smartdriver

Interesting Observation While Charging The Battery In The Cold

9 posts in this topic

My battery went dead after not driving my 2005 Cabriolet for a while. I charged it in above freezing temperatures and left it on a low current (<2 A) for a day after it was fully charged.

 

During this time, the temperature dropped precipitously and when I got home I noticed a large amount of frost on the INSIDE passenger (right) window and the INSIDE of the windshield but not on the driver's side

 

Because of the distribution of the frost it appeared to me that the battery was venting while charging. This was an ominous sign because 5 years previously I had major water incursion into my SAM after a similar dead battery occurrence. Because while overcharging the vented moisture also contained sulfuric acid, multiple traces and even one of the legs on an IC chip in the SAM were eaten away.  

 

It has been my belief that water incursion into the SAM occurs not by windshield leakage, but by condensation on the wiring harness above the SAM from air conditioning or low temperatures and which wicks into the connectors.

 

As a preventative measure 5 years ago I placed a sponge in between the wiring harness and the top of the SAM to mitigate any future water damage. The battery is supposed to have a vent hose to steer such venting to the outside. It is likely that mine is not connected.

 

Just a heads up for any who need to charge their battery and as a preventative measure I would recommend placing a sponge between the wiring harness and the top of the SAM.

Edited by smartdriver

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Gases coming from battery are hydrogen and oxygen. There is no “sulphuric acid gas”.  It is recommended to connect a hose to vent gasses from battery to the outside. 

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1 hour ago, tolsen said:

Gases coming from battery are hydrogen and oxygen. There is no “sulphuric acid gas”.  It is recommended to connect a hose to vent gasses from battery to the outside. 

Perhaps my language wasn't technically perfect.

 

6 years ago when the first incident occurred, opening the car door while the car battery was charging revealed a very strong odour which was enough to irritate the eyes and could be tasted.

 

Although you are correct in stating that hydrogen and oxygen are produced when venting, apparently a sulfuruc acid mist can also occur and hydrogen sulfide gas (H2S) can also be produced. H2S when combined with water will form a weak acid. 

 

 

Edited by smartdriver

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The car should have a tube that vents the battery through the floor.  They all had them when new.

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I suppose it is possible to get battery acid mist if you overcharge using far too high amps which is very unSmart.

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Modern intelligent battery chargers are much safer although they have their limitations and won't charge totally flat batteries because they cannot then determine battery voltage.  I possess three such chargers.  Max amps is 3.8 A and amps will drop down to 0.8 A once battery charge goes above a certain limit therefore no acid mist in the air and no damage to battery if left on for days.  Two of my chargers will eventually automatically stop charging usually after 12 hours or so at minimum charge amps.

I suggest you invest in one of these modern chargers but keep your old as very useful for removing rust and recovering flat batteries.

 

When recovering flat batteries, I charge these initially with a traditional charger until battery voltage is above 10.5 V then continue charging with a modern intelligent charger.  I have found I can usually get the modern charger going by also connecting the old style charger.  Once the modern one starts charging I can disconnect the old one.

 

For battery testing I have two testers.  An old style drop tester which has a large resistor elements and an analogue gauge.  It is not easy to determine battery health with this instrument so recently I invested in a very modern battery analyser.  A Lancol Micro-200 Pro.  This perfect unit not only accurately tests battery (internal resistance, voltage, cold cranking amps etc) but also tests alternator and starter.  Mine cost £17 but you might find this tester for less if you keep looking or give seller an offer he is willing to accept.

https://www.ebay.co.uk/itm/Micro-200-Pro-12V-24V-Car-Battery-Tester-Diagnostic-Tool-Portable-Battery-T-S2K2/264523742862?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

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Thanks for the link.

 

I recently found a new hobby. Buying and fixing used electric mobility scooters which frequently may be purchased for not much more than $100. The most common fault is dead batteries and the meter that you suggested appears to be a very useful tool in determining battery health.

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Yes, buy one of them Lancol tools as strongly recommended.  There is also a Micro-200 which is equally good but the Micro-200 Pro is the latest model.  Also cheaper for some obscure reason.

 

Regarding mobility scooters, that, I think, will be my next and last vehicle.

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The difference between the Micro-200 and the Micro-200 Pro appears to be that the Pro also can test 24 Volt systems.  Otherwise identical as far as I can tell.

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