Balmar alternators or standard?

[John Holbrook]

Ah no I didn't [emoji23][emoji23][emoji23]
Thanks for pointing that out.

Originally Posted by Bleemus

You do realize that this is Maine Sails website right?

[a64pilot]

When you guys are talking about three grand to do twin large alternators, your close to what a generator costs.
Plus if you pull that kind of power from your propulsion engine, it will be the same as being way overpropped, you will be "lugging" your engine when underway.
Unless of course you have a 100 HP or larger engine.

[John Holbrook]

A64 I'm in learning mode here so your thoughts are much appreciated.

What type of generator are you thinking of for 3k?

Re overloading the engine, on say a 57hp Yanmar at 2200rpm the engine makes 50hp per the Yanmar website, the prop aborbs 21hp again per the Yanmar website and two 200amp alternators on bulk charge would use 6hp each per the Balmar website, total 33hp so the engine would not be overloaded. At 2700 to max RPM of 3000 yes the engine would be overload if the both alternators were charging.

Btw the Yanmar 57hp comes standard with a 125amp alternator and a second 125amp alternator is optional.

If you are stationary and run the engine in neutral at say 1000rpm and used a 3.0 to 1.0 ratio on the serpentine pulleys the alternators would spin at 3000rpm and use circa 12hp of the 20hp the Yanmar 57hp makes at 1000rpm. I don't know if this is enough load to prevent glazing.

[a64pilot]

My 3.5 kw Nexgen cost me about 5K all in.
Issue with engine loading is that a prop and engine are pretty well matched, meaning that power required o turn the prop at any given RPM closely matches the power the engine is making, so that at say 2000 RPM your engines X HP, that is right at what the prop needs, so suddenly throw an additional 12 HP demand on the engine and your overloading it, just like if you hit a hill in an automobile, but you don't let it downshift.

My 3.5 KW will pull about 200 amps of chargers and not much more, I have 185 amps of chargers and I can't run them and say an Airconditioner for example or the water heater. But with a generator your not using your main propulsion engine for battery charging, which I think will save in the long run, and you can run air conditioners and other things.
Now just my opinion, but if you want to make loads of electricity which over 200 amps is in my book, loads, then you are better off with a device that has as its sole purpose making electricity rather than trying to dual purpose your propulsion engine.

[a64pilot]

It doesn't take much load to prevent glazing, 12 HP is easily enough I believe and if your worried, snick her into reverse and that is plenty of load at 1000 RPM.

[kmacdonald]

Originally Posted by a64pilot

When you guys are talking about three grand to do twin large alternators, your close to what a generator costs.
Plus if you pull that kind of power from your propulsion engine, it will be the same as being way overpropped, you will be "lugging" your engine when underway.
Unless of course you have a 100 HP or larger engine.

You would need to change the prop then. Maybe even the gear ratio and prop. You are correct in that overloading the engine will reduce it's life. It should come up to full rated RPM's with all alternators putting out max current and boat in forward.

[Jetx]

Compass Marine (a.k.a. Maine Sail, whose excellent information has already been referenced in this thread) also offers a bolt-on replacement for the Yanmar 80A alt.

Compass Marine How To's Photo Galleries at pbase.com

Would be dead simple to fit, and and knowing Maine Sail, top quality. (I'd be interested to see performance curves and know more about how this compares to the Balmar AT series, but Maine is probably too polite to brag on his own kit).

[John Holbrook]

What are the noise levels on the Nextgen 3.5 like?

I don't believe it's correct to say props are correctly matched at any given rpm. In fact props are only matched at WOT. The reason why is when you turn a prop 30% faster it will absorb twice as much HP. So perfectly matched prop on a Yanmar 57hp will absorb 57hp at max rpm of 3000, 28hp at 2,300, 14hp at 1,775 and so on. There is normally a huge mismatch in the HP an engine can make vs what the prop will absorb from idle until say 80% of the max rpm.

Here is the PDF for the Yanmar 57hp showing the crankshaft and prop HP.

http://www.yanmarmarine.com/theme/ya...monRail-HR.pdf

Heaps of room to run 2 x 200amp alternators drawing 6hp each up to say 2600rpm. If you needed 3000rpm you may need to take any load of the alternators.

My view is that as battery technology changes and becomes cheaper so you can run large loads direct or via an invertor such as aircon overnight there will be increasing demand for DC charging of 400amps or more. To me it doesn't make sense to generate AC currect and convert it to D.C.

The main engine that has the HP needed to put 400amps or more into lithium, firefly or whatever comes next batteries in an hour.

