Overcharging a lead acid battery

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horizon
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Overcharging a lead acid battery

Post by horizon »

I'm just getting used to my new (second hand) Smart Halogen lead acid lights. I do like them even if they are a bit of a throw back. For shortish trips down 100% dark and winding lanes they are the bee's knees IMV.

So, two questions:

1. Mine have come with an ordinary DC/AC converter plug-type charger. I am happy to wait 10 - 12 hours for an overnight charge but is there any danger of overcharging? I am presuming that it isn't a fast charge and will trickle charge with little danger of overcharging. Am I wrong?

2. I am presuming run times of around 8 hours for the 2.4W light and about 2 hours max for the 10W. Is this what others have experienced?

Any helpful advice appreciated as well as comments regarding this lighting system.
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
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NATURAL ANKLING
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Re: Overcharging a lead acid battery

Post by NATURAL ANKLING »

Hi,
You need to give battery details Volts and Ahr's :?:
The charger is probably a low current mains plug in charger, again output Volts at Amp's :?:
Remember that a lead acid battery needs idealy 24 Hrs to give full charge from flat, 20 hrs will only give 90% charge :!: In ideal conditions.
Modern high power leds will make your setup look like candels if not on weight alone.
I used to use a lead acid 6 V x 5 Ah would give 4 hours on a 6 Watt halogen bulb.
A powerful "T6" Led will give a more powerful light on half power four four hours on a 18560 battery the size of your Thumb :)

Your details would give you a 6 Volt 3 Ah batt, or a 12 Volt 1.7 Ah :?:
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
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hexhome
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Re: Overcharging a lead acid battery

Post by hexhome »

Providing the voltage doesn't go above 2.3v per cell whilst charging (3 for a 6v battery) overcharging will not be a problem. However, without a smart charger you will have no idea as to the state of the battery. If you have a duff cell, you will be overcharging the others to destruction. Lead Acid batteries are resilient to most things but over discharging which will kill them. The danger when charging for long periods is the emission of flammable gas. Make sure that the battery is charged in a vented area and that the charger is switched off before disconnection. My advice is to buy a smart charger.
thirdcrank
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Re: Overcharging a lead acid battery

Post by thirdcrank »

IME, the problem with this type of lamp is maintaining a charging régime. They are not ideal for occasional use. When they first became widely available - mine are Cateye Daylites - I was still commuting on rotating shifts so they got a lot of use. "The best thing since sliced bread." I had one charger at home and another at work so I always put the battery on charge immediately when I arrived if that ride had been in the dark. Even so, there's a short period in the Summer when lights are not necessary even for shift riding so I did an interim precautionary charge. The cateye's have a space for a spare bulb so I used to carry a 2.4 W which I used if I was going on a longer ride.

Afaik, the main use for this type of battery is as the back-up in burglar alarms. In that use, they are on a permanent float charge. I think their use in other applications, including cycle lamps, has diminished with the introduction of other types of battery. Anyway, the manufacturers' blurb suggests they are made in two types: one, for cyclical charge and discharge and the other for float applications. They are, or used to be, readily available in Maplins. I bought some there when I lashed up my own system before I got the Cateyes. I bought more when I acquired various bits and pieces of these lights from other people who had let the batteries discharge and left them unused. The ones Maplin sell claim to be optimised for float use but they are externally identical to the batteries which came as originals supplied by Cateye, and I've used them without problems at all.

I think that the intelligent charger idea is technically the best, but I'm not sure if it's cost-effective for a use like this. As I've said, IME conscientious charging after every use is adequate. I did consider an intelligent charger and it was megabucks. You would have to ruin a lot of batteries using my method before it would turn out that an intelligent charger would have saved any £££. As with all batteries, the lead acid type are hardly green, but you'll not use many.

I would say, though, that for any other use besides frequent commute-type rides in the dark they are not the ideal bike lamps.
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horizon
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Re: Overcharging a lead acid battery

Post by horizon »

Thanks everyone for the replies. I know that there is a generation of LEDs between these lamps and now but for me they are an eye opener. I frequently have a late night run from the nearest railway station to home (in fact all my "return homes" from anywhere) along about 10 miles of narrow, twisting lane with sudden turns, a poor surface (sometimes flooded) and overhead branches. Most of the time it is impossible to see your hand in front of your face. I negotiate this route by cycling gingerly from one unexpected ninety degree bend to another. The net result is that the downhills (of which there are many and sudden) are slow and the whole ride quite stressful. I currently run two good LED front lights and these together just about do it. But I actually need and want something better. My only regret is that I didn't get a set years ago. I bought these second hand as a try out. I don't know the cost or type of their present day successors so any suggestions welcome.

PS Charger output is 8Vdc 500mA
Last edited by horizon on 5 Mar 2013, 10:25am, edited 1 time in total.
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
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meic
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Re: Overcharging a lead acid battery

Post by meic »

You could follow Gaz's lead.
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horizon
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Re: Overcharging a lead acid battery

Post by horizon »

Thanks for that meic, but I don't see how it helps. The Smart light gives me the run time and lighting that I need. I don't want to sacrifice any light in exchange for run time or weight or high purchase cost. What I would be looking for is the equivalent of 10W for two hours at under £50.
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
thirdcrank
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Re: Overcharging a lead acid battery

Post by thirdcrank »

I hadn't seen that thread (SMIDSY if ever there was one. :oops: ) The LED bulbs do sound useful, although I've never had one of the filament type that came with the Cateye or bought later from Maplins fail. Mine have been immeasurably more reliable than typical torch bulbs.

