Hi all,
I was wondering if anyone could recommend a brand of rechargeable 9V lithium batteries. The old MaximalPower batteries aren’t available any more on amazon. I had bought another brand but they were a tad off spec and just a little bit too big to fit in the compartment of the A9. So I was hoping someone had tried another available brand which did fit, and were rechargeable lithiums.
Thanks!
They seem to be available still:
Though the top is Green instead of the old Red.
Great you found it! Thanks much!
The manufacturer specs change so rapidly and frequently that we can’t find a stable product to recommend, but most of the recent ones seem to fit the current A9 design.
The problem is that the standard for 9V batteries allows a +/- 1.0 mm dimension anywhere except the spacing between the electrical terminals. That means the dimensions can vary by so much that mechanically it is very difficult to design a battery compartment that is large enough for the largest ones but small enough to securely hold the smallest ones. But I think my most recent design update for the A9 case (in early 2018) fits all 9V batteries that adhere to the standard.
I’ve been using EBL 6F22 9V, 600 mAh batteries with Maximal Power 2-Bay 9 V, Lipo Battery Charger for 2 or 3 years. These batteries still power the A9b with 4 coils for close to 8 hours and with 2 coils for well over 8 hours. Be careful with the charger you get; some of them have a high failure rate.
/Jon
I have older A9s and the EBLs i bought back then were a tiny bit too big. Maybe they’ve changed them since. Or Bob’s tweaks to the battery bay of 2018 vintage A9s can now fit EBLs…
I bought my batteries with the EBL charger 2/5/17. The EBL charger was junk and burned out after a few uses. I bought MaximalPower charger 2/16/17 and it’s been working ever since. My A9b was probably around January 2017,
I use these, I think I had one go out on me. Very reliable.
@Bob
I’ve been using these batteries (EBL 6F22) steadily for over 5 years and they’ve been rock solid; probably something over 1,000 recharges. They seem to be not holding a charge as long as when new so I’ve been looking at replacements, which brings me to my question for Bob. You suggest changing batteries frequently for best results, but these rechargeable Li-ion batteries only charge up to about 8.4 volts. Would a fresh rechargeable be like a not so fresh non rechargeable? Some of the rechargeable batteries boast that they maintain their voltage well until they get close to failure when they cut off all at once. Does that imply that there is no great advantage in changing before they go dead? They have some rechargeable Li-ion batteries now that are the full 9 volts. I notice that the AC adapter that comes with the A9 charges at 9.3 volts which makes me think that a battery that charges at 9.3 volts might be better than one that charges at 8.4 volts. These new full 9 V. batteries charge with a USB cable that plugs directly in to the battery. Unfortunately they don’t seem to be ready for prime time. They have reliability problems and have a good chance of being to large to fit into the A9. Also, for those of us who care, they seem to put out dirty electricity/ high frequency transients/ white noise. Without checking this out I would not want one of these batteries strapped to my body 24 hours a day.
/Jon
Batteries are very complex chemical reactors, and the voltages they produce are based on the voltages developed by very old (obsolete) chemistry. It really does not make sense to fall down the rabbit hole of a technical discussion about batteries unless you are an engineer or scientist who studies batteries. Here is what you need to know:
1- I studied batteries in great technical detail and designed our ICES-PEMF systems to use them properly.
2- Use Li-polymer rechargeable batteries as we advise.
3- For best device performance, change batteries often (about every 2 to 3 hours), and keep them charged when not in use. There are many technical reasons for doing this, so I advise you take my advice. Like a car, if the manufacturer tells you to put a certain type of fuel or oil in it, I advise you do what they advise unless you are very well informed and have a very good reason to do otherwise.
Just to add a bit more context:
I did some battery research at U-Michigan back in the day for DARPA (not my project, was helping a colleague), and I also did a lot of testing of batteries for ICES PEMF products. I could easily buy a house for the amount I spent on this testing, which involved:
Continuous testing for about 5 years
Testing all relevant battery chemistries at the time (NiMH, Li-Po, Li-Ion, Alkaline)
Testing all relevant battery sizes and configurations,
Testing discharge voltage and series impedance (ability to deliver power)
Continuously for each discharge cycle
Under a range of loading conditions to simulate all possible system loads for ICES-PEMF devices
So, I tested well over a thousand batteries, each for many recharge cycles (when rechargeable)
It was a massive task, at great personal cost and effort, that took half a decade.
