Battery Charger not Putting Out?
 

I have an old Schumacher Dual Voltage Battery Charger, mod no. SE-82-6.
It has two modes in 12 VDC [6A + 2A] and 1 mode in 6 VDC [6A]
Connected to the battery terminals at 12/6A I read 12.8.
Disconnected, the gator clips read 13.28 on my VOM.
But in 2A mode connected to the battery, I read 11.37.
Disconnected, I get 10.09 on the clips.
Shouldn't I have at least 12 volts in trickle charge? Or is it designed that way?

Re: Battery Charger not Putting Out?
 

What is the reading on the ammeter when charging a battery? You should check the voltage on the clamps while charging a battery just like you would on an alternator. You should be reading about two volts higher than the battery voltage.

Here is the owners manual if you don't have one.

https://www.manualslib.com/manual/76...?page=9#manual

Re: Battery Charger not Putting Out?
 

I have one of those. On a fully charged battery, the VOM on DC read 14V on the 2A rate, 15V on the 6A rate. With no battery, read 11.5 on the 2A rate and 13.6 on the 6A rate and 8.2 on the 6V setting.

The voltage you get on the VOM will depend on how charged the battery is.

Why the lower reading with no battery? These simple 'dumb' chargers are feeding rectified AC to the battery as DC. Most VOM have issues reading rectified AC on the DC setting. The battery evens the voltage out into a mostly pure DC.

Re: Battery Charger not Putting Out?
 

Schumacher has been a round a long time in the early 90's I called them with a problem with a charger that was 15 years old at the time and they went through some tests and they sent me what I needed to get it working you might try search for a wed site and see if they are as helpful as they used to be.

Re: Battery Charger not Putting Out?
 

Thanks, I'll try that.

Re: Battery Charger not Putting Out?
 

I know a lot of the 1980’s on up will not charge a completely dead battery. Will often give error code. There was a trick to connect the dead one in series with a less dead one to get the machine to operate
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Re: Battery Charger not Putting Out?
 

http://sens-usa.com/2016/04/27/nrg-b...ead-batteries/
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Re: Battery Charger not Putting Out?
 

This is a dumb charger. You hook it up. turn it on and it pushes voltage. It's just that on 12v/2A, it's pushing undervoltage, at 11.3.

My question is, is that what a "trickle charge" is? Won't it drag the voltage of the battery down to 11.3?

[No codes, unless you have an Ovaltine Ring.]

Re: Battery Charger not Putting Out?
 

I know mine charges very nicely on the 2A setting with the open circuit voltage of 11.5V.

Here is a link that might help. https://www.electronics-tutorials.ws...s-voltage.html

Your VOM is probably reading something close to the RMS value of the rectified AC. With 2 diodes(I had to replace the ones in mine), it is very possible it is only a half wave value so even lower. But there is some time the output voltage is higher then the average. That is when the battery gets some charge. The diodes prevent the battery from discharging back into the transformer when the voltage is lower then then battery.

Re: Battery Charger not Putting Out?
 

The meter is a Fluke, but I'd have to look for its model number.
I used to have some analog VOMs, but they aren't used much lately. I could try to dig one up.
VetteVet asked for ammeter readings on the Schumacher, so I'll collect that data.

I have 2 trucks -- a '68 C/10 Stepside w/ 292 L6, and a '71 GMC Jimmy w/350 V8. I have just R&R-ed the EVR, ALT and Batt on both of them, and I'm still leery of the results.

Sunday night, the old alternator on the C/10 was not charging. Getting the red ''GEN" light on the dash. Voltage was declining from running. Batt and EVR were new. I gave it a 4 hour charge at 6A, and it started good in the morning. At work, I hooked up a solar panel, since the early pre-dawn run, I had to have headlamps on. In Arizona daytime summer sunshine, it indicated an output north of 20 vdc. Started right up again, after 4 hours of sunlight.

Today, I put a new [reman] Delcotron on the '71 Jimmy, and ran it down to O'Reilly's. They said it was charging good. That's when I picked up a reman Alt for the C/10. That's also installed now. I'll have them check it out tomorrow.

Re: Battery Charger not Putting Out?
 

I wouldn't trust testing of anything by a parts store. One told me that my 4 year old battery in the DD, reading 9V needed a charge. They replaced it with a small age credit and that one also lasted about 4 years. If my charging system wasn't working the new battery wouldn't have lasted.

Re: Battery Charger not Putting Out?
 

Results:
Fluke 114 ''True RMS''
Micronta 22-212 [pocket analog mtr from '80s]
Craftsman 82140

Fluke read batt at 12.22 Motor off, Neg term disconn
Micr = 12.5
Craf = 12.16
So there is a variance between meters.

Schumacher output on terminals at 12/6A:
Fluke = 13.53
Micr = 12
Craf = 11.73

At 12/2A:
Fluke = 11.41
Micr = 10
Craf = 9.98

Schumacher onboard ammeter reads 6A at 12/6A, 1A at 12/2A.

The C/10 started, but the red light was on. Batt read 12.27 with charger attached at 6A, and 12.25 w/ charger detached.

The Jimmy read 12.6, cold. Running, the batt read 12.49, 12.48, 12.47. Shut off, the batt read 12.54. [Fluke only.] The dash ammeter did not move either way. Usually doesn't. Both 4A fuses are good.

Are my ''new'' parts garbage?

Re: Battery Charger not Putting Out?
 

Yeah they are not as careful or as detailed as they used to be. I used to depend on Checker Auto, and had lifetime warranties on most components. Then O'Reilly's bought them out, and said the lifetime warranties would be honored.
I find what I get as a replacement from them is ChiCom Crap. The good brand only has a 3 year warranty now. I save all my receipts, but they print them out in dissapearing ink. I mark the part with a paint pen for month and year installed. Last Alt was from 6/09. Last EVR was from 12/18.
They gave me a hassle about the months remaining on their battery, so I went to Merle's, a local FLAP. [When the AC Delco batt on the Jimmy went out last week, Merle's just trotted out a brand new one, exactly like the old one, no questions asked.]
They bench tested the C/10's Alt, said it was good. I replaced the EVR and the Batt, and they used the tester in the parking lot. They said it wasn't charging, so I made them order me a new Alt. I put it on today.
I'm done with O'Reilly's except if I can get a warranty part. As they reneg or cheap-out, I'll move my business elsewhere. The AutoZone across the street already knows me on sight. One of the Auto Zone guys said, if there was still a Checker on that corner, A-Z would not have opened a new store across the street.

Re: Battery Charger not Putting Out?
 

My readings were with a Fluke 27/FM that also has the 'True RMS' feature. Looks like your charger is operating very similar to mine. You should be able to trust it to do its job.

Re: Battery Charger not Putting Out?
 

So the undervolt indication of the Schumacher is a safety feature to not boil over the calls on a long trickle charge?
What caused me to question it, was that a 22-month old Batt on the GMC was indicating low volt condition. Before I put the charger on the Batt read 12.05 [Fluke]. I put the mechanical charger on overnight, maybe 12 hours. In the morning it read 11.43, and didn't start without attaching the charger back on at 12/6A, and then it caught.
Assuming the Batt wasn't taking a charge anymore, I swapped it over.

Anyway. I have to take the C/10 in to get the O'RAP kid to check it out. We'll see what he says.