Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Batteries & Chargers => Topic started by: Nige52 on November 21, 2010, 02:19:06 pm
-
All Lipo batteries have a max discharge rate on them, usually 10c up to 35c, so you know the higher the rating, the more amps can be drawn, correct? I found this out (Again) when blowing a 15c rated battery through using a too powerful motor, lesson learned. %)
I need to buy 4 NiMH batteries for my new club 500 for next season so I thought to go with the biggest C rating I could find,....but I can't find any batteries with this on? Only the capacity, 2500, 3700 or 4600 etc. It's ok having a high capacity battery, but if it has a low discharge rate it's not much good for racing is it? So how can I tell the discharge rate (Or quality) of Nimh's?
Thanks
Nige
-
Ni-MH are not prone to damage like Lipo with high discharge, they tend to self limit current because of their internal resistance, there are different C rating for NiMH though, most "racing" buggy packs are high discharge, but many high capacity C and D cell Ni-mh have low C discharge rates., those will have a greatly reduced life if asked to put out high current.
the safest way is to buy a buggy pack and strip it down to the 4 cells required, otherwise you will be looking for data sheets on the net.
Nicad had a prefix or suffix Ii don't recall which) that indicated discharge capability.
Nick
-
I buy my packs from Iain at the Component Shop - he also sells on E-Bay (ID is itl-e) and his listings include the maximum discharge current as well as capacity.
My George Turner Bluebird model (seen here: www.gdmbc.co.uk/Club%20Models.htm) is powered by a custom 8.4V 2400mAh pack (from Iain) made from individual AA cells of low discharge capacity. At full throttle, I get a duration of 24min. The motor draws and estimated 5.5A with the set-up described. The pack has been used several times and appears to be lasting well. Only downside is that, having a low discharge capacity, it takes a wee bit longer to get up on the plane. Once it's there, though, it's great O0
-
I use CPC on-line and their catalogue - see link below, there are also tech sheets available if you hunt for them. There are a couple of suitable made up packs for your boat - but they also offer single cells for you to make up your own packs.
CPC don't manufacture as such, they're distributors so sell other company products - some of these packs are made by overlander that advertise in the model mag's so might be another source..
http://cpc.farnell.com/jsp/search/browse.jsp?N=411+1003196+500001
Hope this helps.
-
Try giving Overlander a call they have been in the model battery business for a long while and use a good quality brand like Sanyo. http://www.overlander.co.uk/