FYI: how to SAFELY keep your battery charged during storage or non-usage
In researching how to keep my battery safely charged during non-usage (e.g., the winter time here in the Hoosier Holyland), I came across the Battery Tender (available on Amazon for $49).
The thing that got my attention was the comparison made between it and a trickle charger, which apparently can damage a battery during extended usage, i.e., after a battery is fully charged.
This is what the Amazon advertising material and Deltran (makers of the Battery Tender line of products) say about the subject/product:
(Amazon)
Product Description Battery Tender Plus is the most advanced charger/maintainer on the market specially designed for today's sealed lead acid batteries. The Battery Tender Plus uses micro-processor technology in a four-stage charging profile to charge, improve, and float your battery so it is ready when you are. Constant current charging and regulated voltage patterns allow the battery to be recharged fully and safely without the fear of overcharging.
Product Description Constantly monitors the battery without the damaging effects of trickle chargers (a trickle charger will eventually boil dry or overcharge a battery) Battery Tender Plus` voltage output compensates for temperature changes; providing additional protection Initial charge brings battery to full charge at approximately 14.2 volts After full charge is reached; converts to float charger and monitors battery at 13.2 volts Although a constant charge is being applied to the battery; there is little or no current draw (approx. 10 milliamps) Periodic maintenance is recommended; but Battery Tender can monitor a battery for years without the fear of boiling or destroying the battery Optional pouch for safe and easy storage or transportation 12V Battery Tender Plus has fused quick-disconnect rings with a weather cover Black snap cord available separately; PART #08100696 Pouch available separately; PART #500-0017X Photo`s are for reference only. Please read item title carefully.
How is the Battery Tender Plus battery charger different from a trickle charger?
The Battery Tender Plus battery charger delivers 1.25 amperes during bulk charge mode, holds the battery charge voltage constant at 14.4 VDC during absorption charge mode until the battery charge current drops to 0.1 amperes at which time it then automatically switches to a float charge mode. During float charge mode, the output voltage of the Battery Tender Plus battery charger is 13.2 VDC, which is well below the gassing voltage of a lead acid battery. This keeps the battery topped off, while minimizing any detrimental effects to do gassing. The Battery Tender Plus battery charger is able to perform these complex switching functions because its electronic circuitry is controlled by an on board microprocessor. Although they often appear to be a better economic choice for the typical consumer, trickle chargers do not have the advantage of sophisticated electronic control. Therefore, as they allow the value of charge current to trickle down to what appears to be safe levels, the output voltage of the charger rises well above 15 VDC, sometimes even going higher that 16 VDC depending on the charger type and the battery that is connected to it. Either voltage is well above the gassing voltage of a lead acid battery. If the battery remains connected to this high level of voltage for an extended period of time, even less than 1 day, extreme damage can be done to the battery. What appears to be a cost savings for the charger may actually cost several times the charger price in replacement batteries.
I use trickle chargers on all of our old cars. They haven't done any damage yet... They work really good on the old Pontiac which has charging issues as it is.
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-1994 Mustang GT... K&N filter,GT40 tubular intake,BBK Full Length Headers,modified midpipe & Flowmaster muffs, timing at 12*. Best time- 14.74 @ 93.16 -Check profile for pics of our car collection! -Member of MBMCustoms Car Club - AmericanMuscle ROCKS!! - "Save a horse, drive a Mustang!"
I pass along info as I find it. Everybody who reads it can be the judge of what they think/relay their own experience(s).
I've ordered one of these because (1) I need some form of charging for the winter; (2) it can't harm my battery; and (3) it probably, as the info says, will prevent any potential issues that might arise.
One thing they do claim is that although a trickle charger may not immediately "damage" a battery, it "eventually" boil dry/overcharge a battery, leading to the kind of damage you can avoid with their product.
Because of the possibility of this and the cost of their product vs. a new battery I decided to buy it.
been using battery tenders on all my show cars for over 20 years. its the only way to go. Trickle chargers will overcharge you battery if left on too long.
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2007 Redfire Mustang GT Premium Convertible, Black cloth top, 5 speed, heated seats, IUP, PTP, Dark charcoal with chamois seats, 18" polished wheels, side air bags, Shaker 500, Wheel Locking Kit, Active Anti-Theft System, spoiler delete, Ford racing GTA's & X pipe, FRPP Bullitt cai, Tillmans dyno tune, MGW shifter.. born 10/18/2006
been using battery tenders on all my show cars for over 20 years. its the only way to go. Trickle chargers will overcharge you battery if left on too long.
That's exactly the point: overcharging and what eventually results - battery failure.
I got a float charger at Harbor Freight for about $9 last year. I kept it on my GT all winter (started it up about once a month or so) and it worked great. In the spring the battery was fully charged when I took it off for good.
i have had a battery tender plus on my 99 lightning since i got it in sept of 99.original battery still going strong.it only has 14,000 miles on it so you can see why i need a battery tender.
FYI: how to SAFELY keep your battery charged during storage or non-usage 
