Lead acid battery testers?

[ericmark]

There were 2 amp versions of the 7812, they were the main way that CB power supplies regulated their output, around 1.2 volt across a red LED so put one between the 7812 common and real common, and you got 13.2 volt approx.

But as said it did not work, the extra 0.6 volt drop or so was simply too much.

As to checking the sg at regular intervals, it reminds me of a big bang, we had a container with batteries in, and a charger, two copper pipes as buss bars, with crock clips to add or remove batteries, we also had a 12 volt freezer which we kept the contraband bacon in, this was Algeria.

My colleague went to get the bacon, and he knocked a clip, causing a spark, I heard the batteries exploding like a machine gun, and as he walked out was ready with the hose pipe. I likely saved his sight. but hydrogen burns with a blue flame and a pop, and that was a very loud pop.

In our cool country we tend to forget how dangerous lead acid batteries can be. We would have normally warn googles, and turned off the charger before going in, but he only went for the bacon.

 

[SUNRAY]

When designing my high-current, pulse charger - I used a large toroid, and a triac, to do the switching. at the zero crossing point. From memory, a 7812 was limited to 1amp.

7812 are available as small as 100mA and the largest I've used has been 5A which I suspect is as big as they go.
Making them work at a higher voltage is simply a matter of raising the common voltage WRT the 0V line, typically by a forward biased diode or 3.

 

[SUNRAY]

There were 2 amp versions of the 7812, they were the main way that CB power supplies regulated their output, around 1.2 volt across a red LED so put one between the 7812 common and real common, and you got 13.2 volt approx.
...

Seems you beat me to that point. The bigger CB supplies often used a 7812 and a resistive potential divider to raise the common voltage to around 2.8V to control the base of a pass transistor and not only the cheap crud as this was common for the 5A Bremmi.

I used to repair so many CB PSUs I kept a fair stock of part particularly for Bremmi's as there were so many of them being abused.

 

[ericmark]

Oh the linear amplifier or burner as they called it. And not really the quality of my MM one used for 2 meter.

 

[ericmark]

I have 2 each of ULDG 5.0 A1, ULDG 5.0 B1 & (ULDG 5.0 D2 as yet unused). I believe this means are all 5A the B1 & D2 manuals mention dropping back to 'trickle' when fully charged but no mention of returning to a higher charge current. I can't find my manuals for the A1 version and a very quick www search brought up the B1 version

I had a hunt, ULGD 3.8 A1 was the 3.8 amp version with LED display showing voltage and ULG 3.8 B1 was the 3.8 amp without the display,

they would alternate between 0.1 amp and 0.8 amp with the voltage triggering the change 12.8 volts and 14.4 volts. The ULGD 5.0 D2 shows similar graph

I think the change comes under "Demand recharging" but I find nothing else in the manual. However the battery is often not in a place where I can monitor with ease, so I used an energy monitor, and noted it did return to the 3 amp charge rate.

 

[SUNRAY]

Mine are all 5A versions and all have LCD's, the paper manual I have for the 5B1 version is the same as the English and German parts of this: https://www.manualslib.com/manual/2037383/Ultimate-Speed-Ulgd-5-0-B1.html?page=50#manual however it does not contain the graph shown on page 3 and describes operation as:

I've just found the 5.0A1 manual on there too which contains the similar graph you showed for the 3.8A1.
My D2 versions as yet unused but seems to imply more (better?) features.

From your earlier description I took it to mean it would return to the high (3.8 or 5.0A) charge rate and until now had't really appreciated they have 3 charge rates.

 

[ericmark]

I have put an old battery on charge with the 5 amp version, I had not realised the battery was in such dire need of re-charging, and had hoped to show graph of it charging, but was only showing around 10.5 volts, and on switch on, showed fully charged straight away, which clearly it is not, and the graph just shows

which is second to lowest charge rate, there are 4 charge rates not including the pulse charge, 0.1 amp, 0.8 amp, 3 amp and 5 amp. Calling it a 7 stage charger is a bit tongue in cheek, stage one is it deciding what to do, stage two is pulse charge, so in the main stage 3 is the first stage of really charging, and at 12.8 volt it moves to next stage, so tends to be for a very short time. What they call stage 4, I would call stage 2, and it does not matter if 3.8 amp or 5 amp version, this is at 3 amp, and with a 110 AH battery this can last 36 hours, however it is the next stage they call it stage 5 which can be a problem, as it needs to voltage to hit 14.4 volts to drops to the final stage they call stage 6, and I have found batteries where the internal leakage is too high to ever hit that final stage. But stage 7 is a return to stage 5 so how one can put a number on it I don't know, and it starts when the battery has dropped to 12.8 volt.

