Do gel batteries need equalization? I've been reading and without temperature correction, consensus for charging voltage seems to be 13.6-ish for bulk and absorption, and 13.2-ish for float. But I can't find any consistentcy on equalization recommendation.
Charging voltage depends on battery temps. MK gels in cold weather can be more than 14. Hot battery temps in the low 13's
No equalization
nope
Equalization may cause GEL or AGM batteries to vent needed pressure, which damages battery.
Except for lifeline AGM's. They can be equalized
Good to know. We have gel house batteries.
Thanks
I bought 3 Deka Dominator 8G8D gel batteries in June direct from their manufacturer- East Penn. I was told at that time the batteries do not require equalization. Below is a link to the batteries. I can not find in writing any mention of equalization. I am very happy with the batteries. A very simplistic example- my Keurig coffee maker would always auto-start my generator in the morning when I was not on shore power. Not a very neighborly thing to do at 5 a.m. I had West Marine AGM's at that time . That does not happen with this install.
East Penn Manufacturing | Recreational vehicle batteries (http://www.eastpennmanufacturing.com/applications/recreational-vehicles/)
DO NOT equalize Gel and AGM. Agree with Barry and Cindy.
GASSING IS BAD
Equalization is not good for batteries because it requires eventual replacement of the electrolyte. It is a necessary evil required only for flooded batteries to mix up the electrolyte if the battery has been sitting unused. Equalization is only required if the battery is sitting for weeks at a time. Vehicle motion also mixes the liquid, so equalization is not needed nor good for the battery if it is frequently in motion. Stratification is where the heavier, more acidic solution sinks to the bottom of the cell. Equalization produces bubbles that mix up the top and bottom. These hydrogen bubbles are replaced by adding water, or with a sealed battery, eventually recombined with the electrolyte. With a totally sealed battery, you may see the sides bulge, which could be normal.
GASSING IS REALLY BAD FOR GEL AND AGM
Gel and AGM cells do not have a free-flowing liquid solution and equalization will only cause gassing, not mixing. Gassing is not necessarily good because water will need to be replaced. However for GEL and AGM, the gas will either:
- If the gas pressure is BELOW the valve cap set pressure point it will eventually recombine with the gel or AGM electrolyte.
- If the gas pressure is ABOVE the valve cap set pressure it will BLOW out of the cap. You will hear the hissing of hydrogen gas. Not good since you cannot replace the electrolyte. A little gassing will not destroy the battery, but continued equalization will.
Tim, as Bob said Lifeline AGMs CAN be equalized and it is stated in their leaflets that come with batteries. I seem to remember that the figure is 15.5 v to do it at but do not have papers here so cannot check the volts right now.
JohnH
Here it is from the horses mouth.
Can I equalize AGM batteries? - Lifeline Batteries (http://lifelinebatteries.com/2015/10/can-i-equalize-agm-batteries/)
Our AGMs strongly advise against equalization. Check your manufacturer's website for the best advice not hearsay opinions.
Pierce
Good suggestion. The house batteries were replaced by the PO in 2015. Google search on the description and part from the receipt comes back with DF8D by Prevailer Sonnenschein gel cell batteries. Also has this charging recommendation:
EDIT: Corrected charging voltages as follows: (Deka Gel-tech) are correctly charged at (2.32v/cell)14.1v/(2.3v/cell) 13.8v float @ (68°F) 20°C.
I'm going with NO equalization setting on the MTTP.
Equalization does cause mixing of the acid and water which reduces stratification, however, a more important reason for equalization is to reduce or eliminate sulfation. Sulfation, which is the chemical process that produces current flow during discharging, is not completely reversed during charging. A battery at 100% charge which is discharged to 75% before recharging will charge back to 99% (not 100%), then during the subsequent discharge/recharge cycles will recharge back to 98%, then 97%, then 96%. The sulphates left after discharge/recharge cycles is a white or brown power sticking to the lead plates which adds resistance while reducing the effective capacity of the battery. These sulphates will harden and become more resistant to recharge over time and eventually break off and slide to the bottom of the battery.
Using a desulfator continuously when cycling your batteries will result in recharging back to 100% during each cycle.
Using Equalization, if done frequently enough will also result in recharge back to 100%, but with possible heat damage.
