Does converter overcharge battery?

[pgandw]

There are things being said here that are impossible physically and chemically.

Battery discharge results when sulfate ions come out of the sulfuric acid solution and attach themselves to the lead plates, producing energy in the form of electricity while doing so. To charge a battery, the process is reversed. Extra voltage is applied to drive the sulfate off the lead and back into solution. This charging reaction absorbs energy from the charger and produces heat.

Lead acid batteries have a number of events that lead to loss of capacity and/or battery failure.

If the lead plates become exposed to air, the lead readily oxidizes. Oxygen takes the place of sulfur, but the oxygen reaction with the lead is not easily reversible. So if water levels get low, the top of the plates oxidize, and that capacity is permanently lost.

Lead is a soft metal whose internal bonds are not all that strong. Vibration and jostling as we drive down the highway can result in some of the lead shedding off the plate and dropping to the bottom of the battery case, resulting in loss of capacity. When the shed pile gets high enough to reach the bottom of the plates, an internal short circuit occurs, and the battery is toast. Lead sulfate (when the battery is partially discharged) is even softer and more prone to shedding.

Some of the lead-sulfate reaction creates the crystalline form of lead sulfate. The crystalline form is much harder, and the sulfate does not return to the solution nearly as easily. The deeper the battery is discharged, the more the sulfate will occur as the crystalline form. This is called sulfation, and is where the limit on number of cycles in a battery's life comes from. The more deeply the battery is discharged, the fewer cycles there are in the life of the battery. Car starting batteries generally won't survive more than 4 deep discharges. True deep cycle batteries are designed to do 400+ cycles down to 50%. If you never go below 70%, you gain more cycles. Desulfation can restore SOME sulfated batteries, but by no means all.

Stratification of the solution occurs when the battery sits still for long periods of time. The denser and heavier sulfuric acid sinks, and the water floats on top. Because there is not as much sulfur at the top, capacity is diminished, but the battery will indicate fully charged. If your RV doesn't stay in one spot for long, particularly while being charged, this is not an issue. Equalization, performed by some trickle chargers and converters in trickle mode, seeks to eliminate stratification by imposing a higher than necessary voltage for a short duration. The heat causes a few bubbles in the solution which eliminate stratification as they move to the surface. This, over a long period of time, can result in water loss, just as overcharging does (but at a much slower pace).

Just the facts, ma'am
Fred W
2014 Rockwood A122 A-Frame
2008 Hyundai Entourage minivan

[WolfWhistle]

The term boiling your batteries, is a misnomer, its is actually when a battery runs dry because it isnt checked while being charged continually. 13.6v will not boil them. Of course any charger can go bad. But if for whatever reason the charging current doesn't drop to what it expects, normally around 2 amps at that 13.6v, possible due to 12v things being left on, it will never drop to float.
I still say, you can spend your money on a good charger with intelligence or buy batteries it's your choice. IOTA calls theirs IQ4; PDs is called Charge Wizard; and they do much better than a charger without.
WW

[pgandw]

Originally Posted by WolfWhistle

I still say, you can spend your money on a good charger with intelligence or buy batteries it's your choice. IOTA calls theirs IQ4; PDs is called Charge Wizard; and they do much better than a charger without.
WW

Interesting. In an earlier post, I pointed out that Progressive Dynamic's Charge Wizard does not do a whole lot differently than a standard WFCO converter. PD does remain in boost mode (14.4V) longer than WFCO, and flips to trickle (maintain) at 30 hours instead of 44 hours for WFCO. No differences in voltages in each mode. PD does add equalization (15 volts) for a few minutes each day while in trickle mode - WFCO does not.
From what I can find out, and have experienced, whether you disconnect and recharge monthly or leave continuously in trickle charge mode does not have a significant effect on battery life.
The only reason I am swapping out my WFCO for a PD is that my particular WFCO unit will not go into trickle mode. WFCOs have more of a reputation for not changing charge modes as advertised - but there are a whole lot more WFCOs installed than there are PDs.

Fred W

[kcmusa]

the newer ones say they are 3 stage and do a trickle charge.
WF-8955 | wfcoelectronics.com

[pgandw]

Originally Posted by kcmusa

the newer ones say they are 3 stage and do a trickle charge.
WF-8955 | wfcoelectronics.com

The WFCO in my A-frame is a 3 stage charger. The problem is that it will not go into trickle mode at all. I know by measuring the battery voltage - it sits at 13.7V for weeks on end. Trickle mode should be 13.1 or 13.2 volts, achieved after sitting at small constant load for 44 hours (according to WFCO manual).

I am resolving the problem by disconnecting the battery after a few days of charging. In the near future, I will replace the WFCO with a PD replacement.

There have been other reports of WFCO converters not going into boost mode or not going into trickle mode when it should be. The PD converters don't seem to have this issue.

Fred W
2014 Rockwood A122 A-frame