A question about Top Charging?

BFL13 mentioned in my other thread that charger voltage vs. battery voltage cannot really be measured during charging, as they are a "sort of average of the two". If so, how important is it to get the batts to 0.00 voltage drop? Does .01 qualify, or could the batts still need several hours of charge at that point?

The closest I've come is 0.01, but that was only after 5 hours at 15.42v.

MEXICOWANDERER wrote:
FYI A group 27 that needs top charging will take anywhere from 6-18 hours to reach 15 volts at a 2 amp starting current.

Anyone out there have a constant current charging device? For lead acid batteries? Anyone out there have HAND'S ON EXPERIENCE top charging batteries or throttling CONSTANT current for equalization? Sorry, pushing a button doesn't cut it.

SMKettner's answer comes closest to fact. But no one has a charging device that starts and ends at 2 amps unless they have a full-on power supply with voltage AND current adjustments. Therefore I recommend a 5 amp starting current. It will taper down as voltage rises. A 60 watt potential power delivered is minimum.

I would LOVE TO SEE the flooded battery that "Boils" with this recipe. "Over Time" is not part of this recipe. Leave a turkey in the oven at 300F for three days will produce undesirable results. "But it was 75 degrees under recommended cooking temperature" does not work.

These recommendations are RECIPES. To be followed - not warped, extrapolated, or modified at whim.

It is not I who insists on this, it is the battery. I merely listened when they screamed.

Thanks , Mex.

As far as i know, the gophert 1620 I've ordered can be set to hold a constant current. I've never used such a device so I'm hoping it's that simple... set amps... watch volts rise to ?v... keep track of how long that takes in general... then attach a timer, set to that time, to be safe for future charges.

FYI A group 27 that needs top charging will take anywhere from 6-18 hours to reach 15 volts at a 2 amp starting current.

Anyone out there have a constant current charging device? For lead acid batteries? Anyone out there have HAND'S ON EXPERIENCE top charging batteries or throttling CONSTANT current for equalization? Sorry, pushing a button doesn't cut it.

SMKettner's answer comes closest to fact. But no one has a charging device that starts and ends at 2 amps unless they have a full-on power supply with voltage AND current adjustments. Therefore I recommend a 5 amp starting current. It will taper down as voltage rises. A 60 watt potential power delivered is minimum.

I would LOVE TO SEE the flooded battery that "Boils" with this recipe. "Over Time" is not part of this recipe. Leave a turkey in the oven at 300F for three days will produce undesirable results. "But it was 75 degrees under recommended cooking temperature" does not work.

These recommendations are RECIPES. To be followed - not warped, extrapolated, or modified at whim.

It is not I who insists on this, it is the battery. I merely listened when they screamed.

smkettner wrote:
I am no expert but I would recommend about 2 amps per battery so the voltage will drift up slowly on its own. You could do this manually if you had an ammeter in the circuit. Keep bumping voltage as current tapers off. The idea is to give the chemical reaction some time without beating too hard on the plates.

Yes, this is my main concern. But can high voltages cause damage, or just the high amps that come with them?

We have found here that our batteries will really start boiling out fluids over time with the charge voltage being higher than 13.6VDC.

My highest charge rate is 14.4VDC but this is only for a short two hour period using my smart mode charger.

This is probably the reason for the multiple charging modes with the smart mode chargers. They are designed to re-charge the batteries in the fastest possible time and not do damage to the batteries.

Roy Ken

I am no expert but I would recommend about 2 amps per battery so the voltage will drift up slowly on its own. You could do this manually if you had an ammeter in the circuit. Keep bumping voltage as current tapers off. The idea is to give the chemical reaction some time without beating too hard on the plates.

Your questions have a lot of merit IMO.

Top charging is definitely not merely the application of 15 volts with a large charger. It is a process where 5% of amp hour rating is applied initially to an otherwise "fully charged" flooded battery but unlike equalization the 5% amperage figure can slump as voltage rises. Finish amperage as the battery approaches 15.0 volts can be as low as one ampere. A five ampere 18 volt transformer type wall wort should be ideal for this but they do not grow on trees. An 18 volt power supply used for outdoor lawn care is AC so it would have to have a 5 amp silicon rectifier soldered into one lead. The place that sells CheapOWatts also sells variants that are smaller and cost less. They must not be used for any charging that exceeds their wattage rating. ie. 15 volts at 5 amperes is 75 watts. Used intelligently these diminutive power supplies may be ideal. Starting at 13.2 volts surface charge, this IMO is a viable option. A Schumacher 6 amp transformer charger is also ideal. More expensive but rahter bulletproof.