Batteries for LWB, who has them now? 69-73 double battery

[McOtto]

14.4 CETEC over 14.2, Battery Tender listed post #37 above, would that be safe & not harm the battery? ( Sonnenschein A512/40 )

There are a number of very respectable and knowledgeable folks on the ESR forum that have forgotten more than I ever hope to know, but attached for easy reference is a link to Sonnenschein’s website page providing guidance on charging. Note that it specifically addresses desulfation and charging voltages.

http://www.sonnenschein.org/Charging.htm

[NorthernThrux]

There are 6 cells in a car battery. At room temperature, the A5xx requires 14.4 V (2.4 V x 6) to charge according to the plot above, which is what the CTEK provides.

When the charger (at least the model I have) goes into Stage 7 (Float, i.e. maintaining mode) it applies 13.0 V for the first 24 hours. After 24 hours the float voltage should increase to 13.6V if the charger has remained in Stage 7. So its pretty close to what the A5xx batteries like. The float maintenance mode monitors and charges the battery for up to 10 days in a row before shifting into pulse maintenance mode (stage 8). In this mode, the charger will only send a charging current to the battery when it sees a drop in voltage. Pulse mode maintains a 95-to-99% charge for months at a time. Good for winter storage. The CTEK will adjust voltages based on temperature, so you should be fine in an unheated garage.

Ravi

[Haasman]

Thanks Ravi. Good snapshot of how they work.

[McOtto]

I agree with Ravi. From the Sonnenschein® graph I posted earlier:

Sonnenschein® Cycle Charging Specification - At temperatures between 50º - 86ºF, Sonnenschein® specifies a 14.4V cycle (Bulk and Absorption) charge voltage for a maximum period of 12 hours.

Sonnenschein® Float Charging Specification - At temperatures between 60º - 95ºF, Sonnenschein® further specifies a maximum 13.8V float charge (with no maximum time period indicated).

The key is connecting the battery to a fully automated microprocessor controlled charger when not in use. That keeps the battery “topped-off” and primarily, if not exclusively, in float or pulse mode when charger voltages are lower and Sonnenschein’s float charging requirement is 13.8V. As Mark reported in Post #31, problems occur when Sonnenschein® valve regulated lead acid gel batteries are allowed to discharge and thus get exposed to the high voltage desulphation, bulk, absorption, and reconditioning charging modes. At high charge voltages, bubbles reportedly form in the silica gel electrolyte and can result in permanent damage, as the bubbles do not dissipate when the over voltage condition ceases.

CTEK and Battery Tender charge voltages are shown below:

[Cliff]

Okay, will this CTEC 4.3 be compatible with any Sonnenschein 500 Gel and or AMG..I have two Sonnenschein batteries,` Gel,` NoT AMG. Don't want to harm them. I have an inoperative 911 I want to get running and will be down a while . Hence the inquirer...Thanks a lot too......cliff

Or, would the Battery Tender 4.0 recommended by Lauderdale Battery be a better choice? be a better option!

[McOtto]

Okay, will this CTEC 4.3 be compatible with any Sonnenschein 500 Gel and or AMG..I have two Sonnenschein batteries,` Gel,` NoT AMG. Don't want to harm them. I have an inoperative 911 I want to get running and will be down a while . Hence the inquirer...Thanks a lot too......cliff

Or, would the Battery Tender 4.0 recommended by Lauderdale Battery be a better choice? be a better option!

Cliff, I encourage others to weigh in, but my research indicates the Battery Tender units are not perfect, but better suited for our Sonnenschein gel batteries. Just make sure you keep them topped off. We are effectively using a UPS battery that is not specifically designed for automotive applications (note Ah is stated on the tag but not CCA).

The CTEK units are great, maybe the best, and very versatile, but like every automotive charger, the charge modes are designed for automotive battery types (like AGMs) that are less sensitive to high charge voltages.

[Cliff]

McOtto : Thank you for your information. Much appreciated.