9V Recommendations

[Mr. Glass]

Hello All,

I have a device that is used in the treatment of ADHD and runs on 9V batteries or a wall charger. It is a small box about the size of a cellphone and has two leads that vibrate (with an intensity also similar to a cellphone).

I will go through an alkaline 9V battery after about 6-8 hours of use and the cost has been adding up.

With extremely helpful recommendations here on CPF, I recently purchased a TK-40, some Eneloops and a nice Maha charger.

What would you guys recommend for a high quality make of 9V and a good charger to go with them (that can preferably charge 2 9V's at a time)?

Thanks!

-Glass

 

[Billy Berue]

Although there are a couple Li-Ion 9V replacements, I have no personal experience with them. However, I have used quite a few NiMH 9V's and can recommend a couple different models. You should be aware of a few things with using NiMH 9V's. First, they typically have considerably lower capacity than their alkaline counterparts. Capacities in the 250-300 mAH range are typical with NiMH. Second, similar to their alkaline counterparts, they are made of a number of individual, smaller cells that are connected in series configuration within the battery. Because NiMH cells have a nominal voltage of 1.2v, it is not possible to produce a true 9.0 volt battery in this manner (because 9.0 is not evenly divisible by 1.2). Most of the 9V NiMH batteries are 8.4v nominal (i.e., made of 7 smaller cells in series), although there are a few out there that are 9.6v (i.e., made of 8 smaller cells in series). So make sure the device you are using them in will be tolerant of this voltage variance. Most devices will likely be compatible, but just be sure before you try it, particularly if you are going to try the 9.6v models--don't want to fry your device with over-voltage. The 8.4v models tend to have higher capacity, while the 9.6v models tend to have lower capacity. I have used the following with very good results:

Maha 300mAH (8.4v)

Maha 230mAH (9.6v)

Maha 9-volt NiMH charger (4 independent channels)

EDIT: One other thing to point out is that these cells do tend to suffer from fairly high self discharge, so you either need to use them very shortly after charging, or be prepared to recharge them fairly often.

 

[purduephotog]

Although there are a couple Li-Ion 9V replacements, I have no personal experience with them. However, I have used quite a few NiMH 9V's and can recommend a couple different models. You should be aware of a few things with using NiMH 9V's. First, they typically have considerably lower capacity than their alkaline counterparts. Capacities in the 250-300 mAH range are typical with NiMH. Second, similar to their alkaline counterparts, they are made of a number of individual, smaller cells that are connected in series configuration within the battery. Because NiMH cells have a nominal voltage of 1.2v, it is not possible to produce a true 9.0 volt battery in this manner (because 9.0 is not evenly divisible by 1.2). Most of the 9V NiMH batteries are 8.4v nominal (i.e., made of 7 smaller cells in series), although there are a few out there that are 9.6v (i.e., made of 8 smaller cells in series). So make sure the device you are using them in will be tolerant of this voltage variance. Most devices will likely be compatible, but just be sure before you try it, particularly if you are going to try the 9.6v models--don't want to fry your device with over-voltage. The 8.4v models tend to have higher capacity, while the 9.6v models tend to have lower capacity. I have used the following with very good results:

Maha 300mAH (8.4v)

Maha 230mAH (9.6v)

Maha 9-volt NiMH charger (4 independent channels)

EDIT: One other thing to point out is that these cells do tend to suffer from fairly high self discharge, so you either need to use them very shortly after charging, or be prepared to recharge them fairly often.

http://www.batteryspace.com/li-ion9v400mah36whrechargeablebattery.aspx

I own 4 of these. They've been working quite well in Smoke detectors / and meters- I pull them out of service every 6 months and recharge them with the recommended charger off the site- they've been holding up quite well.

Mind you, they've only been deep discharged on the meter (because I am not intelligent enough to turn it off) and it has recharged fine.

I do charge them over a concrete board... just in case.

