FireFly Battery Operational User Notes

[jack630]

The FF batteries work great. They are a huge leap over wet LA batteries. I think the problem is that alternator technology has not kept up with the battery technology. The FF's made a big leap with the carbon foam technology but the alternators have not matched it. The problem with the alternators is heat. They can put out the amps but can't get rid of the heat or at least can't tolerate the heat they produce. For what you pay for these alternators they should be able to handle the real world of an engine compartment not just a lab bench.

We have the Balmar 200AT alternator, the MC-614 regulator with temperature sensors and the Balmar Smartgauge. I use MarineHowTo's recommended settings. I occasionally use an IR temperature gun to read the case temperature of the alternator and I have seen temperatures of 235 F at the top of the case during bulk charging even with a high BM of 6. That's why I turned the BM to 7. The regulator temperature sensor is on another location that I can't see with the IR gun but the regulator is set at the factory setting of 212 F. The regulator temperature sensor doesn't seem to read the high temperatures that I get with the IR gun.

[zboss]

The firefly restoration charge requires that you almost completely discharge the battery way below 20% and all the way down to 10.5 volts which is basically dead.

When plugged into shore power for more than a day or two we generally set a straight float voltage so we don't overly stress the batteries and let the solar do its thing. Otherwise, we keep the standard 14.4 three stage charging scheme the same for the solar since we are cycling the batteries every night.

I wish there was a system that would automatically set the operating mode of all the charging sources to programmed setting depending on known inputs - like how discharged the batteries are and if we are plugged into shore power - so we don't have to manually configure all those systems.

When we have deeply discharged firefly batteries we do see the balmar regulator attenuate output because the alternator gets so darn hot in bulk mode. We have the belt manager turned all the way down and I recently set the regulator to "small engine mode" to further reduce chances of overheating.

[sailorboy1]

This is thread, but i would think if your alternator was getting hot the answer would be to install a blower to keep it cooler.

[GinoDelG]

We live aboard Our 44 foot sloop full time and have four Firefly 31s as house batteries for the last five years. We recently bought the new Balmar SG200 and its showing the Fireflies still have 100 percent capacity. The batteries rarely drop below 80 percent because our 340W solar panel keeps them topped off. However, when its cloudy for a few days and we don’t move, the batteries will drop well below 50 percent with no apparent damage.
Last fall we did a restoration because I suspected the batteries weren’t reaching full capacity and according to the SG200 they’re operating like brand new. We love these batteries.

[a64pilot]

Originally Posted by sailorboy1

This is thread, but i would think if your alternator was getting hot the answer would be to install a blower to keep it cooler.

Very ineffective as the alternator has two internal blowers anyway, it helps, just not much.
Derating by belt manager is helpful, mine is set to 4, however the alt still temp limits, just with a higher belt manager it takes longer to Temp limit.
I limit mine to a conservative 90C, and at my normal cruise of 1800 RPM that will give me a continuous output of an 90 amps from a 165 alt.

Seeing as how the cooling fans and mass are identical for a 200 amp and a say 150 amp alternator, I’d bet their continuous limit is very close, because of course cooling is what determines that limit and I don’t see any increased cooling with the BIG alts.
Now they are wound differently and that is likely to increase efficiency, but I’d bet the final result isn’t all that much different.

Now of course an alternator is cooled by its internal fan, and fan speed will increase airflow which ought to increase cooling, so if I were to cruise at a much higher RPM, I feel sure I would get more than 90 amps, how much I’m unsure.

On edit, having the alt drop to float by field strength is an attention of course to drop to float when battery acceptance is down, but it’s never really going to work, the reason is it’s a measure of alternator output, not bank acceptance so the boats consumption throws it off, fridge cycling, autopilot, Radar etc will all cause errors, so it’s just at best a guess.

I can’t understand why Balmar resets to absorption on a long motor either?

Personally I’d like a simple switch up is absorption voltage, down float, let me control it, but only one manufacturer that I know of had a “force to float” switch.

My personal opinion is that an alternator ought not be considered a primary charge source for a long term cruiser. Solar and or maybe wind as primary and a generator to fill in any shortcomings as necessary

[sailorboy1]

I am 100% positive of reading a Calder article showing a blower was VERY good in cooling an alternator.

But this is thread drift

[admiralslater]

I installed 120 alternators with a constant rating of 80 amphr (I think) one of them got very hot . It was a new install and one of the belts needed tightening. I am not sure what level the batteries where that required such a long heavy charge but our 5 charge so quickly that alts. shut them selves down. We also have good solar
I second a controller that integrates the different charge sources

[a64pilot]

Originally Posted by sailorboy1

I am 100% positive of reading a Calder article showing a blower was VERY good in cooling an alternator.

But this is thread drift

It’s thread drift sure but you started it, why not go with the same guy’s generator then? Pull 7,000W continuous?

If it were that effective, I guess Balmar and others etc are missing the boat because a blower is cheap to add and they could jack the price way up and make good money. In fact I’m surprised they haven’t done just that.
Blower ducts for alternators do exist, Porsche and other car manufacturers use them, mostly I believe to duct cool outside air, but it would be simple to add a bilge blower and hose

If you choose to add a blower, do so to the backside as it’s the hottest as the diodes are back there.

