LaCrosse BC-900 vs LaCrosse BC-700

[tsu3000]

Hi

I cannot decide which LaCrosse charger to buy and hope someone can give me some advice.

I have read some user reviews (Amazon etc) about the BC-900 melting batteries, but under what conditions is a bit unclear. Also one reviewer said that the newer V33 also melts batteries. Hopefully someone will shed some light on this.

With this in mind, I thought about getting the BC-700 which does not seem to be as popular and has less charging currents. But I have not seen any reviews of it malfunctioning or melting batteries. Has the BC-700 been redesigned to be more reliable than the BC-900 or do they still share the same charging circuits, algorithms etc. with the potential to still melt batteries if the right conditions are met?

I'd much rather get a "lesser" charger with the knowledge that they will not melt my batteries than get one that has the potential cook batteries/charger.

I plan to use Sanyo Eneloops using a low current (maybe 500mAh). Both models fit the bill. But which one do you recommend? Is the extra 1000mAh charging current on the BC-900 ever needed in practice now that Eneloop or equivalents are available.

Thanks in advance.

J

 

[Raymond]

Hi, and welcome

There have been a few discussions on the BC-700 (use the google searchbox at the top of the page, not the forumsearchbox at the bottom).

The chargers seem to be identical, except for the chargingcurrents. Pricedifference is next to nothing: http://thomasdistributing.com/shop/index.php?cPath=147_149_152&sort=3a&filter_id=23

$34 vs $39

I think the higher charging current of the 900 is nice to have. But if you're not comfortable with that charger, just go for the 700

 

[geek4christ]

Hi tsu3000,

Let me start by saying :welcome:

I would recommend the BC-900, for the ability to charge at higher rates as Raymond mentioned. It is easier to charge in the recommended .5C to 1C range on the BC-900. This means your cells will give a more reliable end-of-charge signal, and it's less likely the charger will miss termination and ruin them.

 

[tsu3000]

Hi

Thanks for the replies. Excuse my ignorance but what does ".5 to 1C" mean? Are there links available to explain the terminology? I am new to all of this .

I will probably use Eneloop 2000mAh batteries or Sanyo 2700mAh batteries for the LaCrosse. Are these batteries recommended for the LaCrosse?

Thanks in advance.

 

[worldedit]

Could i charge D cells with the BC-900? I connected one to my BC-700 and it always stops chargen after reaching a fixed charge. Does the BC-900 have the same protection?
Can i wire two or more of the charging channels in parallel to charge higher capacity cells?

 

[geek4christ]

Hi

Thanks for the replies. Excuse my ignorance but what does ".5 to 1C" mean? Are there links available to explain the terminology? I am new to all of this .

I will probably use Eneloop 2000mAh batteries or Sanyo 2700mAh batteries for the LaCrosse. Are these batteries recommended for the LaCrosse?

Thanks in advance.

The C rate is a function of the charge current and battery capacity. If you charge a cell with a capacity of 2000mAh at a 1000mA charge rate, then you are charging at .5C. Likewise, charging that same cell at 2000mA is charging at 1C.

There is a lot of good information in The Welcome Mat about this and many other topics. It's a good place to start your flashaholism

In an ideal circuit with no losses (not actually attainable), charging at 1C would mean your cell gets charged in an hour, 2 hours for .5C. In the real world, it will take a little longer than that to charge.

Those batteries will be fine for the chargers in question. Just stick them on to charge at the 1000mA rate.

One thing to note is that the LaCrosse chargers have a reputation for heating up too much. It's a good idea to put the charger in a baking dish or on some other non-flammable surface away from things that could burn. I have my BC-900 sitting on a large ceramic tile :thumbsup:

 

[geek4christ]

Could i charge D cells with the BC-900? I connected one to my BC-700 and it always stops chargen after reaching a fixed charge. Does the BC-900 have the same protection?
Can i wire two or more of the charging channels in parallel to charge higher capacity cells?

What is the capacity of your D cells? I believe the BC-900 stops charging after putting 3000mAh into a cell. There may be something similar in the BC-700 that you are running into.

 

[SilverFox]

Hello Tsu,

Welcome to CPF.

When you charge at 1C, your charge time is about 1 hour. When you charge at 0.5C, your charge time is about 2 hours.

This range of charging rates is what the battery manufacturers recommend when using a charger that uses a -dV signal to terminate the charge. Slower rates generate a weaker end of charge signal, and you run the risk of damaging your cell through overcharging.

Eneloop cells have a capacity of 2000 mAh. A 1C charge rate would be 2000 mA. A 0.5C charge rate would be 1000 mA.

The LaCrosse chargers utilize -dV termination, along with a few other back ups.

Keep in mind that it is possible to charge at lower rates, but you run a risk of damaging your cells due to overcharging.

Tom

 

[tsu3000]

Thanks everyone for your time in posting replies - its much appreciated.

So would you say that the min charging current to avoid issues of mis-termination and overcharging is 1000mA for the BC-900? Or is this an over simplification? If 1000mA is indeed recommended then it begs the question: what is the point of the other lower currents (esp 200mA) if they can cause problems with cooked batteries/charger?

Having a metal plate etc under the charger and installing fans is a good precaution but its seems over the top for a product that is suppose to "just work" out of the box.

I am beginning to think whether the LaCrosse range of charger is worth bothering with.

Thanks in advance.

