| Can I use rechargeable batteries in the RCX? |
| User Opinions |
|
No users have voted.
|
|
Thank you for rating this answer.
|
The short answer is yes. Alkalines are preferred, but you can use rechargeables. However, there are several disadvantages of which you should be aware.
Disadvantages of Rechargeables:
- Most rechargeables, when fully charged, are only 1.2V instead of
1.5V. Thus, six batteries provide the RCX with only 7.2V instead of the
9V that alkalines provide. The RCX turns off when the charge is less
than 6.5V, so you only have about 0.1V to lose in each of your batteries before the RCX
turns off.
- When the voltage of rechargeable batteries drops off, it continues to decline at a quicker rate than alkaline batteries.
- Rechargeables tend to loose voltage at about 10% per month when they are just sitting on a shelf, depending on the type of battery.
- Not all rechargeable batteries are the same size and shape as
alkalines - they vary in length and in the shape and position of their
positive contacts.
- Because you will be changing rechargeables more frequently than
you would change alkalines, more opportunity for the
RCX firmware to be lost or corrupted is created. (When changing batteries, you
might want to plug a "plug pack" into the RCX so you don't corrupt or wipe
your RCX's firmware. Radio Shack sells an inexpensive 6xAA pack with a
9V clip on top and a cable that plugs into the RCX.)
All that said, some RCX users are successful with rechargeable batteries, and they save money and waste! Here are the issues to consider before purchasing rechargeable batteries for your RCX:
Type of Batteries:
- NiMH (Nickel metal hydride) - Most common, seem to be most consistently the correct size for the RCX
- Rechargeable alkaline -
Ideal, because they are 1.5V when fully charged. But they don't last as
long as normal alkalines and have a limited number of recharges.
- NiCad (Nickel Cadmium) - Not recommended, as they have a chemical memory effect.
- Other - Eneloop batteries have long shelf life, and are worth looking into: Eneloop Information.
Size of Batteries:
- Because not all rechargeable batteries are the same size as alkalines, we strongly recommend that you verify the physical size characteristics of any rechargeable battery brand before you purchase in quantity.
- Try a "battery snugness" test: take off the RCX bottom and gently
shake the RCX. If any of the batteries fall out, they are not the
correct size, and you'll need to purchase a different brand of
batteries.
Charging of Batteries:
- For optimum performance, rechargeables should be charged in the
same group or pack in which they will be used. In other words, if
you use six rechargeables, they should be charged together and used together to prevent uneven discharging and sudden shutdown of the RCX.
- Unless your rechargeable batteries are charged and discharged at
the same rate over the same time, they build up a chemical memory. In a
classroom where you may have 60 batteries and a number of 4 battery
chargers, you will find that they are being charged and discharged at
different rates. The result is that one battery will decline more
quickly than the others, and the RCX will turn off sooner than you
expect.
Downloading Firmware:
- The best method for downloading firmware is to have the RCX powered by an AC adapter plugged in to the wall electricity unit.
- If you are having trouble downloading firmware, either with
rechargeable or non-rechargeable batteries, switch to an AC adapter for
RCX power.
Troubleshooting:
- If you find that you are losing firmware all the time or that the
RCX is suddenly shutting down, it is likely that your batteries are not
the correct size and thus are losing contact with the connections
inside the RCX battery case. Use a different brand or switch to
alkaline or the AC adpater.
- Some people use electrical tape to secure the batteries in the
RCX. However, if you have to tape in the batteries in order to keep
them in the compartment, chances are very good that any physical change
in orientation of the RCX during the build process or operation of the
assembled robot could cause unexpected shutdown and loss of firmware.
- When changing batteries, you might want to plug a "plug pack"
into the RCX so you don't corrupt/wipe your RCX's firmware.
|
| Visitor Comments |
|
No visitor comments posted. Post a comment
|
| Attachments |
|
No attachments were found.
|
Search the Knowledgebase
Browse by Category
Print this page
Email this page
Post a comment