Faulty Technoline BL-700 (La Crosse BC-700) charger?

IvanOpinion

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I think my Technoline BL-700 (La Crosse BC-700) charger has developed a fault, but I wonder if any charger experts have any thoughts on whether I'm right. (It is 10 years old.)

I have a few dozen LSD AA batteries for various uses, but the biggest consumer of them is a digital radio that I use in the bathroom. Recently, they seem to be lasting only a few days in the radio, whereas they used to last a week or two. I have this problem with several different sets of batteries, so I don't think the cause is likely to be that the batteries are faulty (or worn out). The battery sets are of various ages, so they they would be unlikely to develop the same fault at the same time.

The latest set seemed to last a bit longer: perhaps a week. But they stopped working this morning, so I put them on to charge (at 200mA). Within an hour, one of them was displaying FULL, which seemed too quick to have replenished a week's worth of use in the radio. On a hunch, I took it out and put it back in. It resumed charging (at 200mA). A few minutes later, another did exactly the same thing. Both are now still charging at 200mA, 7 hours after the charger told me they were full. (They are nice and cool, by the way.)

Does that sound like my charger is faulty? If the charger has been stopping charging way too early, this would explain why the batteries have been running out far too quickly. It could be the batteries, but, as I say, I've been having problems with several different sets of batteries.
 

ChrisGarrett

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I've had my LC BC-700 for just about seven years. You need to charge up your batteries and do a discharge test at 350mA and see what you see.

Batteries can start failing all at once. I'm losing quads at a time of my Duracell Ion Core AA and just pitched four in the recycling bag last week. I think I'm now down to 3 left of 12, which are on their last legs.

These batteries, even Eneloops, start developing high internal resistances, which can be rejected by the BC-700, or my Maha C9000. Prior to those thresholds, the charger will work harder to charge the batteries and the batteries will have a harder time delivering current, especially higher currents. They might read 1.4x volts, sitting on the counter, but they'll crash and burn.

Discharge test at the rate of the device you'll be using them in.

The LC/TL BC series doesn't remember the discharge numbers, so you have to time it for a rough guess-ti-mate when the discharge stops and the charging phase begins.

Chris
 

IvanOpinion

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Thanks, Chris.

So you are suggesting that if my batteries have developed high internal resistance, this could be triggering the charger to think they are full, prematurely? That seems plausible.

However, why would the charger not just continue to say the battery is full if I put it back in? Is it a bit random, so sometimes the charger somehow pushes past the internal resistance and keeps charging them to their true capacity? (They are now saying full, again, but that is after charging for a further 19 hours after the charger said they were full.)

When you say do a discharge test, you mean a test to check the capacity of the battery? The charger does have a TEST mode which is meant to do this, but are you saying that it is better to manually time how long discharge takes?

How would this test help me work out where the fault lies? Let's assume I set it to discharge at 350mAh and it takes an hour to discharge, whereas the batteries are meant to have capacity of 2000mAh or more. Should I conclude that my batteries have lost most of their effective capacity, due to high resistance, and throw them away? Or that the charger is faulty and is failing to charge them correctly?
 

ChrisGarrett

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Thanks, Chris.

So you are suggesting that if my batteries have developed high internal resistance, this could be triggering the charger to think they are full, prematurely? That seems plausible.

However, why would the charger not just continue to say the battery is full if I put it back in? Is it a bit random, so sometimes the charger somehow pushes past the internal resistance and keeps charging them to their true capacity? (They are now saying full, again, but that is after charging for a further 19 hours after the charger said they were full.)

When you say do a discharge test, you mean a test to check the capacity of the battery? The charger does have a TEST mode which is meant to do this, but are you saying that it is better to manually time how long discharge takes?

How would this test help me work out where the fault lies? Let's assume I set it to discharge at 350mAh and it takes an hour to discharge, whereas the batteries are meant to have capacity of 2000mAh or more. Should I conclude that my batteries have lost most of their effective capacity, due to high resistance, and throw them away? Or that the charger is faulty and is failing to charge them correctly?

You need to start ruling things out one variable at a time.

My BC-700 is notorious for missing terminations, even on brand new batteries. Been that way since day one, especially on 700mA and even on 500mA charging rates. The charger will keep charging and increasing in mAh, as well as temperature.

Here's what I'd do:

You charge all of the batteries up on your TL BC-700 and then discharge all of them at the highest rate possible...in this case 350mA. You don't mention the batteries by name, so I'm guessing Eneloop Standards--1900mAh-2000mAh.

Using the .gov standard for doing things, at 350mA, it should take just under 6 hours to discharge down to 1.00v (I think that's what these chargers use--Maha C9000 is .90v.)

Now, you can also find a light that puts one amp (turbo/high,) or 500mA, on the battery and see if you get 2 hours out of the battery, or 4.