 

[SilverFox]

Hello Tsu,

There is another charge rate that the battery manufacturers recommend. Starting with a discharged cell, you can charge it at 0.1C for 16 hours. This is a timed charge. The charge is terminated at the end of 16 hours.

With an Eneloop 2000 mAh cell, the 0.1C rate is 200 mA. Since the BC-900 has a safety shut off at around 3000 mAh, you may be able to use the 200 mA rate if your cells are completely discharged prior to charging.

The problem with this is that if the charger has -dV sensing termination, the charge may be aborted before the cells are charged. This is known as a false peak.

Another problem is what to do with a cell that is only partially discharged. The 0.1C rate is supposed to be low enough that any damage from overcharging at that rate is minimal, so that may not be a big issue.

Another safety used is maximum voltage. The charger will quite charging when the cell voltage reaches a maximum value. This method of charge termination is hardest on new cells, and won't completely charge older cells, unless a top off charge is added to the main charge.

As you can see, there are several ways to charge, and terminate the charge. It seems like each charger has strong, and weak points. You have to decide what charger has the possibility of doing the best job of charging your batteries, without destroying them. You then have to settle on a price that you are willing to pay, and evaluate the price/performance ratio of your charger.

If you charge batteries twice a year, you can get by with a charger that does not treat your batteries all that well. However, if you charge batteries twice a day, charging without damage becomes very important.

I have a BC-900 and used it a lot before the Maha C9000 came out. I had it on a heat resistant surface, and usually charged at 1000 or 1500 mA. I like the features of the C9000, so my BC-900 is not in retirement. My C9000 is also on a heat resistant surface, as are the other chargers that I use.

Good luck on your choice...

Tom

 

[tsu3000]

Hi SilverFox

Thanks for the info. Its much appreciated.

I will probably get the BC-900 in the end since I think its the most comprehensive charger for the price. The C9000 is a bit too much for me and I will probably never use half the available functions it offers.

If I stick with Eneloop's and charge sensibly and take proper precautions I think the BC-900 will be pretty reliable.

How hot do the Eneloop's get when using the BC-900 say when using 1000mAh rate?

tsu

 

[SilverFox]

Hello Tsu,

They warm up a little, but don't get hot.

They should do just fine charging on the BC-900.

Tom

 

[N162E]

Most batteries don't die - they are tortured to near death, then murdered...Tom

Our motto

 

[SilverFox]

Hello Fred,



Tom

 

[NA8]

LaCrosse
$46.32 with economy shipping.

Maha C90000
$59.97 with free shipping.

http://www.thomasdistributing.com/index.htm


The difference is $13.65.

For $13.65 you're going to buy a product with a long history of problems ?

Mine hasn't melted, but it has a knack for shutting down due to "over temperature" until it cools off and then starts charging again. That sound like the way you want to go ?

Does the Maha give you an extra $13.65's worth of value ? You decide, take a look here:

http://www.candlepowerforums.com/vb/showpost.php?p=1761060&postcount=37

Which do you want to invest your money in ?

 

[bryaninperson]

I was in your shoes on trying to decide a few weeks ago. I went with the LaCrosse BC-900. I am glad I did. Very easy to use and what little I have used it, it is going strong. The deciding factor for me was the extras you get with BC-900. However, I did a test on the AAA's and three were good pushing close to the 800 mAh capacity and one was only at 330 mAh. Now I have a chance to use the refresh function on that battery. I am very happy with the BC-900.

 

[geek4christ]

Mine hasn't melted, but it has a knack for shutting down due to "over temperature" until it cools off and then starts charging again. That sound like the way you want to go ?

While that is a huge pain, I get around it by keeping a small fan blowing on mine. I know I shouldn't have to do that, but it's not too inconvenient since my charger is in my junky office anyway.

I haven't had mine very long, but the fan does keep the cells nice and cool and I haven't missed a termination yet, FWIW.

 

[N162E]

LaCrosse
$46.32 with economy shipping.

For $13.65 you're going to buy a product with a long history of problems ?

Mine hasn't melted, but it has a knack for shutting down due to "over temperature" until it cools off and then starts charging again. That sound like the way you want to go ?

What charge rate are you using? I really like the default 200mah rate, very little heat at that rate. I also use 500 and 700 when I'm in a hurry, the batteries tend to get warmer toward the end but not what I would call hot.

Does the Maha give you an extra $13.65's worth of value ? You decide, take a look here:

http://www.candlepowerforums.com/vb/showpost.php?p=1761060&postcount=37

It gives you a lot more work to do at almost twice the size.

Which do you want to invest your money in ?

I use both. I do all my charging on the LaCrosse and my Discharging on the MAHA C-9000. My PERSONAL experience is that while the standard nimh cells seem to thrive on being "Beat Up" the newer LSD'S seem to do just fine with gentler handling.

 

[sandbasser]

Disregard...

 

[NA8]

What charge rate are you using?

I ran into the over temp/cool down mode while charging at 1Amp. Going to 700mA works much better esp for just one or two batteries. I think that's why you see the 700mA limit on the BC-700 model. It's never been clear to me if they're still making the BC-900 model or if they just had a lot of stock left. I'd hope the BC-700's are actually the old BC-900 circuit boards, and the "new" BC-900's have some sort of improved design, but LaCrosse is keeping quiet about all that.

It gives you a lot more work to do at almost twice the size.

I got around that problem by buying the C808M.