[Shop-talk] Float chargers

[Bob Spidell]

FWIW, I put two Interstate batteries in my '08 Mustang--almost daily 
driven over 70 miles on the freeway--and they both failed at 2 years (no 
warning, just wouldn't start my car at work).  Interstate used to be a 
'go to' brand, but I believe they're now made in Mexico like most 
'American' brands.  An experienced starter/generator rebuilder told me 
Mexican-made batteries are crap (and he's Hispanic).  Deka is now my go 
to brand; they're made in Pennsylvania, and competitively priced.

My guess is your Interstate is getting ready to fail.

Bob


On 4/7/2020 7:34 AM, Jimmie Mayfield via Shop-talk wrote:
> The recent discussion about solar-powered float chargers has reminded 
> me of an issue that I've yet to understand or resolve...
>
> I have a Battery Minder 12248 (12V 2/4/8A) charger/de-sulfator with 
> temperature compensation sensor.  While I've never been able to 
> appreciably restore a dead UPS battery using the de-sulfation mode, it 
> seems to work fine as a slow charger.  It has several modes -- 
> gel-cell, AGM or flooded -- which, near as I can tell, adjusts the 
> threshold voltage at which the charger switches from bulk-charge mode 
> to float-charge/de-sulfation mode.
>
> Every 12V battery that I've ever connected to the charger, even the 
> old AGM batteries taken out of my UPS units, eventually reached the 
> threshold voltage and switched over to float mode (usually within 
> 30-45 minutes for a nearly-fully-charged battery).  Except one.
>
> About 2 years ago I installed an Interstate battery from Costco (size 
> 27F, 890CA, 710CCA) in my truck.  It's a flooded battery and if I 
> understand Interstate's spec correctly, its capacity works out to 
> around 100Ah.  The battery has a resting voltage of 12.6V so it 
> doesn't appear to have any shorted cells and has no trouble starting 
> my truck.  So it seems to be a normally healthy battery, right?
>
> Thing is...I've never seen my charger go into float mode when 
> connected to this battery even when it was nearly new.  With the 
> recent pandemic stay-at-home orders, yesterday I decided to connect my 
> truck to the charger to stave off parasitic drain (measured to be 
> 20-30mA) that may have accumulated over the past week of inactivity.  
> I'm currently at 16 hours (@4A) and it still seems to be in 
> bulk-charging mode.  I have difficulty believing that the battery 
> needed 50+ Ah.
>
> So what's going on here?  This is the only battery that I've come 
> across that behaves like this.
>
>
>
>