM.

I guess we could make a BMSFC graph by plotting HP/ LPH every 200 RPMs.

[john61ct]

Originally Posted by jmh2002

Balmar DC genset
…
We moved our existing water maker HP pump from the main engine to sit on a platform at the back and be belt driven, and we ran a dive compressor from the front PTO too. Both with clutches, and the whole setup was variable speed.

Excellent.

Now what would it take on a small boat, for all that to be also integrated with the propulsion function?

[Q Xopa]

Originally Posted by jmh2002

For interests sake, we had a Balmar DC genset in the past. Some people didn't like them but we were very happy. It was a small 2 cylinder yanmar, with a shaft driven big alternator on the back (about 300amp I think).

We moved our existing water maker HP pump from the main engine to sit on a platform at the back and be belt driven, and we ran a dive compressor from the front PTO too. Both with clutches, and the whole setup was variable speed.

We went this route because we didn't want/need AC, and we were trying to move towards an all DC boat, at least how it was possible back then. It all worked very well for us.

It was quite amazing to sit somewhere at anchor, make water, charge the batteries, and fill our dive bottles.

This was around 20 years ago when this all DC type of thinking was still quite new at the time.

Nice.

I'm doing a similar setup myself at the moment. I'm sure I will be happy with it but honestly it's not a justifiable expense. It is costing a mint.

I bought a new Yanmar 2YM15 $5,700, 28V 400A + 12V 100A CE DC brushless Alternator $400 and a custom made drive adapter $1,200, Regulator $94. Total $7,400 and not quite done so still counting. Still need a Generator controller (in the works) Realistically it might be 7kW.

Water maker pump and Dive compressor. I have considered doing this stuff, even fridge compressors. So far my thinking is to not bother trying to do mechanical drives and try and keep it electrical drives, but yours sound nice.

[Q Xopa]

Originally Posted by john61ct

Just stop feeding the VR and the load comes off.

I like the idea of a propulsion engine that can "switch over" to being a HO DC genny on the hook, fully taking advantage of all the HP available.

Practical suggestions for implementing that would be welcome.

Yes, I agree. I am going some way down this path.

My initial thoughts were to go the DC gen route. In fact i have gone a long way down that route already. However I'm not sure if it was the best place to spend my efforts and not insignificant money $7.5k ish for maybe 7kWs. Time will tell.

Actually my overall my plan was to have a power generation hierarchy, with as much redundancy as possible. Something like- Solar as much as possible, main engine when it is being used anyway, then DC gen when it's not needed and I still need more than solar. So I guess form that perspective maybe a DC gen is still relevant.

Recently I am leaning more towards just loading the main up with a good amount of generation capability. Especially when I think about LFP recharge capability.

Most practical IMO is 2x , as big as you can practically fit and afford, Alternators hanging off the front of my motor. In my case it is 2 x 24V 110A large case units. But it's not as simple as I can say it quickly. I'm certainly having some fun with brackets, pullies, spacers and belts. Getting around raw water pumps and getting good belts and pulleys aligned etc. It's not for the faint of heart. I'm pretty much there though. This has run me around $2k ish for 5kW ish (on a good day).

2 Big Alternators seems to me to give some good redundancy and is nice and balanced. So there is 2x not overly taxed Alts either side. I have a Yanmar 4JH4-TE. They actually have an original 2nd Optional Alternator kit that I started with. Of course their one wasnt meant for large case Alts and bigger belts etc.

So I tend to think the engine Alternator project has been better practical value.

At the risk of being called completely out of my tree. (No risk really, I would be disappointed if I dont get that response).

I'm not going to be doing this anytime soon, but it does look interesting. All be it a far bigger (ie more expensive)

https://www.youtube.com/watch?v=w2Bngp8gFlo

I'm not really too interested in the electric propulsion side of it, possibly for a bit of redundancy. But as a main motor electrical generation setup it's interesting. If I did do that sort of thing I would do my own. The clutches look interesting, the top one an electric tooth clutch, the bottom a manual dog clutch. I've no idea where to find that sort of stuff.

