Firefly Batteries are now in stock!

[a64pilot]

I think if I was in a marina for extended time, that I would disconnect the bank and run my charger in power supply mode.
I wouldn’t want to continuously cycle it daily, that surely would shorten life.

[OceanPlanet]

Originally Posted by jkleins

So when you say no float, does setting the float to something like 12.8 do that? What do you actually mean by “no float”. When we are plugged in to shore power any power you use is basically “pass through” at whatever the float voltage is I guess. Is the battery doing anything at a lower voltage like this?
When I first bought mine I was told 12.8 then “no float” then 13.2 now 13.4. I have decided since you can’t decide I won’t either and just randomly pick one whenever I happen to be in a marina. [emoji3]
Seems as scientific as anything I have heard but I am open if there is actually new data. [emoji3]

We had originally been given 13.2 by FF, then a couple years ago they upped it to 13.4-13.5. however simply cycling (using) them is apparently preferred to floating.

Another option is if you have a shore charger that is rated as a power supply, when plugged in and after batteries are charged the batteries could be switched off completely and the boat simply runs off the shore power supply.

[billknny]

We have had our Firefly install for almost two years of real life cruising mostly away from shore power.

We couldn't be happier with them. We use an Balmar SG200 to monitor. After several months away from shore power, and not always bring them to 100% every day, we saw the SG200 report a "state of health" of 78%. With one deep discharge and full dockside recharge, they are back to 100%.

More details here: https://fetchinketch.net/boat-projects/battery-upgrade/

On a scale of 1 to 10, our happiness with these is 11. Especially since we are getting 80% of the benefits of a Lithium conversion at half the cost.

[FlyingScot]

Originally Posted by OceanPlanet

IIRC, one of the Firefly engineers said something about 13.2 being too close to the fully charged resting voltage, and that for some reason that wasn't good. Couldn't get a detailed explanation, but 13.4-13.5 was what we were told so we're going with it!

I think the lowest voltage that prevents any use of the batteries would be best.

If you have a battery monitor with shunt (or accurate clamp on meter), you can see if any power is leaving your batteries once at float voltage. If so, a little higher float voltage would prevent 'micro cycling' and I think that would minimize wear.

[s/v Jedi]

Originally Posted by OceanPlanet

We had originally been given 13.2 by FF, then a couple years ago they upped it to 13.4-13.5. however simply cycling (using) them is apparently preferred to floating.

Another option is if you have a shore charger that is rated as a power supply, when plugged in and after batteries are charged the batteries could be switched off completely and the boat simply runs off the shore power supply.

We simply use the “emergency switch” to parallel the starter battery, then disconnect the house bank with it’s main switch and run on starter battery + solar & shore power We have left AGM batteries disconnected for long periods, like 8 months and find them at 70% SOC after that.

[john61ct]

Really best to store any lead at 100% Full, and counteract self-discharge by topping up every few weeks.

A voltage lower than resting 100% Full means losing a lot of lifetime cycles.

Fully isolated, that's what no Float means, use Starter to buffer shore power if needed.

If you can't do that, then the balance between Solar input and Loads outgo will determine how you handle it, whether or not House needs to be involved or not and if so what setpoint you adjust to.

Optimized care for longevity is simply not possible in many circumstances, compromises often required.

[jkleins]

So what does float do when set to a low value? Doesn’t it just keep the voltage from going below that value by providing charge if needed? If the batteries are full and the float voltage is set to some value below that and nothing is being taken out of the batteries because the power is all being supplied by the charger does the battery really cycle?

I ask because our boat has solar that is just enough to keep the batteries up if the sun is out with the refrigerators on. If it gets dark for several days the batteries may get too low so we have been reluctant to leave it in the charger standby mode while not on the boat (which is what we do when on the boat).

When we originally bought our Firefly’s the technician interpreted the “no float” to be 12.8 and set the charger up to that. Bruce put out a Balmar settings guide that had 13.0 set as float shortly thereafter (that is what I still have on my regulator settings - Do I need to upgrade that value as well?). I have kept up with the changes mentioned on this forum to float to 13.2 and now to 13.4 but that doesn’t mean the reasoning has been any clearer to me.

Since I don’t hook up that often it has been a minor issue in the past 3.5 years but I am going to be at a dock for a while and would like to leave the fridge running and am more interested now in how best to do it. I may just do what Jedi suggests since I have similar setup but I would like to understand what is going on in float even if I do that.

