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I'm storing my car for 4 months out of the year and took my battery indoors to hook up to a smart charger that I bought. This charger works by charging up the battery and then entering a maintenance mode that cycles charge between 95-100% to prolong battery life.
Couple of questions:
Is this smart charger the same as a "trickle charger" or "battery tender"? The instructions say I can keep it hooked up to the battery for months. I read on other posts that some chargers should only be used for 24hours a month or something. Is there anything to gain or lose by keeping the smart charger on for the whole storage period?
Also, I share an apartment and am wondering if there are any dangers to charging the battery in a living or sleeping area. Again, the instructions mention a slight risk of explosion if charging near flames or ash, but nothing more.
I have one of those, and I do not recall in the manual anything about a 24 month max period. Batt tenders have a simple logic circuit as I recall, which can determine the battery's condition its voltage - they of course are not exactly 12V, and the voltage they hold is a good indicator.
I just made a cheaper solution for a friend. bought a 500 ma 12V wall-wart at Radio Shack, soldered some middle size alligator clips to the output of the cables after determining which is positive (by instructions or using a digital multi-meter) - you can leave the 500 ma on all the time, but what I did was plug the wall-wart into one of those AC timers, setting it so it is on/off 12 hours out of 24.
If you have a garage, I would leave it in there, in case for some reason there is leakage (is the batt a wet cell?) and there is usually more air circulation in a garage, eliminating even the slight chance of a hydrogen buildup.
While the wall-wart described by RR will work for short-term battery maintenence I would want something more specialized for the 4 months you are talking about. It sounds like the charger you have is fine for what you need. They probably have the note about fire/explosion risk as a CYA measure for the litigation-happy public, just like US automakers have to put cupholder warnings in cars.
A couple things to note:
If you're talking about a regular lead-acid car battery it will generate hydrogen gas when it charges. If you are charging it at a high rate (like if it's half-dead) and it's in an enclosed area (like a closet) you could have a serious problem if you walk into the closet with a lit cigar.
If you are putting an already charged battery indoors just for maintenence, the charging rate will be low enough it won't generate enough hydrogen to be a problem.
If you put it in a garage try not to put it directly on the concrete floor because it will cool down to the temperature of the floor. Depending on where you live, if you have cool weather with high humidity (rainy season) and the temperature of the battery drops to the dew point, condensation will form on the outside of the battery. When it mixes with normal deposits near the terminals it can actually create a current path between + and -. This will either cause the battery to discharge (seemingly by itself) or it might interfere with the charging cycle of your smart charger.
Trickle chargers are essentially "float chargers". They are designed to provide a low current at a fixed voltage to "float" the battery at it's optimum fully-charged terminal voltage. This is in contrast to "cycle chargers".
Cycle chargers will charge at a much higher current and to a higher voltage level, but for a short period. Most car battery chargers used by shops or those "20-amp" or "50-amp" chargers you buy at Sears are cycle chargers. Some of them may have float charge capabilities or may have smarts built in, but for the most part they are cycle chargers.
I'm not sure what a "battery tender" is, probably a brand name?
Car batteries are 'traction' batteries. They are designed to provide short-term high-current disharge rates (engine starting), followed by immediate high-current re-charge, then a period of relative inactivity (driving where alternator powers everything). Traction batteries HATE to be deep-discharged (run your stereo till the lights go out) and they HATE to be float charged (trickle charged). I've seen high-quality car batteries that would easily last 5 years in a car go dead in a year when used in float applications where they are on a constant charge with no disharge cycle. This is why the smart chargers do the charge/disharge cycle thing.
The guys talking about only charging a battery once a month are probably talking about using a cycle charger. This is an acceptable method to maintain a car battery, because it gets a short charge cycle followed by a disharge cycle (it self-discharges some with time). Traction batteries like that.
Well, I really don't know if this is a charger, or used to maintain a charge to your battery. My buddy used to work at VW dealership, and these are in all the cars on the lot because in the summer, the heat here in the desert is brutal on the battery. I have one in my daily, and would put one in the S, but it is always in the garage and wouldn't work since it's solar powered.
All you do is plug it into your cigarette lighter, and the solar energy is transmitted to your battery. I don't know how it works, but I think it does. Sending this unit on to my pops in KS where the winter is brutal on the battery. Any of you guys have these in your neck of the woods?
There seem to be lots of different terminology floating around that I can read about. "Trickle chargers" "Float chargers" "smart chargers" "battery joggers" and so on.
My charger starts charging with a high current until the battery is 80% charged, then it maintains the voltage while decreasing current to a very low level to fill up the remaining 20%. When done, it enters the maintenance mode which basically lets the battery drop voltage and the charger gives it a little charge every so often to maintain 95-100%.
Guess I'll keep it hooked up for the winter period.
The Battery Tender is a float charger. http://www.batterymart.com/battery.mv?p=DE...DEL-022-0150-DL Another option is a battery desulfator. They emit an electronic pulse that breaks up lead sulfide crystals. They also maintain charge like a float charger. I currently have a Battery MINDer that I keep my S2K charged with, and I used to use a PowerPulse by PulseTech.
The PowerPulse worked great until my kid borrowed it and returned it broken. I suspect he hooked it up backwards, or fried it when jump starting his car. When I first got this thing, I hooked it up to a battery that couldn't start a car when fully charged (not completely dead, but drawing high amps on a cycle charger), and a few weeks later I was able to reinstall that battery back into my car (Yeah, I know that I'm better off just trashing the battery at that point rather than screwing up my alternator, but you get the idea of what it can do).
If you do a Google search on battery desulfators, you'll find lots of information on the theory behind this product. You have to weed through some of the BS propoganda that some of the manufacturers use, but it does appear to work.
Modifry: I've heard many times not to put a car battery on the concrete floor, but nobody ever explained to me why. Thanks for the explanantion. And as always, I find your explanation of anything electrical insightful.
Some of the older batteries were made of wood, and when leaking the battery acid would make the wood wet and discharge against a concrete floor. So this was much more a problem in the past.
01-18-2004, 01:01 PM
Battery tending indoors?
