Topics

9 volt rechargeable


John - KK4ITX
 

I have all the Crickets, the Cricket-Key, The Muriana and the QRPoMeter....... and a host of other requirements for a 9 volt battery like test equipment....... I do need some money left over for retirement and other kits but the cost of these 9 volt guys are wrecking my IRA.

 I have looked at several rechargeable options but the full charge is only 8.4 volts max, so the question is...... what is the acceptable cutoff voltage for the devices listed above ?  Few specs give a operational voltage range.  My Yaesu FT-818 for instance cuts back on power output when my external battery nears 12.0 volts.  If my Crickets drop to 1/2 power I’ll be @ 3/8 of a watt...... I enjoy challenges but that’s really not much to work with on a regular basis.

Another issue might be with the physical size of the battery as some appear to be larger in length and thickness so some of the kits may have to be modified for the battery to fit ?

Any thoughts out there ?  Any experience with 9 volt rechargeables ?

Appreciate any help.

John
KK4ITX 


raoverton16
 

Have you thought about 12 volts portable with an adjustable down voltage regulator? That is what I use. 12 volt 8 amp hour sealed lead acid cell with an adjustable 5 amp "Buck" down converter. Works great for me! Hope this helps.
--
Bob Overton

WD5ILB


raoverton16
 

Oh yes, I forgot... Wire up a 9 volt battery plug in "reverse" and connect to component battery terminals.
--
Bob Overton
WD5ILB


Greg Troxel
 

"John - KK4ITX via groups.io" <jleahy00=yahoo.com@groups.io> writes:

I have all the Crickets, the Cricket-Key, The Muriana and the
QRPoMeter....... and a host of other requirements for a 9 volt battery
like test equipment....... I do need some money left over for
retirement and other kits but the cost of these 9 volt guys are
wrecking my IRA.

I have looked at several rechargeable options but the full charge is
only 8.4 volts max, so the question is...... what is the acceptable
cutoff voltage for the devices listed above ?  Few specs give a
operational voltage range.  My Yaesu FT-818 for instance cuts back on
power output when my external battery nears 12.0 volts.  If my
Crickets drop to 1/2 power I’ll be @ 3/8 of a watt...... I enjoy
challenges but that’s really not much to work with on a regular basis.

Another issue might be with the physical size of the battery as some
appear to be larger in length and thickness so some of the kits may
have to be modified for the battery to fit ?

Any thoughts out there ?  Any experience with 9 volt rechargeables ?
I have had mixed experiences. I got two Imedion rechargeables and the
Maha charger. I am 98% sure these were 9.6V nomimal batteries, with 8
cells, vs the 7 cell 8.4V nominal. My general impression is that
8-cell batteries are preferred.

With so many cells in parallel, they seem prone to damage from a
reversed cell. One of my two batteries seemed to have a slightly weak
cell to start with, and now, maybe 6 yaers later, the other seems
troubled. Compared to AA cells, with which I've had great experiences,
I wasn't really happy with them. But, the basic issue is that the 9V
battery is a very difficult form factor.

I recently contemplated getting a new one to try:

https://www.bhphotovideo.com/c/product/1407442-REG/watson_9v_250_9v_rechargeable_nimh_battery.html

which is said to be 8 cells, but 9.9V at "full charge" doesn't really
compute, as charged-and-resting is usually 1.35 Vpc for NiMH.

Apparently powerex (same as maha/imedion) has both 8.4 and 9.6, with
different capacities:

https://www.bhphotovideo.com/c/search?Ntt=powerex%209v%20precharged%20rechargeable%20nimh%20battery&N=0&InitialSearch=yes&sts=ps



I would also wonder about making a regulator to 9V from 12, and some
snap connectors, and operating off a power supply or larger battery even
if portable.

73 de n1dam


Jim, N5IB
 

If you should choose to go with a higher voltage battery with a regulator, take a look at this adjustable regulator/current limiter project, that was in CQ back in Feb of 2018 (I think) :

https://qsl.net/n5ib/A%20Current%20Limiting%20Accessory%20for%20QRP%20Power%20Supplies.pdf

It has the advantage of being a linear device, so no RF noise from buck/boost switchers. And has internal, adjustable current limiting to protect connected devices. The regulator is low drop-out, so needs only about 10V input to regulate at 9V.

Jim, N5IB