How much capacity do flooded golf cart batteries start out with?

[JmanC]

If they need to be cycled up to get to full rated capacity over many cycles 100+
Then how much capacity do they start out with in early life? For those who only use them non fulltime is there some rough number to de-rate them by?

I have read some stuff that suggest their starting capacity could be as low as 70-80%.

[ranger58sb]

Depends on what size, although many assume "golf cart" = BCI Group GC2 (and Lifeline's equivalent for that is GPL-4CT).

"Deep cycle" should mean a projected 1000+ (lab) cycles, each usually recommended to be no more than 50% depth of discharge.

Common for a GC2 is about 220 Ah at the 20 hour rate, but see tables:

https://www.odysseybattery.com/Specs/ExtremeSeries

http://www.eastpennmanufacturing.com...10-17_FULL.pdf

https://lifelinebatteries.com/

I think Maine Sail has some articles about initial cycling to achieve full rate, but I don't remember it being any sort of huge number. See marinehowto.com.

-Chris

[sailorboy1]

Originally Posted by JmanC

If they need to be cycled up to get to full rated capacity over many cycles 100+
Then how much capacity do they start out with in early life? For those who only use them non fulltime is there some rough number to de-rate them by?

I have read some stuff that suggest their starting capacity could be as low as 70-80%.

I don't know, but:

When I got my current set 3 years ago they seemed lower in capacity for the first week or so (based on the AH out and the voltage in the morning), but after a week they seemed to get over it and everything was as expected.

At the time I found info suggesting to "commission" them when new by discharging down to 50% and then fully charging. I never did that and as I said they just "got over it"

[Stu Jackson]

Breaking in New Wet Cell Batteries: "Breaking In" New Wet Cell Batteries

[GordMay]

Originally Posted by JmanC

...
I have read some stuff that suggest their starting capacity could be as low as 70-80%.

FWIW: I've read 75% to 85%.
So, either way, significant.

[john61ct]

Following the proper commissioning process is **very** similar to doing an initial capacity test, timing a CC load discharge.

The former will increase overall lifespan of the bank, along with keeping C-rates low during the break-in period.

The latter will yield an objective accurate answer to the OP question, which will of course vary by many factors.

It should be repeated after capacity has reached its peak, and regularly thereafter as needed to keep a coulomb counting BM accurate.

_______
Breaking in lead batteries properly, including initial "commissioning charging" is critical to getting max longevity, and as noted, will often increase their capacity.

This process for lead banks does involve a very similar process to load testing, and done properly, and infrequently over the bank's lifetime, neither causes any damage.

But yes, capacity will likely further rise***after***the breaking in period, so do a 20-hour test before and after, and use the higher Ah result as your benchmark for comparison later on.

If not done then, your test must be compared to the mfg rating, which with quality makers in the US, is the 20-hour AH rating, but often not accurate, as MS points out, too optimistic.

Obviously the other specs are for a different purposes, so IMO just ignore them.

___
protocol:

The first few dozen cycles, go easy, avoid high current rate discharges***and***charges.

First step, really fully charge, takes 6-8 hours at Absorb Voltage, stop as per mfg spec, or endAmps tapering to .005C (0.5A per 100AH)

Then, manually follow mfg equalizing instructions, if applicable.

Next, discharge at .05C (5A per 100AH) for about 20 hours, but***stop discharging before***10.5V.

This discharge cut off voltage is by definition SoC 0%, and***much***lower than what should be ever be used in normal cycling.

But do not believe anyone claiming such maintenance routines are as "harmful" as the usual routine abuse from user ignorance.

It***would***be harmful to let the battery sit at such low SoC, so immediately as possible after that 10.5V is reached, start recharging, ideally at a slow rate, ~.15C or lower

Such slow charging should continue for the rest of the break-in period, say two months if regularly cycling, or 50 cycles over time, trying to avoid huge draw currents as well.

http://www.amplepower.com/primer/break-in/index.html

https://www.catalina36.org/comment/51915#comment-51915

http://www.sailnet.com/forums/showthread.php?p=3779746

___
load testing for SoH / 20-hour residual capacity

Note this procedure is similar to the above, so that they could be done in conjunction with each other.

This one is just more precise, requires maintaining the load at a constant as possible current rate as SoC and voltage drops.

CTRL-F search for

20 hour capacity

At MS's site here*https://marinehowto.com/programming-a-battery-monitor

Better yet, read it all, and check out the rest of the site.

[sailcrazy]

following

[EmeraldCoastSailor]

I didn't do anything special for my 4 6v batts 4.5 years ago. I hope I didn't make a mistake.

