I'm super excited for the batteriser... - Page 1
Forum section: electronics / general

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: September 17, 2015, 10:18:43 pm
content: Because it seems as though my goddamn DSLR has a cutoff voltage of like 1.98V per cell. Sorry for the flamebaitI've got a Pentax K100D I haven't used in forever, mostly because every time I grab it, it's complaining about dead NIMH batteries, and alkalines seem to last 5 minutes in the thing. Oh, yeah, we're talking about AAs, because Pentax hates user experience.It looks like my options are down to either this or these Kentli lithium AAs, which also have a built-in switching converter,https://ripitapart.wordpress.com/2014/12/06/teardown-of-kentli-ph5-1-5-v-li-ion-aa-battery/Of course, the batteriser DOES say in their FAQ not to use them with rechargeables. I wonder why.

author: hayatepilot
author_rank: Frequent Contributor
timestamp: September 18, 2015, 06:56:34 am
content: ...or use eneloop NIMHs, they have very low self discharge. Even after years of storage, they retain most of their capacity.Greetings

author: Wytnucls
author_rank: Super Contributor
timestamp: September 18, 2015, 07:05:44 am
content: Kentli lithium would be the best solution for high voltage cut-off or large draw current devices.Batteriser would also help with Alkaline AAs if the problem with your camera is a high voltage cut-off. In the more likely case of high current draw, it could help if the current draw is less than 300mA. Batteroo claims 1.5A, but this is unlikely.Fully discharging rechargeable batteries (0.5V) shortens cell life, so boost converters like the batteriser are not recommended.

author: RJFreeman
author_rank: Regular Contributor
timestamp: September 18, 2015, 07:30:05 am
content: Alkaline batteries are not usually much chop in DSLRes, they do not last very long at all try Lithium primary cells they cost more (and curiously when my son tested them as a science experiment did not have much more capacity on regular current draw, although they did have a flatter terminal voltage through the discharge curve and I suspect handle higher current surges better - but we didn't get to testing that).my old Canon Digital compact camera can take maybe a couple of dozen pictures on Alkaline cells but a couple of hundred with Lithium primary cells.

author: samgab
author_rank: Frequent Contributor
timestamp: September 18, 2015, 08:23:53 am
content: Quote from: alexwhittemore on September 17, 2015, 10:18:43 pmPlease just buy a pack of eneloop Pro's and give them a go in your Pentax. I can pretty much guarantee it'll solve all of the battery problems you've been having with that camera. You won't need any sleeves or addons. They (eneloops) have much lower ESR than Alkalines, so the voltage doesn't drop anywhere near as quickly under high current draw. It seems counter intuitive because theratedvoltage is lower than Alkalines, but in an application like this for almost all of the discharge curve they actually have a higher voltage than a NiMH. This chart is just standard eneloop vs Alkaline; enloop pro's will perform even better with high current draw, but they have a lower cycle life span (500 cycles vs 2100 cycles rated).And as was previously mentioned, they don't have the self discharge problems that older style high capacity NiMH's used to have.Of course, Lithium primary's are good, they handle the current draw well, they're lighter, they perform well in the cold, and they have great capacity. But they are only single use then throw away, and they are expensive to keep buying. A set of eneloops will last hundreds of cycles.For the record, I have no affiliation with "Big Battery" or "Big Panasonic/Sanyo" or eneloop. I just appreciate and have experienced the benefits, and don't like to see someone needlessly experiencing a problem which has been satisfactorily solved.Edit:Here's another chart which shows discharge curves of Alkalines, eneloops, eneloop Pro's, and e2 Lithium's discharged at 1A:This is sourced from HKJ's website:http://lygte-info.dk/info/ComparisonOfAABatteryChemistry%20UK.html

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: September 18, 2015, 08:50:38 am
content: I've used the full gamut of batteries in this camera, and lithiums seem to be the only reliable option. But they're expensive to burn through, so I try to keep them only as backup. I'll admit, most of my NiMHs were from way back when 2800mAh was hot shit but they wouldn't last two weeks on the shelf and they'd be toast after a few recharges. I just ran some through a quality charger/tester and the ones that weren't shorted took maybe 300mAh before 'full.' Whomp.I've never tried eneloop pros, they didn't exist last time I used this camera a lot. I bet they'd be good, but I'd probably trade life for lower self discharge, the way I use the camera. Unfortunately, even with good, healthy eneloop (regulars) (some older sanyos and newer panasonics alike), the camera seems to only get a few shots before crapping out (even when it started with an indication of full battery). I just put a 'depleted' (camera's words) set on the charger and they took 300mAh before showing full, in 3 hours at 100mAI think the Camera just sucks terribly.

author: samgab
author_rank: Frequent Contributor
timestamp: September 18, 2015, 09:39:55 am
content: I know of several people with that Pentax SLR camera who (anecdotally) manage fine with eneloops (I have used it [edit, half finished this thought when I first posted] but never owned this model). But maybe in your case you'll just have to stick with Lithium primary cells.Note this thread, FWIW:http://www.candlepowerforums.com/vb/showthread.php?194180-eneloop-vs-Kodak-Pre-Charged-Voltage-Maintenance"This dSLR is well known to be very battery fussy -Ref: Post #49 (link) in thread - K100D - "Low-Battery" Problem gives details of the meter voltage levels.The poster measured these voltage levels for the Pentax K100D dSLR -Battery meter shows full charge at > 1.25v per cell, i.e. >5.00vBattery meter shows half charge at 1.25v per cell, i.e. 5.00vBattery meter shows empty and camera shuts down at 1.19v per cell, i.e. 4.76v"..."the eneloops continue to show full charge on the Pentax dSLR, whereas those Kodak P-C show half charge.This tells me that the eneloops seem to maintain a higher voltage level Under-Load than the Kodak Pre-Charged."