Originally Posted by a64pilot

My 3.5 kw Nexgen cost me about 5K all in.
Issue with engine loading is that a prop and engine are pretty well matched, meaning that power required o turn the prop at any given RPM closely matches the power the engine is making, so that at say 2000 RPM your engines X HP, that is right at what the prop needs, so suddenly throw an additional 12 HP demand on the engine and your overloading it, just like if you hit a hill in an automobile, but you don't let it downshift.

My 3.5 KW will pull about 200 amps of chargers and not much more, I have 185 amps of chargers and I can't run them and say an Airconditioner for example or the water heater. But with a generator your not using your main propulsion engine for battery charging, which I think will save in the long run, and you can run air conditioners and other things.
Now just my opinion, but if you want to make loads of electricity which over 200 amps is in my book, loads, then you are better off with a device that has as its sole purpose making electricity rather than trying to dual purpose your propulsion engine.

[01kiwijohn]

I've got several requests for additional info, so, rather than send a private e mail, I'll just put it here.
1. I stuck with the 80A alternator because I didn't want to incur the expense of going with a serpentine belt, or twin belts (a poor second choice.) this is about as big an alternator as you can drive on a single 3/8 inch belt, which is the standard item. To date, the belt life had been excellent, over 4 years @ about 200 hours per year. No belt dust in the engine room either.
2. The Sterling regulator has a "soft start" feature that keeps the alternator out of operation for the first couple of minutes, after start up, then gradually ramps up over 14 volts and begins "bulk charge".
3. The Sterling regulator is wired directly into the appropriate brush and you leave the original regulator in place. ( If you are in the Tacoma area, I could help you perform this , or maybe I can get a picture for you) A handy feature as, if the remote regulator fails, it defaults to the original. Obviously, this degrades the charging output, but it will get you home.
4. I mis-stated the output wire temperature. It measures about 110 (not 11) degrees F, when charging at max. I didn't record the alternator temp., although I did measure it. I did make sure I fitted both the alternator and battery bank temp sensors that came with the regulator.
5 The alternator I used is from DB Electrical, their #12272 ($80). It is listed as for the JH series Yanmars, because it has an electric tach. pick-up, which you just may not need to use.
Hope this helps get you on your way. Let me know if you still need help.

[01kiwijohn]

You know, it would be a good idea to add a small cooling fan, if you've got a tight engine compartment. I didn't measure the alt temp, but the overtemp light has never come on to date. The output wire measured at 110 degrees F, not the 11 I sent previously!

[kmacdonald]

Read and understand this: Automotive Alternators vs. Deep Cycle Batteries Photo Gallery by Compass Marine How To at pbase.com
before doing anything.

[a64pilot]

The Nexgen is way quieter than my main engine, orders of magnitude quieter.
It may not make much sense to you to make AC and convert it to DC, but in fact the best chargers there are in my experience are shorepower chargers, the alternator regulators are just not as sophisticated as a shorepower charger.
You know your alternator doesn't make DC power don't you? It makes AC power, that is why it's called an alternator, cause it makes alternating current run that through a bank of diodes and you get pulsating DC or I think you do anyway.

I started out thinking that a monstrous battery bank with inverters to run everything and a rather large DC generator to charge that monstrous bank made the most sense, then ran into the reality that while there are many AC generators so the price and availability is good, name one big DC generator?
Doing what you want is going to be a science experiment and not inexpensive as opposed to buying off the shelf proven equipment with product support and parts availability.

[Dockhead]

Originally Posted by John Holbrook

What are the noise levels on the Nextgen 3.5 like?

I don't believe it's correct to say props are correctly matched at any given rpm. In fact props are only matched at WOT. The reason why is when you turn a prop 30% faster it will absorb twice as much HP. So perfectly matched prop on a Yanmar 57hp will absorb 57hp at max rpm of 3000, 28hp at 2,300, 14hp at 1,775 and so on. There is normally a huge mismatch in the HP an engine can make vs what the prop will absorb from idle until say 80% of the max rpm.

Here is the PDF for the Yanmar 57hp showing the crankshaft and prop HP.

http://www.yanmarmarine.com/theme/ya...monRail-HR.pdf

Heaps of room to run 2 x 200amp alternators drawing 6hp each up to say 2600rpm. If you needed 3000rpm you may need to take any load of the alternators.

This

With respect to A64 -- the potential of lugging a boat engine with PTO loads is not at low power settings, but rather at high ones.