[john61ct]

True for 99.99% of owners.

Result is that bit less longevity, impossible to quantify.

Might still last a decade, if. . .

[Jim Cate]

In reality, the chances of a cruising sailor having the equipment and facility to go through the break in or even one proper test cycle as advised are pretty slim. So, simply trying to avoid big loads and over high charging currents (not usually a problem!) with new batteries is about the best you will do... and this is how we've done it for decades. have we lost some minuscule fraction of life... who knows, and really, who cares? The money savings in slightly extended lifetimes surely wouldn't pay for the test equipment and time expenditure for the elaborate break-in and frequent testing.

And the "need" for this procedure to accurately calibrate a coulomb counter... sheesh, we don't have such an item to start with and feel no need for one, calibrated or not! The obsession with knowing (maybe) just how much charge is left in your bank is over played IMO. A little time spent monitoring rest voltages gives a rough idea, one good enough to avoid excessively deep discharges, and for the non-plugged in cruiser, that's the crucial factor.

Does my less than "best practice" system work? We (full time anchor-out cruisers) have been getting around 4 years from a bank of 4 T105s. With a recent upgrade in solar power, we expect to improve that a bit, mostly from keeping the average charge state higher in low sun periods. Would a SOC monitor improve that? I really doubt it, for it won't increase insolation or reduce consumption or make the wind blow harder.

But as always, YMMV due to different usage factors.

Jim

[john61ct]

Yes these maintenance protocols are easiest to perform on mains power on a bench.

And most will not bother acquiring the knowledge and gear needed.

But it is possible to get most of the way there with crude approximations, once the best practices are understood, for those that are motivated.

[JmanC]

All good replies, thanks!

In my area trojan t105 are pretty pricey so I would at least stick to good practices & try get the best out of them. Only small loads and never go over .13C charge rate. Try get back to 100% as much as possible and EQ when ever needed. This by the looks can be all done in field without lab equipment.

For me a capacity test in nothing more than a light bulb drawing around the C/20 load at full and count the AH with monitor.

I love flooded for their simplicity & toughness.

I had a 1year old 155AH 12V floor sweeper style true deep cycle used for standby & never cycled besides a few dozen re-charge absorb cycles, that I accidentally let drain down to 4V OCV over a month or so from small loads (few led lights). After a top up I let sit on float for a few weeks until my charger with EQ arrived. Took about 4hrs+ of EQ until all cells were even according to 20$ hydrometer. As a rough crude guide it looks like it has roughly 80% of its capacity still judging by running it down to 12V under load. So I wonder is that faded capacity mostly from going down to 4V or simply not breaking it in?

[JmanC]

Originally Posted by Jim Cate

Would a SOC monitor improve that? I really doubt it, for it won't increase insolation or reduce consumption or make the wind blow harder.


Jim

Very wise words. It's so obvious to me that Monitors are alot of learning to get right & offer no real advantage for the experienced and well setup. All they do is waste the user's time with babysitting. Always wondering are they accurate. Such nonsense. They make absolutely no difference to the clouds and once you know solar it becomes second nature how to setup panels based on location, time of year etc.

[Pete7]

Originally Posted by JmanC

I have read some stuff that suggest their starting capacity could be as low as 70-80%.

New Trojans fitted in the Spring. Possibly 70-80%, but we didn't measure or actually couldn't be bothered to sit there and measure the voltage for 20 hours what we did notice is the first couple of days the voltage did sag quite quickly in use and perhaps more than I was expecting. However, after a fortnights use of discharging and charging the capacity rose, the voltage didn't sag anything like the first use and the observed voltage at dawn as expected from new batteries.

As Jim says few have equipment or inclination to do a capacity test on each battery in a bank of new FLAs. That's the difference between internet theory and practical application of people with boats replacing a bank, no easy task on a mooring buoy or at anchor. Even lugging them down the pontoon and on board is quite enough thank you.


Pete

[Pete7]

Originally Posted by JmanC

Very wise words. It's so obvious to me that Monitors are alot of learning to get right & offer no real advantage for the experienced and well setup. All they do is waste the user's time with babysitting. Always wondering are they accurate.

Hmm, yes and no. Our Sterling BM is plug and play and has no facility to enter battery capacity. Doesn't appear any the worse for that.

It does have a useful function in that it tells me how much we are using at any one time and a running total of what we have left. Just occasionally we may modify our routine, but you tend to know when there is going to be a problem, as you say "clouds" and using a lot of power at the same time.

Pete