Gel or Flooded?

[Pete7]

Originally Posted by a64pilot

I keep getting back to this one thought though, if the Gel is so good for deep cycling Solar systems, how come it hasn’t taken over the market completely?

Gel ought to the true install and forget battery, no maintenance at all, no equalizing, but three times the cost of flooded.

I suspect that the vast majority of batteries supplied for boats by chandlers are cheap SLA or FLA and the upfront cost of Gel is the problem. 3x price being the factor that people focus on to choose batteries, rather than the overall cost for the life of the battery. However, that is no reason to follow the average weekend sailor. Those who read forums like CF for any length of time will have a far greater understanding of battery technology, but they are in a minority.

Pete

[Michael Cobbe]

Calcium batteries are becoming popular details are: Calcium replaces antimony in the plates of the battery to give it some advantages including improved resistance to corrosion, no excessive gassing, less water usage and lower self discharge. Calcium batteries require a higher charge voltage than conventional batteries.I don't know if they are sold in the USA.

[Pete7]

Calcium is a popular additive to engine start batteries in Europe, just not sure it's added to good quality deep cycle batteries.

Pete

[Sternwake]

There is a maximum charge rate for gels, but what is it? 20 amps per 100Ah of capacity? 15?

I know that Gels are supposed to have lower absorption voltage, but that does not mean one can just deplete it to 45% SOC then fire up their 100 amp charger set to max out at 14.1v on 175Ah of gel capacity, as 100 amps will still flow for a minute or 5 and perhaps cause the capacity destroying voids in the gelled electrolyte.

How are gels from a CCA standpoint? voltage retention under high loads like an inverter powering a microwave? I've never read much on that ability either concerning gels. Seems all I read about gels now is their incredible longevity in some applications. The horror stories of yesteryear are apparently forgotten.

Are these minstrels in the hills writing their poetry about Gels in off grid home, mainly fulfilled by low and slow solar? Low and slow solar only recharging makes my AGM lazy, even achieving the threshold amps at absorption voltage regularly. The sucker craves high amp recharges from a well depleted state, in my experience, and I got 1300+ deep cycles from my last one, before retiring it to light cycling duty.

As a datapoint,

I had my 3 month old 103AH g31 Northstar AGM 72Ah from full last night, and it accepted 133 amps for a few minutes before the 15amp AC circuit breaker tripped, with two PFC power supplies in parallel, something I'd never try with gel. I continued on with ~93 amps from the one source and it took a ~10 minutes more for it to hit 14.7v.
It was an experiment, I am not going to charge at this rate every time.

I still don't know how many amps would be required to hit instant absorption voltage from that level of depletion. I assume 150 to 160. I can't achieve that with my charging sources, and never am in so much a hurry that I'd need to, and the '100 amp' converter which maxed out at 93.7, is not mine. I was installing a better voltmeter, adding ventilation, and a more precise voltage adjustment potentiometer into it.

Lowering absorption voltage is likely not be enough to protect a depleted gel from overcurrent, if one has a capable alternator spinning fast, or a mac daddy mains charging source capable of 100 amps or more.

I personally like a battery which is not going to be damaged by high currents, charge or discharge, and with gel it seems one needs more capacity to prevent this potential occurrence, or a method to prevent overcurrent when charging, not sure whether current limits apply to discharge as well.

Does Firefly spec a minimum/ maximum charge rate?

[a64pilot]

Old Gels you had to baby a little as to how hard you put charge in and took it out, I’m pretty sure that was to prevent gassing, if a gel gassed then I believe it could form a bubble on the plate, that bubble kept the electrolyte from touching, so you lost that portion of the plate, cause being a gel and not a liquid the bubble was trapped. Flooded battery the bubble rises to the surface and I think an AGM is sort of a wet blanket if you will so the bubble goes away also.
However the Sonnenschein link that was posted earlier says you can now hit their new gels pretty hard, and includes the Deka battery in that statement.
Only “hit” my bank sees is starting my little baby Diesel and that’s for about 1 sec., so I want concerned about that.

But either way I wasn’t worried, 40 amps per battery is about the limit for Gel and if I have 6 of them, that 240 amps of charging, which is more than I have, and I wouldn’t mind turning my charger down to 100 amps anyway.
Primary charging is Solar and I never see more than maybe 40 going in because by the time of day that the panels can put out a lot, battery acceptance rate limits what they can make, so I’m in absorption voltage.

Firefly claims that they will accept a higher charge rate than any other LA battery and hold it to higher SOC before it tapers off than any LA battery.
You can pretty much take any claim about a LA battery and Firefly says it’s better, so much hype that it make me mistrust the clams, wondering how much is real, and how much is marketing magic.
If their claims weren’t so outlandish, I’d be way more acceptable of them.

