Need input on true 9v rechargeable batteries

[BC1969]

So I've exhausted the search function for rechargeable true 9 volt batteries, and there does not seem to be any current topics. using google yields mixed results. So can anybody recommend what is the best true 9 volt rechargeable battery ?
my new/used cz3d takes 9 volts and well rechargeable seems the way to go, providing they are true 9 volts.
also looking for a top notch charger.

Mike

 

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[mikeraydj]

I use tenergy 9 volts in my F5. They work great. They are 250 ma. They are the exact size of a alkaline which is important for my F5 because the battery compartment is a tight fit. I use the smart charger which charges them in 2 hours from a completely drained state. You can find them on Ebay.
TN141 2 Bay 9V Charger 4pcs 9V NiMH 250mAh Batteries | eBay

 

[Moresound]

I usta use rechargeable 9volts to power wireless microphones but they don't keep their charge for very long compared to regular 9volts.

 

[CaptEsteban]

I use Tenergy as well , but their " Premium " batteries. I use these in CZ's , Tesoros, & Fisher F2's , pinpointers, & other items.

 

[BC1969]

Thanks for the replies/info, I really appreciate it.

Mike

 

[Frankn]

You don't want NiMH batteries unless you use them right after you charge them. They bleed off the charge in a short time. Li batteries hold there charge for a year. I don't know who makes 9v Li batteries! If any one knows, please post it. Frank

 

[BC1969]

I found them Frank, in lithium ion, and lithium polymer.
Li-Ion 9V 500mAh (4.5Wh) Rechargeable Battery

iPower PRO 9V Battery Rechargeable Lithium Polymer Battery IP9V520 520mAh

those lithium polymer sound perfect..price though..sheesh

Mike

 

[mikeraydj]

I have used mine for a week no problem. If my detector sets for a year something is wrong. I guess that would come in handy for the zombie apocalypse.

 

[BigDawg30701]

These guys are working out great for me in my Teknetics Delta 4000 and Omega 8000, and also in my Deteknix X-Pointer.

EBL® 855 4 Bay 9V Li-ion Battery Charger with 4 Pack 600mAh 9V 6F22 Low Self-Discharge Lithium-ion Rechargeable Batteries

Purchased on Amazon for $25.99.

I get several detecting trips on each battery prior to recharging.

 

[Professor of Engineering]

Hello BigDawg30701,

Thank you for the information.

Regards,

 

[CincinnatiKid]

I prefer conventional batteries. Unless new, my experience has been that, rechargeables lose juice much faster?
I only keep rechargeables as backups to backups.
GL
Peace ✌

 

[texasred777]

Mike, I don't want to lead you down the wrong path, but I've been using EBL 9 volt Li-ion batteries for some time now. I've had fabulous luck with them. I bought a 4 pack, with EBL charger for almost chump change on Ebay. I liked them so much, I bought an extra 4 pack. I also use the same brand AAs and am charging them with just whatever charger I am using at the time. I've had great performance from the EBL brand. I have 4 Bounty Hunter detectors that use 2 nine volt batteries each. I haven't used the detectors much, but I've used these 9 volts in a variety of different electronics with great success. I have bought several different brands of 9 volts, but nothing has compared with these.
Oh, also, they are 600 mAh! If you happen to try them, let everybody know how they work for you.

 

[BigDawg30701]

I agree with CK that rechargeable Ni-MH batteries lost charge fairly fast. Not the case with Lithium Ion. My Teknetics Delta 4000 and Omega 8000 will last through several hours (20+) of detecting before losing their ability to operate the machine. That is one 9V per machine. Cannot state how many times they will take a full charge, as I have only had these for a few months.

 

[Clay Slayer]

I'm doing a test right now...

I came across this post at a good time. I'm actually running a comparison test on a PowerEx NiMH rechargeable 9.6V versus an off-the-shelf Duracell Duralock alkaline.

A couple of things before I go any further...

Not all 9V batteries are exactly the same physical size, the industry has a set of guidelines for sizing and there is a millimeter or so of tolerance on the min and max measurements. Rechargeable 9V batteries, more often then not, are slightly wider, thicker, longer, or a combination of those...it's just the nature of their design. Usually, it's only a millimeter or so, but when your detector has a very tight battery compartment, like my Tesoro µMax, then it makes a difference. I originally was going to test the EBL 840 9V Li-ion, but I couldn't close the battery cover properly, so I returned them, did a little sizing research and tracked down the PowerEx...this particular battery is exactly the same size as off-the-shelf alkalines.

