How cheap can a cheap battery charger be?


How cheap can a cheap battery charger be?
Do all chargers except the very cheapest turn off when the battery is charged, or are there still some big expensive ones that don't do that, as for a golf cart? Or is the difference more subtle than that, and important?
That is, the people with the golf-cart (see follow-up post on that adjacent to this one) bought a new charger, mail order, from a site on the web that is about golf carts only.
The thing costs 360 dollars!, not what I would call cheap. But on its label it says, "Check the charger periodically to avoid damaging batteries. Initial charging rate should be [I forget, 15 maybe] and at the end the rate should be 2 amps." Does this imply they should turn off the charger when it's charging at 2 amps? Or it will damage the batteries? This is it: http://www.buggiesunlimited.com/product.asp?sku618 It doesn't say much but it calls it an automatic charger. Doesn't that mean it turns off? But is that still not good enough and the fancier one below is needed to keep the batteries from being damaged?
The more expensive charger in the catalog they sent is about $455, and the first words in its description in the paper catalog are "Avoid over-charging batteries". Does that mean this one has auto-turn-off and the one for 360 doesn't? Or are they just not mentioning it for the cheap one to get people to buy the expensive one? Here's the expensive one: http://www.buggiesunlimited.com/product.asp?sku=CHG%20EZ2%20002 It says "How often should you charge your golf carts batteries? A good rule of thumb is to plug them in after as little as 15 minutes of driving. However, you also want to avoid overcharging your batteries, which causes water loss and subsequent failure. With the Buggies Unlimited 48-Volt Microprocessing Charger, you dont need to keep tabs on your golf cart while its charging this smart charger continuously monitors your battery voltage and charges it exactly as much as it needs no over- or undercharging.
[One of the chargers on Amazon for 310 dollars said the user had a choice of 4 charging protocols. They were all similar, but there must be some worthwhile diffence, or no? The one I just quoted just says "Exactly as much as it needs"!!]
Youll get more daily power and extended life from your batteries.
* Features full float charging capability, which holds your batteries at an appropriate voltage, ensuring that they're fresh and ready to go even after long periods of storage [If the cart is used every day 9-5, M-F, and never has long periods of storage, does this matter?] .... * LED status lights show the charging progress from 0% to 100% [it has 6 led's.]
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Harbor Freight is selling a device that senses charge and supposedly avoids overcharging, and they are running a special on it. Normally about $9, special at about $5.
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On Thu, 19 Aug 2010 01:50:39 -0700 (PDT), Michael B

Thanks.
But I searched on overcharge prevent and found solar charge controller for 75 dollars http://www.harborfreight.com/30-amp-charge-controller-94790.html
on voltage sense found nothing on voltage foudn 8 things, pliers and testers
Anyhow, I guess youre just saying that the circuit might be very cheap. I'm out of this project now, and if she has to spend 100 dollars more for the better charger, even though it costs the maker only an extra ten, she'll have to. That one charger is better than the other is all I need to tell her.
Thanks.
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www.batteryuniversity.com will answer most questions you have on battery care. I would just verify what it does with a good volt meter and learn to check cell gravity with a accurate gravity gauge, one that you put a drop of acid in the tool and look at it is accurate. If you learn how to really care for batteries they will last longer
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mm wrote:

Can you see all the components inside? If there's nothing there except a transformer, some diodes, an ammeter, and a circuit breaker or two, it's a manual charger and can overcharge batteries and damage them. OTOH the simplest automatic chargers for lead-acid batteries have voltage limiters calibrated to about 2.3V per cell, meaning at full charge they'll put out less than about 1/2 amp and can be left connected for at least a couple of days after full charge. These voltage limiters usually consist of a regulator chip controlling an SCR (about 1/2" square plastic thing with 3 leads on it). Better chargers will shut off completely at full charge but will restart when the voltage drops to roughly 2.1V per cell. Old style chargers are heavy because they have a big 60 Hz transformer, but newer designs use a much smaller transformer that works at high frequency, and these always have elaborate control circuitry to completely shut off the current at full charge.
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On Thu, 19 Aug 2010 08:14:42 -0700 (PDT), "larry moe 'n curly"

These are 36 Volt golf cart Chargers. The OP is correct that the more expensive one, which is microprocessor controlled is what is commonly called a "smart charger". It will charge the batteries faster, and will not overcharge them if left connected for extended periods of time.
With the price of golf cart batteries, buying the smart charger is well worth the extra money.
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On Thu, 19 Aug 2010 12:53:16 -0400, snipped-for-privacy@dog.com wrote:

I coudl have take it apart when I had it, but I didn't. Too late now.

Thanks.

Well, that's what I told her but I promised her a follow up email, where I would have back tracked some if you hadn't confirmed this.
Thanks, and thanks all.
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wrote:

My cheapest battery charger is a variac (surplus - no cost) and a bridge rectifier with a cheap voltmeter. If you need to limit the current just hook a heater in series with the output or a 100 watt bulb in series with the input
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On 8/19/2010 12:53 PM, snipped-for-privacy@dog.com wrote:

That's my take also. It seems doubtful the existing charger will damage the batteries, it's more likely it won't maintain them as well.
Buggies Unlimited certainly doesn't load you down with any "excess" information to worry about.
Since you have the charger you can observe it and see if it shuts down (which seems likely) and if it trickles back on (which seems unlikely).
I'd say the new charger is at least as good as the old. ;-)
Jeff
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snipped-for-privacy@dog.com wrote:

What in my reply doesn't apply to 36V golf cart chargers?
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wrote:

Hey, MOE!
It applies.
He just can't apply it.
nyuk. nyuk.
Steve
visit my blog at http://cabgbypasssurgery.com
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