Do flooded batteries prefer 10 percent or higher discharge?

[wopachop]

For charging I see a spec of 10-13 percent of the 20ah rating.

I'm manually discharging in the garage and curious if flooded wet cells prefer a strong discharge? Or is something like 5 percent sufficient?

[pianotuna]

Hi Mex,

Thanks for two more wisdom gems.

[MEXICOWANDERER]

BTW when the Peukert Factor becomes an issue, that's the limit for normal economic discharge in amps.

[MEXICOWANDERER]

Ablative shedding PT 🙂

A 5-amp battery maintainer would allow safe storage when the battery is at 95%. Don't play games trying to store a battery with <85% full. You will lose. I do realize tenders of 5 amps are not common but try for the highest potential.

This is where you see the value of a Meanwell or Megawatt. Mere TOP CHARGING eliminates the need for equalizing up to 95%. Set for 15 volts. When 15 volts is reached a vague timer can be used to charge one hour per battery additional then shut off. VAGUE is just that. 15 volts. If curious do look at the cells. When they bubble you're done.

Triple-digit IQ allows a user to incorporate a wristwatch to TIME the top charge and then incorporate the elapsed time from then-on instead of using visual bubbling.

But then you can forget all this and just buy batteries twice as often.

EVERYTHING above is for flooded batteries.

And is calculated from 30 years of experimentation and verification by autopsy.

[Sam_Spade]

pianotuna wrote:

Each and every time the batteries are cycled there is positive plate shaling. There is no way to reverse that.

GASP. :E
How dare you tell the truth about how wet cell batteries actually work.
:B

[Sam_Spade]

BFL13 wrote:
If in "storage", the guides say to do a deep cycle every month or whenever.

What "guides" exactly ?
And we are talking about conventional lead acid batteries....right ??

I have NEVER seen a recommendation from a battery design engineer or from a company that makes batteries that said constant float at the proper voltage is NOT the best thing to do.

If there really is a recommendation contrary to that.....from a real authoritative source, that does not sell fancy chargers, I really would like to see it.

[pianotuna]

wopachop,

Self discharge in an old aged battery may be 30% per month (less at cold temperatures, more at high temperatures). For a brand spanking new unit that may only be 5%.

Each and every time the batteries are cycled there is positive plate shaling. There is no way to reverse that.

[BFL13]

wopachop wrote:
Let me please back up and make this more of a general question. Ignoring factors like ambient temps and abuse.

Do golf cart batteries like to be exercised with normal cycling?

Or would they last longer sitting on a shelf and getting charged when they reach 70 percent?

They will last longer doing shallow cycles than if doing deep cycles. If in "storage", the guides say to do a deep cycle every month or whenever. The frequency of this occasional deep cycle depends on the ambient temp. More often in hot temps, less often in cold temps.

There is a school that says 6v GCs should not be floated so much. Just disconnect once full and let them self-discharge to about 75% then recharge them to full again. I don't know if that is better. Xantrex Truecharge chargers had the option to shut off the third, Float stage, for that reason.

[Sam_Spade]

wopachop wrote:

Or would they last longer sitting on a shelf and getting charged when they reach 70 percent?

In general, they last longer if they are KEPT fully charged when not being actively used.

That is what a smart automatic battery tender is for.

[Sam_Spade]

wopachop wrote:

I'm manually discharging in the garage

Why ?
Conventional wet cell batteries do NOT benefit from "manual discharging".

[wopachop]

Let me please back up and make this more of a general question. Ignoring factors like ambient temps and abuse.

Do golf cart batteries like to be exercised with normal cycling?

Or would they last longer sitting on a shelf and getting charged when they reach 70 percent?

[BFL13]

Of course the amount of furnace AH used depends on the RV. In the 5er barn it was a lot. 35F ambient. In the MH we have now, not so much.

30% charging rate from 50% SOC will not boil the batteries at all. In fact you get to Vabs at 60.X % SOC and then amps taper. The trick is to restore enough AH in a 50-80 or 50-90 to get by till next day's recharge.

You have to juggle AH use in a day vs how big a battery bank your RV can carry, vs how big a charger that needs, vs how big of a generator can you carry. We got away with it with the 5er because the Honda 3000 went in the truck. With the MH (see photo in Profile) no room for that big Honda (and no built- in gen), but also it is easier to heat.

You do what you have to do.

[PNW_Steve]

BFL13 wrote:
" When it comes to charging, I would not charge my FLA's at 30%"

BC is not in the PNW of course, but if you ever camp here in a provincial park in February, with your furnace eating over 100AH a day, plus whatever else you are doing 12v-wise, you would have to.

BC Campground rules say gen hours from 9-11 am or else wait till after dark 6-8pm. So if you want to get your 50-80 or 50-90 done in that two hours 9-11 when you can see what you are doing, you will need a high amp recharge and a big enough generator to run that high an amp charger.

Or else forget it, and stay home! 🙂

Wow!! 100A/H in a day!

I think you need a new furnace. In weather comparable to Vancouver BC I use 1/3 that.

There is definitely a limit to how fast you can charge FLA batteries without damaging them. 30% of C20 is going to boil your batteries and require close attention to electrolyte level. Ignore that and you will destroy your batteries.

[BFL13]

" When it comes to charging, I would not charge my FLA's at 30%"

BC is not in the PNW of course, but if you ever camp here in a provincial park in February, with your furnace eating over 100AH a day, plus whatever else you are doing 12v-wise, you would have to.

BC Campground rules say gen hours from 9-11 am or else wait till after dark 6-8pm. So if you want to get your 50-80 or 50-90 done in that two hours 9-11 when you can see what you are doing, you will need a high amp recharge and a big enough generator to run that high an amp charger.

Or else forget it, and stay home! 🙂

[MEXICOWANDERER]

The shareholders at Chevron really prefer you charge at 10% if using a generator.

Money rules. I am not spending an extra hundred dollars to save sixty dollars in battery life while charging them on a generator 🙂