Anyone use a Schumacher battery charger before?

[CRXBMPN 5,000+ posts]

I am on my second Schumacher battery charger, returned the first one because it was not what I wanted and I got a 75/25/5/3 charger. My question with this gdmf thing is that at any charging rate it will bring my battery up to 16.20ish volts on my dmm. After it reaches 100% it will float them lower but regardless of which battery I put on, how many at a time are charging (c&d tech up front, batcap 4000 out back both hooked together, and even a small brick Deka wet cell stand alone), it brings em up to a pretty scary level. They rest around 12.7-12.75 and load test fine seperately, so the batteries themselves are not the issue. I am curious if anyone has had similar results. I replaced my old 10 yr old 10/6/2 Black&Decker from Home Depot for this one at Wal Mart and while it does its job, it concerns me. On a devilish note, it would be fun to pop off a burp on my saz3000d's while at a 75a charge and sitting around 16v :-D but I won't do that in fear of blowing things up.

Thoughts?

Click to read more...

 

[mylows10 5,000+ posts]

I've used them before. The digital ones are pretty decent They don't charge that high for to long

 

[CRXBMPN 5,000+ posts]

if not too long you mean possibly up to an hour or longer, then I agree //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif I just don't want to see my batteries taking a dump on me because of the charger.

 

[mazdakid 5,000+ posts]

I have one and it seems like the voltage just keeps rising when charging batteries so I just stopped using it.

 

[CRXBMPN 5,000+ posts]

yeah i was shocked when it went to 15.xx, then crawled up to 16.xx, the % charged seems ok but the voltage scares the shizm out of me.

 

[NASTY08IMPALA 5,000+ posts]

Ive been using my digital schumacher for about 4 years it gets up to 15.4 but ive never had a problem ..my car also charges at 15.1

 

[CRXBMPN 5,000+ posts]

Sounds like you have an older one than me, I would like to get an answer from the company so I may ask about it. Perhaps they have a FB page.

 

[argenis69 10+ year member]

I have one also, I never had an issue yet.

 

[CRXBMPN 5,000+ posts]

which one? and have you put a multimeter on it while it was charging? just curious.

 

[VWBobby 10+ year member]

I have one of the 50/12/2A models and it does well. Not sure what voltage it goes up to, but you do have to have a little higher than 14V to put a decent charge on the battery. Otherwise the battery would only charge to 12V or less, and it should be up around 12.5V - 12.7V.

 

[CRXBMPN 5,000+ posts]

Thx. Put a multimeter on it the next time you charge, you may see similar results.

 

[keep_hope_alive Premium Member]

Typical charging curve:

From Batter Tender:

Stage 3) Equalization Charge Mode: The equalization charge mode is optional and usually only included at the request of a specific battery manufacturer. At this time the battery is approximately 95% recharged. To speed up the delivery of the last 5% of the recharge, one of two things usually happen.

1) The charger switches over to a true constant current mode where the value of the charge current is a small percentage, usually never more than 20%, and typically in the 5% to 10% range, of the numerical value of the battery’s 10 or 20-hour capacity in amp-hours. Since the charger circuitry does not have the ability to directly sense the battery capacity, these relative percentages will only be true for a specific range of battery capacities. There is also a safety timer engaged and there is often a safety voltage limit, a “lid” or “ceiling” that performs an automatic shutoff or switch to stage 4) if the battery voltage attempts to rise higher than the safety limit. In either case, the higher constant voltage, or the lower true constant current perform a similar recharge function. That is to safely replenish the last 5% of the battery’s charge, in a minimum amount of time.

2) The charger voltage is set high, maybe 3 to 4 volts above the battery no load fully charged voltage with a safety timer. The battery then draws current until the timer shuts off. The reaction of the battery during this time is first to force the charger to deliver its maximum current. Then the amplitude of the charger current gradually decreases until the timer forces the charger to switch to the next charging mode. It’s almost like repeating the bulk and absorption charge modes together in a compressed time frame, with different voltage limits.

http://batterytender.com/resources/battery-basics.htm/#answer9

From West Marine:

Equalization Stage: this stage is used to prevent flooded lead acid batteries from aging prematurely, and is an optional, frequently omitted phase. After the battery reaches the end of the acceptance phase, the battery continues to be charged at four percent of C until the voltage stops rising, usually around 15.5 to 16.2 volts. This forces the battery to its highest possible state of charge, boiling the electrolyte in a controlled manner and dissolving the lead sulfate crystals that have collected on the battery’s plates. In industrial applications where maximum energy storage is important, this phase is done every charge cycle. In the marine environment, it is more likely to be done every 20-50 cycles to extend the life and capacity of wet batteries. Gel and AGM batteries should not be equalized. Since electrical equipment and light bulbs can be damaged by high voltage, the battery should be disconnected from all loads during equalization. This type of battery charging, consisting of multiple stages, is not possible with automotive-type alternator regulators, unregulated solar panels, ferroresonant chargers, or taffrail generators. West Marine strongly encourages the use of efficient charge devices, both for shorepower charging and alternator regulation, that use modern multiple-step regulation.

 

[CRXBMPN 5,000+ posts]

thanks, i'm going to have to read that about 30 times to absorb it all, but good info. on a side note, i do not have my vehicle nor electronics on when i do the charge, i erred on the side of caution due to what i was seeing.