[EVDL List]

Mark Freidberg wrote:

> The Deka Intimidator 9A31 AGM batteries (12v, 100ah @
> C/20) in my Geo EV (www.austinev.org/evalbum/701)
> have been emitting a noxious odor. The odor is strong
> enough to encourage maintaining cross-ventilation in
> the 14'x25' garage that the EV resides in. That's even
> if the batts simply remain idle for a day and longer.
>
> Its a chronic odor that increases on the discharge.
> When driving, a 2" fan in the rear battery box pulls
> some air thru the cabin, but its not enough.

As you are aware, your AGMs shouldn't emit any odour when driving or
charging.

When driving, do you notice the odour very soon into your trip, or does
it only become apparent after you've driven a fair distance?

One of my AGMs failed, and I would get a pronounced odour in the cabin
while driving once I'd driven long enough to remove about 20Ah. There
was no odour from the start of the trip until then. Even then, there
was no odour during charging. The odour I would get if I drew the pack
down far enough would dissipate quickly enough when the load was removed
that it was not evident at all the following morning after charging
overnight in a relatively sealed garage.

> There is one 3 amp output Soneil/ACI charger per
> battery. The chargers are bringing the batts to
> 14.5v-14.7v then floating at 13.6, increasing to 13.9
> if left plugged in for a few hours.

You have the chargers mounted where you can verify that each and every
one has finished sucessfully before you drive away? Have you verified
the outputs to confirm that each one is bringing its battery to the
required voltage?

> Perhaps the chargers are taking the batts a little
> high now. But the batts were stinky thru the winter
> since installation when if anything, the Soneils were
> slightly undercharging the batteries.
>
> So it is not obvious to me that overcharging is a
> cause of the odor emissions.

It is hard to believe that a 3A charger could overcharge a 100Ah battery
to the point of venting, expecially if you aren't leaving them running
for extended periods, however, if you weren't over-charging they
shouldn't be venting.

Do you have any idea how many Ah you typically remove from the batteries
between charges? I'm wondering if the problem here isn't that these
little chargers just can't get your batteries refilled before you take
the car back out, and so you've been chronically undercharging the
batteries. For instance, if you pulled 30Ah it would take these little
chargers about 12hrs to refill the batteries (possibly longer, as there
is no guarantee that they actually deliver 3A right up to full battery
voltage).

> I'd like to eliminate these battery emissions in the
> near term. Suggestions?

If you've got a voltmeter, connect it to one of the batteries and keep
an eye on the meter while you drive. If the meter has a min/max hold
feature, you could use that to track the minimum voltage so you don't
have to keep glancing at the meter all the time. Record the minimum
voltage seen on your typical drive, and repeat this process for each
battery in the pack. Hopefully you should find one that stands out as
sagging significantly more than the others. If you have an electric
heater, DC/DC, etc that allows you to put a 15-20A load on the pack, you
might be able to speed this test up by measuring each battery's voltage
while loaded at 15-20A after a drive and before charging.

Hope this helps,

Roger.

 

[EVDL List]

--- Roger Stockton <[email protected]> wrote:

> As you are aware, your AGMs shouldn't emit any odour
> when driving or charging. When driving, do you
> notice the odour very soon into your trip, or does
> it only become apparent after you've driven a fair
> distance?

The odor would intensify from a baseline after perhaps
10 minutes of driving. Usually the dashboard fan is
run on a high setting to push air thru the cabin in an
effort to keep the odor at bay.

> The odour I would get if I drew the pack down
> far enough would dissipate quickly enough when
> the load was removed that it was not evident at all
> the following morning after charging
> overnight in a relatively sealed garage.

Was it more of a tangy or rotten egg smell? My batts
are the former and the odor is stronger under load,
dissipates when the load is removed, but remains at a
lower intensity even if the batteries sit idle for a
day or more after recharging.

> You have the chargers mounted where you can verify
> that each and every one has finished sucessfully
> before you drive away? Have you verified
> the outputs to confirm that each one is bringing its
> battery to the required voltage?

Yes to both of these, and a Paktrakr has been onboard
since May so the individual battery voltages are
viewable in real-time.

> It is hard to believe that a 3A charger could
> overcharge a 100Ah battery to the point of venting,
> expecially if you aren't leaving them running
> for extended periods.

I agree with this.

When I installed the Paktrakr in May, it revealed 3
batts with voltages that sagged more then the rest.
That was expected because range had dropped off
sharply after a couple of trips getting too far out
and going into turtle mode before reaching safety. So
i suspect these 3 batts had suffered cell reversals.

Those 3 batts were replaced with new ones. At the same
time, all the batteries were repositioned in the
battery boxes so that they were all easily accessible.



> however, if you weren't over-charging they shouldn't
be venting.

When I was installing one of the newer replacements, I
noticed it was stinky just handling it. That was prior
to any charge, discharge, or connection to the pack.
This makes me think that the so-called "sealing
valves" in these batteries are really nothing of the
sort. They are simply leaky.

With subsequent trips, other old batts have become the
weak ones. When they've tumbled below 9.5 volts after
too few miles on a trip, they've been replaced.

So as it stands now, 5 of the AGMs installed in
October remain in the EV.

And 6 new replacements have been installed since the
Paktrakr came online.