Jim

[john61ct]

Originally Posted by jkleins

So what does float do when set to a low value? Doesn’t it just keep the voltage from going below that value by providing charge if needed? If the batteries are full and the float voltage is set to some value below that and nothing is being taken out of the batteries because the power is all being supplied by the charger does the battery really cycle?

Even if there is no load, batteries self-discharge.

Instead of Float, which means "voltage to maintain 100% Full",

a lower voltage will result in maintaining a lower SoC%, let's call that a Storage voltage level.

That is more appropriate for LFP, where storing at Full is harmful, as opposed to lead banks, where storing at Full is required for longevity

So, if at 100% SoC, VOC isolated at rest is 13.15V, then a storage charge maintaining 12.8V for example might result in the bank sitting at ~90%, which for long periods, is not ideal.

If your solar input is enough so that the Starter motors or other much cheaper lead is enough buffer, and the FF bank can sit isolated at 100% Full, that is best for its longevity.

If not, then you need to let it shallow - cycle to carry the "storage loads", at the usual 14.4/13.4V settings.

In another "pure Float storage" scenario, no loads, I personally would stick to the original 13.2V, but in reality

No Float isolated storage, and just a topup to counter self-discharge every few weeks would be best.

In any case, after such a long time sitting or barely cycling, I would run the Restore Capacity protocol before resuming cruising / normal deep cycling patterns.

If stored for years doing that say every three months would probably be a good idea.

[jhulmer]

Originally Posted by john61ct

From my past notes:

Charge the FF to between 14.2V and 14.6V, 14.4V ideal, with temp compensation of course (CC/Bulk phase) and continue*charging*until the*charging*current*drops to 1.5A (CV/Absorb phase, time will vary).

The Oasis does not require a float charge when cycling, ideal is "just stop" as with LFP.

But, if you need to float: 13.2V is better for longevity than 13.4V, especially for charge sources that may be active for an extended period of time (solar, shore or even an*alternator*if motoring for a while). 13.4V for an alt on for shorter periods is NP.

Reset to bulk phase: for programmable charging sources, adjust the “reset to bulk phase” to occur if the*battery*voltage drops below 12.0V for >1 minute.

Corrections from Bruce or Rod most welcome.

Originally Posted by OceanPlanet

Should go for the custom programming...whatever it takes to get to the desired 14.4V charging voltage. I don't know what the Pronautic "carbon foam" setting are, and they never asked us what to use, that I can recall.

Thanks guys this helps a lot. I will program in these parameters and see how it goes.

[OceanPlanet]

FWIW, here are the latest Balmar programming specs and general manual.
Note that both the Wakespeed WS100 and Mark Grasser R210A regulators have a preset selection for Firefly already programmed in.

[jkleins]

Originally Posted by OceanPlanet

FWIW, here are the latest Balmar programming specs and general manual.

Note that both the Wakespeed WS100 and Mark Grasser R210A regulators have a preset selection for Firefly already programmed in.

Thanks. Those are different then my sheet.

[paradox]

What is the difference between the G31 and E31 Firefly batteries?

How does the BMS function?
is it one bms per battery or one per bank?

[OceanPlanet]

Originally Posted by paradox

What is the difference between the G31 and E31 Firefly batteries?

How does the BMS function?
is it one bms per battery or one per bank?

In North America we're only selling the G31. The E31 is/was simply a lower capacity version, as far as we know.

What BMS? Typically for a Pb battery system no one uses a BMS.

However, on a big bank built up with the 4V packs (3S for 12V x 450Ah, 6S for 450Ah, etc.) you could use 2V Pb cell balancers that we've tested in the shop lately. They work for balancing, although jury still out as to whether they're really needed. Will take extended monitoring of a large bank using 4V packs to assess, and most boats tend to sail off and can't be bothered to check the 2V cell segments...;-)

[john61ct]

As with any manufacturer, the different sizes may share the same chemistry, similar care requirements, but different performance details.

Obviously the different sizes fit different Ah totals in different space limitations.

4V units will get you to larger total bank sizes with fewer balance issues than 12V units, and everything else being equal will last longer.

What makes you think there's a BMS involved here? Have yet to see one used for lead.

[Mick of 42]

I have these that seem to have the same technology...

https://www.aussiebatteries.com.au/b...n-lead-battery