So the old 3.8 amp charger if I applied a load, would only return to stage 5, it would never reactivate stage 4, where the CTEX MSX 3.5 and 5 would return to high output under load, so better in a caravan or similar use. However I have had batteries with shorted cells, and there can be some debate as to if returning to full output is good or not, for a battery left unattended on charge?

If I assume the 80 Ah battery off the Jag is completely discharged, at 0.8 amp looking at 100 hours to charge, just over 4 days, I don't need the charger for anything else, and since an AGM type, (VRLA) I don't want to use any high powered charger. It was renewed with the Jag in error, but I had kept it to use with the caravan, the starting fault was not pressing on the brake peddle hard enough, it was turning off the warning telling one to press brake peddle, but must be multi-contact switch, as not allowing the starter motor to engage.

Full marks to RAC man who found this out over a year after battery was changed. Caravan scrapped, after water damage over Colvid when I could not visit it to check it, and not sure I could have used a AGM battery as the caravans charger was to my mind too high of a voltage. So it has just sat on the kitchen counter for last few years.

 

[ericmark]

Five days at 0.8 amps, or 15 watts, no sign of change, off charge voltage has risen, but it does seem I have left it too long.

 

[ericmark]

Well come to charge two 35 Ah AGM one with Lidi 3.8 amp, other with Lidi 5 amp, the 3.8 amp one has been running for around 3 days so that one has gone to trickle charge, the other (5 amp) went on today

and it is returning to 3 amp charge rate, which the old 3.8 amp version never did. Sorry @SUNRAY it took so long before I could confirm the latter versions will return to 3 amp charge rate.

 

[SUNRAY]

Well come to charge two 35 Ah AGM one with Lidi 3.8 amp, other with Lidi 5 amp, the 3.8 amp one has been running for around 3 days so that one has gone to trickle charge, the other (5 amp) went on today View attachment 384873 and it is returning to 3 amp charge rate, which the old 3.8 amp version never did. Sorry @SUNRAY it took so long before I could confirm the latter versions will return to 3 amp charge rate.

Interesting, my manuals for the 3.8A B1 and 5A D2 versions don't appear to to show that operation and observing the screens displays I've not seen any of them (including the 3.8A A1 version) return to the higher voltage, however I must stress the batteries and chargers are not exactly 'in full view' so occurances are easily missed.
What power monitor do you use, everything of mine is purely cumulative?

 

[ericmark]

Now seeing the charge rare reducing, I use these

from Energenie, I have one which will also switch on/off, and one monitor only. The 3.8 amp versions will not return to 3 amp, only the 5 amp version. I will look at the model number tomorrow, but the instructions do not tell you they will do this.

This morning the report is

so it seems to returns to 3 amp then drops to the 0.8 amp and then off, until the voltage drops to below 12.8 volt again.

 

[SUNRAY]

I have similar sorts of devices except they only showing current and recorded max, min and cumulative. I can't get a picture as the plastic screen has gone brown over the years and there is no LCD backlight.
After an event on Sunday 29th June I put an eldery 115AH leisure battery (known to be well down on capacity) on charge using a D2 version, it showed an increasing 54 to 68W for 5 to 6 hours (between ~9&10pm) at which piont I reset the count to zero, since then it shows max of 17.2W and min of 5.8W so no sign of returning to the higher charge rate, the charger shows 12.8V \& DMM shows 13.0V whenever I've looked.
Now taken off charge and instantly applied my ACT battery tester, it shows 13.7V & 27AH, I predict tomorrow it will be more like 12.5 to13.2V and 40AH.
(I suspect the elevated voltage [13.7] falls far more rapidly than the settled voltage [~12.8] and accordingly the ACT tester shows a lower capacity).