i just brought the 6.0 Volt Ni-MH 1600mAh Battery Pack [BAT-03]
lynxmotion.com/Product.aspx? … egoryID=48
the charger i am using: (not from LM)
ROCKWELL 328r09-001
input = 240v
135Ma
5.8vdc
i think a recommened charge of about 15 hours for first charge but i havent got any info on initial charge times?
Not sure about the charger, but it sounds like a trickle charger. I’ve never used one. We use peak detecting chargers. They can charge a pack in 1-3 hours depending on your charge rate and battery capacity.
I have similar question as well as I bought the 6.0V 2800mAh.
I didn’t charge but use the battery upon receiving, since there is 6.20V across the terminal. Finally it deplete, and I charge it with a third party charger as well, with delta peak and trickle charge and temperature sensor. Trickle voltage for termination is default at 7mV.
I charged it at 1.2A, I follow lynxmotion charge current, though I read somewhere we can charge up to 1C. It should rate at 7.25V off the charger.
I just did my charging, almost 3 hours, and the voltage increase to 7.40V but yet to terminate.The battery was warm to touch. So I terminate the shutdown.
Is there anything wrong with my charger? I like to hear some recommendation 
Sounds pretty normal. Warm is ok, hot is bad. I do not know the exact temperatures. It’s best for the health of the battery to charge it as slowly as possible. 0.5 C would be the best.
I don’t know if there is anything wrong with your charger but a couple observations may help. a fully discharged 2800mahr pack being charged at 1.2a (1200ma) could take 2-1/2 hr easily enough.
As I recall there are two ways of terminating charge on NiMH packs, -dV/V and dT/T. When charged at a constant current the charger looks for the pack voltage to peak and then decrease. At the same time there will be a sharp rise in temperature. Either event (or both) are indications the pack is fully charged. Many chargers assume charging at a 1C rate (2.8A in your case) and have an 80 minute time out. Also if the charger has a temperature sensor it will typically terminate charging when T=45C.
Now here is something to consider when using a charger that relies just on dt/dT… if the charge rate is significantly below 1C then the rate of temperature change when the pack is fully charged may not be fast enough to trip the termination threshold. This is why there is also an absolute temperature at which charging terminates. If your cells don’t get much above 45C then they should be fine, however if they get above 50C they will start to loose capacity.
So if you want to charge them at less than 1C just set an egg timer and pay attention to how warm the pack gets. Some temperature rise in the pack is to be expected. 40C is slightly above body temperature (37C) so if the pack feels a fair bit warmer than your hand it is close to being fully charged.
I would not disagree with the 0.5C being better for tha packs comment necessarily as it helps get a more even charge across all the cells in the string however see my comments above about some chargers that look at pack temperature not necessarily being able to correctly determine charge termination at charge rates < 1C.
Whoa, yeah my comments were not considering the temperature probe chargers. I thought it was just a failsafe, I didn’t know it could be used to determine the charge state.
Hi guys, thanks for the fast reply. The charger I used is an intelligent Lipo/Li-ion/LiFe/NiMH/NiCd/Pb battery charger/balancer.
It has the following function:
i) Able to adjust charge current, from 0.1 to 5A (set at 1.2A)
ii) Cutoff timer, adjustable (set at 180 min)
iii) Temperature cutoff, adjustable (set at 50 C)
iv) Trickle voltage for charge termination, adjustable (default at 7mV)
There is an LCD on the charger. I notice that the voltage increase sloooowly, then suddenly it drop like about 50-70mV, for 1~2 sec, then it goes back again, happen like once every 3-5min, when the voltage hits more than 7.10V.
The battery didn’t feel warm during the first 2 hours. Before this, I never bother about NiMH charging approach, the battery I use for my camera used to get very hot after charging.
I guess I’m over concern. I should let the charger handle it, will try and just let the charger to take care of it the next time. Thanks guys.
Calculate charge time*
Battery Capacity +10% / Charger output = (Charge time in hours)
1600 +10% / 240 = 7.5
= 7.5 hours charge time.
Please tell me the 240 I emphasized in your quote is not from the “input = 240v” line in the orriginal post and is instead a 240mA output setting of the charger. 
yeah a few typos there. my bad.
i wrote the equation wrong then calculated the 7.5 from that. should have been:
1600 +10% / 135 = 13 hours charge time.