No, by taking over the Solar market by Gels, I don’t mean our tiny little banks on our boats, but some of the house guys build buildings and fill them with batteries to hook up their multi kilowatt Solar banks to. I would expect to see massive 2v gel cells in those buildings, in series to make a BIG maybe 60ish V battery? I mean little entire buildings dedicated to where the batteries are stored.
The higher the voltage, the better, and parallel wiring of batteries I believe brings about different SOC’s in each battery that worsens over time.
Other than the ability of being able to remove a bad battery and drive on, paralleling is I believe not the best way to connect a string of cells or batteries.
I had hoped that with regular equalization, that would bring my individual batteries all to 100% SOC, and then of course they would begin to drift in SOC, then equalize again.

[Montanan]

Whether you go with Gel or Flooded just be sure to use caution when loading from the dock.

http://solifequotes.com/wp-content/u...animals-23.gif

[a64pilot]

Originally Posted by Pete7

I suspect that the vast majority of batteries supplied for boats by chandlers are cheap SLA or FLA and the upfront cost of Gel is the problem. 3x price being the factor that people focus on to choose batteries, rather than the overall cost for the life of the battery. However, that is no reason to follow the average weekend sailor. Those who read forums like CF for any length of time will have a far greater understanding of battery technology, but they are in a minority.

Pete

Go to a nice Marina, the ones with the newer high end power boats, not cruisers.
Every year in early Winter when the owners arrive you start to see the local mechanics with wagons full of West Marine 8D AGM batteries, they all want AGM’s cause the guy at WM says they are the best, they must be, they cost the most, right?

So average person I believe just really doesn’t know squat about batteries, period, average cruiser doesn’t either. So they go to the local Chandlier and the most expensive battery in stock is that God awful monster of an 8D in AGM, so it must be the best or it wouldn’t cost the most, right?

Every day last year in Georgetown after the cruisers net there were several people wanting to borrow battery testers. They had been there for a week or so and now are waking up to low battery alarms. They must have a bad battery, cause the little light comes on their solar controller every day often by Noon telling their battery bank is full.

None would believe that their batteries were fine, just chronically undercharged and that their little solar panels weren’t fully charging them up every day.
They works fine on the trip over from Fl because they motored are least every other day or so, but now after a full week at anchor they have battery problems.
The batteries are charged, they have to be, the light comes on. They won’t accept any other possibility.

The others without Solar run their engines at idle for 30 min every afternoon, so they too know they are charged.

OK, so I’m being a little mean, but honestly most don’t even have a clue.
I need to make up some cards with Marine How To’s address on it and just pass them out.

[RickG]

Originally Posted by a64pilot

Firefly claims that they will accept a higher charge rate than any other LA battery and hold it to higher SOC before it tapers off than any LA battery.
You can pretty much take any claim about a LA battery and Firefly says it’s better, so much hype that it make me mistrust the clams, wondering how much is real, and how much is marketing magic.
If their claims weren’t so outlandish, I’d be way more acceptable of them.

Fireflys work as claimed for us. They recommend charging at 0.4C or higher and up to 3C. We can only put 120 amp into our 800ah bank. They recommend discharge at up to 0.7C. The key for us is that our solar chargers can stay in bulk charge up past 95% SOC; they love to suck up all the current they can without getting hot or gassing.

Cheers, RickG

[a64pilot]

With the way the firefly works, why did you go to such a huge bank (800 Ah’s)?
You should be around 400 AH or less, assuming 80% useable capacity.
Just wondering.

[sailorboy1]

So A64 what is your verdict?

[rslifkin]

Originally Posted by a64pilot

With the way the firefly works, why did you go to such a huge bank (800 Ah’s)?
You should be around 400 AH or less, assuming 80% useable capacity.
Just wondering.

Bigger banks handle high momentary loads better (some chemistries also do this better, but within a chemistry, bigger bank will be better). So for someone who has some high momentary draws from their inverter or something (like making coffee or toast), they may want a bigger bank than they strictly need capacity-wise just to reduce voltage sag under those loads.

[RickG]

Originally Posted by a64pilot

With the way the firefly works, why did you go to such a huge bank (800 Ah’s)?
You should be around 400 AH or less, assuming 80% useable capacity.
Just wondering.

You know about keeping the Admiral happy? I occosaionally travel back to the US for work. The Admiral wants nothing to do with that. I designed our system so that we can go three cloudy days without having to run our Honda generator. I leave the generator fueled and ready to start. She’s only ever run it to heat water.

The last time we used the shore charger was at Puerto del Rey Marina, Fajardo PR after hurricane storage last year. The batteries were at 12.7V after storage and no charging; the solar panels were stored below.

Fireflys just work.

Cheers, RickG

[argonauta1]

Forget Gel. I switched to golf cart deep cycle and never looked back. Lots of flex in configuration and stowage no more no less.

[KetchJohnB]

AGM. Duracell AGM Deep Cycle Marine and RV Battery at Sam's club. They are East Penn's and are identical to what West Marine supplies (as of 1.5 years ago).

[lituya1617]

My 43-foot cruiser featured two 8D heavy equipment batteries and a Delco 65 amp automotive alternator (internally regulated). This setup lasted for ten years and the batteries were like new. The boat used a lot of power because a large freezer, many lights, a forced-air galley stove, and electronics. So, what is wrong with this old fashioned way of battery use?