On Thu, Mar 09, 2006 at 01:45:08AM +0200, Arne Ansper wrote: | Must get new battery for TX. Current one is down to 500mAh (from 750mAh) | and lasts only for 2.5 hours. I can get 1100 mAh NiCd or 1650 mAh NiMH | (both Sanyo) at the same price. Which one is better for TX?
The TX doesn't really care -- both will work. The current draw is low, so NiMH cells will work just as well as NiCd cells, and with the added capacity, will last longer. Some simple math suggests about eight hours for the 1650 mAh cells -- basically all day. Your slow wall-wart charger will work just fine, but with a pack that's 3x as large, a full charge will take 3x as long. A fast charger will work as well, as long as it can do NiMH properly (and nowadays, most can.) NiCd cells do last longer (i.e. more years, more cycles) in general, and will tolerate abuse better (i.e. fast charging, or leaving it on the slow charger for weeks at a time) but the difference isn't that large. NiCd cells also handle high current draw abuse and vibrational abuse (more of an issue in glow plane RX packs) but for a TX, neither one is a problem. You can also charge NiCd cells faster (2C or so vs 1C) but I'd rather just not have to charge at the field at all if I can avoid it, so ... NiMH cells do have a larger (2-3 times as large) self-discharge rate, so after a week or two they'll be more discharged than a NiCd pack, but if you charge the night before flying, you won't have any problem. And so I make NiMH packs for my TX's nowadays in most cases, especially for my computer TX's that draw a lot more current than the old non-computer ones. -- Doug McLaren, [EMAIL PROTECTED] `The only time you have too much fuel is when you're on fire.' RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