9 volts does not always mean 9 volts. A typical off-the-shelf alkaline battery is made up of 6 individual 1.5V cells arranged in series to give you 9V(about 9.5V fully charged). Rechargeable batteries use 1.2V cells and rechargeable batteries generally come with stacks of six, seven, or eight 1.2V cells. This would make your actual fully charged voltages 7.2V, 8.4V or 9.6V (actually a little higher, but for a brief period of time).

99% of the time you see an advertisement for a 9V rechargeable battery; it will be the 8.4V flavor with seven cells. If a company is selling a 9.6V rechargeable battery, they will definitely state that fact, because it will be more expensive since they have to squeeze in that eighth 1.2V cell to get the 9.6V rating. And for the most part smaller cells mean higher quality cells and higher quality cells mean more expensive cells. Also note that a fully charged 9.6V battery actually has a charge of a little over 11V. But this voltage will quickly drop to a 10V range where it truly begins to operate at a solid voltage level.

Anyway, on to my testing. My background is electronics and control systems...PLCs, RTUs, flow computers, etc. Stuff used for personnel safety systems, gas measurement, oil & gas refining. This allowed me to setup a bench test for testing 9V batteries under different conditions fairly easily. Of course, all of this is done during my lunch breaks. I just enjoy tinkering with that kind of stuff.

I programmed a small PLC to run a duty cycle to apply and remove a load to the battery. This is done through an external relay attached to one of the PLCs discrete outputs. Right now I have the program set to a one hour duty cycle, in other words the battery is under load for one hour then is unloaded for one hour. This on/off cycle continues all day and night. I am constantly monitoring the batteries current draw and voltage and trending this data (5 second sample rate). The test will automatically stop when the battery voltage drops to 7.5V for a period of ten seconds or more. 7.5V is about as low as I would like to go and a drop in performance will start to become noticeable on some 9V systems below this level. Also, the reason I'm repeatedly starting and stopping the load test is to try and simulate turning the power system on and off as you would probably do during normal short hunts. Good thing about using a program is that I can change this length of time to any value I like to simulate different usage patterns.


As for the battery load I'm using, I was originally going to go with a simple static resistive load. But I decided against that route since it wouldn't be a very accurate test of the batteries performance because if the load resistance remained constant, then the current value would have to drop to compensate for the lowering battery voltage (Ohm's Law). Instead I went with current regulative diode (CRD). This cool little transistor will maintain a constant current load on the battery even as the battery voltage starts to drop. The setup I'm using in this test is 24mA constant current draw. This will remain stable anywhere between 5V and 12V...plenty of range for its use here. If you notice 2 diodes in the picture on the breadboard, that's because I'm using two 12mA CRDs in parallel to get my 24mA, but it serves the same purpose.

This is my little setup...yes I know it's messy, Ha! Left to right is the PLC (AB Micro1100), analog input module, two configurable isolators. One allows me to convert the battery voltage 0-12V range to a 4-20mA signal that my input module prefers. The second isolator converts the 0-50mA battery current range to 4-20mA signal. Next are a few terminal blocks and fuse holders for wiring things up and then a couple of 24V relays, one being used to make and break the actual battery circuit. Finally a power supply on the end. All of this hardware I already have in my office and use for other work-related testing.





I'm going to explain what's happening in a simple manner. Current flows from the positive terminal of the battery through the two diodes on the breadboard then to the common contact on the relay. When the relay energizes, the relay contact will close allowing the current to continue to the input of one of the isolators where it is calibrated to an analog signal that the PLC can read. In the picture you see the little green light on the relay indicating that it is energized and the battery is loaded. Now the 4-20mA current signal leaves the isolator and is terminated on the analog input module (where the two white wires disappear under the flip cover). There is another red wire coming off the breadboard on the left side that goes to one of the termination blocks. This is the battery voltage reading that then gets conditioned by the other isolator and changes from a voltage reading to a current reading that the PLC is happy with. The two black wires coming off of the analog module are the signal-return or "common" wires that allows the current to return back to the negative terminal of the battery(via the green jumper). And that completes the test circuit.

