Seeking suitable rechargeable batteries for the EEVblog BM235 - Page 1
Forum section: electronics / beginners

author: DustinWright
author_rank: Newbie
timestamp: November 22, 2020, 05:01:05 am
content: Hello all.My EEVblog BM235 arrived today. I would like to get rechargeable AAA batteries for it. The manual calls out 1.5-volt cells. I'm having a tough time finding anything other than 1.2-volt rechargeable AAA cells. Can anyone point me to a suitable battery?Thanks all!

author: drvtech
author_rank: Regular Contributor
timestamp: November 23, 2020, 09:52:50 pm
content: The most common rechargeable cells are NiMH or NiCd and these have a terminal voltage of 1.2. I don't think there is a rechargeable cell with a voltage of 1.5. If you use 1.2 volt cells then they'll still work but the battery low indication will be inaccurate. I haven't got a BM235 so I don't know whether it will be on all the time or just come on early - room for experiment there!

author: GLouie
author_rank: Regular Contributor
timestamp: November 24, 2020, 04:25:59 pm
content: I've been using Eneloop NiMH AAA in my BM235 with no problems. I do tend to refresh the batteries when I think about it, maybe every several months. I never see the "low batt" sign, even with the backlight on.I feel strongly about not using alkaline batteries if at all possible, due to leakage.

author: wraper
author_rank: Unknown
timestamp: November 24, 2020, 04:36:31 pm
content: Freshly recharged NiMH cell has about 1.45V voltage. After some time it drops to about 1.35-1.4V. Usually there is no problem using them, the only issue might be that battery indication works incorrectly. However if its only a battery low indication, it will work properly. It's best to get low self discharge cells, such as eneloop or white IKEA LADDA which is eneloop with a different print on it's shell. Especially if you don't use multimeter constantly, since usual NiMH cells will completely discharge by themselves in 6 months or so.

author: Simon
author_rank: Unknown
timestamp: November 24, 2020, 04:54:50 pm
content: I wonder if it would cope with the 3.7V of a lithium or would that be 4.2V when fresh?

author: David Hess
author_rank: Super Contributor
timestamp: November 27, 2020, 04:09:19 pm
content: If you want a reliable (no leaks) replacement for alkaline cells, then I suggest lithium cells:https://www.amazon.com/Size-NiZn-900mWh-Rechargeable-Battery/dp/B00W1GDNZKThere are also rechargeable 1.5 volt cells like these but ... yeah:https://www.amazon.com/Lithium-Rechargeable-Batteries-Charging-400mAh/dp/B07WYRVDFJ/Quote from: drvtech on November 23, 2020, 09:52:50 pmRechargeable alkaline cells are 1.5 volts but I do not recommend them. Uncommon nickel–zinc rechargeable cells are 1.6 volts but I have no experience with them:https://www.amazon.com/Size-NiZn-900mWh-Rechargeable-Battery/dp/B00W1GDNZK

author: wraper
author_rank: Unknown
timestamp: November 27, 2020, 04:25:04 pm
content: Quote from: David Hess on November 27, 2020, 04:09:19 pmWhat's the point when you can buy pre-charged LSD NiMH of the same capacity for less? And you don't need to throw them away when empty. NiMh has flatter discharge curve than alkaline. So generally lower initial voltage is not a problem, as past about 50% discharge NiMh actually has higher voltage than alkaline.QuoteFully charged they go up to about 1.8V, so may potentially damage the device. And you need a specialized charger which supports them. BTW they sneakily replaced mAh with mWh to look better than they are.

author: David Hess
author_rank: Super Contributor
timestamp: November 27, 2020, 04:54:47 pm
content: Quote from: wraper on November 27, 2020, 04:25:04 pmLow self discharge NiMH cells would be my first choice but the question was about 1.5 volt cells.Currently I use low self discharge NiMH cells for my camera, GPS, and calculator. All of my multimeters take 9V batteries and I am dubious about all NiMH 9V cells whether low self discharge or not; maybe I should try rechargeable lithium 9V batteries. I used to use them for my wireless mouse and keyboard but have gone back to a wired mouse and wired keyboard.

author: ejeffrey
author_rank: Super Contributor
timestamp: November 27, 2020, 10:08:06 pm
content: The BM235 works fine with low discharge NiMH. In fact I have never run across any device that takes AA/AAA and won't work fine with NiMH although I have heard that there are some poorly designed devices that do not function well with them. As mentioned, battery gauges and low battery indicators may not read correctly.

author: james_s
author_rank: Super Contributor
timestamp: November 27, 2020, 10:22:15 pm
content: 1.5V is the nominal voltage for alkaline and 1.2V is the nominal voltage for nickel based cells, this is determined by chemistry and there is nothing anyone can do to change it. Fully charged NiMH are closer to 1.5V dipping below 1.2V only when they are almost completely drained. Fresh alkaline can be over 1.6V and will drop down to under 1V when close to drained. The important aspect is that 1.2V NiMH cells will work perfectly fine in almost every application designed for 1.5V alkaline cells. This is especially true for something that uses only a few cells. When you get up to 6+ cells then the difference in voltage between the two chemistries starts to become more significant.Pick up some Eneloop NiMH cells, they'll work just fine and will last many years.

author: FriedMule
author_rank: Frequent Contributor
timestamp: November 28, 2020, 02:40:38 am
content: Sorry to say but eneloop is no longer of the same quality they used to be! I have always bought eneloop and did swear to them, but in the last years are they gotten awful! If you want the same quality as eneloop once was, then buy the IKEA LADDA, they are still produced like the old eneloop was.

author: james_s
author_rank: Super Contributor
timestamp: November 28, 2020, 02:43:53 am
content: That's unfortunate, I have not bought any in several years. Mine were all made in Japan, are they selling Chinese cells under the Eneloop brand now?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 28, 2020, 04:44:40 am
content: A note, choose low self-discharge types (Panasonic Eneloop, Tenergy Centura..), lest it leak away in mere months.These are what I use and I go, I don't even remember, maybe months of frequent use, maybe years, between charges?Tim

author: Simon
author_rank: Unknown
timestamp: November 28, 2020, 07:41:18 am
content: Do multimeters need rechargeable's? I suppose if it's on all day good idea. I don't use mine enough to bother. But any decent device should be designed to work down to 1V per cell which is what made the whole batteroo thing mute.

author: james_s
author_rank: Super Contributor
timestamp: November 28, 2020, 08:07:03 am
content: I use rechargeables in everything because alkaline batteries leak. Also my 87-III has a backlit display so with the rechargeable battery I can just use it all I want and not worry about draining batteries.

author: David Hess
author_rank: Super Contributor
timestamp: November 29, 2020, 09:19:47 pm
content: Quote from: FriedMule on November 28, 2020, 02:40:38 amThere are several generations of Eneloop brand cells with different characteristics.