Can I charge NiMH batteries with a NI-Cd charger?

d12345

Can I charge NiMH batteries with a NI-Cd charger?


If not what is the best charger for NiMH batteries?

patman99

The answer is 'No'.
Due to the different charge-rates of Ni-Cad & Ni-Mh batteries, one of three things may happen if you attempt to use a NI-Cad charger to charge Ni-Mh batteries.
1. The charger will only ever part-charge the Ni-Mh batteries - this is the most probable scenario.
2. The charger will over-charge the batteries - low probability of this happening.
3. The charger will correctly charge the batteries - Very low chance of this happening.

The best sort of charger is one of the more expensive types that can auto-detect when the battery is fully charged and switch to trickle charging mode. Avoid the ones that will simply charge for a set time period as they may well over charge the batteries and shorten their life.

Norman_Castle

The answer is yes. Use the guide to find the correct charge time for your charger and batteries.
http://convert-to.com/491/recharging-rechargeable-nimh-nicd-batteries.html

fenlander_uk

patman99 wrote: »

The answer is 'No'.

Norman_Castle wrote: »

The answer is yes.

Well, that's useful...

Do people use NiCD batteries any more? Everything seems to be NiMH nowadays. Chargers aren't expensive: I'd get one designed for the job.

thescouselander

No, don't do it. As already said chargers are cheap now so use the correct one for the job.

Oblivion

Unless you want to re-enact The Big Bang theory, never mix battery / charger types. NiCds and NiMhs have very different requirements.


I use a variant of this NiMh charger ...
http://www.amazon.co.uk/Vapextech-Super-Smart-nimh-Charger/dp/B008ETHO7G/ref=sr_1_1?ie=UTF8&qid=1393767155&sr=8-1&keywords=nimh+charger

Norman_Castle

Apart from pre-set charge times, assuming they have timers, and the name, whats the difference between a NiCd charger and a NiMH charger?.

Oblivion

Norman_Castle wrote: »

Apart from pre-set charge times, assuming they have timers, and the name, whats the difference between a NiCd charger and a NiMH charger?.

http://www.greenbatteries.com/nimh-battery-charger-faq/#charger%20differences


What's the difference between a NiMH battery charger and a NiCd battery charger.
The biggest differences are in the charge rate (how fast the charger can charge batteries) and the charge control (how the charge determines when to stop the charge). Many of the inexpensive NiMH battery chargers are simply NiCd chargers that have been modified slightly. Typically a 5 hour NiCd charger has a switch that allows the charge time to be increased from five hours to eight hours. Thus a 5 hour NiCd charger becomes an 8 hour NiMh charger. As we mentioned above, we do not recommend this type of charger design. While a timer type charger is less expensive to manufacture than a smart charger, it can lead to overcharging and battery damage if batteries are frequently charged before they have been discharged (that is, the batteries are used for a short time and then fully charged again).
NiMH smart chargers have actually been designed to detect when a NiMH battery is fully charged and then shut off or go into a trickle charge mode. Because of the more complex circuitry, this type of charger costs more to make, but should lead to greater battery life. Some of these chargers only cost slightly more that the "dumb" chargers. We strongly recommend investing in a smart charger for your NiMH or NiCd batteries.

Norman_Castle

From your link

Can I use an older NiCd battery charger to charge NiMH batteries? The answer to this question depends on the type of NiCd charger. Depending on the type of NiCd charger you have, the older NiCd charger may undercharge NiMH batteries (most likely), it may overcharge them (less likely), or it may charge NiMH batteries properly (but it's not likely to do so automatically and could take a very long time). Let's take a look at the three cases.
Many of the older NiCd chargers are the simple timed type charger which will charge batteries for a fixed amount of time and then shut off. Unfortunately, since NiCd batteries have a much lower capacity than NiMH batteries, the timer is likely to shut off long before the NiMH batteries are fully charged. This won't harm the batteries, but the NiMH batteries won't be fully charged since the timer will have stopped the charge cycle too soon.
Also common among older NiCd chargers are the so called "overnight" chargers which charge batteries at a low rate as long as the charger is plugged in. This type of charger can fully charge NiMH batteries, but it might take a very long time to do so. It's possible that an old NiCd charger could take as long as 48 hours to fully charge new high capacity NiMH batteries! This type of charger is not likely to damage NiMH batteries unless the batteries are left in the charger for weeks at a time, but it may not be very convenient to use. If you have this type of charger you can get an idea of how long you'll need to charge your batteries by using the calculator found above.
The final possibility is that the older NiCd charger is a rapid charger that will charge NiMH batteries but will not have the necessary circuitry to stop the charge cycle once the NiMH batteries are fully charged. If the NiCd charger is designed to charge batteries in less than two hours it may be this type. In this case the risk is that the older charger will overcharge NiMH batteries. This will be apparent if the batteries get very hot during the charge cycle. (It is normal for NiMH batteries to get warm as they become fully charged, especially in a rapid charger). If the NiMH batteries get too hot to handle and stay that way for more than 20 or 30 minutes, then the NiCd charger is most likely overcharging the NiMH batteries and may shorten their life. You would be most likely to encounter this type of charger if the charger was designed for rapid charging radio control (RC) vehicle batteries. We would recommend that you not use an NiCD rapid charger to charge NiMH batteries.


If you adjust the charging times you can charge NiMH batteries with a NiCd charger.

Kernel_Sanders

fenlander_uk wrote:

Do people use NiCD batteries any more?

Nobody said they did.

d12345

The Ni-Cd battery charger is a Uniross model KB 8 with an output of 140mA so probably not overcharging the NiMH 2500mA capacity batteries.

Just need a day or 2 to charge them.