Rechargeable batteries is it a con?

[ericmark]

My wife proudly said how she had got a pair of 800mah for a pound compared with the 4 x 2500mah batteries I got for £2.98. But did I really get the better buy? Hers were ready charged and are claimed to hold charge for 1 year and mine had to go straight into the delta V charger.

Charge times is another question. Mine say 7 hours at 500ma hers say "Ready for use" with no requirement to charge before use. With my delta V charger not a problem one looks at the LED and when it goes from red to green they are charged. But with the older charger it was designed to take 16 hours and no indication as to when charged.

My Delta V rated at 250ma (Minwa Electronics Co Ltd) so although it takes 10 batteries looking at 12 hours for 2500mah rated. The smaller UniRoss X-Press 300 is rated at 320ma but it has an auto cut off after 9 hours. Likely will over charge 800mah batteries and under charge 2500mah batteries. My Philips (SCB5050NB) USB charger also 250ma so also 12 hours charge time. It does in the instructions give times for 2600mah, (12½), 2100mah (10), 1800mah (8hrs) and 1300mAh (6¼hrs) but nothing for Poundland 800mAh cells.

OK as an electrician I understand but how many "Normal" people will realise the difference between 2500mAh and 800mAh when they both fit same appliance and charger? I will continue to buy mine from Lidi at 2500mAh rating.

 

[mattylad]

I will continue to buy mine from Lidi at 250mAh rating.

Did you actually mean 2500 rather than 250?

 

[bernardgreen]

To many variables to answer the question. Different types of battery behave differently in the same charger. If cost of recharging important, as in solar of wind powered re-charging then the type of battery can be critical when considering how efficient the battery is at converting charging current into charged energy. For example one type of 2500 mAH battery may need 12 hours at 250 mA while another may require 14 hours at 250 mA or some can require 120 hours at 25 mA

To design for re-chargable batteries to be used and charged correctly is difficult at the best when specifying which battery that must be used in an item of equipment used by professionals. Add the general public and consumer equipment into the equation and it comes down to any battery charged in any charger is possible and so protecting the equipment from abused batteries is important.

 

[ericmark]

I will continue to buy mine from Lidi at 250mAh rating.

Did you actually mean 2500 rather than 250?

Yes thanks corrected.

bernardgreen hadn't considered efficiency but if they are in fact fully charged. Delta V charger will not charge over discharged batteries but at least will fully charge any size and show when charged.

Philips USB not bad as a temperature control as well as time but one has collected chargers over the years and many designed for NiCad not NiMH and no indication as to if charged or not.

To be fair once the batteries start to get old only chargers which charge then individually can really do the job those which charge as pairs have little chance of getting it right. Other than where used and charged at all times together like in cordless phones.

I like I am sure many electricians put my finger on the battery and work out if charged from the temperature. But what chance does Joe Public have?

 

[Space cat]

Lots of information on batteries here:

http://batteryuniversity.com/

 

[AndyPRK]

these pre charged type batteries are brillant, holding a good charge for a year and are also better in other aspects.

eneloop were one of the first, but seam difficult to get now.

 

[acmedone]

OK as an electrician I understand but how many "Normal" people will realise the difference between 250mAh and 800mAh when they both fit same appliance and charger? I will continue to buy mine from Lidi at 2500mAh rating.

How many charger manufacturers understand how it should be done? I have some 1800mAh cells and my delta V charger only gets them halfway. Cell matching is also extremely poor so a perfectly good cell that's short of charge is at risk of damage by reverse charge when used in a pack. I don't know whether the charger trickles after cut off so I put them in a pack and continue with a current limited power supply.

Really, fast charging should be done by temperature measurement.

 

[ban-all-sheds]

My wife proudly said how she had got a pair of 800mah for a pound compared with the 4 x 2500mah batteries I got for £2.98. But did I really get the better buy?

Even if you have absolutely no idea what a mAh is, how can you think that 1600 <somethings> for £1 is a better buy than 10000 of them for £2.98?

When you think you can risk it, as her if she thinks that 2 800g bags of potatoes for £1 is a better deal than 4 2.5kg ones for £2.98.

Note - there are 2 risks here.

a) you might upset her

b) if she says "yes" you're going to have to start doing the shopping...

But back to the plot...

I'd be amazed if all batteries were the same quality and that mAh was the only thing to consider.

 

[bernardgreen]

I'd be amazed if all batteries were the same quality and that mAh was the only thing to consider.

That has to be the greatest understatement of the decade.......

 

[ericmark]

I have some odd AA rechargeable cells which are 1.5 volt not 1.2 volt and my Delta V charger will not charge them. However all the other cells seem to charge fine once they start charging. As you say temperature is the best indicator and finger on battery will soon show when fully charged. I would think there is some thing wrong with your Delta V charger.

However your point about reverse charge is very valid and once under 1 volt my Delta V reverse polarity protection kicks in and it will not charge the battery. I have some cheap USB chargers from PoundLand which will charge single cells (not pairs) and I use them for 1/2 hour to get batteries back up to 1 volt then transfer into Delta V charger.

