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Charge gel cell with car charger?

Started by Mike Cook February 24, 2013
On 02/25/2013 05:07 PM, krw@attt.bizz wrote:
> On Mon, 25 Feb 2013 15:54:23 -0800, dave <ricketzz@earthlink.net> > wrote: > >> On 02/25/2013 10:54 AM, Michael A. Terrell wrote: >>> >>> dave wrote: >>>> >>>> On 02/24/2013 05:37 AM, SoothSayer wrote: >>>>> On Sun, 24 Feb 2013 05:17:53 -0800, dave <ricketzz@earthlink.net> wrote: >>>>> >>>>>> On 02/24/2013 05:14 AM, Phil Allison wrote: >>>>>>> "dave" >>>>>>>> >>>>>>>> You answered your own question. As long as the battery doesn't heat up on >>>>>>>> a big charge you're probably OK. >>>>>>> >>>>>>> >>>>>>> ** SLA or "gel cells" are prone to gassing when overcharged. >>>>>>> >>>>>>> The pressure builds up inside until something gives - then you have bits >>>>>>> of battery and acid all over the place. >>>>>>> >>>>>>> Voltage & current limited charging is the only safe and sensible way. >>>>>>> >>>>>>> >>>>>>> >>>>>>> ... Phil >>>>>>> >>>>>>> >>>>>> >>>>>> They have vents. >>>>> >>>>> Which are NOT meant for overcharge relief. >>>>> >>>> >>>> I didn't say they were. I was speaking to the "bits of battery and acid" >>>> prediction above. >>> >>> >>> I've seen the results of several car batteries exploding. Maybe your >>> head should be under the hood when one blows. >>> >> >> Why is everyone so rude around here? > > Why are you here? >
I am here for entertainment, mainly. most of the substantive stuff is over my head, but the lead-acid battery is on the FCC exams you take for an advanced license, plus I used to maintain a fleet of trucks at a construction company, where I also serviced 2-way radios and 5 mW surveyor lasers.
On Mon, 25 Feb 2013 07:06:43 -0800, dave <ricketzz@earthlink.net> wrote:

>On 02/24/2013 05:37 AM, SoothSayer wrote: >> On Sun, 24 Feb 2013 05:17:53 -0800, dave <ricketzz@earthlink.net> wrote: >> >>> On 02/24/2013 05:14 AM, Phil Allison wrote: >>>> "dave" >>>>> >>>>> You answered your own question. As long as the battery doesn't heat up on >>>>> a big charge you're probably OK. >>>> >>>> >>>> ** SLA or "gel cells" are prone to gassing when overcharged. >>>> >>>> The pressure builds up inside until something gives - then you have bits >>>> of battery and acid all over the place. >>>> >>>> Voltage & current limited charging is the only safe and sensible way. >>>> >>>> >>>> >>>> ... Phil >>>> >>>> >>> >>> They have vents. >> >> Which are NOT meant for overcharge relief. >> > >I didn't say they were. I was speaking to the "bits of battery and acid" >prediction above.
I wasn't saying you said something wrong. I was merely iterating that those vents are not for charging pressure relief, per se.
On Mon, 25 Feb 2013 07:26:22 -0800, dave <ricketzz@earthlink.net> wrote:

> >13.6 Vdc is the float voltage.
No shit, dumbfuck.
> Virtually all amateur radio equipment, >most mobile communications equipment and power supplies (for above) are >rated at 13.6 Vdc,
No shit, dumbfuck.
> the nominal Voltage of a 6 cell lead acid battery.
But you very likely have no clue as to why.
>That is a fact, no matter how rude you become.
It is also a FACT that a battery at 12 Volts is NOT discharged as you claimed, DORK. It has nothing to do with rudeness, it has to do with your lack of accuracy.
>Here's another flash, your 1.5 V "AA" NiCads are only putting out 1.2 Vdc.
I don't need a primer from a dipshit who cries like a wimp when he gets corrected. And almost everyone knows that rechargeables and alkalines are not at the same voltage. AND, asshole, they are NOT "1.5 Volt NiCads". They ARE 1.2 volt NiCads. so, I am "rude", but YOU are "stupid".
"dave"
> >>> ** SLA or "gel cells" are prone to gassing when overcharged. >>>> >>>> The pressure builds up inside until something gives - then you have >>>> bits >>>> of battery and acid all over the place. >>>> >>>> Voltage & current limited charging is the only safe and sensible way. >>>> >>> >>> They have vents.
** Most do not - eg: http://cdn-products.austinkayak.com/p_8037_700.jpg An acquaintance had a 12V gell battery like the one pictured explode violently while doing just what the OP here is contemplating. He was sleeping nearby at the time an got one HELL of a scare !!!! Makers all warn against using unregulated ( ie raw, rectified AC ) chargers with gell or SLA batteries. BTW: Makers also warn against shorting the battery and often quote a max safe discharge current. The penalty for ignoring this advice is a dead battery when the deliberate (weak link ) fuse inside goes open. .... Phil
On Mon, 25 Feb 2013 22:45:10 -0000, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