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: September 18, 2015, 01:37:58 pm
content: Holy crap, seriously!? It ACTUALLY cuts off at 1.19/cell? I haven't yet been able to measure cutout with a PSU for some reason.Good god, I might actually back this project.

author: Wytnucls
author_rank: Super Contributor
timestamp: September 18, 2015, 01:56:21 pm
content: Don't get your hopes too high. If the camera shuts off that high it is because the batteries stopped delivering the current required. The batteriser would have to draw even more current to maintain 1.5V, which it is probably unable to do and, if it can, will reach 0.5V per cell cut-off very quickly.

author: free_electron
author_rank: Super Contributor
timestamp: September 18, 2015, 02:04:06 pm
content: shuts off at 1.98 per cell..cells are 1.5 how on earth did you ever get it powered up ?

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: September 18, 2015, 02:09:53 pm
content: Quote from: Wytnucls on September 18, 2015, 01:56:21 pmIt's not, this camera's battery management is God-awful. I'm CERTAIN it's cutoff voltage has nothing to do with power delivery.But still. 1.19. God.

author: digsys
author_rank: Unknown
timestamp: September 18, 2015, 02:18:59 pm
content: I've got bot the K100D and K200D since release. The K200D is a LOT better at handling lower voltages, I can pretty much use any LSD battery type.I also always keep 2 packs of primary lithiums as a backup. The first release K100D did have issues with high cut-off, but there was a firmware releasethat made it a lot better (I applied it to mine). I also had it apart and did a mod I found online to tweak the V-sense point. It was years ago, but it shouldstill be out there. Checkwww.dpreview.com

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: September 18, 2015, 02:22:18 pm
content: Digsys: it looks like the latest FW is 1.02, which my camera is on. Is there another?Also, I figured maybe a hardware tweak was possible to nudge a regulator, do you have any more specific info? I'd love to dig into that. The camera has a lot of marks against it, and I'd love to replace it with something modern that can, say, shoot video. But I've got a lot of glass, the sensor is good, and retro manual lenses are cheap and fun. I'd hate to throw it out over such a trivial problem.

author: Wytnucls
author_rank: Super Contributor
timestamp: September 18, 2015, 02:24:57 pm
content: If current draw is light, you would have a reasonable usage time, even at 1.19V shut off.I would measure current draw before jumping to conclusions.

author: digsys
author_rank: Unknown
timestamp: September 18, 2015, 02:40:13 pm
content: I loaned my K100D to a friend, so I won't be able to check for a few days. There was a LOT posted about this issue on that forum I mentioned, which is theDSLR equivalent of eevblog. Their search function is very good. I'd need to search my history there (jkirk@oz), which is a bit late for me to do right now - near 1am>Wytnucls : this isn't a "jumping to conclusions" issue, it IS (WAS) well know.

author: Wytnucls
author_rank: Super Contributor
timestamp: September 18, 2015, 02:43:03 pm
content: What is the current draw then?

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: September 18, 2015, 02:47:34 pm
content: @wytnucis I'm just late to the party. There was a BIG party.@digsys I'll have a look, thanks for the pointer. I'm down for an integrated hardware mod solution.

author: digsys
author_rank: Unknown
timestamp: September 18, 2015, 02:55:26 pm
content: Quote from: WytnuclsLOL .. whatever. :-)It was a minor firmware / hardware design flaw, a well documented issue. Yes, I spent years dis-assembling, reverse engineering several DSLRs and added aK100D page on my repair / assist pages on 15 DEc 2006.www.digsys.com.au/s602/s602.html... eep been that long.So, if you're interested, go do some reading, I'm not into nerd fights :-)Edit: OOPS, just checked, all my K100D pages are missing. I'll have to fix that.

author: KL27x
author_rank: Super Contributor
timestamp: September 19, 2015, 04:48:53 am
content: QuoteYou can buy 14500 li ion cells (AA size). Full 3.7V output. You would need fine wire to solder them in parallel and then cover the contacts on one of the cells. That would give you the equivalent of ~1.85V on a fresh charge and 1.45V when dead. Heck, just one of them might give you an increase. Put a dummy "cell" in the other slot.

author: marshallh
author_rank: Unknown
timestamp: September 19, 2015, 04:56:45 am
content: I have a similar problem with my thermal camera. The solution is to get a set of Eneloop Pros, and a suitable per-cell chargerhttp://www.amazon.com/Ambient-Weather-BC-2000-Intelligent-Rechargeable/dp/B00LUZHL4C/ref=sr_1_1?ie=UTF8&qid=1442638579&sr=8-1&keywords=ambient+battery+charger

author: ginbot86
author_rank: Contributor
timestamp: September 20, 2015, 09:22:35 am
content: For anyone who hasn't seen my performance analysis of that Kentli AA battery (here), its capacity isn't very good, even at low loads. I got a maximum of 1700 mAh at 250 mA, and only got 1200 mAh at 2 amps. At least the voltage remains steady until the very end of the discharge curve.But hey, at least the DC-DC in the Kentli can actually supply a fair amount of current, considering that the Batteriser likely won't be able to supply more than a few hundred milliamps with a relatively fresh battery...