You need to time things and be there when the charger quickly switches over to CHARGE mode, so watch the voltage drop as you get close and you should be able to time things. Get a pen and paper and write things down.

Next up, you can buy some new AA Eneloops and start over.

I've said it for 7 years here, I wish I would have just bought a second Maha C9000. It's bigger, but it's better.

Chris
 
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markr6

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My BC-700 is notorious for missing terminations, even on brand new batteries. Been that way since day one, especially on 700mA and even on 500mA charging rates. The charger will keep charging and increasing in mAh, as well as temperature.

I can confirm! Mine has been sitting unused for years now.
 

IvanOpinion

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Thanks, Chris.

These particular LSD batteries are "7 Day Shop" brand, which I doubt you have in the US. They did quite well in consumer tests in the UK. 2150mAh capacity.

I think I've worked out a way to determine if the problem is the batteries or the charger. I've borrowed a charger from a friend, so I'll see if the batteries are different in that charger. The friend's charger is the BL-700N, which is the new version.

Interestingly, the UK importer claims the BL-700 is a higher spec than the BC-700. In the product page on Amazon UK, someone asked what is the difference and the importer replied (in May 2017):
"The BL-700 is the high specification version of the Technoline BC700 battery charger. The BL-700, which has been sold exclusively in the UK for over ten years, specifies very tight tolerance components throughout which in turn lead to very accurate readings and performance. The Technoline BL-700 is the original intelligent battery charger that was first sold in the UK in 2007 and has an established pedigree and thoroughly proven service record. BC700 versions of this charger sold in the UK tend to be older European versions without the latest firmware or hardware which is under constant revision and improvement. For example, the latest BL-700 battery charger incorporates N-Start charge technology which will successfully charge a fully depleted battery that a previous BC700 version with older firmware might reject due to a combination of high impedance and low voltage. The BL-700 is also supplied with a soft touch rubber finish. Please be aware of the many misleading clones of this battery charger that have recently appeared which are crudely based on old BC700 firmware that have no association with Technoline whatsoever."

I don't know if this comment applies to the LC version sold in the US. (I note LC now sells the BC-700N, which seems to have the same N-Start technology.)
 

ChrisGarrett

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Very interesting and there's no doubt that chargers get cloned, or just licensed out for sale in other markets.

Honestly, I can't say one way, or the other. There is such a thing as 'tolerance stacking' and as I know from HiFi, you can get better/worse tolerances in various components, so I get that part as well.

As I stated above, you need to start ruling out one variable at a time, so having your friend's charger is at least a step in the right direction.

I'm one of these 'three is two, two is one and one is none' kind of guys, so I have spares just to have them. I still want to emphasize that batteries bought at the same time and used in a similar fashion, can start dropping like flies, in a somewhat singular moment.

Good luck getting it sorted out.

Chris
 

IvanOpinion

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In case it helps anyone else with a similar problem, the borrowed charger has helped confirm that the problem is my charger. With several of my batteries my old BL-700 will only charge for an hour or two and if I run a discharge test they discharge about 200-500mAh. In the borrowed charger, they charge up to around 2000mAh. In fact, some batteries that I had concluded were completely dead are absolutely fine with the borrowed charger.
 

Nev

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That's the reason I payed £35-£40 for my two lacrosse bc700's instead of £20-£25 for the cheap clones , I've had mine about four years & still working like new ,they've never overheated & ive only seen one missed termination & that was on 200ma ,I've never had a missed termination on 500ma or 700ma.
 

IvanOpinion

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That's the reason I payed £35-£40 for my two lacrosse bc700's instead of £20-£25 for the cheap clones , I've had mine about four years & still working like new ,they've never overheated & ive only seen one missed termination & that was on 200ma ,I've never had a missed termination on 500ma or 700ma.
Paying more for mine did not prevent these problems, but it is 10 years old, which seems like a reasonable lifetime. It is a pity that the other highly-rated chargers (Powerex MH C-9000; Opus BT C-700) don't currently seem to be available in the UK (except at silly prices), so I'll probably go for the BL-700N.[h=4][/h]
 

Nev

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Technoline is a clone , it doesn't matter what you paid for it , lacrosse is the genuine one
 

IvanOpinion

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Me not speak Russian.
Me neither! Weird, it was in english when I posted the link. The google cache is still in english:
https://webcache.googleusercontent....technoline-lacrosse+&cd=1&hl=en&ct=clnk&gl=uk

It said:
"The programmable chargers sold under the brand names of Techno Line (Germany) and LaCrosse (France) are OEM products manufactured in China upon request from various wholesalers. An identical device can be found under yet other brands such as Voltcraft (an in-house brand of Conrad Electronik Germany), AccuPower (Austria), Japcell (Denmark) and so on. We offer exactly these two brands for two specific reasons: (1) The end-user price for the TechnoLine model is the best, and (2) The LaCrosse model has a slightly newer modification microcontroller chip."
 
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