Mixing Battery types in 1 Bank

[sailorchic34]

Actually 13.8V and 14.4V would be correct for lead acid batteries.

13.4 and 14.1 is what gels are normally charged at. That would not hurt the LA ether, though may not charge the LA all the way.

It's possible that your battery charger has a equalizing mode which raises the voltage once a month to desulfate the plates.

Another cause of out gassing is a shorted/bad cell in on battery.

BTW Colemj beat me toit and is correct. Absorption for LA can go anywhere from 14.4v to 14.8v. Most chargers are set by default at 14.4V.

[colemj]

Originally Posted by sailinglegend

I'm sorry if some didn't understand my expanded water tank analogy, but this is a standard Nigel Calder explanation of battery charge acceptance, but he uses membranes within the tank not additional tanks with a restrictive pipe in between. So if you disagree with my analogy then argue with Mr Calder. I have taken his analogy with two tanks with different internal resistances, or different membranes, and I have even joined them together with a very large pipe. Some people here just do not read posts properly before jumping in with both feet. That is plain rudeness. Nowhere did I suggest these internal tanks were cell analogies, they are representing the difference between the surface areas of the plates and the internal areas.

You know, I had a peek at Calder's book and the explanation you are citing.

He not only was discussing series cells (as I stated), he was discussing an individual cell. Like you state in your last sentence, he was describing an analogy for a high surface charge to migrate throughout a thick plate.

His analogy has nothing at all to do with with mixing batteries, or even putting two of the same type of batteries together.

My description the water tank is correct - if used to describe two batteries (of any LA type), then the pipe connecting those batteries is large in comparison to the fill and drain pipes.

Your expansion of Calder's description, as well as your application to multiple batteries, is incorrect. I don't have to argue it with Calder, because I agree with his analogy (although I always find water tank analogies more confusing than the actual electrical models they are trying to represent).

Mark

[colemj]

Again, I don't understand the "boost" function, but 13.8V would be a bit high to float FLA's - if that is what the lower number means. Probably would not do much damage floating it there, but it is a bit high.

Mark

[monte]

OK thanks, though that's not helping much if the cause of the smell isn't related to the charging levels.
Heres a pic from the manual and details below.
The smell is rotton egg gas and the electricians working on board agreed is is pretty strong.


BOOST in ON position
With this setting the CPS3 charger delivers a 3-state load curve IUoU: BOOST, Absorption, Floating

U Boost: BOOST voltage (see table above)
U Floating: Floating voltage (see table above: voltage with no BOOST)
T Boost: BOOST maximum duration (see table above)
Boost phase: starts up automatically when the charger is turned on if the battery is flat. The current is
then at maximum output.
Absorption phase: begins when the voltage has reached the maximum BOOST level. The current level
starts falling.
These two phases combined last a maximum of TBOOST (depending on setting). If the current falls below
20% of rated current, the floating phase automatically kicks in. Duration and current intensity depend on
how charged the battery is.
Floating phase: starts after TBOOST or if output current has reached 20% of the charger's rated current.
The voltage switches to the Floating value and the rated current continues to drop.

[monte]

Heres a pic of the boost function

[sailorchic34]

Originally Posted by colemj

You know, I had a peek at Calder's book and the explanation you are citing.

He not only was discussing series cells (as I stated), he was discussing an individual cell. Like you state in your last sentence, he was describing an analogy for a high surface charge to migrate throughout a thick plate.

His analogy has nothing at all to do with with mixing batteries, or even putting two of the same type of batteries together.

My description the water tank is correct - if used to describe two batteries (of any LA type), then the pipe connecting those batteries is large in comparison to the fill and drain pipes.

Your expansion of Calder's description, as well as your application to multiple batteries, is incorrect. I don't have to argue it with Calder, because I agree with his analogy (although I always find water tank analogies more confusing than the actual electrical models they are trying to represent).

Mark

Boy's Boys.... Be nice.

I've never read Calders book, but being an engineer who wrote a hydraulic analysis program ages ago I know a thing or two about piping and hydraulics.

Piping like electrical cable has an internal resistance to flow based on the size of the pipe and flow rate through it. Pretty much just like electrons and wire, though without inductance.

Like electrons, water travels the path of least resistance. So you will get unbalanced flow between batteries with with conductors (wires) of different lengths. You will also get different acceptance rates based on the internal resistance to the batteries or tanks. Water tanks with internal bladders set at different pressures will accept water at different rates.

Nothing tells the electrons which battery to go to, except cable resistance and battery resistance. Thats why even with the same battery types as the OP was talking about, but of different ages, the internal resistance would not be the same. This as resistance rises as batteries age too.

OK that's a bit simplistic as there are other factors too with electron flow and battery aging too.

[colemj]

OK, they are just using uncommon terms for "bulk" and "absorption". "Boost" would be what is normally referred to as "Bulk" (or even more properly "absorption 1"), and "Off" would be what is normally referred to as "float".

