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How many times have you opened a small battery operated device and frowned when you saw it was powered by one of those small rectangular 9 volt alkaline batteries with the button connectors on top?
Yes, they’re expensive most places, and it’s normally not the battery you keep around for a spare.
I have a Sears garage door opener that is 35 years old, it’s given me a few years to study the use of these 9 volt batteries pulling duty in small transmitters where the battery spends a second or two running a tiny transmitter and then going back into a no load state.
It’s some years before they go dead normally, but always good to look at the date on the battery and know how old it is when you put it into service.
About seven years ago, I decided to take some test clips and put one of the 9 volt batteries that was too weak to power the garage transmitter across a 12 volt battery, I may have left it there for about three or four minutes and then back into the transmitter. It worked for more than a year, and I do use it quite a bit in the shop. Next time it went dead, I did the same thing, and another year or two of service.
And several days ago , I looked around and no spare! So I charged it again! working just fine…
So Yesterday, I’m at a place where nothing gets fixed.. there’s a remote key pad between the garage doors than has had a dead battery in it for the last six months or longer. on the floor, I see a standard 12 volt car battery charger.. I gave it a three minute charge and presto!
I know, we hear you shouldn’t do this, but I did, and it does seem viable is this application.. the power draw is very small, the stand by position is open circuit across the battery..
I’ve seen no leaks in this one battery, but that’s always a risk.. keep the charge short, and do experiment..
GB
And who are these people in the picture?
Nothing at all to do with batteries..Marc Chirico and Francis Rogollo. Marc is a local PG Instructor and Rogollo’s simple brilliant design allowed a lot of us to take our very first foot launched flights, two of my Hero’s.
.
here is one for you George
back in the mid 90’s while out in the middle of the western washington peninsula my motorola cell phone battery died, i had no car charger with me at the time.
i used two paper clips and then removed the dome light cover on my service truck, using the clips as crude jumpers i did a 15 second charge on the battery across the 12volts, iirc the cellphone battery was something like 4.4 volts or some things much less than 12volts
i reasoned that the small dome light wires would likely heat up and drop the voltage abit, as would the steel paper clips.
anyway it got me back up and i got about 20 minutes of call time out of that charge! i did it twice more on other occasions when i found out it would work.
no i would not suggest anyone try this at home, but in an emergency one is left to try some desperate measures.
bob g
Hey.. you’re a DIYer.. we expect you to get out of a jam 🙂
The Rogollo wing was a milestone achievement in free-flight…I’ve always been a powered flight operator myself, but someday will experience “true flight”…GB, did you ever get to meet him (was that you behind the camera?)…with your passion for FF, the encounter would be like me meeting Robert Goddard, Frank Whittle or Neil Armstrong…I did briefly meet Chuck Yeager back in the early 90’s at EDW (I was on medevac stby for the shuttle)…wasn’t the warmest of people…kinda crushed my larger than life image I had of him…I guess that what happens when heroes walk on earth as mortals?
Glad you asked! The kid on the left is now in his Fifties! Marc Chirico at the time was somewhat of a bum by his own account, addicted to the air and competition in the hang gliding sport at the time. He spend a lot of time in Europe, and who knows where else.. and you can imagine that he looked up to Francis Rogollo as a step above most mortals at the time. I don’t know the circumstance of this meeting, but I’ll attempt to remember and ask Marc..
I would imagine the embrace we see in this picture was genuine respect for one another, Mr. Rogollo’s creation, and Mr. Chirico’s skill in making the design do what many others only dreamed of doing!
Now.. get back on topic, and try recharging a few 9 volt alkys and report back Sir!
G
Sorry for the hijack…bad manners…I use 9 volt batteries in my David Clark ANR headset at work and get about 7-9 hours of run time, so that mean I go through a lot of 9 volt batteries! I’m going to try this with some of those and see if I can extend their usefulness? I’ll do some testing and get back in a month or so.
Doug Bradford
Just kidding you Doug..
Here’s what I think might really work with an alky battery. Charge it with a milli amp or two at intervals when not in use.. don’t let it go dead. a dedicated processor that can be programmed might discover the better way to extend alky no charge batteries t0 the max, some say these batteries are rechargeable, they just can’t handle a normal charge without a rupture and leakage. One of you Ardiuno experimenters should build a charger for the purpose..
is this your YouTube video? 🙂
Over 30 years, I have a fair idea what the charge is with a quick lick 🙂
I bought a battery charger designed for alkaline ( non rechargeable) batteries a while back. It works pretty good but the more you recharge a battery, the less capacity it seems to have. Also some batteries are more long lived than others and not necessarily the name/ Expensive brands.
I have mainly used this charger on AA and AAA batteries in high discharge current devices so they may work better on cells used in lower discharge devices.
On everything except 9V batteries, I use mainly Nickel metal rechargeable Batteries.
I am also well known and Ridiculed by friends for my proclivity for strapping larger, often SLA batteries to anything I can that will remain practical.
I have enough batteries and capacity in my truck to leave the headlights on for 2 days and still be able to come back and start it.
And guess what George, it’s retro fitted with Sealed Beams! :0)
I prefer them to the Halogen things in their light spread and progressive fall off. I have some Driving lights on the High beam side but the SB’s are definitely better for the close up driving.
David,
As we know there’s a lot of different reports on Alkaline batteries, and I think you’ve hit the nail on the head, some are better than others, but we should have low expectations of these batteries charging at typical amperage for batteries declared rechargeable, my thought anyway. Another recommendation I see if recharging well before the battery is dead.
My interest is using a small solar PV and charge controller to maintain alkys in services such as drive way alarms etc.. I think a tailored solar charger for 9V alky could have a market. Others might say.. just buy the Nickel Metal, but alkys have a lot of capacity, and floating them, or recharging them often may be viable.