Charging antimony-free VRLA batteries without float

Be EVER so careful interpreting an exercise such as this into real world practicality.

The mere evolution of 1% calcium added to the negative plate (i.e. hybridization)can skew all of the data beyond uselessness.

I do not care for this paper. Complete qualifications need to be prefixed, suffixed and annotated to the text. First up, what is/was the construction methodology of the units under test? Plate thickness? Plate paste? I did not even get so far as to read if the electrolyte was absorbed, or gelled. Some VRB's use liquid electrolyte. What was the density of the electrolyte? Variances per pack after test?

There are innumerable methods to determine inappropriateness of battery maintenance voltage amplitude.

The article mentions early failure of VRB used for standby. It does not mention the sloppiness, variance from design specification found in apparatus chargers.

For crying out loud 99% of the VRB maintenance chargers out there have zero temperature compensation.

There exists a formula expressed in kWh / ampere hours capacity used to determine the amount of energy needed to maintain a lead acid battery. Yes it must be emended for temperature.

I am looking not to cook my AGMs. For a while I was thinking 24x7 float was the best thing for them while in storage. I am rethinking that. Maybe what the PWM does is fine.

Float is a very specific temp corrected voltage that leads to a certain current level. This is a charge rate below that. I guess below float might be more accurate.

I devised a way to watch for outgassing on my AGMs and they will evolve hydrogen and oxygen much more easily than many people think. A little does not hurt, but much dries out the battery...forever reducing capacity. I am looking for that tightrope between sulfation and outgassing.

Jim

The test procedure was interesting, but you title was misleading.

Your title stated charging "without float". The test is "low float".

Also; the article is for a proposed better method to charge batteries used to power emergency lights, critical computers, etc., when 120v, ac, power is lost.

These batteries spent 95% of their life being "float charged" until the time comes that they actually get used. Because of this the battery life end up short for batteries rarely getting used.

I fail to see how this could help any of us for RV use, unless the RV has been stored for a long winter (like the current). My 9-watt, 0.625 amp, solar panel accomplishes this goal for me each long winter.

In your case you get out much more often and need to recover to "full" charge much more often. I guess what it really means is that if your batteries were really "fully" charged, if you could manually lower your float charge to the very low "float" it MIGHT help in the long run. Not an easy job since you need to know the discharge rate of each battery being stored to calculate the lower "float" rate.

Mark B

Hi Jim,

Great article thanks for posting it.