Here is a screenshot of the program I'm using to view what's going on in the PLC program; it's called an HMI interface. It allows me to see the data change in real-time, allows me to trend and print the accumulated data and allows me to stop and start the program at will using the pushbuttons on the screen. The red pen at the top shows the battery voltage values and the blue pen at the bottom shows the current load across the battery. You can see a 24mA load is applied for one hour and then removed for one hour again and again. You can also see how the red pen (battery voltage) has a corresponding dip in voltage when the load is applied and how it recovers when the load is removed.



So anyway, there it is. I'm going to run the load test all day and night on the rechargeable battery till it drops to 7.5V and then it will shut off the program automatically. I'll do the same on the alkaline battery and then we will have some useful comparison data. I'll probably update my finding in a few days. I just started the test on the first battery a few hours ago, as you can see from the screenshot, and from the look of it, it will probably last a couple of days before the test stops. Sorry for the long post, but I figured there might be a few people out there who also find this interesting. HH!

PS -

My pictures seem to come out as thumbnails that you have to click on to get the full resolution. If someone wants to enlarge the pictures to full resolution so there is no need to click on them, feel free. Thanks!

 

[BigDawg30701]

Nice test jig! You must get longer lunch hours than I do!!

The first pair of 9V Lithium Ions I purchased from Amazon were these in early 2013: Maximal Power Combo 9V MaximalPower 9V Battery and Charger Pack of 2 9V li-ion Rechargebale Batteries

I agree that the EBLs are a bit bulky and could be a problem in a tight battery compartment. The Maximals are rated at 500mAH and are about the same, if not a bit smaller, than a conventional 9V. You may want to see if this brand is still available on Amazon. Mine are still going strong and getting close to a year in service.

Good luck with your testing. I'm interested to see your results.

 

[Clay Slayer]

Tested a couple of batteries...

I tested my first two batteries these past couple of days. Short version is this -

The rechargeable 9.6V NiMH battery maintained a minimum of 9 volts through all of it's 10 one-hour cycles...then immediately dropped below 7.5 halfway through the 11th cycle and rapidly discharged.

The Duracell alkaline dropped below 9 volts on it's first cycle then only recovered to 9 volts one time. After that it operated between 8.75V and 7.5V through 12 of it's one-hour cycles, gradually decreasing voltage after each cycle.

So basically, it depends on what the user is looking for in a battery. If you want to maintain a true 9 volts for a moderate amount of time...again, again & again then a rechargeable 9.6V NiMH might work for you. If you want a longer battery life, and an 8 volt range is fine with you and your equipment, then an alkaline may be the way to go.

IMPORTANT NOTE - The 9.6V NiMH battery does charge up to a little over 11 volts. But this value is right off the charger and the voltage level drops about a volt very quickly before it stabilizes. I personally don't see this small over voltage as an issue, but someone else might. Just an FYI...

9.6V NiMH

Average Voltage - 9.875V for 638 of 648 minutes(about 10 3/4 hours) that the circuit was loaded. The voltage dropped from 9 volts to 7.5 volts in only 10 minutes at the end.

9V Alkaline

Average Voltage - 8.25V for 760 minutes(about 12 and 2/3 hours) that the circuit was loaded. Voltage drop was consistent across entire test and there was no sharp drop off in voltage at the end.


This first trend is a Powerex IMEDION 9.6V 230mAh NiMH battery(MHR9VI). Cost is $10 - $15 bucks apiece.






This second trend is a Duracell DURALOCK 9V 580mAh alkaline battery(9V-6LR61). Cost varies greatly, cheapest I found was $16 bucks for a 12-pack + shipping(Amazon).




HH!

 

[BigDawg30701]

Good test. Would like to see another comparison with the Lithium Ion.

The over voltage should not be an issue at all, as most electronic devices have a tolerance of 20% above the stated voltage requirement. And, as you stated, the peak voltage quickly drops down once a load is applied.

Good stuff!

 

[Clay Slayer]

BigDawg, I ordered a couple of the of the MaximalPower Li-ion batteries you mentioned in your earlier post. They have double the Ah rating as the NiMH I just tested, but are 8.4V instead of 9.6V. Testing that battery should give a much truer comparison with the 9V alkaline. I'll probably run that test next week.

 

[BigDawg30701]

Cool! Good batteries IMO.

 

[rwd mo]

Don't u have to have a battery charger that charges Li-ion batteries rather than a bat.charger that just charges reg chargeables ? shortribs rwd mo