 

[gramps416]

I am wondering how is the self discharge rate on those MAHA 8.4v cells. Are there low discharge versions of a 8.4v cell that may be better? I plan on using them in my stud finder. Where can low discharge versions be found at reputable online dealers? I have checked batteryjunction, batterystation and thomas distributing, not low self discharge!
-g

 

[TakeTheActive]

...I have a device that is used in the treatment of ADHD and runs on 9V batteries...

...I will go through an alkaline 9V battery after about 6-8 hours of use and the cost has been adding up...

...What would you guys recommend for a high quality make of 9V and a good charger to go with them (that can preferably charge 2 9V's at a time)?

...You should be aware of a few things with using NiMH 9V's:

1. First, they typically have considerably lower capacity than their alkaline counterparts. Capacities in the 250-300 mAH range are typical with NiMH.
   .
2. Second, similar to their alkaline counterparts, they are made of a number of individual, smaller cells that are connected in series configuration within the battery...

...I own 4 of these. They've been working quite well in Smoke detectors / and meters- I pull them out of service every 6 months and recharge them with the recommended charger off the site- they've been holding up quite well.

Mind you, they've only been deep discharged on the meter (because I am not intelligent enough to turn it off) and it has recharged fine...

IME (over a decade), Rechargeable 9V BATTERIES (i.e. a GROUP of cells connected in SERIES) are one *ROYAL* PITA! :toilet:

1. First of all, it's a SEALED PACK (with *NO* Balancing Taps), so DISCHARGING *AND* CHARGING require some finesse. :touche:
   .
2. Second, you have to be careful NOT to DISCHARGE any ONE cell below ~1.0VDC, but, since they're all SEALED INSIDE THE PACK *WITHOUT* Balancing Taps, you're working 'blind'. :tinfoil:
   .
3. Finally, you can't CHARGE at the recommended 0.5-1.0C for cells, so you're (kind of) forced to CHARGE at 0.1C TIMED for 16 hours to 'balance' everything out. :sleepy:

So, what's a poor soul to do? :shrug:​

My current thoughts are:

1. Buy a BATTERY that's definitely GREATER in CAPACITY than your needs. Not EXCESSIVELY greater, but, enough to avoid #2. If you buy one that's TOO big, you won't regularly exercise ALL of the chemicals and they'll "atrophy".
   .
2. *NEVER* DISCHARGE the battery below 1.0VDC per cell:
   • 7.0VDC for a 8.4VDC battery
   • 8.0VDC for a 9.6VDC battery
   .
3. Buy a 'dumb' 0.1C charger. For example:
   • 30mA for the Maha 300mAH (8.4v)
   • 23mA for the Maha 230mAH (9.6v)

This Maha 9-volt NiMH charger (4 independent channels), RAPID CHARGING @ 70-90mA sounds interesting (and CPF member Billy Berue sounds pleased), but how does it insure that *EACH* of the 7 or 8 cells is being properly charged? :thinking:

I've tried:

1. RadioShack 23-126 ??mAh NiCD:
   • Bought 4 on 09/03/97. Last one died a few months ago.
   • CAPACITY??? Slow Charge: 7mA 14Hrs; Fast Charge: 22mA 4Hrs
2. DieHard 150mAh NiMH:
   • Bought 4 on 12/xx/00. Lost #2 a few months ago, but *NOT* because it died, but because some GREEN CRAP ate away the rivet holding the NEGATIVE terminal. This also happened to #1! :shakehead #3 has one dead cell so it's down to 7.2VDC MAX and #4, I can't remember...
3. Varta 150mAh NiMH:
   • Bought 2 on 01/xx/03. BOTH died *WAY* TOO SOON! Last year, IIRC.

Currently, I'm "experimenting" with (~6-9 months):

1. Chicago Electric (aka Harbor Freight) 8.4VDC 100mAh NiCD
2. Chicago Electric (aka Harbor Freight) 8.4VDC 160mAh NiMH
3. Maha PowerEx 9.6VDC 230mAh NiMH

...so we'll see what happens.

