>From: "Robert Woodard" <woodardr_at_tidalwave.net> >For those buying the small motorcycle batteries for their kayak, you should >also take the same care you would for storing a full size battery, such as >not sitting it on a concrete floor for any length of time... > >Woody I'm neither a mechanical nor an electrical engineer, but why would this cause any permanent damage? I've heard car mechanics (who should know better)talk about the floor wicking the electrical energy from the battery. But neither terminal is in contact with the floor, and I believe concrete is more an insulator than a conductor in any case. The only thing I can imagine is that if you leave a battery on a cold concrete floor, its thermal conductivity will cool the battery, slowing down the chemical processes in the battery and thereby reducing its output, at least until it is warmed up again. But would this be a bad thing for storage (I store my spare flashlight batteries in the fridge just so they will not prematurely "burn up"). Or am I missing something here (often the case)? Philip Torrens N49°16' W123°06' *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
Philip Torrens wrote: > > I'm neither a mechanical nor an electrical engineer, but why would this > cause any permanent damage? I've heard car mechanics (who should know > better)talk about the floor wicking the electrical energy from the battery. > But neither terminal is in contact with the floor, and I believe concrete is > more an insulator than a conductor in any case. The only thing I can imagine > is that if you leave a battery on a cold concrete floor, its thermal > conductivity will cool the battery, slowing down the chemical processes in > the battery and thereby reducing its output, at least until it is warmed up > again. But would this be a bad thing for storage (I store my spare > flashlight batteries in the fridge just so they will not prematurely "burn > up"). Or am I missing something here (often the case)? > > I believe the problem with batteries and concrete has to do with the lime in the concrete reacting with the acid from the battery. The way I was told was that putting a battery on concrete, especially "green" concrete could cause the concrete under the battery to explode. Charging a battery on concrete was even worse, for obvious reasons. That is how I understood it as it was explained to me. No one ever said anything about concrete causing a battery to discharge to me, but any story changes each time it is told. Most wives tales and urban legends have a basis in fact, but it is often almost impossible to find out what the fact was through all the distortions. Mike -- Paddling along through fog so thick that only one's thoughts are visible, your reverie is abruptly shattered by the ancient cry of a great blue heron as she lifts uncertainly from the brilliant blue of a mussel-shell beach witnessed only by the brooding, wet spruce....your passage home seems as much back through time as it does through space. Mark H Hunt *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
The concrete myth was probably more relevant in the days of hard rubber cased batteries where there were often case leaks. I've never seen case leaks these days and I have a whole slew of old car and motorcycle batteries waiting patiently on my garage floor for the trip to the recycle place. For large lead acid batteries, the problem with placing them on concrete has to do with the fact that the concrete is often colder than the ambient room temps and this causes thermal stratification (as it was put on several battery company web sites) which causes the battery to internally discharge. Search on the words battery and concrete and you'll find all sorts of explanations for this axiom of modern living. Glenn ----- Original Message ----- From: "Michael R Noyes" <mnoyes_at_gsinet.net> To: <paddlewise_at_lists.intelenet.net> Sent: Tuesday, February 01, 2000 1:31 PM Subject: Re: [Paddlewise] concrete battery facts? > Philip Torrens wrote: > > > > > I'm neither a mechanical nor an electrical engineer, but why would this > > cause any permanent damage? I've heard car mechanics (who should know > > better)talk about the floor wicking the electrical energy from the battery. > > But neither terminal is in contact with the floor, and I believe concrete is > > more an insulator than a conductor in any case. The only thing I can imagine > > is that if you leave a battery on a cold concrete floor, its thermal > > conductivity will cool the battery, slowing down the chemical processes in > > the battery and thereby reducing its output, at least until it is warmed up > > again. But would this be a bad thing for storage (I store my spare > > flashlight batteries in the fridge just so they will not prematurely "burn > > up"). Or am I missing something here (often the case)? > > > > > > I believe the problem with batteries and concrete has to do with the lime in the > concrete reacting with the acid from the battery. The way I was told was that > putting a battery on concrete, especially "green" concrete could cause the > concrete under the battery to explode. Charging a battery on concrete was even > worse, for obvious reasons. That is how I understood it as it was explained to > me. No one ever said anything about concrete causing a battery to discharge to > me, but any story changes each time it is told. Most wives tales and urban > legends have a basis in fact, but it is often almost impossible to find out what > the fact was through all the distortions. > > Mike > > > -- > Paddling along through fog so thick that only one's thoughts are > visible, your reverie is abruptly shattered by the ancient cry of a great > blue heron as she lifts uncertainly from the brilliant blue of a > mussel-shell beach witnessed only by the brooding, wet spruce....your > passage home seems as much back through time as it does through space. > Mark H Hunt > > > *************************************************************************** > PaddleWise Paddling Mailing List - All postings copyright the author and not > to be reproduced outside PaddleWise without author's permission > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.paddlewise.net/ > *************************************************************************** > *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
> I'm neither a mechanical nor an electrical engineer, but why would this > cause any permanent damage? Someone else asked me this question back channel, so I looked it up on the web to see if what I was told as a kid still holds true. It appears to be mostly an urban legend since today's battery materials don't have the came problems of batteries of yesteryear. There were other explanations that thermal stratification could cause problems (Cold ground would cause the heavy acid to sink, leaving mostly distilled water around the lead plates). All lead acid batteries must remain at full charge to get the most life out of them, so if thermal stratification does drain down the battery, this could contribute to the urban legend living on through to today. I don't sit batteries on concrete because about 30 years ago my dad told me not to... Old habits die hard. <g> Woody *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
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