Battery charger (outcome)

This is a continuation of the story where I complained that "smart battery chargers" were not working well for my batteries. Mine are about 160 AH deep cycle batteries.

The charger that I bought on eBay, that turned out to be a Walmart charger in fact, also did not work. It would "hang" showing partial charge 88%, only to overcharge the battery. It was a piece of garbage with poorly written software.

I gave the suggestion to use a big ol' power supply a second look and decided to do just that.

formatting link
I decided to use a PP-1104B/G power supply that is almost exactly the same as PP-1104C/G. It has two ranges: 13.5-19 volts, up to 100A, and

26-39 volts, up to 50 amps.

I tried using one to charge my deep cycle batteries. I noticed right away that it has a very annoying quirk. When powered off, if connected to a battery, it exhibited "reverse current", with the battery quickly drained through the power supply. I think that it is due to the supply having a big capacitor bank and a beefy discharge resistor -- so that the battery would discharge itself through that resistor.

That problem was solved by adding a diode to the output so that DC current can only flow one way. Problem was solved. (see pictures)

I also added clamps, and casters to this power supply so that it can be easily moved. Having casters moe or less addresed the weight issue.

I will also buy and install a Intermatic timer to it so that I can limit the amount of time that the charger runs before shutoff. I will buy one that has a hold capability in addition to timer capability.

Future plans also include making a linear regulator to further limit voltage and current to make into a CC/CV power supply. I have two Darlington transistors and people over at sci.electronics.design said I could use them.

The handles that I added on top come from Logistech dehumidifiers.

i
Reply to
Ignoramus11477
Loading thread data ...

NO ! gut the output filter , batteries can't "see" ripple and dont care . Pulsating DC charge is fine ...

IBMPC power supplies can be made to do 150 amps ( 3 or 4 in parallel) and they regulate better . Im doin a MIG welder with 10 PS's . 100% duty cycle ..

Batteries need to be tapered off above 13.9vdc ( 25 C amb , )

Reply to
werty

Low ripple is good for other purposes though. For $18 that I paid for this supply, low ripple is a nice addition to what it does.

Would be very interesting.

i
Reply to
Ignoramus13308

they sure see AC ripple, and don't like it.

Here's some johnson controls literature:

formatting link

Reply to
Cydrome Leader

I browsed Logis-Tech website a few days ago for a different reason and saw that they sell very high end battery chargers for armored fighting vehicles and the like. These chargers are unlike what is sold at Walmart or my PP-1104B/G supply. Logis-tech chargers charge batteries by providing high voltage pulses to the batteries, for some reason it is a superior technology. I may guess that the reasons have to do with de-sulfation of batteries.

formatting link
i

Reply to
Ignoramus16175

pulse chargers are different from AC ripple from a shitty power supply.

do as you wish with your batteries.

Reply to
Cydrome Leader

Pulsating DC and AC ripple are 2 different animals. Pulsating DC is actually good for nicads and possibly other chemistries.

AC ripple is not good.

Reply to
Jim Stewart

It's been a long time, but I seem to recall that pulsed DC tends to replate the cell metal in a more even and dense structure than plain DC, thus increasing the cell life.

Reply to
Jim Stewart

No not AC power supply , a DC power supply , gutting the filters just means ya get pulsating 120 hz DC , batteries like that fine . They actually like it better !

Reply to
werty

Im an electrical engineer . I dont write books i do power supply design "AC ripple" is bogus . Its an intent to deceive , its hype . There is only one *ripple .

Pulse charging is for higher currents into the plates . It forces the charging current to apply more equally , thru the plates , it equalizes the resistance in the plates . Amps charging a plate will see a higher resistance taking some paths , than other paths , but increase the current and those lower R paths start to increase faster than the others , so they tend to equalise . faster charge .

But you cant maintain steady high currents into the plates for the excess heat , warps plates . especially at end of charge , pulse charging works great .

  • we use NOISE to describe spurious , unwanted stuff on an AC signal , we use ripple to mean unwanted stuff on DC signal . we have a "working" language in electronics . "Hard" means the voltage does not vary with greater load . Like a MIG welder . Soft is CC welder . The voltage must drop as you arc . Our words for Darlington and IGBT is "crap" , Vsat too hi ..., use a common BT for hi volts and MOSFETS for low voltage .
Reply to
werty

AC ripple ? No such thing , AC must reverse the current , " ALTERNATING CURRENT "

Power supplies NEVER reverse current , they may have "ripple" but ripple dont reverse the current either .

If you need some help with batteries and switchers ( high freq' power supplies ) i do free design .... EE , KC7CC

Reply to
werty

Yeah, it's never possible for current to flow back into a power supply, ever. It's also never possible for there to be an AC component riding on the output of a DC power supply. Cannot happen. What else happens on this flat earth you live on?

Reply to
Cydrome Leader

Current flowing back into power supply is something that happened to me a week ago. I described it on this newsgroup. I had to install a diode so that it does not happen again.

i
Reply to
Ignoramus26070

There CAN be an AC component, but if the amplitude is LESS than the battery DC voltage, it is only ripple because it never falls below zero. If the amplitude is sufficiently high that the bottom of the sine wave drops below zero it is no longer ripple - but that takes a peak to peak voltage of over twice the DC value if it is riding "on" the DC. It can also be "on" the ground - in which case it is "noise" , not ripple, and IS AC. (Certainly not very common). Batteries like pulsed DC,.

Reply to
clare at snyder.on.ca

EVERY POWER SUPPLY has current flowing BACK into it. Think.

Reply to
buffalo

Well if it dosen't reverse polarity it just "aint" AC. (period) If there is ripple on the output it's just that RIPPLE. ...lew... (retired electronics engineer)

Reply to
Lew Hartswick

Of COURSE there can exist AC on a DC supply output. It's merely AC with a DC offset from ground.

You remind me of the ET instructor in the Nav who told the class, "DC is merely the sum of all AC harmonics."

I asked him to tell us the fundamental frequency. Got thrown out of class.

LLoyd

Reply to
Lloyd E. Sponenburgh

Got another silly question or two: A transformer "transforms" _only_ AC, right? A single capacitor in series in a circuit acts as a simple high-pass filter for _only_ AC, right?

So how is it, on a single-ended amplifier that ONLY puts out "DC", you can derive and dereference the output of that amplifier through a transformer or capacitor?

Or, is that impossible, too?

LLoyd

Reply to
Lloyd E. Sponenburgh

Writing like an engineer would be a big credibility plus.

Reply to
Jim Stewart

tell that to werty, not me.

I think you missed the flat planet part. Try again.

Reply to
Cydrome Leader

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.