I don't know what the lamp lenses are like on your set-up. My original Cateye (with the single lamp) had a weird affair - I've previously described the beam pattern as looking as though the light was shining through a Terry's chocolate orange. I replaced it with a plain lens which gives a simple beam. It's obviously important to be careful where it's being pointed, especially with a 10W bulb in there. I did acquire some of the twin head type and decided they were unnecessary.

I've little experience of anything more recent but most of it seems to be pricey. I'd reiterate that for the type of riding which fits in with the need for regular charging, gel cells are ideal. They would be useless for touring because there would be no reliable charging available. Occasional use would risk the batteries going flat between uses, or would require regular top-up charging. Gaz's LED's should extend the runtime considerably. They also are on the heavy side for anybody who is weight conscious.

Compared with Never Ready Night Lights, this system is brilliant - word play fully intended. They certainly made me feel safe in the heaviest night time traffic.

PS Horizon,

you posted just before I did. I'd say, before shelling out on anything pricey, try some different bulbs to extend run time. Also, if you already knew this, sorry, but you can calculate the nominal run time by dividing the capacity of the battery by the power of the bulb. Also, although you sound committed to the idea of using the brightest bulb routinely available, 10W, I'd suggest trying something less powerful before shelling out for another system. My original single lamp Cateye came with a 6W bulb. That was completely OK for me both to be seen in heavy traffic and to see on unlit roads. An eye opener, if I may use another weak metaphor. As I've mentioned, whenever I was going somewhere further, I swapped to 2.4W and the lighting was still excellent (although my comparison was with ancient dynamoes and Ever Readies.) I've also used the 10W bulbs but in terms of perception, rather than anything properly measured with a light meter, they are not 4 times better than the 2.4W - nor anything like that.
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horizon
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Re: Overcharging a lead acid battery

Post by horizon »

Hi thirdcrank, thanks for that. I might sound a bit obsessed by this but I did follow all the obvious reasoning - these lights are too heavy and impractical for ordinary riding and touring. My commuting when I did it was along well lit roads. LEDs were also quickly filling the gap and we have at least two CatEye opticubes kicking around doing excellent stuff. However when a forum member put his Smart lightset up for sale at a reasonable (i.e. knockdown) price it was time to give it a try. It is the particularity of this ride home (the alternatives are longer and even hillier) that makes it a frustrating and even at times quite dangerous ride when really I just want to get home. I only need an hour's run time on full blast. I don't mind the weight, I don't mind the charging. I just want the light (at an affordable price). I should have done this years ago but the real driver (commuting) wasn't there, so I compromised (albeit with ever better LEDs). If these lights do what they say then I am happy until the next Christmas present round.
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
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meic
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Re: Overcharging a lead acid battery

Post by meic »

horizon wrote:Thanks for that meic, but I don't see how it helps. The Smart light gives me the run time and lighting that I need. I don't want to sacrifice any light in exchange for run time or weight or high purchase cost. What I would be looking for is the equivalent of 10W for two hours at under £50.



http://www.bike24.net/1.php?product=682 ... gc=139:515

Though if you dont have AA batteries and a charger already it will go over budget.
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horizon
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Re: Overcharging a lead acid battery

Post by horizon »

Thanks for that meic. The original 84 euro price tag may have put me off but we are in new territory now. At the moment I am getting old technology cheaply but even the new is getting cheap now. As a matter of interest how did you measure/compare the light output/brightness of the two lights?
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
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meic
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Re: Overcharging a lead acid battery

Post by meic »

Which two lights?
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horizon
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Re: Overcharging a lead acid battery

Post by horizon »

My Smart Lead Acid halogen set and the Busch Muller that you linked to. How do I know from the spec that it will be as bright as my Smart lead acid? (candles/lumens/watts/number of motorists blinded etc etc). It says 40 lux but I've no idea what that means.
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
thirdcrank
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Re: Overcharging a lead acid battery

Post by thirdcrank »

horizon

I think we may be at cross-purposes. (Unless that should be crossed purposes.)

Afaik, the Smart lights you have work in the same way as Cateye Daylites. If they don't, stop reading now.

I'm saying that this system is brilliant - in both senses of the word - for commuting-type rides. I'm throwing in a bit of my own experience of using them to try to save you shelling out more for something that won't necessarily be any better. Had I still been working shifts (as some people starting out in work today may still be doing at my age - 68) I'd probably still be using them now. I still have them in my stores, AKA in with the rest of the junk in my garage.

Only on the matter of the wattage, bear in mind that the widely-praised modern dynamo hubs are rated at 3W. Reflect ( :oops: ) on some of CJ's comments about the excellence of modern dynamo headlamps, which apparently achieve much more with the available wattage.

On the money saving theme, you can buy cheapo LED torches which seem bright enough to strip paint.
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