HF Power Conversion Battery Charger, a look inside for free. SC1000A

How many things have you taken apart just to look inside?




I’ve been doing that all my life, and maybe just like you… when I was a kid… I got a spanking for taking a few things apart that didn’t go back together right.

The Schumacher model SC1000A might make a good product to hack, but first, let’s figure out how to open it without breaking something, and we’ll look around.

If you look inside the handle, you’ll see two screws you can remove.  Looking further, I didn’t see any warnings about voiding a warranty.  I looked for the trick of opening the   case without prying and breaking off tabs, etc.

As I ran my finger tip across the front panel, I found those tell tale holes that screws often hide in. I discovered the front panel cover (art work) is near magic. It is easily removed and stays sticky! Once removed, make sure you set this up where you don’t put something on top of it, I accidently put a piece of paper on it, and it stuck fast. I then put it under the kitchen faucet and let hot water help remove the paper, a little rubbing with a finger tip and it was all gone. I then flung as much water off as possible, and dried it under my desk lamp, and it was sticky and clean as new!




In those four  holes, you’ll find  small Philips head screws, easily removed. We’ll discuss those pieces of plastic later.. (no worries).

Just pull the light-colored plastic apart, and you’ll see how the end caps are sandwiched between.



Above you see the main board, There’s a few wires that connect this board to the front panel.  As I look around, I give the mechanical guys an ‘A’ for this case design, it’s light, compact, rugged enough, and that handle is strong and flexes, it’ll likely hold up to my abuse.

About now, some might ask, why is it important that we get in here at all?  My replay is, cords get old, they get cut, slammed in doors, chewed on by pets, and more.  With this easy to access case, we can replace our cords if we need to.















Above is the most important reason to get into this case, and that is to replace this fan, and here is another reason for the ‘A’ grade, the fan is plugged into the main board with what looks like a standard pin plug found on a PC.  The two screws holding the fan in place are again small Philips, and easy to get to.  Many of these designs just quit charging all together if that fan quits, or they default to a very low charge, beware, if the fan isn’t running the unit is likely smart enough to shut down.



Here’s  The very accessible front panel, the micro appears to be the EM784 20pin 8 bit micro using a masked ROM. When you plug this unit in, you can hear a high freq osc noise, unplug the front panel from the main board, and then plug the unit in and there’s no noise, so it’s likely the micro is the osc source. Unit draws  approx 7 watts plugged in, no battery attached.  The LEDS and the two switches used to pick battery type and charge rate. If you remember my mention above about those two pieces of plastic, if you remove this board, the ‘buttons’ you press, can fall out.. watch for them and make sure you put them back in before you put the front panel board back in place.

If you read my previous post about this product or a model quite similar, yes, this unit does need a battery with some juice in it to get started, but I found that to be no problem.

I reached into my desk drawer and pulled out a tiny 12 volt commonly found in a key chain transmitter, when I put it across the battery clips, the unit took off! I laid the battery down, and quickly tapped the battery clips together, sparks flew! It stays hot, it’s likely you can now put the leads across a dead battery and charge it.. Seems the designers use that little bit of voltage from the battery to prove polarity is correct.

So that story told by a reviewer that he sent he charger back because you can’t charge a dead battery?? well…. that wouldn’t have stopped a DIYer, and we know it’s going to be very rare when we find a battery so dead, and there’s an easy work around if we ever need to try and revive a totally dead one.

We have an easy work around already..  but there’s more,  next, I put a single AA battery across the terminals; again with the correct polarity and again the unit came alive and I could feel the battery getting warm, as I pulled the battery clip away, the unit takes off fully with the fan running and the clips still hot and ready to be put across a battery.

Certainly, we have fooled the charger into starting and it is now our responsibility to get the polarity right, there may be other protection, but let’s not rely on that.

With this said, it’s my recommendation that you use some electrical tape to mount an AA battery to the handle with the ends exposed. If you ever have a reason to use the charger for a source of DC, or need to attempt to revive a dead as a door nail battery, just put the clips to the ends in the correct polarity, and this unit will take off.

The  only thing I found this unit needs is your small effort to solder the connections between wires and clips, my HF power conversion Vector Brand unit got hot here when brand new, and the added voltage drop fooled the processor into giving up on the charging of a battery, it’s such an easy thing for you to do, and Murphy say it will be a problem if you don’t.

Compact, Light weight, rust proof, easy to get into, cords easily replaced, fan easily replaced.. I like it! This one is easy to take to your cabin.  One more note, if you have a small generator NOT equipped with 12 volt charging, this is a potential solution.

one negative review found:

First, let me say that this charger performs flawlessly and deserves five stars
when it is in charging mode. I have used it for three years and hundreds of
successful charging cycles on a dozen different batteries of various sizes and

However, on two different occasions and with two different
batteries (both brand new when hooked to the charger) I left them in “trickle
charge” mode. The batteries were part of an emergency communications station
that must to be ready at any time with full batteries. This charger burned up
both batteries after three months of trickle charging. This mode is supposed to
allow a battery to be hooked up indefinitely and maintain it at peak
performance. Not destroy it. Other folks in the emergency communications service
use other chargers and leave them in trickle mode for years. DO NOT use this
charger for that kind of operation.

Suggested experiment, if you have a battery floating off an old style charger, plug in the KILL-A_WATT and study the power factor and total wattage draw.., it likely sucks, and you’ll find it is costing you far more than you knew to float that battery. If you have an inverter with a built in charger that uses AC to maintain the float, look at the power consumption, you may be amazed by the inefficiency of the charger WHEN in float mode. A custom DIY power supply based on this product may pay dividend in a shorter periodthan you expected.   