Check this out yourself by measuring the finish voltage of a recharged at each cycle. Without desulfation this voltage will be slightly lower after each recharge, until equalization. With desulfation this finish voltage will remain constant after a month of desulfation.
The voltage for Bulk/Absorption of a Gel battery was in a previous post said to be 13.6 volts, however, the effective voltage for Bulk/Absorption of a Gel battery is 14.1 or 14.2. Using desulfation, I Bulk/Absorb Gel batteries at 14.3 or 14.4 because the finish voltage of desulfated Gel batteries is 13.1, not 12.9.
Wyatt my buddy says desulphurators do not work on gels?
Bob, desulfation seemed to work on my Gel battery that was still useable when I gave it away after 13 years of service (it had an amphour capacity of only 65 and was 210 when new). This battery is still being used at 17 years.
Desulfation even works on NMH batteries, not sure about Lithium.
My experience with desulfators started fifteen years ago when they were not commercially available. I bought a kit and built my own. I experimented with dead batteries and became convinced about the positive effect of desolation.
I still use them today when cycling my batteries, however, I disconnect the desulfators when at home for the summer and not cycling my batteries.
Because my manufacturer recommends it I do.
The Lifeline article over-simplified lead-acid battery handling. It is NOT SIMPLE given the following factors:
Type: Flooded, AGM, Gel, (and don't get me started with lithium batteries)
Seal: Open vent or sealed-vent VRLA (Valve-Regulated Lead Acid).
Temperature compensation: Most alternators and chargers do not compensate, which reduces battery life. Batteries are charged to 100% with voltages, based on temperature.
Definitions: Equalization, desulphation (pulse or non-pulse), gassing, VRLA(Valve-Regulated Lead-Acid), electrolyte, temperature compensation.
VENDORS, BATTERY vs CHARGER
Battery vendors have minimal interest in battery longevity outside the warranty period and know that the layman views batteries as "black magic". Battery charger vendors don't want to be responsible for OPB (Other People's Batteries) and limit their liability. Conspiracy theory?
I sometimes think battery manufacturers want customers to be confused so that more batteries are sold. Even my expensive IOTA four-stage charger does not have a setting for flooded, AGM or Gel and has no temperature compensation. This is dissapointing. I am in discussions with Morningstar Corporation solar charger/controller tech support about their lack of understanding of lithium battery charging because their TS-MPPT-45 solar charge controller recently over-charged one of my lithium cells.
There are two separate issues with lead-acid batteries:
ACID STRATIFICATION
AGM and Gel batteries are highly resistant to this phenomenon. An hour-long equalization of these batteries will cause gas pressure build-up as mentioned above.
LEAD SULPHATE CRYSTALS
I might agree with with using a professional pulse desulphating system on AGMs and Gels, but not one using a flooded battery equalizing scheme. This would produce WAY too much gas, and the valves would certainly "pop" and let hydrogen has escape. This gas is part of the irreplaceable chemicals in sealed batteries. There are two types of desulphation:
PULSE: Pulse-desulphators can send 16 volt pulses into your electrical system. This may damage some sensitive components.
NON-PULSE: My IOTA DLS-90 permanently keeps my flooded batteries at 100% by floating them at 13.65 volts and equalizes them at 14.8 volts weekly for an hour. This is a combination non-pulse desulphation and equalization system. It will not harm the electronics in the U270.
The lifeline article was correct in one area: Keeping your batteries at 100% will extend the life of your batteries.
I edited my earlier post above to correct the charging voltages.
Tim, I totally agree with your comments here:
Battery vendors have minimal interest in battery longevity outside the warranty period and know that the layman views batteries as "black magic".
I sometimes think battery manufacturers want customers to be confused so that more batteries are sold.
Tim, you said:
Even my expensive IOTA four-stage charger does not have a setting for flooded, AGM or Gel and has no temperature compensation.
I contacted IOTA via email to ask why they rate the output voltages of their converter at 14.2 and 13.8 when those are the open circuit voltages. When connected to a battery or drawing current the output voltages drop to 14.0 and 13.6. I also asked how I could increase those output voltages to take advantage of their IQ4 (optional four stage battery charge controller). I never received an answer or even an acknowledgement. I have never used the IQ4 controller.
Sorry to Mark, I noticed after I posted that you had revised the voltages stated.