AGM battery setpoints?

MEXICOWANDERER wrote:
Therefore any specification I happen to read from Optima is applied with not a grain of salt but an entire salt lick, the ones carried in the bed of a pickup truck for cattle.

LOL

Almot wrote:
Have added one more line just as when you typed your response - I have 3 batts in parallel.

With 3 in parallel I change my recommendation of FLOTR 3 to be FLOTR 6
Again to be adjusted up if storage absoption remains greater than 15 minutes after a week of charging.

RECHARGE RATE

If I am on a generator regimen time means money. If I am on constant adequate power. Rate of recharge means money. I choose to save maximum money, always.

Also, after having to threaten to use bamboo splinters on the "Application Engineers" at Optima, I am convinced beyond a shadow of a doubt that their advertising department TRUMPS their authentic almost impossible to get to real battery design engineers. Therefore any specification I happen to read from Optima is applied with not a grain of salt but an entire salt lick, the ones carried in the bed of a pickup truck for cattle.

Almot wrote:

full_mosey wrote:

I am seriously considering the discount club $170-$180 AGMs when I need replacements.

Kind of cryptic, yes. Which "club" did you mean? UPG 100 AH cost about that much.

Costco and Sam's Club.

Others have reported AGMs at Costco, I have no personal knowledge.

Sam's Club in eastern states has Duracells which are rebranded Deka. Otherwise they have Johnson Controls grp 31.

HTH;
John

Thanks much Jim! I actually understand that.

In the practical world, regarding AGM's and "inrush current level", there is probably nothing to worry about. To attain an inrush of current with a high DC voltage, enough to damage a battery, you would need some serious power supply and huge transformers. I believe they may be using the term "in rush level" to define the initial charge rate rather than the standard electronic meaning.

FWIW, I dabble with inrush current in some of the amplifiers I build. It is a matter of taming the AC inrush current so that a transformer or components immediately downstream are not damaged or their lifetime reduced. The current is limited by a soft-start circuit or the use of thermistors.

Best inrush analogy is:

Filling a tire with air..

At first the tire will take all the air your compressor and hoses can give it...That is the inrush...

As it fills up...pressure of the tire begins to increase... If your supply air is only 1 cubic foot a minute at 50 psi the tire will take longer to fill than if you had a 50 cubic foot/min at a 100 psi source.

Batteries and converters:

Our pump is the converter/charger. Current (CFM) and voltage (PSI) which are both set by the mfg.

An empty/low battery that is good will be like an empty/low tire.

The higher the current ability of the converter the more current will flow into the battery. This is restricted initially by the voltage of the converter..The higher the voltage the greater the current, up to the limit of the converter.

Filling two tires at once you could take 2 time the air at first v/s a single tire, if your compressor/ hoses had the capacity. Same?

Charging multiple batteries follows the same rules.

Hoses are like wires. Small hoses= slow filling, Small wires = low current slow charging .... Oh... Resistance...

More inrush:

Converters have inrush spec's when 120vac is initially applied.
The capacitors in there are like the tires but fill up rapidly.
about 2 cycles of the 60 per second cycle (hertz) 120vac 60hz to accomplish this, like Sal said.

DC and AC motors have inrush... When the motor is starting from stop the initial current will be great.. Not long about 2-3 cycles of 60 cycles (hertz) for most depending on the load and design of the motor.

Lastly:

Our converters have those capacitors both for input "Primary" 120vac and the output (secondary) 12vdc.

If your converter has been disconnected from 120vac and disconnected from 12vdc for a couple of minutes and you re-connect the 12vdc to the battery.... You will pull a substantial arc/flash as you connect the battery lead...completing the + and - path to the converter. That is Inrush to the DC side of the converter. Those same kind of capacitors as in the AC side...

The AC side inrush is not noticeable but those "primary" input side caps will charge.... Inrush/startup...



Jim

full_mosey wrote:
Battery specs can be a bunch of wibbly-wobbly like the phrase 5C in-rush. Precision without accuracy.

I am seriously considering the discount club $170-$180 AGMs when I need replacements.

Kind of cryptic, yes. Which "club" did you mean? UPG 100 AH cost about that much.

mena661 wrote:
I wonder how long they'll last doing that. It would be interesting to know. Still wouldn't buy them. :)

Me neither and I was not recommending them. I don't see any RV needing that unlimited charge rate. I do feel I am taking advantage of the 125F feature because mine have been IR gunned at 110F while under charge.

OTOH, I used the Deka like that last year and it seems to be healthy.

Battery specs can be a bunch of wibbly-wobbly like the phrase 5C in-rush. Precision without accuracy.

I am seriously considering the discount club $170-$180 AGMs when I need replacements.

HTH;
John

full_mosey wrote:
Optima's definition of their rapid recharge spec.

Maximum voltage 15.6 volts. No current limit as long as battery
temperature remains below 125°F (51.7°C). Charge until
current drops below 1 amp.

That trumps everyone else.

5C seems sort of puny! :)

HTH;
John

I wonder how long they'll last doing that. It would be interesting to know. Still wouldn't buy them. :)