[darylat8750]

Originally Posted by john61ct

To drive a large alt, say 570A @24V, it seems going with gasoline you need more horses than with diesel engines.

I assume related to the difference in torque?

I would say that it is the engines max continuous power rating. Few gasoline engines are M1 rated these days while virtually all diesels driving gensets are.

[a64pilot]

Originally Posted by Q Xopa

Yes a BMSFC (Brake Mean Specific Fuel Consumption) chart would be interesting. I'd be curious to see it, if you could post it. Always handy to have that stuff to refer to.



I have got a set of 2 'Performance' graphs on a 2 page Yanmar 4JH4-TE series brochure. These graphs are Power, Torque and Fuel Consumption.



However it's only HP vs RPM, TQ vs RPM and Ltrs/Hr vs RPM.



I guess we could make a BMSFC graph by plotting HP/ LPH every 200 RPMs.

Attached specific fuel consumption chart for Yanmar 4JHE.

[tanglewood]

Generating a lot of power from a DC "alternator" can really be a false economy compared to an AC genset.


First off, lots of people cite the need to convert generator AC output to DC, and the associated losses. True, but exactly the same thing happens in a DC alternator. The alternator is a 3 phase AC device with the output rectified to DC. The losses are very similar.


But the real killer is the lower operating voltage of the alternator compared to a generator. For the same power output, you need 10x the current from a 24V alternator vs a 240V generator. And the power loss and heat generated by the windings in the devices varies as the square of the current. So 10x the current is 100x the power loss. It's a bit of a simplification, but that's fundamentally why alternators are only about 50% efficient.


And isn't it silly how we call the thing that produces DC power an Alternator, and the thing that generates AC power a generator? It's exactly backwards from what they actually are. Of course there is history behind those terms, but amusing none the less.

[newhaul]

Originally Posted by tanglewood

Generating a lot of power from a DC "alternator" can really be a false economy compared to an AC genset.


First off, lots of people cite the need to convert generator AC output to DC, and the associated losses. True, but exactly the same thing happens in a DC alternator. The alternator is a 3 phase AC device with the output rectified to DC. The losses are very similar.


But the real killer is the lower operating voltage of the alternator compared to a generator. For the same power output, you need 10x the current from a 24V alternator vs a 240V generator. And the power loss and heat generated by the windings in the devices varies as the square of the current. So 10x the current is 100x the power loss. It's a bit of a simplification, but that's fundamentally why alternators are only about 50% efficient.


And isn't it silly how we call the thing that produces DC power an Alternator, and the thing that generates AC power a generator? It's exactly backwards from what they actually are. Of course there is history behind those terms, but amusing none the less.

hence I will be using a generation on my engine and not an alternator. 12volt 90 amp Chevrolet generator.

[tanglewood]

Originally Posted by newhaul

hence I will be using a generation on my engine and not an alternator. 12volt 90 amp Chevrolet generator.

Not sure what you mean by that. I haven't seen a true DC generator on a car since about 1965. All have been alternators since then.


Just for clarity, here's what I mean from my post above.


An "alternator" is the thing on most main engines, typically belt driven, and producing 12VDC or 24VDC at it's output. Internally that is a 3 phase alternating current "alternator" - hence it's name. It produces AC. That AC is then rectified with diodes to produce something sort of like DC, with it's real output wave form hidden by the battery it's connected to. So fundamentally it's an AC device with conversion to DC.


A "generator" is a synchronous device producing AC output at 240/120VAC/60hz, or 230VAC/50hz, or 120VAC/60hz. It directly produces AC output. To get DC to charge a battery, you run it through an AC to CD converter, commonly called a battery charger.


I'm not sure if you are talking about one of the above devices, or a very old actual DC generator. That doesn't have any rectifiers in it, so no losses there, but it will still suffer the big losses which are based on teh square of the current flow through the windings. I think it's efficiency will be fundamentally the same as an automotive alternator. There is a reason the auto industry abandoned them 60 years ago.