Alum battery conversion.

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DavidA:
Here are the results of today's discharge test. Load was the same 12 Volt 50 Watt lamp as before.

Note.

The battery had been charged for around 24 hours after the last test, then left standing for 5 days. The voltage across the battery prior to the test was 10.6.

12:30 7.3 Volt 3.3 Amp

12:45 11.2 4.2

13:02 11.6 4.3

13:16 11.7 4.3

13:30 11.7 4.25

13:45 11.5 4.25

14:00 11.8 4.2

15:00 11.4 4.2

15:20 8.4 3.5

15.30 11.7 4.2

15:45 11.3 4.15

16:00 8.7 4.15

16:30 11.3 4.1

16:45 11.3 4.1

17:00 11.3 4.1

17:15 11.2 4.15

17:30 11.1 4.1

17:45 11.3 4.1

18:00 11.2 4.1

18:15 10.8 4.1

18:30 10.7 4.1

Duration of test 6 hour.

This battery appears to be improving.
Notice how the measured voltage is higher when under load than it is when it was standing with no load connected.
There are a couple of occasions when the voltage drops, but it recovers .
At the time the test was discontinued it was still providing 4.1 Amp although the voltage was beginning to drop off.

The next test is to use two lamps to double the current.

Dave.

vtsteam:
So that's something like 26 amp hours (so far), and 1.9 V per cell (more or less). Which is pretty good for a dead battery!

I don't know how the capacity holds up against a similar size lead acid battery in good condition. I do have some bigger deep cycle marine batteries, about 50% larger that have 100 amp hour capacity. I always assumed a regular car battery was up around 60, but I don't know for sure.

The rise from a lower resting voltage seems typical for these alum batts, and the ability to hold a charge for a longer period without self discharge. Also, somewhat lower cell voltage.

DavidA:
VT,

...I don't know how the capacity holds up against a similar size lead acid battery in good condition...

I was wondering along the same lines.

I have a good battery off one of my cars that I will charge up and run a test (or two)on.

Next step with the alum battery is to investigate the Specific Gravity aspect. Does it behave the same as when using Sulfuric acid ?. Much measuring to be done.

But I really do need to automate the measuring process. Taking readings every quarter of an hour is ok if I'm in the shed, but a bit of a chore if I have to make special trips.

I do have the data gathering and logging equipment, just need to set it up.

Dave.

awemawson:
No problem, get the wife to take the readings when she's between ironing session :lol:

DavidA:
Just need you guys to humour me for a bit.

During my trawl through the various desulphating offerings I found the following.

Some of you may have seen it.

But regardless, I would like you to have a quick look at it, the first minute is enough, and see if you spot some thing odd.

Dave.

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