So, I feel I can say, with sincere humility but firm confidence that I know a bit about batteries.
The first thing I can tell you is that you can’t say much about a battery by taking a single voltage measurement on a few batteries. Batteries are too variable in their manufacture, they change with use, abuse, loading conditions, recharge cycles, and other factors.
So, I graphed all of this out, wrestled with the data for a year or so, and developed several designs, which I tested extensively to optimize their use of batteries. I selected a small number of battery forms that would achieve the primary design objectives: biologically active ICES-PEMF that was ultra-portable.
Most of the behavior of the selected battery types is baked into my system designs for the M1 and A9. That is, a big part of the hardware and firmware design is specifically to optimize for battery performance. And it works; I tested it, I measured it, and I can prove it. ICES-PEMF devices will run at least twice as long on the batteries for which they were designed than any other similarly designed knock-off PEMF system. For almost all of the PEMF systems that pirate my technology, they change the circuit a bit to save a few pennies, but then they lose this aspect of the design. So, their pirated system will:
(1) drain the battery about twice as fast, or
(2) run longer if they do not bother to actually energize the coils (a sham system)
The newest 9V Li-Po batteries, the ones that are USB chargeable and claim to be “real 9V” have internal voltage boost which generates a less clean voltage than a simple battery, but in that case the voltage output is limited to fixed values by the battery chemistry, for example, about 8.4 volts for Li-Polymer.
The ICES-PEMF battery management strategy will handle this type of battery well, and it will also minimize the amount of “dirty” voltage you get from this type of battery in two ways.
First, the internal voltage regulation and charge storage will smooth those ripples out so that they do not get sent to the ICES-PEMF coils.
Second, the bursts of “dirty” voltage from those batteries are minimized by the way that energy is drawn from those batteries.
So, you can rest assured that I put a great deal of thought into battery management, optimization, and use for ICES-PEMF systems. My advice is that you will get the best overall performance if you follow my simple recommendations for charging and swapping batteries. The complex stuff is all baked into the internal hardware and firmware.
gotta say… anyone that spends this amount of time, effort, and money into such details is truly working from a passion for the work, tech, and or cause.
thanks for filling in the blanks that we as outsiders don’t get to see in the elements and the making of “an overnight success.”
I don’t know about other (normal) people, but I seem to get a lot of crappy products. My wife estimates that I need to fix/modify about 80% of the products we buy just to make them work properly.
For example, two days ago I had to fix the design for the little plastic feet on our new kitchen chairs, which are modern-looking and made from welded tapered steel tubing. But the little plastic feet broke off within a few months, so the chairs became unusable because they gouge our hardwood floor.
So, a lot of people my wife knows have these chairs. They are very good at first, for a few months. But when the plastic feet break off, they become frustratingly useless. So my wife and all her friends took to putting plastic water bottle caps beneath each foot of each chair. These never stay in place, and it was really starting to irritate me.
So, I re-designed the feet using a good design and the correct material for that application. They look great, slide well on hardwood, are very strong, and will last for decades.
I usually end up having to fix most products to get them to work properly.
I hate that I can’t just buy something that works. I do not mind spending the money to have well-designed objects, but you almost can never find them.
My point: ICES-PEMF is designed to work as well as possible. I put an enormous amount of work into every aspect of it, probably hundreds or thousands of times more effort into each detail than would normally be appreciated. The systems are not perfect, but it is not from lack of effort.
Hi Bob or anyone else who might be able to answer,
Are these batteries ok for the A9? I can’t find lithium polymer… these seem to be lithium ion. Or if anyone has a specific place where I can purchase a lithium polymer rechargeable battery ??
Thank you so much for the help.
They should be fine as long as they are rechargeable 9 volt batteries.
https://www.amazon.com/gp/product/B09NZTMQYL
These 9V USB-C charging batteries do not fit in the A9 (too large).
NOT a complaint against the A9, just wanted others to be aware so they don’t waste money on something that won’t work in their device.
Had hope since the regular MaximalPower 9V do fit.
