LITHIUM BATTERIES FOR DUMMIES!

[kmacdonald]

Originally Posted by a64pilot

Your kidding aren’t you? Cause there is no load until after the generator has been stabilized in RPM for one minute.
Do you realize that torque and horsepower are the same things, expressed differently?

They are not the same thing. Do all 100ft-lb torque engines have the same HP? Of course not. Force and power are not the same thing. Directly proportional but not the same.

[a64pilot]

Originally Posted by kmacdonald

They are not the same thing. Do all 100ft-lb torque engines have the same HP? Of course not. Force and power are not the same thing. Directly proportional but not the same.

Do some research, they are exactly the same thing, and it’s why ALL dyno charts HP and torque curves cross at exactly 5252 RPM

[kmacdonald]

Originally Posted by a64pilot

Yeah, your probably right, it’s going to have a lot of side load even with a loose toothed drive belt.
I guess if your concerned, then a jackshaft driven off of the front of the crank is about the only way?
Or two alts, on opposite sides, 180 out?

I looked for PTO's but didn't find any that seemed to be of use. A PTO off the gear would be nice but I didn't find anyone making them. Two alts, one on each side might be the best solution.

[evm1024]

Originally Posted by a64pilot

SNIP

Do you realize that torque and horsepower are the same things, expressed differently?

Not really the same but related. Torque is force and HP is power.

HP = torque * RPM ÷ 5252 (where torque is in lb-ft)

Back in my 20's when I road raced production motorcycles I learned that torque determines acceleration and HP determines top speed.

[kmacdonald]

Originally Posted by a64pilot

Do some research, they are exactly the same thing, and it’s why ALL dyno charts HP and torque curves cross at exactly 5252 RPM

HP=(Torque X RPM)/5252

Clearly they are not the same but directly proportional.

Watch this:

https://www.youtube.com/watch?v=lt7iUBE3_AE

5252 is not a magical number and most diesels don't even rev that high.

[kmacdonald]

Originally Posted by a64pilot

Do some research, they are exactly the same thing, and it’s why ALL dyno charts HP and torque curves cross at exactly 5252 RPM

At 5252 RPM's they have the same value but not the same units of measure.

[Q Xopa]

Torque is a force, twisting force specifically. There is no time/ rate component. So you can have a Torque at 0 RPM. Ie like a bolt torque.

HP/ Watts etc is Power, ie a Rate of that force (Torque) being applied.

Practically for our sailboat diesel the max torque 'curve' RPM is where it will exert the most amount of turning force. It is where it is most efficient with valve sizes, cam profiles inlet runner cross sections etc. It is the best use of our diesel burned to force out.

HP max RPM 'curve' will still continue to increase because although the force will start to decline the rate of producing that all be it reducing force is being produced at a proportionally greater rate. The RPM that the rate cant increase fast enough to compensate for the decreasing force/ torque is the point of max HP curve. The Engine has 'run out of breath'.

Hopefully I haven't muddied the waters too much.

[john61ct]

Originally Posted by a64pilot

The big alternator for battery charging just makes too much sense to me, although I want it ideally defeated whether automatic or manual cause I’d suspect that under normal cruise the engine would be overloaded with the big alternator pulling a lot of power

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.

[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?

[kmacdonald]

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?

Yes, I think that's true, at least that's what I've come to believe. I know the formula for calculating the HP motor to drive a high pressure water pumps is different for electric vs gas engines. The gas engine needs to be larger.

[kmacdonald]

Horsepower required for pressure washers:
Electric HP = (psi x gpm) / 1460 Gas Engine HP = (psi x gpm) / 1100

As you can see it varies significantly between electric and gas engines. Diesel engines would be different. I think differences would apply to running alternators and generators also. I guess there are big horses and small horses.

[hzcruiser]

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.

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

[evm1024]

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.

I've got the Delco 28Si (200 amp) running on a Balmar MC-612 with the Balmar output derated with the belt manager parameter. I get about 135 Amps at the current setting.

I have thought that there might be times when I would like to get full output and would need to go change that parameter with the waving of the magnet. Not very convenient to say the least.

I could use the small engine mode (short the alt temp sensor leads together to activate) but then I lose the alt temp sensor protection. If the small engine mode is derated enough then the reduction in output make make the temp sensor moot.

It would be nice if the battery temp sensor could be used at the small engine mode switch. That way one could keep the alt temp sensor.

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.

I've not measured what output I get yet in small engine mode on this alternator. Some day I will.

I've not even entertained changing the voltage set point as a way to get more output. 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. Lots or presumptions in there about how the regulator calculates the field current.

OR...

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.

[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?

[newhaul]

Well here are a couple dc generator options https://www.ebay.com/itm/New-CE-NIEH...0AAOSwDTNavkJY

And for my boat

https://www.ebay.com/itm/Powermaster....c100005.m1851