Plus, 1 Deka Dominator 8G31 gel was installed late
last week. Simply to see if it would be less stinky.
Of course its respective Soneil charger doesn't have
an ideal charge curve for it, but its all i have at
the moment.

So far it seems the gel might be less stinky (or not
stinky at all) then the AGMs. It is right behind the
driver's seat in its own Quickcable polypropylene
battery box. And that makes it easier to tell if it is
stinky and not confuse it with the smelly AGMs.

So that makes for a total of 12 batts. Six are
upright, six on their sides.


> Do you have any idea how many Ah you typically
> remove from the batteries between charges?

No, I could only estimate from how much is pulled from
the wall during charging. No ah or wh meter onboard
yet.

> I'm wondering if the problem here isn't that these
> little chargers just can't get your batteries
> refilled before you take the car back out,
> and so you've been chronically undercharging the
> batteries.

The Paktrakr is confirming that the chargers are
taking all 11 AGMs up to 14.5-14.7v before going into
float of 13.6v. Quite conveniently, once they are in
float, the Gel batt has arrived at about 13.9v in cc
stage. So at least its getting that much charge.

After shallow discharges, the Soneils are simply
plugged in. On deeper discharges, the onboard Russco
takes the batts up to 13.5v-13.8v and then shuts down.
Then the Soneils are plugged in to finish the charge.


Mark







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[EVDL List]

Mark Freidberg wrote:

> Was it more of a tangy or rotten egg smell?

A bit of both, I suppose, but definitely a distinct sulfur (rotten egg)
smell.

> > You have the chargers mounted where you can verify
> > that each and every one has finished sucessfully
> > before you drive away? Have you verified
> > the outputs to confirm that each one is bringing its
> > battery to the required voltage?
>
> Yes to both of these, and a Paktrakr has been onboard
> since May so the individual battery voltages are
> viewable in real-time.

Great. (Perhaps you can tell us more about life with the PakTrakr in a
different thread? I've just got a couple in to play with and will be
evaluating it against my HP3497A data acquisition unit to see just how
accurate the PakTrakr is from channel to channel.)

> When I was installing one of the newer replacements, I
> noticed it was stinky just handling it. That was prior
> to any charge, discharge, or connection to the pack.
> This makes me think that the so-called "sealing
> valves" in these batteries are really nothing of the
> sort. They are simply leaky.

Brings new meaning to the expression 'to have gotten a few stinkers'!
;^>

I doubt this has to do with sealing of the valves. I've received 100Ah
AGMs from a customer for testing, and several were damaged in shipping
such that the posts were just about broken right off and the post seals
damaged. I cycled a pair of these damaged batteries while awaiting
replacements and there was no noticable odour during charge or discharge
despite the fact that they were venting noticably around the posts where
the seals were compromised.

> With subsequent trips, other old batts have become the
> weak ones. When they've tumbled below 9.5 volts after
> too few miles on a trip, they've been replaced.

9.5V is kind of low; ordinarily 10.5V under load is considered 100%DOD.
If less than 9.5V after "too few miles" is grounds for replacement, what
are the "good" batteries holding under the same conditions?

> Plus, 1 Deka Dominator 8G31 gel was installed late
> last week. Simply to see if it would be less stinky.

> So far it seems the gel might be less stinky (or not
> stinky at all) then the AGMs.

I've got some experience with the 8G31's and can say with some
confidence that they should not smell at all; not when new, not when
driving, and not when charging.

> So that makes for a total of 12 batts. Six are
> upright, six on their sides.

Have you noticed any trend either with the stinkers or weaklings tending
to be more likely to occur in the upright or laid down sets?

Of the ones on their sides, have you noticed any dampness/droplets
anywhere near the terminals or vents, or generally anywhere near the top
of the battery case, or the seam where the case top is joined to the
rest of the case (if applicable to your battery construction)?

> > Do you have any idea how many Ah you typically
> > remove from the batteries between charges?
>
> No, I could only estimate from how much is pulled from
> the wall during charging. No ah or wh meter onboard
> yet.

What are you waiting for? The 600A hall effect sensor for the PakTrakr
is only $50 (and it's a cute little guy, too ;^)

How far do you drive between charges, and what sort of driving (speed,
hills, etc.)? Do you have any idea what the farthest you can drive on a
full charge is?

I wonder, if every battery you've gotten has smelled even before
installing in the car, if perhaps there is some sort of contamination on
the outside of the cases that smells even more strongly when the battery
warms up, as it might during charge or discharge? Have you tried
washing the batteries off thoroughly to try to eliminate the smell?

That said, if you've replaced over half of your pack since October
(almost the entire pack, it seems since you mention having replaced 3 in
May and six more since then, though you also note that 5 of the
originals remain so it seems that some of your replacements have been
replaced), then something is definitely not right with your charging or
discharging.

The fact that you are experiencing odour while driving suggests
overdischarge of some cells; paradoxically, odour while charging
suggests overcharge of some cells.

I suppose the good news is that if we can figure out what is going on,
you will be able to eliminate the odour issue and enjoy much better
battery life!

I've cycled new AGMs ranging in size from 20Ah to 400Ah without odour,
and I've run a set of tired old Optima YTs in my EV for the past year
without odour except when that one battery failed on me. There is
definitely something unusual about your supplier/batteries if every AGM
you get stinks even before you use it.

Cheers,

Roger.