I am finding lately that more and more rechargeable 9V batteries are not fitting the A9, and in many cases they do not fit any of my equipment that used 9V batteries, such as volt meters, smoke detectors, remote control, etc. Lately this always seems to be batteries that advertise “1300 mAh” or more.
So last week I decided to test some of these newer 9V batteries that advertise large energy capacity. I have tested a few of these and none of them come even close to 1300 mAh capacity. Most were only about 650-750 mAh.
One brand was so bad that I wrote a scathing review on amazon:
Reviewed in the United States on June 6, 2024
Size: 8 PacksVerified Purchase
I do a lot of battery testing for use in various products. I have tested pretty much all available brands of lithium-polymer USB rechargeable batteries currently available on amazon. I bought a pack of 8 of these about 2 months ago and tested them.
Results:
2 of 8 failed to work right out of the box
6 of 8 did take a charge the first time
When used in a device, all 6 lasted much less time that older 9V Li-Po batteries that were rated only at 650 mAh. I conclude that the real capacity of these batteries is more like 350-450 mAh, not 1300 mAh as advertised.
Upon recharging, additional batteries began to fail.
After only 4 recharge cycles, all but 2 of the original 8 batteries have failed and will not take a charge, and will not deliver usable power.
Here is the actual battery on amazon that I wrote this review for:
Here is the problem:
People always search for the maximum energy capacity to select a battery, but most people do not know how to actually test batteries, so they just believe what is printed on the label. Then they buy the largest number they see printed because they don’t want to change batteries frequently.
But here is the problem:
There is an industry standard (ANSI 1604) that defines the maximum and minimum outer dimensions for “9 Volt Transistor Batteries”. If you build a battery right to the maximum dimensions, then that’s it. Using a certain battery chemistry (such as lithium polymer) you just can’t cram in any more. So, in the quest for customers, battery companies can only do one of two things:
1- Make the batteries bigger, thus more volume, thus more chemicals to react, thus more energy. In this case batteries no longer fit into any device designed for ANSI 1604-compliant batteries.
or
2- Lie. They can print any number on the label that they want to. After all, who is going to check? Well, actually I will check.
The worst thing is that many battery companies now do both #1 and #2 above.
I have tested hundreds of batteries. Here is the truth:
All 9V rechargeable lithium batteries have about the same energy density. It is always about 650 to 750 mAh. The Li-Po batteries that do not have internal charging circuits may have a bit more energy because they do not have a charge control circuit built in, so they have a bit more internal volume for the actual battery chemicals. They are still only around 700 to 750 mAh.
That’s it. That’s the limit. You can’t pour two gallons of milk into a 1 gallon jug, and you can’t cram more battery chemicals into a volume that is already at its maximum constrained dimensions, no matter what they print on the label.
But here is the good part: if you buy a 9V battery that is honestly advertised to deliver 650 to maybe 750 mAh, it tends to be properly sized to fit into devices (including our ICES-PEMF A9 and P9 products). And generally I find that these batteries actually tend to last longer than over-sized 9V batteries with wildly false claims printed on them.
But, keep in mind, all batteries are actually fairly crude chemical reactors, and battery performance varies a lot, even within a single manufacturing batch.
Here is my advice:
1- Abandon the quest for a forever battery. Buy one that is labeled honestly, definitely less than 1000 mAh.
2- Change the battery about every 3 hours. This will give you the best performance from your ICES-PEMF devices.
For people in Europe, these seem to be working well (Amazon link): * 9V Blockbatterie Akku, Keenstone 3 Stück 800mAh Wiederaufladbare Lithium Akku, USB Ladekabel - sold and shipped my Amazon itself. Is for me a hint, that they take the business risk and its not total crap.
Current status: 10h at Omni 8, intensity 10 and still running (with snapping sound of the coils like a new battery) with my P9. The whole package looks fine and they fit “snugly” into the P9.
And for folks in the states, these are still my go to for the P9:
4 pack: https://www.amazon.com/EBL-Rechargeable-Batteries-Lithium-4-Packs/dp/B097RNN9L7/
4 pack with charger: https://www.amazon.com/EBL-Batteries-Rechargeable-Battery-Charger/dp/B00HV4KFSA/