Pignose 7-200 Hog 20 - charging/powering

[jondoe]

Hi all,

Does anyone here have a Pignose 7-200 Hog 20? I picked up a battered old one some weeks ago as a project and for the most part it's much happier now it has some knobs, clean pots and all the jacks are fixed, but the one thing that's confused me is the charging system. This didn't come with a power adapter/charger, all the 3rd party adapters available are 12v, it even says 12v above the input, but this can't be right as you can't charge the internal battery on 12.4v coming out of the adapter.

The two 6v batteries in series would need about 2.30v per cell (13.8v total) so they aren't every going to even slow charge on the third party 12v adapter. I've seen some google image's of 15v charger/adapters, despite the 12v rating above the power input, 15v sounds more in the region of charging.

[shortcircuit]

If your wall wart is only putting out 12.4v I'd suspect a bad wall wart, most 12v adapters put out any where from 13.5 and above.Grabbed the first one in front of me.

[jondoe]

Is that a regulated or unregulated wall wart? Unregulated tend to read high when not under load, but regulated should be pretty much on the money.

[shortcircuit]

The example is from my car's jump pack , intended for charging , and I think would work for your situation. I do agree it's a different circumstance when it's an specific operating adapter such as a Boss PSA-120, not 12v but you get the jest.

[jondoe]

This is the 15v supply I've seen mentioned as the original (despite the 12v input designation), it states switching power supply which *normally* means a regulated output.

[shortcircuit]

That does answer a question I had, after doing the no no (assuming) they were SLA batteries. I'm thinking the 15v designation is Pignose way of getting you to buy their adapter. it does give you the info that you can go up to 1amp. Just make sure it's 12v design for SLA batteries , NOT, NiCD,NIMH,Lithium

[jondoe]

15v does get us well into the charge zone for a SLA battery, I'm assuming the amplification circuit can handle the extra few volts, but would happily run on 12v while not charging the batteries at all. Everything I've read says that these should be left on for no more than 8 hours to charge, so I can't imagine it's dumping the full 15v into the batteries as that would cook them. I'll go take a voltage reading from the wall wart and across the battery terminals, see if there is a voltage drop.

[shortcircuit]

Do the batteries have any voltage in them ?? If you can get to them,disconnected,give them a shake , if you hear any rattle like grains of sand , they are sulfated and are junk. The only schematic I found, not sure if it's correct, list a TDA7240A as the audio amp , max operating supply V 18V.

[nevetslab]

I had to stop and look to see which Pignose Amp I have had sitting up on the shelves for the past many years. It too is the Hog 20, with the pair of 6V Sealed Lead Acid batteries. I've never looked at it, and by now, the batteries may not even respond to charging up. I'll give that a whirl with a 0-16V -10A lab supply and see if I can wake them up. Whatever the gaffer's tape note on the top of the cabinet said has long since faded, so I've no idea what was wrong with it in the first place. One of several items I rescued from CenterStaging's junk pile back in 2010. Each battery states 7.5VDC charging @ <1.2A, so that's no problem.

[shortcircuit]

I'll give that a whirl with a 0-16V -10A lab supply and see if I can wake them up.

The odds are stacked against you,especially after 9+ yrs, again if you can give them a shake, may save time and effort. Good luck !!

[Jazz P Bass]

Pignose.com calls out a 15Vdc supply: https://pignoseamps.com/product/regu...g-series-amps/

[jondoe]

The batteries in this were dead as a door nail, I stuck them on a dumb 5 amp charger for 5 days but that didn't wake them up. I stuck it on my CTEK smart charger and it refuses to start charging, so yup, they are paper weights now.

I've been running it on a much much larger SLA battery, that worked a treat on a test signal, although I've just plugged a guitar in with a wall wart 12v supply and it has way too much buzzing coming from the guitar, although not from test signal generator

Fun times, no wonder someone threw this away

[jondoe]

Pignose.com calls out a 15Vdc supply: https://pignoseamps.com/product/regu...g-series-amps/

I wonder how it knows to stop? There's nothing clever going on in the amp, unless the newer ones are different, so it must be a clever charger, not just a power supply.

[J M Fahey]

1) get two new batteries

2) Sealed Lead Acid batteries need an SLA charger,period.
They are as complicated as NiCads, Lithium, NiMh, etc. , just with their own set of rules.

Repeat with me: a-battery-is-not-a-resistor

3) problem with regular wall warts is that if close to 12V batteries do not charge; if higher, current taken is unpredictable (well, it actually is, but you need to refer to graphs depicting charging curves).

This is a "12V" graph, it applies for you because you are charging 2 x 6V batteries in series anyway:



Notice voltage across charging battery terminals varies *wildly* between 11.8 and 16.4V depending on stored charge and charging rate

in principle: voltage below own internal battery one at that instant wonīt charge sh*t ;voltage higher than that will see a short.
Yet batteries are being charged all the time.
Although many times not efficiently

Cheapest simplest one is NOT a "voltage source" but a voltage source above maximum voltage expected, some current limiting device (remember you are feeding a short which will happily blow your wall wart to pieces) and some element to stop overcharging ... which may be as simple as owner unplugging charger after "X" hours ... or designing chargers for "8 hour" charge time, so he plugs it at night and unplugs when he wakes up.

Too hurried now, but later will post a couple schematics, included a simple "intelligent charger" easy to make with junk bin parts.

EDIT: think of a lead acid battery as of a 1000W Zener (meaning you wonīt blow it) , with slowly varying voltage, from 11 something Volts to over 16V and in series with a few milli ohms internal resistor.
Would you feed constant voltage (what wall warts try to supply) to such a Zener?
Or would you limit current somehow?

Add to that the fact that batteries can take quite a lot of current when flat, that diminishes with charge, and after full charge such current *damages* them, big time, unless itīs below a very small value called "trickle charge" which "just" replaces self discharge and keeps them charged forever.

[Jazz P Bass]

Here is the schematic that I have: pignose-hog-20-001.pdf