Best way to get high power from an alternator is to either go with a larger frame alternator that’s designed to produce high power and has better cooling to begin with, or remove a large portion of the heat producer, remote mount the diodes $$$.

However as Yanmar publishes 4 HP being the max I’m allowed to pull off of my crankshaft at 1800 RPM and 4HP = 100 amps from an alternator, I’m happy to live with 90 amps and leave a little room before I exceed the engine manufacturers limit.

With the exception of very large banks, or lithium banks, pulling 100 amps for long from an alternator doesn’t happen often, depending on SOC and bank size, you hit absorption voltage in 10 to 15 min or so and from them on the amps begin to decrease of course.
Now if you have an inverter and are using it to run your AC watermaker, then you can pull a lot of amps for quite a long time, it takes 90 amps or or to run my watermaker.

Point is however, in the search for higher power from an alternator, don’t forget to look up how much power your allowed to pull from the front of the crankshaft.

[sailorboy1]

Originally Posted by a64pilot

It’s thread drift sure but you started it, why not go with the same guy’s generator then? Pull 7,000W continuous?
.

Wish i just knew everything

Btw it the balmar alternators are great at cooling themselves why do the regulators have temperature input.

Never mind it doesn't matter to this thread. All that matters is Firefly battery users should consider protecting their alternator. That is only IMO of course.

[a64pilot]

Well to continue with the drift if you will, I don’t think Balmar or any other alternators alternators are that good at cooling themselves, they are pretty much simply off the shelf factory alternators that have been modified or “hopped up” if you will, and I believe that the cooling isn’t any better than the stock alternator.
I don’t know of any high performance marine alternator that is an actual special build just for boats, I think they are all modified.

However I’d also bet that the acceptance rate of a Firefly may not really be all that much higher, but it’s that people are more comfortable with discharging their fireflies deeper, and it’s the depth of discharge that is the reason why they may be harder on alternators, if you discharge a Lifeline to 30% then it’s going to be a long bulk phase too.
However if you look in the Firefly Manual, deeper discharges cut into cycle life just like any other lead acid battery.

The cost of thermal protecting an alternator if you have an external regulator that will do so is so small that it’s foolish to not do it.
I also believe that pushing an alternator past 100C won’t cause it to fail immediately, but it will shorten its lifespan.

[jack630]

I agree. These alternators are probably only marginally better than stock alternators. My understanding is that the diodes could be moved to a cooler location but in my opinion that will not solve the problem entirely because the next thing to go is the varnish on the coil wiring resulting in the whole alternator shorting out. They probably haven't improved the varnish for 50 years. I'm sure there are companies out there that make high temperature tolerant diodes and coatings. Until these companies step up their game, controlling the temperature with the regulator is the best you can hope for.

I like the previous comment, that the alternator shouldn't be considered your primary charging source.

[Capdave360]

Originally Posted by jack630

I agree. These alternators are probably only marginally better than stock alternators. My understanding is that the diodes could be moved to a cooler location but in my opinion that will not solve the problem entirely because the next thing to go is the varnish on the coil wiring resulting in the whole alternator shorting out. They probably haven't improved the varnish for 50 years. I'm sure there are companies out there that make high temperature tolerant diodes and coatings. Until these companies step up their game, controlling the temperature with the regulator is the best you can hope for.

I like the previous comment, that the alternator shouldn't be considered your primary charging source.

Alternators like this Electrodyne are designed for the kind of charging people describe with continuous high charge rate. I installed one of these on a 250hp Cummins in an Oyster 61 and drove it really hard - it was awesome.

E-Series Models | Electrodyne | Brushless Automotive Alternators

[sailorboy1]

Any consensus for a setting for the Charge Efficiency in a battery monitor for FF?

And yes no matter what you chose it is only at best good for a narrow charge amperage and WAG.

[RickG]

Originally Posted by sailorboy1

Any consensus for a setting for the Charge Efficiency in a battery monitor for FF?

And yes no matter what you chose it is only at best good for a narrow charge amperage and WAG.

Good question. I had it set at 95% and still saw 22 amps going into the bank when the BMV-712 thought it was at 100%. At the beginning of this thread I dropped it down to 92% and then 90%. Not much changed other than the weather. I do see 52 synchronizations on the BMV-712 in the last 3 months. The Victron SmatSolar 100/30 controllers rarely go to float unless we are on shore power overnight. I think trying to reconcile the numbers is a hopeless task given the assumptions, modeling, and best guessing going on. We are in Grenada so a cool battery compartment is 86F.

Cheers, RickG

[sailorboy1]

I got my new FireFly G31s down into the boat and into their boxes today.

Talk about fancy, they come in individual boxes!

So since they come in a sealed box I wonder how long since they were charged. But they measured between 12.78-12.81V. Since I don't have the jumper cables yet only 1 got wired up. It was only accepting 1.5A at 14.2V so it basically is completely charged after who knows how long.