Although some batteries are plainly marked others are not. I have one in my hand marked "Tronic accu 2000 rechargeable" in large letters and one would think it would be 2000 mAh but in very small writing it says "Mignon 1.2v 600 mAh" must be about the smallest capacity one can get.

Also some of the non rechargeable have very similar stilling to the rechargeable type this one

Mouse 4

• ericmark
• 11 Dec 2009
• 5

I think may have been mixed up although when it went bang it was at least a day after being recharged in error. The damage to mouse was the big issue.

Mouse 3

• ericmark
• 11 Dec 2009
• 3

Mouse 5

• ericmark
• 11 Dec 2009
• 2

the Delta V charger does refuse to charge 1.5 volt batteries so not so easy to charge in error but most others will and it's up to user to see what they say. Although they say do not recharge the writing is so small it's easy to just read the "recharge" word without seeing the "do not". With AAA it's even worse.

At least the rechargeable type do have the mAh marked the non rechargeable just say things like "Heavy Duty" or "Super" with no indication of how much power they hold. Some say Zinc Chloride but others have nothing to say what type other than "No Mercury Added" which does not mean I suppose No Mercury.

I can't think of another produce where we buy it with no idea of how much we are buying.

 

[ericmark]

My wife proudly said how she had got a pair of 800mah for a pound compared with the 4 x 2500mah batteries I got for £2.98. But did I really get the better buy?

Even if you have absolutely no idea what a mAh is, how can you think that 1600 <somethings> for £1 is a better buy than 10000 of them for £2.98?

When you think you can risk it, as her if she thinks that 2 800g bags of potatoes for £1 is a better deal than 4 2.5kg ones for £2.98.

Note - there are 2 risks here.

a) you might upset her

b) if she says "yes" you're going to have to start doing the shopping...

But back to the plot...

I'd be amazed if all batteries were the same quality and that mAh was the only thing to consider.

She is bigger than me. Risk assessment has been done and I have opted not to confront her. Anyway got to go out now and get Milk and Bread!!!!

As to Quality Yes I am sure you are correct. It does state "Charge up to 1000 X" but not guaranteed to do that. Clearly they would need to stipulate charger used. I have a Mini-Disk player hardly used and the battery has failed clearly using the player to charge it and well under 1000 charges. Marked NH-10WM Nickel-Metal Hydride 1.2v 900mHh (min) and unlike the AA cells I can hand on heart say it has only been charged in the Sony charger (Mini-Disk) but with AA cells I have not started putting a dot on the battery each time it's charged to see if it does as the packaging states.

 

[acmedone]

I would think there is some thing wrong with your Delta V charger.

Yes, it's a delta V charger...

Out if interest, have you ever measured the result of your charger?

I have a Maplin ADC/PIO USB board & cobbled up a discharge logger in order to find a matched set of 4. Only possible with trickle charging.

 

[ericmark]

The first Delta V charger I used was made by Icom for their U16 transceivers that we used on the building of Sizewell Power Station and we did have problems so I did build a test rig to test the chargers.

They were 6 bays in each charger and after testing we did find that some batteries with faulty cells were kidding the charger into thinking they were charged when in fact they were not.

There was a second type of charger with a temperature method of working out when charged and we found swapping batteries around seemed to help.

There were two secondary problems which compounded.
1) Radios were left switched on in the charger.
2) It had a auto discharge before charging to stop chemical memory at that time still using NiCad cells. So any power cut and it would start to discharge them all again.
The second problem was got around by only having one bay with the discharge enabled so on average one in six it would be discharged.

But I did find using my test battery with a hour counter that we had a few faulty chargers. With 300 radios on site it was easy to compare results but at home with a single Delta V charger one does not really have the option to compare one charger with another.

For a cell costing 75p each one is unlikely to set up a test rig for cells it was only when a battery cost more like £20 that I went to the trouble of testing and even replacing cells.

The charge curve for NiMH is flatter than that of a NiCad and it would not surprise me to find chargers designed for latter failing with the former type.

 

[Gavin77]

these pre charged type batteries are brillant, holding a good charge for a year and are also better in other aspects.

eneloop were one of the first, but seam difficult to get now.

Bought a load of them recently, so far they have been great.
Search on amazon for them.

 

[sergeantash]

My wife proudly said how she had got a pair of 800mah for a pound compared with the 4 x 2500mah batteries I got for £2.98. But did I really get the better buy? Hers were ready charged and are claimed to hold charge for 1 year and mine had to go straight into the delta V charger.

There's many types of rechargeable batteries, the main ones are NiMH (Nickel-metal hydride battery), Nicad and LiPo (the latter, Lithium Polymer) are rare in AA form at this time), they all hold charge at different rates.

Nicads discharge the quickest, NiMh the second whereas LiPo can hold their charge very effectively for up to a year. They all perform differently too.

Do you know whether the two batteries you're comparing are of same type? Nicad's will generally be cheaper than NiMh's. Also, are they both 1.5v, generally the cheaper rechargeable's tend to be 1.3v.