I currently have a radio shack 13 hour NiMH charger and two sets of rs NiMH batteries. One set are 1500 the other 1600. These batteries don't last very long at all. Maybe 30 or 40 shots on an HP618. Would I see better results going with an intelligent charger and/or another brand of battery? Are the RS chargers and batteries any good? Thanks.
I haven't tested the RS chargers or batteries lately. I had a RS charger a while back that was a 1-hour unit, got the batteries *very* hot. Haven't tested the 13 hour ones, and don't know about their batteries. - I may take a little shopping trip to RS to see what they've got these days, pick up a few samples to test. (It'll take a while to get results on them though, as it's time-consuming charging them up, discharging on my test setup, etc.) The one thing I'd suggest in the meantime is to try leaving the batteries in there for a full 24 hours. A charger with that long a charging time is mostly likely a "trickle" charger, with a fairly low charging rate.
- 1500 mAh NiMHs would take proportionately longer. As long as the batteries don't get noticeably hot (warm is OK) in the charger, try leaving them in for a long while. (pause) I just checked the test data in our review of the HP 618, it's actually a bit on the lower side of the normal range, in terms of power consumption. A fully-charged set of 1500s should run it for a couple of hours worst-case. See what happens with just longer charge times.
I don't think they'd be that bad though, my guess is the charger just isn't bringing them up to full charge...
The specs from the unit, RS part #23-033, states that in NiMH mode that 1500mAh batteries will take 12h20 and and 1600s will take 13h10. The unit has a 13hr timer and I suspect that the timer shuts it right off. That leads me to wonder what sort of resistance the charger has when not charging, discharging my batteries. I too suspect the charger. I've tried unplugging the charger and plugging it back in for a couple of hours to see if that would help. Nope.
It is supposed to be an intelligent charger. I will report back my results with the new charger and with the new batteries. I won't likely try the sanyo batteries in the RS charger tho. Unless I get really bored :0) (or someone urges me to) Will you be reviewing the LP4000? Thanks!.
Ah - it's probably more than a trickle charge then, and it sounds like the rating is indeed intended to relate to the higher-capacity batteries. Strange. I'll see about getting one of those, it'd be interesting to experiment, see what it's actually doing. We don't have one of the Lighting Pack units here yet. I have a few more Maha units to do, a Quest Q2 charger that's pretty nice, does about as good a job as the C204F (although it seems to have developed a defect in use now), a Kodak wall unit, and an Olympus. (Yeesh) I'd like to get to some of the newer RS units too, as I suspect a lot of people may have them.
It's hard to find time for the battery/charger stuff, even though it's something I'm really interested in, because I'm always so bogged with the camera/scanner/printer review work. I'm going to make a concerted effort to keep chipping away at it though. (The batteries are looking very interesting as well - I built a little load tester with a microprocessor to monitor voltage, etc. It turns out there's a lot of variation between what the mfrs rate their cells at and what they actually do. Stay tuned on that front, I'm going to try to get something coherent together on batteries in another couple of weeks, after I've gotten more testing done....
The RS unit came with a set of 4 1500mAh batteries though! So it's not so bad. I also got a 20% discount, as here in Canada when you pay with a RoyalBank Visa you get 20% off batteries and I talked the guy into giving me the discount on the combo as well I am very interested in reading your reviews. There is very little information out there on batteries and chargers. Or at least few reviews that go into any details. I am also interested in your load tester. Is it just a resistor, an ADC and a pic or something like that? That would be an easy way for me to test my batteries and charger :0) Feel like sharing your design or at least dersign considerations with me? David..
Oh - well, that's a much better deal, then! Actually, the load tester these days is a 5 ohm load, an 0.1 ohm current-sense resistor (not really necessary for the way I'm using the system currently), a relay (to terminate discharge when the 4-cell pack hits 4.0 volts), a 1298 ADC chip (to tell when that happens), and a Basic Stamp to keep watch over things (overkill, at least in the present form). The Basic Stamp samples the pack and sense resistor voltage once per minute, recording the values so I can extract the true mAh later if I want. When the pack voltage hits 4.0 (1 volt/cell, the recommended minimum terminal voltage for NiMH to avoid damage), it cuts off the relay, and waits for terminal input. When I type "go" on the attached host computer's keyboard, the Stamp spits out the series of voltage readings it collected. This is really only an approximation of a camera, but it is a fairly harsh test - It draws roughly 800-1000 mA continuously. Where it differs from a digicam is that cameras are constant-power loads, this one is constant-resistance.
I have on my "to-do" list to make an active load for the tester, using the Stamp to compute actual power, vs just measuring the voltage, and then drive a power transistor to vary the current, keeping power constant. It's on the list, I think I'll actually get to it sometime this fall. (Right now, I'm building a timer with high-intensity LEDs for readouts, to improve accuracy in measuring shutter lag & cycle times. I think that'll be finished in another week or two (my leisure time for this sort of thing is pretty limited), after which I'll perhaps turn my attention back to the active-load thing. I've been collecting battery data with the above system for a while, hope to organize the results into a review of batteries and chargers..
I bought a sample of that RS charger and batteries. They're not terrific, but not horrible either. (The 1500s ran about 84 minutes in my torture-test.) More later as I get more test data on them. - But it seems to me that only 30-40 shots is abnormally low with them. - Are you leaving the camera running for a long time between shots? That'd drain the batteries, with relative few shots taken...
The only thing I can think of is I do remove pictures from the camera relatively often. Does this action use a lot of power? I do try to get it done quickly so the camera is rarely on for a couple minutes. I am stil waiting for my batteries and charger so I cannot compare my findings yet. Also still looking for the ADC before I can build the tester. Though it will be a few days before I am capable of writing the software anyhow. Thanks!.
Someone has reported abysmally short battery life in the HP618 forum using 1200mAh batteries. Is the difference between 1200mAh and 1500mAh batteries merely 25% or are there more factors at play here?..
I wonder: Some cameras have a rather high cutoff threshold, the point at which they shut down because they think the battery voltage is too low. It's possible that the 618 is one of those, which would explain very short run times, even though it's power consumption is actually quite modest. The difference between batteries can also be much more than the mAh rating suggests. A number of batteries don't come close to their supposed capacity.....