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Naio's avatar
Naio
Explorer II
Jun 25, 2016

Battery troubleshooting help, please?

This regards one of my elderly 90aH gel cells in my shave ice machine. Though old, they have been performing awesomely. Possibly until now?

There are 2 12v batteries running a 24v motor. I'll call the batteries A and B.

I usually charge them with a 24 charger, but those chargers die often and then I sub a 12v until I get another 24v. I have been doing this for 9 years, have great battery life. The charging setup is not the problem.

Battery A had an incident with a 12v charger, though, about a month ago. The charger's clips were large, and the only way to get them on the terminals was to cross the handles. After 9 years doing this with no incident, I guess there must have been a gap in insulation bec a small fire started, melted off one of the handles. Luckily I was right there and smelled it. I have been worried about this battery ever since, but it seems fine. In fact, my problem today is with the other battery, but I am trying to give you all any info that could be relevant.

I also mentioned the other day that my 'smart' charger continues to charge at diminishing amperage after it indicates 'done'. Now that I know this, I leave it on until it gets down to about half an amp. ('Done' is about 2 amps.)

Today's problem: I charged both batteries to half an amp last night before bed. This morning, A reads 12.92v (they are usually 13.13 or so when full) and B reads 12.30. Yipes!

B has the following wires connected to it. All connections are tight, wires have no cracks or wear in housing.

Positive terminal:
- Cable to battery A negative terminal
- Cable to an Anderson connector (unused)

Negative terminal:
- Cable to controller
- Cable to Anderson connector (unused)
- Small wire to socket for 24v charger
- Small wire to solenoid to start motor

...and nothing else.

While charging right now (5.5amps from a 10a charger), the wires to solenoid and unused charger plug both read about 0.5 amps. Is that normal? Or within the margin of error of my cheap ammeter?

Can a solenoid go bad in such a way as to drain the battery?

When charged, I will put a small 12v load on the battery to see what voltage it has reached. Maybe it's sulfated?

Battery A also seems to have lost more overnight than it should, though not as bad as B.

Any ideas are welcome!

19 Replies

  • Try this guy. he regularly is up in the LA area picking up batteries ffrom Concorde and trojan.

    He delivered a Lifeline GPl-31XT to my door fresh from the Concorde's west covina factory, and hooked Niner up with his Tellycom AGM.

    http://37.60.234.146/~deepcycl/
  • Naio's avatar
    Naio
    Explorer II
    ::munch munch munch::

    Yes, I will replace both. I wonder where to find a good deal? I don't supose people ship batteries. I am still in greater LA area, if anybody knows a good source.

    Thank you, Mex, for the virtual shot of jack ;). And one for you!
  • Well, applying a known load on the battery individually while watching the voltmeter will tell you and us, a lot.

    Voltage held under a known load with a known AH removed from the battery is how I mainly judge battery capacity retainment, or lack thereof, but a basis for comparison when the battery was newer or healthier is required for the judgement.
  • She was individually charging the batteries. This is the base of architecture of my response above. Nine years of total cycling is a l-o-n-g battery life. Replace both batteries not just one. The other "good" battery now has an aged zombie-like metabolism. It will eat any new battery it sees.
  • Naio's avatar
    Naio
    Explorer II
    There is no engine starting battery. (This is not in an rv.)

    I am only charging one battery at a time.

    I think B was fully charged because it was only pulling half an amp (Down from 5.5 at start of charging.). However, I did not put a load + voltmeter on it.
  • When these solenoids fail, often they fail with the contacts closed, meaning no battery isolation. See if 12.3v battery is in parallel with engine starting battery.
  • Nine Gel Battery Years Is

    NINETY

    Human Years

    A shot of Jack Daniels for you and Rosary Beads for the corpse.
  • I would say that battery B did not get a full charge. It is not uncommon for battery A to lose a few fractions of a volt overnight, same thing will happen if you put a 1 amp load on it for a minute or so (such as a light bulb).

    Are you charging both batteries at once with 2 chargers? This could cause problems, especially if the charger used neutral for a ground on negative terminal of the charger. It could cause another melt down of the 12 volt chargers.

    I would recommend only charging one battery at a time, in case there would be a problem with the first charger preventing the second charger from properly grounding, unless you want to take time to disconnect the wire between battery A and B so that B is not grounded at 12 volts above the ground of battery A.

    Fred.

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