> > >"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message >news:72pWs.41135$Q91.3308@newsfe26.iad... >> Mike Cook wrote: >>> A friend has a battery powered Ryobi lawn trimmer ("weed whacker") which >>> doesn't work. The 12vdc wall wart puts out only ~ 12.4v. >>> >>> I charged the lead-acid gel cell using a car charger. The charge rate >>> (selectable) was 0.5A. Afterward the trimmer seemed to work as new. Can >>> the car charger be used to charge this battery? He can install a timer to >>> limit charge time if that's something required. >>> >>> Thanks. >>> >> >> >> THe OEM charger most likely is unfiltered. Put a cap on the output but do >> not connect it to the battery and then do a voltage check. > > >The old "iron-transformer" chargers were usually impedance limited, so the >off load voltage will be significantly more than nominal (enough to get a >mildly sulphated battery going). In addition a capacitor would charge to the >AC peak so what you read would be even higher still.
Until you load it. Unloaded, an old xformer/rectifier battery charger always had significantly higher voltage without a battery on it. BIG ripple! But once a battery is charged and even peaked out, that higher voltage peak can blow the damned things up, so all charging sessions had to be monitored to keep them from exploding. Then better chargers came out. Now, I wouldn't be surprised if there wasn't one you could operate or observe with your iPad. There are Wi-Fi and/or bluetooth handheld meters now. That would be enough to know when to go shut it off.
On 02/25/2013 08:26 PM, SoothSayer wrote:
> > NiCads. > > so, I am "rude", but YOU are "stupid". >
From my first comment on the thread: "I'd find a smartcharger with a "lead-acid" setting." _______________________________________________________________________ "Smartcharger" being a generic term for a charger than knows what it is charging and the best way to charge it. http://www.globalsources.com/gsol/I/Switching-power/p/sm/1058385043.htm I have no doubt that you know way more than I do, but your actions betray a profound insecurity. I prefer being "stupid" to the obvious heavy burden of knowing enough to justify insults and abuse.
On 02/25/2013 08:27 PM, Phil Allison wrote:
> "dave" >> >>>> ** SLA or "gel cells" are prone to gassing when overcharged. >>>>> >>>>> The pressure builds up inside until something gives - then >>>>> you have bits of battery and acid all over the place. >>>>> >>>>> Voltage & current limited charging is the only safe and >>>>> sensible way. >>>>> >>>> >>>> They have vents. > > > ** Most do not - eg: > > http://cdn-products.austinkayak.com/p_8037_700.jpg > > An acquaintance had a 12V gell battery like the one pictured explode > violently while doing just what the OP here is contemplating. He was > sleeping nearby at the time an got one HELL of a scare !!!! > > Makers all warn against using unregulated ( ie raw, rectified AC ) > chargers with gell or SLA batteries. > > BTW: > > Makers also warn against shorting the battery and often quote a max > safe discharge current. > > The penalty for ignoring this advice is a dead battery when the > deliberate (weak link ) fuse inside goes open. > > > .... Phil >
"An absorbed glass mat battery has the electrolyte absorbed in a fiber-glass mat separator. A gel cell has the electrolyte mixed with silica dust to form an immobilized gel. While these batteries are often colloquially called sealed lead&#2013266070;acid batteries, they always include a safety pressure relief valve. As opposed to vented (also called flooded) batteries, a VRLA cannot spill its electrolyte if it is inverted." -https://en.wikipedia.org/wiki/VRLA_battery
On Tue, 26 Feb 2013 06:42:48 -0800, dave <ricketzz@earthlink.net> wrote:

>they always include a safety pressure relief valve. > > As
For NORMAL battery utilization. NOT a vent for charging pressure relief.. The device and or person doing the charging has to keep the process below any overt gassing level.
On 02/26/2013 06:52 AM, SoothSayer wrote:
> On Tue, 26 Feb 2013 06:42:48 -0800, dave <ricketzz@earthlink.net> wrote: > >> they always include a safety pressure relief valve. >> >> As > > > For NORMAL battery utilization. NOT a vent for charging pressure > relief.. The device and or person doing the charging has to keep the > process below any overt gassing level. >
OK. My only other point was that 12 Vdc nominal is never 12 Vdc, except when the battery is severely discharged. A lot of mobile equipment will not work properly on 12 Vdc. "A car battery is considered charged at 12.4 volts or higher. It is considered discharged when it's at 12.39 volts or less." -http://www.autobatteries.com/basics/voltage1.asp You are allowed to nag precise, and I am too.
On Tue, 26 Feb 2013 06:58:16 -0800, dave <ricketzz@earthlink.net>
wrote:

>On 02/26/2013 06:52 AM, SoothSayer wrote: >> On Tue, 26 Feb 2013 06:42:48 -0800, dave <ricketzz@earthlink.net> wrote: >> >>> they always include a safety pressure relief valve. >>> >>> As >> >> >> For NORMAL battery utilization. NOT a vent for charging pressure >> relief.. The device and or person doing the charging has to keep the >> process below any overt gassing level. >> > >OK. My only other point was that 12 Vdc nominal is never 12 Vdc, except >when the battery is severely discharged. A lot of mobile equipment will >not work properly on 12 Vdc. > >"A car battery is considered charged at 12.4 volts or higher. It is >considered discharged when it's at 12.39 volts or less." > >- http://www.autobatteries.com/basics/voltage1.asp > >You are allowed to nag precise, and I am too.
Damn! I didn't know that Larkin and Jamie had joined up to provide a page of ignorance on Lead-Acid batteries >:-} ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.