I don't see any problem taking 12hp off this engine at 1000 - 1200 RPM. That's a perfectly good load.

The propeller power curve vs the engine power curve will tell you how much headroom you have.

Originally Posted by John Holbrook

My view is that as battery technology changes and becomes cheaper so you can run large loads direct or via an invertor such as aircon overnight there will be increasing demand for DC charging of 400amps or more. To me it doesn't make sense to generate AC currect and convert it to D.C.

The main engine that has the HP needed to put 400amps or more into lithium, firefly or whatever comes next batteries in an hour.

The difference is just the efficiency losses in this vs that direction, and how much of each type of power you use. Most big boats use a good bit of both types of power, so in practice it's going to make very little difference whether you have DC or AC charging.

The main thing I like about DC charging, personally, is that you're not stuck with a constant speed engine which is not happy at low loads.

Using the main engine to drive a high powered DC alternator is very attractive -- you can possibly save a whole diesel engine in the boat. Lithium batts start to make this interesting.

[John Holbrook]

Dockhead thanks for your response. The positives I see in DC generation are mainly 1. Speed 400amps plus from two alternators on your main vs 120amps from a genset and 3kva inverter / charger, 2. Simplicity, weight saving, cost - no genset and 3. Reduced noise - main engine running for an hour to make 400amps vs a genset running for three hours to make 360amps.

Either way I'm planned big on having a large battery bank probably 1100 amp/hr of fireflies and solar panels.

I guess there are a million different variations and arguments. With a genset you can have aircon 24/7 vs maybe overnight in one sleeping cabin, you can run your watermaker, etc. You can add another charger with your genset etc.

Originally Posted by Dockhead

The difference is just the efficiency losses in this vs that direction, and how much of each type of power you use. Most big boats use a good bit of both types of power, so in practice it's going to make very little difference whether you have DC or AC charging.



The main thing I like about DC charging, personally, is that you're not stuck with a constant speed engine which is not happy at low loads.



Using the main engine to drive a high powered DC alternator is very attractive -- you can possibly save a whole diesel engine in the boat. Lithium batts start to make this interesting.

[jbinbi]

OK. I read this thread, and all linked threads with great interest. I have 2 yanmar 3ym30s with stock alternators, 460AH exide wet cell, and 580W of solar. I am in the North East USA. Primarily do weekend cruising, but boat is also in part time weekly local charter (within 100 mi of base). No generator. Was thinking of upgrading alternator or regulator. Assume 100Ah of useage per day. Also assume 1 hour of motoring a day, but with 2 engines.

Well, this thread started off well, but as all CF cruising threads that get past 2 posts, of the 44 posts here now a bunch are on gensets, a bunch of OT, etc. And maybe I missed it, but not a consensus yet on the OPs question: Buy a Balmar of keep the standard or upgrade it".

However, I think I have found some very pertinent information, at least for me, from a post from Maine Sail. I will link the post, but put in the conclusion. I think I might be OK with my current system mostly because of the solar, and the 1hour of motoring is actually at low temp and giving me reasonable V and I have 2 motors at the low temp point (even though I am getting 2 hours of charging, it is 2 alt by 1 hour vs. 1alt by 2 hour), though I am thinking of adding another 140Ah, at which point I might I need external regulation, though at this point, I don't know what external regulation I need would be.

Automotive Alternators vs. Deep Cycle Batteries Photo Gallery by Compass Marine How To at pbase.com

Do I Really Need a High Performance Aternator?

This is a premium high performance "small case" alternator and it is Denso hairpin based. For a small case alt these do quite well. When ever possible, when charging massive banks, it is best to fit a large frame alternator designed specifically for heavy duty applications. The alternator pictured here is a 165A Balmar hairpin wound alternator. Its performance to size ratio is extremely impressive but you may not need this level of performance.

Despite everything I have just written the answer may actually be; no you don't. What you need will depend largely on use, bank size and desired daily Ah use when compared to maximum desired daily engine run time.

What should I do if I have a?

Dumb Regulator W/Low Voltage Set Point - If you have an old 13.6V - 13.8V regulator, and wet cells, ditch it and get a regulator that is a minimum of 14.2V - 14.4V or even 14.6V and you will charge a lot faster. Battery gassing generally begins above 14.3 volts, though is temp dependent, so a dumb reg that does 14.5V - 14.6V will cause your batteries to need water added more often. 14.4V would be better maintenance wise but 14.6V will charge even faster and is arguably going to fend of sulfation better. If you are a coastal cruiser doing 40 engine hours per year this is a perfectly adequate option. Best case here is to convert to external regulation.

