Flooded Batteries on Float

MEXICOWANDERER wrote:
You are reading bank balance not deposits. Disconnect changing devices after chopping off all loads. Insert DMM ammeter leads in series with charger to battery positive lead. Switch to milliamps if you have to. You'll get a reading. Voltage of batteries must stabilize at float first for this to make any sense.

Thanks MEX. Will do.

You are reading bank balance not deposits. Disconnect changing devices after chopping off all loads. Insert DMM ammeter leads in series with charger to battery positive lead. Switch to milliamps if you have to. You'll get a reading. Voltage of batteries must stabilize at float first for this to make any sense.

There is a point. A biggee, in which incoming milliamperes are reduced without the specific gravity sagging one whit. This is the witching hour as far as float is concerned. You'll know where it is and down the road if it changes a lot you'll have an excellent alarm bell is/was point.

Don't forget to factor in temperature. Doing this test on days apart with the same battery temperature is the way to simplify this.

Yes the effects are linear to a degree. This is not quite the same as computing critical mass for a lump of U-239. But it is a reference point as used correctly it can be a lifesaver.

MEXICOWANDERER wrote:
When I FLOAT a loan, I guarantee there is going to be flow, regardless of my bank balance.

Whatever is powering the float charge, power supply, panel, etc. has to be sending amperage of some quantity to the battery. Think about it.

Some of you are trying to measure amperage in -el place wrongo-

The device powering the float does something for a living.

Just remembered. My battery monitor is in series to the negative wire coming from the batteries. In other words, the negative wire comes from the batteries directly to a bus bar then through the shunt and off to the chassis ground. The monitor uses a 500mA shunt though. Not sure if that makes any difference here.

The far left in this pic is the shunt.

Well ... it might be a few milliamps, since my built in three-place ammeter can only resolve around +/- 100 milliamps. However, as I've noted, jacking the charge voltage up via the alternator still finds the ammeter saying "zero".

The DCS-100HIT model from this spec sheet is the latest version of what I think Interstate relabeled and sold me two of way back in 2006. Note the recommended float voltages that are perfect for a stock converter. Also note the "Equalization and Cycle Service Charging and Current Limits" are just that - limits - not requirements. My batteries almost never see more than 14.4 volts - so I guess their cells may not be very equal after nearly 8 years. I do still see it sitting around 12.84 volts after arriving at full charge:

http://www.cdtechno.com/pdf/lit/12_1061_10.pdf

Not even a few milliamps, eh? Boy that most be some battery...

MEXICOWANDERER wrote:
The device powering the float does something for a living.

Not much ... with regards to AGM batteries. So little, in fact, that my digital ammeter thinks the device has left the building.

By the way, once my AGMs draw so little that the three-place ammeter can no longer detect/resolve/show it ... hitting the batteries with the higher 14.4 - 14.5 voltage from the engine alternator does no good ... still the three-place ammeter shows zippo. That's what I mean by a "hard stop".

In the old days, my wet cells used to gurgle-on approximately forever with a trickle charger on them ... or until they were dry ... whichever came first.

By the way, when folks say that "although fully charged AGM batteries may not gurgle when being slowly dried out by too high float voltages they are still drying out and self-destructing". I'll bet that if and when this is occuring with AGM batteries, a charging ammeter would still show some current flow as being necessary to power the drying process. If so, I take this to mean that when my AGM batteries get fully charged and show zero current flow (even with only a three-place ammeter) ... they are in fact not sitting there drying out from the 13.8 volt converter voltage resting on their terminals.

When I FLOAT a loan, I guarantee there is going to be flow, regardless of my bank balance.

Whatever is powering the float charge, power supply, panel, etc. has to be sending amperage of some quantity to the battery. Think about it.

Some of you are trying to measure amperage in -el place wrongo-

The device powering the float does something for a living.

BFL13 wrote:
If self- discharge shows in amps, and your Float is perfect to replace that, would the meter show any amps going in or would it show "net" of zero amps?

I'm thinking it would show net amps (zero in this case).

For there to be current flow, there has to be a voltage differential. If the battery can achieve the float voltage, there will be no current flow. Generally float voltage is set just slightly above the "full" battery voltage.

At a float voltage of 13.4 I see a float current of 300 mA when the four GC2 batteries are full. Is this charging the batteries? Not really. Some counteracts self-discharge. A little is converted to heat and the rest is electrolysis.

The higher one sets float voltage above battery full voltage, the more current draw will be seen, but the batteries will not be charged to a higher state. There is just more heat and electrolysis.

A Trimetric or any battery meter will register the current going to the batteries but is not smart enough to know that some is "smoke up the chimney".

Ya measure the float energy amperage señor BFL13. "something" has to sustain the batteries. It's a curious person's objective to know how much that "something" is, and then put it to work by establishing historical trends and tendencies. Variations. Wanna know what happens to absolutely precise float voltages amperage flows when a battery sulfates? There are many ways to skin el gato. One of the best is dead simple instrumentation, and a log book.