My 9VDC Devices are:

• 1 Digital Bathroom Scale
• 2 X-10 Motion Sensors (Home Alarm)
• 2 X-10 Alarm Consoles (Backup when AC fails)
• 1 RadioShack AM/VHF Aircraft Radio

Before I became a DEDICATED CPF 'Batteries Included' Archive reader, I used to run all those devices until they stopped working . I don't think *ANY* of my 9VDC batteries ever reached 50 cycles, probably less than 30, some less than 15... :sigh:

Now, I know better .

Best of luck to you with whatever you decide to buy! *PLEASE* keep CPF informed of your results...

 

[moldyoldy]

you may want to check out this thread or similar threads:

http://www.candlepowerforums.com/vb/showthread.php?t=182226

Whether for church, school, or my collection of maybe a dozen smoke alarms and various gas detectors, the Maha 9.6v cells with the Maha MH-C490F 4 slot "smart/fast" charger have proven themselves to be consistent over the years. These cells last much longer than 6 months in gas/smoke detector usage. The normal time frame before the low-bat detector sounds is close to a year. I have had ample opportunity to verify that the low battery detector does still function correctly for a sufficiently long time period to hear it when I return to the house. and even when the low-battery beeper is going off, the alarm will still sense cooking smoke and sound the full alarm.

However, there have been battery and charger failures. Maybe 6 batteries have failed in 3-4 years with low capacity - worn out. A couple batteries seemed functional in alarms and wireless mikes, but multiple C490F chargers still gave a failure indication with those cells - recycled them. The mechanical design of the cell contact attachment leaves something to be desired when ham-handed users try to stuff them into a battery slot. The result is that one of the terminals breaks off the battery - unrepairable. We had a C490F charger fail after over 2+ years of constant use keeping 4 wireless mikes operational in the church. an IC fried. recycled.

 

[moldyoldy]

addendum:

Were the rechargeable 9.6 batteries worth the bother and cost of paying for rechargeable batteries and charger? For the church and school - absolutely worth it! For the gas/smoke detectors - still yes, even with low-current draw devices. Why? the house is in an older neighborhood with old buried 13800vac wiring in the neighborhood - thus leading to relatively frequent power outages. How often does the main electric power fail? about once a quarter, more often in the spring and fall when the ground can be soaked. The failure is usually because of a short in the high voltage bus underground next to the transformers sitting on the ground in someones yard. That usually means an electric outage of the rest of the day into late evening and maybe the next day. Stuffing a dozen or more new primary batteries into smoke alarms and gas detectors every time the AC power fails, or soon thereafter is a real pita! Now I just swap out and charge.

edit: I am impressed with the huge large-truck-mounted vacuum that can suck up the dirt in front of these transformers sitting on the ground. The underground wiring is far too dense to even think about digging with any sort of a metal object.

 

[gramps416]

by the way, what is the voltage of the 9.6 when fully charged???

 

[SilverFox]

Hello Gramps416,

Welcome to CPF.

The voltage for an 8 cell NiMh battery should be around 11.5 volts when fully charged.

Tom

 

[WDG]

FWIW, I've used the iPower 500mAh Li-Polymer 9v (8.4v) batteries and their four place charger since mid 2007. http://www.ipowerus.com/ They've held up very well in microphones, radios, shooting muffs and smoke detectors, and have excellent capacity and low self-discharge. I have not had one fail or go weak, to date.

I bought mine from Thomas Distributing: http://www.thomasdistributing.com/s...html?SP_id=&osCsid=vb6r7t3ncbalj5anl2ejtbfd94

They aren't cheap, so I probably would have gone with NiMh, had I not been wanting the higher capacity for mics, but I've been very pleased with them in all roles.