With this stated, it would be fun to use an AVR or other programable micro to run this thing, perhaps, a programable float voltage where we simply disconnect charge  until battery voltage drops below our threshold, and then we hook it up again? No need to put in panels or buttons, just a usb port in the side, and use your smart phone as a dumb terminal to set the parameters for floating the battery connected.

Perhaps, the better float plant will use a latchable relay on the AC power side, the micro in sleep mode most of the time, but wakes and checks battery voltage and then starts charger till float voltage is again at the cut off point.. the avr runs off the battery plant of course.

I see fun here, and there’s smaller and cheaper chargers from this company, I think I saw one for $31.00, you can’t buy surplus parts to play with for that price.

Another side note, this well known battery charger company has a warning sticker right on the back of this unit. “Replace worn cords immediately.” sounds like an invitation to open the case to me.. 




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5 Responses to HF Power Conversion Battery Charger, a look inside for free. SC1000A

  1. Michael Lawton says:

    Good one George.

    I will have to put up pics of my old sears charger. Yes actually says sears and not craftsman or die hard. Its a 10/2/50 amp charger. It looks like this one but has the added 50 amp selection.


    The closest I have to smart charging is the plug in transformer type battery tender for my harley. This stays plugged in all winter and keeps the battery topped off. I have noticed through the years that it really just maintains the charge thats already there but dont really fully charge the battery. So I give it a deep charge at the beggining of the season.

    Even with my car batterys I try to fully charge them once or twice a year after I add water or check them for maintainance.

    A friend of mine that works for a major battery manufacturer told me a secret with regards to warrantys. There are 18/24/30 month replacement warrantys and you pay more for a longer warranty. He states the only difference in the battery is the distance of the plates from the bottom of the batt.

    When debris falls off the plates and settles to the bottom it rises and finally touches the plates, which in turn cause the battery or plate to fail. The higher warranty batt have a larger distance and take longer to accumulate debris.

    Now technically if you took a battery and emptied all the crude from the bottom say every two years, plus recondition the battery by removing the sulfur that accumulates on the lead plates of the battery, corroding them and blocking electric current flow. You can use a common household chemical, magnesium sulfate (Epsom salts), to recondition a lead-acid battery.

    Never tried it and have not found anyone who has. I assume its a convienence thing and people dont want to be bothered, but I bet you can make a battery last until the plates disinegrate. 20 yrs ++++???????

    I wonder if a good test is someone who has those expensive deep cycle batteries that they may be able to extend the life dramatically.

    Just my thoughts.

    Mike NJ

  2. George B. says:

    Mike, one battery I bought and sold was around $11,000 retail, there are no unheard of tricks, and telcos have spent a fortune on battery research, maintenance and fixes. Most lead acid batteries last longest when floated, how high that float should be is often debated, hotter floats required water added.. You are right, good batteries do have a larger setiment area below, but so many other things come into play. Rolls Surretes are considered one of the high end batteries in deep cycle technology.. batteries are built accordign to need, start batteries designed not to be discharged etc.. OH goodness, then there’s all the the battery types, AGM, Gel,… on and on..

  3. Elden says:

    My mom used to holler at me for taking my toys apart. She used to say “can’t you at least wait until it breaks?”
    I’ve been told about cadmium sulfate as a way to “rejuvenate” sulfated batteries. What I’ve been told is anything that interferes with the sulfation also interferes with the chemical reaction of the batteries. I guess I just figured if there was anything new under the sun, (as far as lead acid batteries are concerned) the Germans would have figured it out by now….George, I’ve got a rolls surrette battery bank at the cabin, I think they are having sulfation issues. Their website has an equaliztion process whereby you closely monitor the batteries temps so as not to damage the plates. I’ve got to give it a try, generator won’t put out enough voltage through the inverter, it has to be done with panels and the charge controller. No magic potions are mentioned.

    • George B. says:

      Elden, I doubt there’s too many DIYers out there that have your in depth knowledge of chemistry AND you tenacity when it comes to research… period!
      Few entities did more research on batteries that Bells Labs, and they even had a few of their own Germans. I believe you are correct, anything you add to the battery has a down side, and it will more than likely shorten the life expectancy of your battery, it’s best to save the magic potion for a Wall Mart Deep Cycle experiment, your Rolls batteries are certainly at the other end of the spectrum.
      Here’s what I’d consider in your situation. Go to your MPPT, and raise your float voltage, going up two tenths will use more water, so re schedule your water check routines more often.
      Next, look around your community for a good sized 2:1 for 48 volt plant 4:1 24 volt plant.. auto transformer, take a 120 leg off the ST gen head and drop your voltage to around 60 volts at 60 HZ. Now add a rectifier bridge with the amperage capacity required and make up a charge cable for your battery string..
      Back off the governor, get your engine running and then adjust the throttle upward until you have the amps you want, and watch the gassing.
      A charger system like this is great because the current drops automatically and tapers off as the battery charges..
      If your electrolyte is stratified, the dynamo charger should cure that in a hurry.
      Some Telco power engineers kept the old Motor Generators in place for a long time, as they knew just how valuable they were in getting a string back into condition after a long hard discharge, this of course doesn’t happen very often, unless things go wrong.. in bigger wire centers, the Diesel AC Generator(s) is often auto start and should pick up all the AC power rectifiers that normally >FLOAT< the telecommunications office at 52.2 volts.

      • Elden says:

        Thanks for the tip, George. The specific gravity won’t come up to where I would like, and over the winter the batt bank was not fully charged (who knows how long?)! I’ve installed an auto start propane generator to make sure this doesn’t happen again, unless Murphy pays me a visit. There’s always those remote sensors that one can monitor, should have had this feature last year and I wouldn’t have been dealing with this.

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