10-30-2005, 12:39 PM
I have a nice HobbyZone 5208 DC Peak Charger.
Wondering if anyone has measured the trickle charge rate.
Specifically wondering if it is a constant trickle charge rate , or if it varies with the amperage knob setting.
I'd like to know if I can leave my 6- and 7-cell 900 Mah Ni-MHs on this charger for a while (hours? days?) after peak charging, or if I need to disconnect them right away after the light stops blinking and glows steadily.
I have figured out that I don't need to discharge them between uses if I use a peak detector charger like this one.
Charger Manual at: http://www.horizonhobby.com/ProdInfo/Files/hbz1026-manual.pdf
01-27-2006, 03:20 AM
Got a new digital multimeter for Christmas and just tonight measured the trickle charge current I asked about. Turns out that with a 6-cell NiMh hooked up, it was 16 ma regardless of the knob setting. So I can relax and not have to rush to disconnect the charger as soon as it stops blinking.
02-03-2006, 09:33 PM
You're right about leaving them on a "trickle" it's a good practice to do that with a new pack, it equalizes the individual cells, in fact it is better to C/10 overnite charge new packs. Also if you slow charge your pack the nite before flying, then let it trickle on the way to the field, that first flight will be the best performance you'll get out of the pack that day, the fast charge to "peak" on later flights will have less "goesintta" than the slow charge.
02-04-2006, 05:00 PM
What is trickle charge?. According to most manufacturers, trickle charge is defined as C/250 to C/300. Slow charge is defined as C/10 and is what is used to form new (or ones that have been in storage a while) NiCad or NiMh cells. Also most (all that I have checked) manufactures say that it is very bad to trickle charge NiMh as it will slowly destroy them. Just check out "NiMh charging" on one of the search engines and read a few of the manufacturers recommendations and cautions if you do not agree with this. These are not my words but the info direct from the distributers/manufacturers. They all seem to agree that for best battery life charge at 0.1C for 12 to 16 hours and most state that if you leave the cells on charge a lot longer than that you may damage them although some overcharge at 0.C will usually not damage them as they are designed to allow the rate of recombination of oxygen at the positive terminal to be safe at that charge rate; i.e. not build up enough pressure to blow the seal but will cause an increase in cell temperature which, if long term will damage the cell.
02-04-2006, 05:22 PM
Thanks for the clarification on Ni-Mh charging, up till now I have only used Ni-Cd's for my radios. My current project (4 Star 60) is running on the tail heavy side, a 5 cell, 1200 or so Mah. Ni-Cd for the Rx will fit fine and reduce the amount of lead in the nose.:D I would imagine it takes a lotta time at a true "trickle" to degrade the Ni-Mh cells:rolleyes:
02-06-2006, 09:19 AM
What is trickle charge?. According to most manufacturers, trickle charge is defined as C/250 to C/300. Slow charge is defined as C/10 and is what is used to form new (or ones that have been in storage a while) NiCad or NiMh cells......
Sorry for any inadvertent confusion I may have have caused.
In my case, my packs are 900 mAH capacity.
1C (typical field) charging would be .9 Amps. I normally (at home) run my peak-detector charger at the lowest setting, 300 mA, which is 900/300 = C/3 or 0.33 C.
After the peak-detecting charge is over and my charger goes down to the 16 ma whatever-you-want-to-call-it lower charge rate, for my cells, that is 900/16 = C/56 or .018 C.
I was not suggesting leaving the NiMh cells charging at that rate for a long time (days), just saying that at that low charge rate I don't need to watch the charger like a hawk to disconnect it immediately after it stops blinking.