**A word about rechargeables in smoke detectors... It's possible for the rechargeables to die with insufficient warning, in part because the battery monitoring in them is designed for alkalines. There's a thread somewhere in this forum discussing this. For this reason, I charge these monthly. I would discourage using rechargeables in smoke detectors unless you're prepared to do this kind of regular maintenance.**

 

[Mr. Glass]

FWIW, I've used the iPower 500mAh Li-Polymer 9v (8.4v) batteries and their four place charger since mid 2007. http://www.ipowerus.com/ They've held up very well in microphones, radios, shooting muffs and smoke detectors, and have excellent capacity and low self-discharge. I have not had one fail or go weak, to date.

I really like the capacity of these batteries and will probably pick up two.

Can I use the Maha 9-volt NiMH chargerhttp://www.thomasdistributing.com/s...html?SP_id=&osCsid=a98rm8a91donrsllit8gi3gna7 to charge them?

-Glass

 

[Billy Berue]

Can I use the Maha 9-volt NiMH charger to charge [the iPower LiPo's]?

No, the Maha charger is dedicated for NiMH chemistry cells.

 

[WDG]

Can I use the Maha 9-volt NiMH charger to charge them?

Li-Poly requires its own charger, which Thomas Distributing also has available. It is switchable to also charge NiMh, but be sure it's set correctly when you put the Li-Poly batteries in it, else it could be a fire hazard.

 

[InHisName]

Another source for 9v LSD (8.4volt) batteries is from lowmarkup an ebay seller. He has an 800 number and sometimes speaks instead of voicemail 24/7. 200MAH LSD $14/2 incl shipping USA. The brand is NexCell EnergyON LSD.

 

[Planz]

I read a review recently in Amazon and that was about the voltage quoted.
11.5V seems way too high for a fluke digital multi meter, doesn't it?
Will it fry the meter?

Anybody who has design/experience with multi meter care to comment on whether 11.5V input will cause damage?
Thanks.

Hello Gramps416,

Welcome to CPF.

The voltage for an 8 cell NiMh battery should be around 11.5 volts when fully charged.

Tom

 

[Sub_Umbra]

Be aware that form factor creep can be a factor with some 9v NiMH secondaries. It has been reported in at least one old cpf thread that some of these batteries won't fit into the battery compartments of the devices that they were purchased for. I would get dimensions before I ordered.

 

[Planz]

Thanks. After some consideration, I have more or less given up on 9V NiMH as I could not get confirmation whether the 11V plus would damage my Fluke meter. It may work but there is a risk which I am not willing to take as the Fluke meter is very expansive.

Be aware that form factor creep can be a factor with some 9v NiMH secondaries. It has been reported in at least one old cpf thread that some of these batteries won't fit into the battery compartments of the devices that they were purchased for. I would get dimensions before I ordered.

 

[StorminMatt]

I have had good luck with Tenergy batteries. They make an 8.4 volt 9V battery which might work well for your application. It's available in both the high capacity Premium line and the low self discharge Centura line. You might even get both, depending on your needs. As far as the 8.4 volt output, I wouldn't sweat the voltage being lower than 9 volts. Remember that alkaline batteries are famous for both voltage sag under a load and voltage that drops with use. In other words, the 9 volt output of an alkaline battery is basically for a brand new battery with no load. For anything else, the voltage will be lower, and devices using 9V batteries are designed to account for this. 8.4 steady volts should be perfectly fine.

 

[Planz]

Thanks for sharing. Yes, I think the 7 cell 8.4V would do just fine for this particular application but I wanted to standardize only on the 9.6V so that I can use it across high drain equipment as well. My primary concern was leakage causing damage to the meter as I have many bad experiences with alkaline. I think I will just look for lithium primaries.

 

[StorminMatt]

I think I will just look for lithium primaries.

Compared to alkaline batteries, lithium primaries have a number of advantages. For instance, they don't leak, they have a flatter discharge curve, and don't sag as much under a load (among other things). However, at least in low drain applications (which most applications using a 9V battery ARE), they do NOT have a higher capacity than alkalines. So you will still have your current problem of quickly going through batteries and having to pay a fortune to replace them. Only with lithium promaries, you will be paying even more! I would SERIOUSLY try NiMH batteries before resorting to lithium primaries.