Advice please: Initial charge for Sanyo 1000mAh aaa with Lacrosse BC-700

[bfguilford]

Please help a newbie with some advice.

Just bought a Lacrosse BC-700 and Sanyo 1000 mAh (model HR-4U) aaa's for use with my phones.

Do I need to condition the batteries before using them, and if I do, what settings should I use for discharge/charge (my options are 100/200; 200/400; and 350/700mA), and for how many cycles before I use them.

Once they have been conditioned (if I need to), what charge setting should I use to get the best performance and life out of them (options are 200/400/700mA).

Any other advice (except for return the charger or batteries - my sone already opened them) are welcome.

Thanks.

 

[Mr Happy]

When you say phones, do you mean cordless phones?

I think these batteries don't really need conditioning and the phones have a built in charger to charge them. (Important: were the phones originally supplied with NiMH batteries?) It is typically sufficient just to install the batteries in the phones and leave them to charge until the phone says they are charged.

In my experience the lifetime of batteries in a cordless phone depends more on the quality of the phone than on the quality of the batteries. (It seems to me that Panasonic phones are good in this respect.)

 

[Mr Happy]

If you happen to mean headphones, you would be best using the 400 mA charge setting for the batteries and 200 mA discharge. The Eneloops don't really need conditioning though; you can just use them, or charge them and use them.

 

[bfguilford]

Thanks for the questions, Mr Happy.

The phones are Panasonic cordless phones that originally came with 630 mAh NiMH batteries.

The batteries I bought are not Eneloops, but standard 1000mAh Sanyo NiMH.

My concern about just putting them in the phones is that the phone charger is a timed charger (7 hrs), and I don't want to either under- or over-charge the batteries.

 

[bfguilford]

More info. I just looked at the Panasonic phone charger, and found this on the label: Power source 6.5V - 350mA, which makes no sense at all to me if it charges 2 630mAh aaa cells in 7 hours.

 

[Mr Happy]

Hmmm...does the user manual actually say the phones use a timed charger? My Panasonic phones (admittedly a fairly recent model) also came with 630 mAh cells, however they have a smart charger with a charging light on the phone that goes out when the batteries are fully charged.

 

[bfguilford]

Mr Happy... Thanks, and good question. I don't know if it is a timed charger, and a search on the Panasonic web site specs section for the product just says "Charge time: 7 hours".

I also get a message to "Charge phone for 7 hr" on the phone screen when it is discharged, so I assumed it was a timed charger. When the phone is charging the light is yellow; when it is finished charging, the light turns green (but I don't know if they throttle down to a trickle charge).

I don't keep them in the chargers all the time.

It also looks like the charger in the phone's base unit is rated as 500 mA, while the secondary charge units are rated at 35omA.

I was inclined to put it through a 200 mA discharge/400 mA charge cycle to start it off, and then charge at 400 mA as the regular recharge rate, but, after reading a very long thread on rates for a Maha charger (which you contributed to), it looks like charging at .5C - 1C suggests that I use the 700mA setting for charging (not sure about the initial discharge).

Any more suggestions would be appreciated.

 

[Mr Happy]

I think the charge phone for 7 hours message is about conditioning the batteries for first use, to ensure they are fully charged and balanced. Most devices have a similar message.

I would say charging at 700 mA would be fine, but check the cells and drop the rate to 400 mA if they seem to get hot during charging.

Have the 630 mAh cells actually failed? The ones in my new phones seem quite high quality, but I don't know how long they are going to last before they wear out.