Your manual has mixed up the proper settings for Gel and FLA in its instructions. You should be using the Gel settings as they are stated in the manual, and I feel sorry for anyone with Gel batteries who have used these instructions.

Again, that float voltage is a bit higher than most recommend, but won't really do much harm.

I don't know why you are smelling rotten eggs. If it truly is hydrogen sulfide, then that is poisonous and indicates your batteries are severely damaged. They will probably be hot, not have much water and boiling like mad before HS is produced.

I suspect that what you are smelling is the result of fine sulfuric acid vapors landing on your nasal mucous membrane. This will also smell like rottten eggs, but not be indicative of poison or damaged batteries.

Since the manual is wrong on the Gel/FLA settings, is it possible it also has the FLA setting wrong? Did you actually measure the charging voltage at 14.4V at the battery terminals? If it is 15.1V because of another mistake in the manual, you may be vigorously boiling them and releasing sulfuric acid vapors.

Mark

[monte]

A bit confused about the not smelling rotton egges comment though. I understood
"Over-charging a lead acid battery can produce hydrogen-sulfide. The gas is colorless, very poisonous, flammable and has the odor of rotten eggs."
So is it correct to assume the float charge of 13.8 instead of 13.4 was enough to cause gassing? Or the absorption at 14.4 instead of 14.1 was the problem? Or...I still have a problem unresolved...
BTW, currently the battery monitor states 13.95V

[sailorchic34]

Originally Posted by monte

Heres a pic of the boost function

Ah so boost is just bulk charging to 13.8V then absorption charging to 14.4. So boost is the same as bulk charge.

[colemj]

Originally Posted by sailorchic34

I've never read Calders book

We were discussing a specific analogy in his book in terms of how he applied it and what he applied it to.

The rest of what you wrote didn't pertain to this specific analogy at all.

Mark

[sailorchic34]

Originally Posted by monte

A bit confused about the not smelling rotten eggs comment though. I understood
"Over-charging a lead acid battery can produce hydrogen-sulfide. The gas is colorless, very poisonous, flammable and has the odor of rotten eggs."
So is it correct to assume the float charge of 13.8 instead of 13.4 was enough to cause gassing? Or the absorption at 14.4 instead of 14.1 was the problem? Or...I still have a problem unresolved...
BTW, currently the battery monitor states 13.95V

Actually even 14.4V should not cause out gassing. Either the charger was doing an equalizing or you might having a bad cell in one battery. Not uncommon.

To find the bad cell, turn off the charger and disconnect the Ground cable from each parallel battery. Lt it sit for a 1/2 hour then measure voltage at each battery with a VO meter. if both batteries have the same voltage, somewhere around 12.8V life it good. IF one battery reads low, say 12V or 11. something then you have a bad battery.

[colemj]

Originally Posted by sailorchic34

Ah so boost is just bulk charging to 13.8V then absorption charging to 14.4. So boost is the same as bulk charge.

I read it as boost is bulk and absorption - run up to 14.4V, keep it there based on a time calculated by some type of "turbo boost" (??!!??), then drop to float at 13.8V.

If monte comes back and tells me there is also a "super turbo boost" that modifies everything, I'm outta here!

Mark

[sailorchic34]

Originally Posted by colemj

We were discussing a specific analogy in his book in terms of how he applied it and what he applied it to.

The rest of what you wrote didn't pertain to this specific analogy at all.

Mark

You say the sweetest things....

Actually I had reread SL's posting about the tanks, before posting, so pretty sure I understood his position anyway. Which I oddly find to be correct.

[colemj]

Originally Posted by monte

A bit confused about the not smelling rotton egges comment though. I understood
"Over-charging a lead acid battery can produce hydrogen-sulfide. The gas is colorless, very poisonous, flammable and has the odor of rotten eggs."
So is it correct to assume the float charge of 13.8 instead of 13.4 was enough to cause gassing? Or the absorption at 14.4 instead of 14.1 was the problem? Or...I still have a problem unresolved...
BTW, currently the battery monitor states 13.95V

Actually, over-charging a FLA to produce HS gas is a difficult thing to do. It will require a huge dump of current, the battery will need to be very hot, and the cells will probably be dry or very low. In other words, to produce HS gas, you need a considerably damaged battery taking high currents at high voltages from a charging source. And HS is heavier than air, so unlikely you would be noticing it just in the general area.

Float at 13.8V and absorption at 14.4V would not be a problem unless you do have a very damaged cell (and even then, only maybe).

Again, most likely sulfuric acid vapors, and not hydrogen sulfide.

Mark

[colemj]

Originally Posted by sailorchic34

You say the sweetest things....

Actually I had reread SL's posting about the tanks, before posting, so pretty sure I understood his position anyway. Which I oddly find to be correct.

Did you read Calder's?

Mark