flooded lead acid batteries and "bubbling noises"

Re: flooded lead acid batteries and "bubbling noises"

samuel wrote: »

Q1: If the bubbling is a regular occurance is this charge rate sufficient to mix the electrolyte?

The bubbling is normal. T105 Trojans aren't as demanding on mixing as the tall case L16's. If you got bubbling you got mixing. If you get really good at battery "alchemy" you can judge the efficacy of the charge rate by how fast it's bubbling.

Q2: Being a cabin it is occupied about 1/3 of the total days in a year - does this affect how often the batteries should be equalized (how often should they be equalized in this case)?

Trojan recommends equalizing on an as needed basis; not "regularly". This usually works well for most other similar batteries. Check the SG, if it's more than 0.010 difference it needs an equalization. The batteries that sit all Winter will not be subject to draw, and as such will recharge quickly daily and stay in Float most of the time. Check them before you go, check them when you arrive. They'll be fine unless something is very wrong with the system. Here's a tip; you can reduce the Absorb Voltage level a couple of tenths in Winter and let them charge slower. Less likely to use water at lower, longer charge rates.

Q3: Is this the founding arguement for sizing a battery bank to the panels?

It's the other way 'round: you size the panels to the battery bank. The battery bank size is dependent on the Watt hours needed per day. The panels are there to recharge that bank in the "window of opportunity" of daylight.

Now it's admonishment time.
1540 Amp hours is too large for a 12 Volt bank in my opinion. If you need that many Watt hours you should be increasing system Voltage. The current needed to recharge that bank properly is 150 Amps, which is difficult to produce and manage.
You should be able to get 40+ Amps from 810 Watts of panels @ 14.4 Volts charging. 30 Amps is slightly under 2% charge rate and will barely stay ahead of the self-discharge rate of those batteries. Basically they are condemned to an early death if you can not charge them at a rate of 5% or more. Your 60 Amp charge controller can't even handle the minimum 5% (75 Amps). I also can not imagine you are keeping the current flow even through seven parallel sets of batteries. It is nearly impossible to do, even with bus bars and perfectly even connecting wires.

Re: flooded lead acid batteries and "bubbling noises"

samuel wrote: »

Q1: Is this small movement of current in and out of the batteries going to effect the longevity/health of the batteries?

Self-discharge happens even if the batteries are just sitting there not connected to anything. The older the batteries get, the higher the rate goes. They are a vat of chemical reaction, and that continues to some extent whether or not there's anything drawing current. AGM's are less effected by this, but still lose power over time. Keeping ahead of it by periodic recharging is necessary to maximize the life of the battery. Otherwise it's like using it without getting the benefit of the power.

To follow up regarding equalizing - I'm cosidering making it a 2/yr habit followed by a recording of specific gravity to monitor the aging of the batteries. Perhaps it is better to forgoe the equilization until needed; after taking my spec grav readings.

The best thing you can do with FLA's is charge them fully when new, let them rest, take SG readings of each cell, and write them down. That creates a baseline that you can refer to for all subsequent readings Since there's quite a number of things that can affect SG (including which hydrometer you use to begin with) it's good to have this number that means with your system "X.XXX" is a fully charged cell. You should check SG at least once a month and EQ if necessary.

Q2: On the Deep Cycle Battery FAQ it was stated that equalization every 10-40 days can extend the life of the batteries. Is this no longer true?

It depends. Generally you should follow the manufacturer's recommendations. If there aren't any, the "as needed" process works for any of them. Big industrial/forklift batteries need more EQ'ing, as they are designed to discharge deeper. There are batteries you do not EQ too. Some AGM's say they can be equalized "lightly". It's a dizzying world of many configurations.

Q3: What is the harm of equalization too often with flooded lead acid?

EQ is done at elevated Voltage. The higher the Voltage, the more bubbling = greater loss of water and higher internal battery temps. You can cook the battery and get warped, shorted plates.

Q4: I don't quite grasp the rational behind "early death" of the <5% charge-rate-battery when bubbling commenly mixes the electrolyte (avoiding acid stratification) and water levels and full charge storage are diligently maintained.

There's bubbling, and then there's bubbling. Just as too much EQ'ing will cause problems so will undercharging. Got to get the sulphur back off the plates and into the water (reforming the electrolyte). A low charge can produce the electrolytic action that gasses off the hydrogen and oxygen with shifting the sulphor to any significant extent. Allow the sulphor to stay on the plates and it crystalizes, welds itself on, literally covering the plates with an insulative layer. Net result: smaller exposed plate area which equals less battery capacity. One day your 220 Amp hour battery is down to 22 Amp hours which you notice because it seems to charge up, but it discharges very quickly.