Dumb Regulator - (Non thermistor model) This can do fine provided you have minimal voltage drop in the system and it regulates to around 14.4V or so and matches the absorption set point of your batteries. While a single absorption voltage is arguably less than ideal if you are not a full time cruiser an arrangement like this can work perfectly fine. Be aware that with a large bank you can literally burn up a "dumb regulated" alternator because it has no self protective features.

Super Dumb Regulator - (temp compensated) If you tie to a dock after each sail and shore charge, you can probably keep this alternator. If you actually cruise regularly, & deeply cycle the batteries convert it to external regulation or upgrade to a higher performance alternator & regulator.

Voltage Sensing Improvements: On top of the voltage gradient issues stock alternators usually suffer horribly from voltage drop issues between the alternator and battery bank. Many stock alternators can be set up or wired to provide external voltage sensing at the battery terminals as opposed to the back of the alternator itself. Please do not try this if you don't know what you are doing. Any good alternator shop can help you with this and it can make a big difference in charging performance. The only accurate way to get accurate voltage sensing is for the negative regulator lead and the positive sense lead to be direct wired to the battery bank.

How Do I Measure The Voltage Set Point Of My Existing Regulator?

With the batteries at 100% state of charge run the engine and test the voltage output at the B+/Output terminal of your alternator with the DVM neg lead to the case or neg terminal of the alternator. The voltage should be somewhere between 14.2V & 14.4V but I would not go much above above 14.6V with a "dumb" regulator. Many regulators on Universal engines were factory set at 15.0V to try and compensate for the horrible factory wiring.

When do I Need a High Performance Alternator & Regulator


This is another high performance small case alternator. These particular CMI Alternators are a great value and start at $489.00 for a 100A model (without the regulator). The pictured alternator is a 160A model but with that type of amperage you then jump into a serpentine (multi-ribbed belt) kit.

Did I over Think My System?

In my opinion a lot of coastal & weekend only boaters, with cheap flooded batteries & whom are tied to shore charging all week, can & do often drastically over think and over blow charging systems.

With certain battery types though you really do need to over think the system. The reality for me is that I see less than 20% of the boats out there that have AGM, GEL or AGM TPPL batteries, yet nearly 60% of the coastal/weekend cruisers have fully gourmet 1.5K+ alternator charging systems with no dire need for them. Money wasted? Some times yes, when based on actual use. Like anything be realistic about your usage.

When Should I Use External Regulation?

Flooded Cell Batteries - If the bank exceeds the hot rated alternator capacity by more than 80% I recommend a smart regulator & temp sensing of both the battery bank and alternator. Eg; a 400 Ah flooded bank is comfortable with about 100 amps in bulk so a 70 amp alternator, using its hot rating, would get external regulation with alternator temp sensing at the least.

NOTE: I generally prefer to go one size larger with the alt than is needed & then derate the current output with the regulator. This allows the alternator to work less hard and run cooler. This can be done with Balmar regulators.

AGM Batteries - I always recommend external regulation with alternator and battery temp sensing at a minimum. I have seen a number of dumb & super-dumb regulated alternators burned down by the high acceptance rates of AGM batteries. Temp compensation of the batteries is a requirement for these expensive batteries and factory alternators don't do it correctly.

GEL Batteries - I always use external regulation with alternator and battery temp sensing at a minimum. GEL's require specific voltage ranges that dumb regulators just can't accommodate very often. Battery temp compensation is a must with GEL batteries.

TPPL AGM Batteries - Same as AGM

Dumb Regulator / Temp Compensated (Hitachi/Yanmar etc.) - These factory alternator regulators are horrible for deep cycling applications. Almost every Yanmar engine with a Hitachi alternator, if used regularly in a deep cycling application, should have be converted to external regulation or convert to a new alt & regulator.

Dumb Regulator / Low Voltage Set Point - If your alternator regulator is set to less than 14.2V it would be wise to invest in a better regulator.

Inaccurate Voltage Sensing - This piece of the charging puzzle can not be over looked. Many factory systems have horrendous voltage drop between the battery bank and alternator. These alternators are what is commonly referred to as self-sensed meaning they measure system voltage at the alternator BEFORE ANY VOLTAGE DROP has even occured. This can cause the alternator to go into CV / voltage limiting mode prematurely. External regulators correct for this by allowing positive and negative regulator wires (volt sensing) to be routed directly to the battery terminals. This can yield significant increases in charging performance.