battery for field-box

these type of sealed batteries last a long time, same type used in emergency lights, I've use 7ah batteries for flight box and last one was way over 10 when i replaced it, i do however doubt that they'll still hold 17ah, but to run a starter, glow driver (whats that?) you should be good, iron...not so much.

They have not bounced around in a vehicle for years so that's good and they are also clean with no cross leaks going on over the years from an oily/dirty film, another plus. Give 'em a try!

but that doesn't mean you can't get into them. Those covers can be popped off pretty easily. You can then check the electrolyte levels and add distilled water as needed. I have rejuvenated UPS batteries this way and they are/were sealed as well.

I over the course of a few years have a lot of the 12Vdc 7AH bats out of my 7 home use UPS's...

Many are over 7 years old and still charge and hold just fine for my infrequent needs

They are ALSO great building weights

The only ones I do the recycle thing with are any that show bulging or cracks in the case

Thank You for the comments guys. These batteries weigh a whopping 13lbs. each.. but if I build a field-box for one, it will wheel like a dolly and have a detachable-handle for ease of transporting in the car. If these batteries won't hold a charge.. I'll just bring them back to work for their original recycling destiny. They didn't cost me anything. I've had two Hobbico TorqueMaster 12V 7Ah lead-calcium field-box batteries.. and neither one lasted very long.

I bought these off ebay and I have them driving glow plugs fine off a 12V battery.

https://goo.gl/fOaGP5

Just solder gozinta and gozouta wires on and you're rolling.

PeterJGregory wrote:I bought these off ebay and I have them driving glow plugs fine off a 12V battery.

https://goo.gl/fOaGP5

Just solder gozinta and gozouta wires on and you're rolling.

Only $.89 each in a Qty of 10? Seems like a fair deal. But, but...how do you control the "adjustable"  step down voltage?  Does 12v in automatically make 1.5 volt out?

There is a small precision potentiometer on the circuit board.

https://servimg.com/view/19403788/33

Funny i had a guy give me one this size and two smaller 12v batteries from the same kind of operation were the computer MUST have the correct AMPS at all times for back up , he checks them and if not up to par changes them . Just the right size for lawn mower and field boxes Dam Peter i wish i would have known this part was so easy available i tossed a power panel because it was blowing glows with too much voltage !

Yup - the glow drivers on the power panels don't have much, if any overcurrent protection. I wrote those panels off fast for driving glow, at least.
So far the little voltage regulator circuit has worked fine. You can use them with LIPO's in the field.

Geez.. I've never had problems with the glow-driver in my Tower (Hobbico) power-panel.. and it's over 25 years old. Mine has the usual analog ammeter/needle scale with 3A being at the top of the "green-scale". I've never exceeded that point. I always assumed it was accurate. I haven't experienced what you'd call a high-rate of glow-plug failures.. at least with the genuine Cox glow-head.

Regulators are something I'm very interested in lately. My application would be for reducing the 6.6V of a LiFe receiver battery, down to 5-6V for the avg. Rx. I just wouldn't run the system on the hope that the +.6V wouldn't fry my Rx...

It's good to know that there's regulators out there.  

I should restate my problem with the panels. I make a lot of craigslist hauls that come with a flight box or flight boxes thrown in, and I find that most  of the glow drivers are blown, for some reason. Whether that comes from disuse and storage in less than ideal environmental conditions, I don't know. Simple light oxidation of terminals, even rust on some parts might contribute to that.

When I did get a panel that worked, I believe I zapped it with a glow head clip for 1/2A that I didn't notice would close all the way when not connected to a glow head, i.e. short out. As a guy that does do some electronics maybe I have a higher rate of failure by "trying new things out." If you use the glow charger with only regular glow plugs, the contacts are set apart very well and things like that don't happen. Doing things by the book has its merits!

I have some current meters coming from China via ebay to try out with the voltage regulators

The LiFe voltage drop to what you need is pretty slim - I would have to look up the specs on the circuit to see what the lowest voltage drop it supports would be. You might solve your challenge with a simple zener diode, or other diode.

I also have a Hobbico power-panel that someone gave to me a few years ago. I haven't needed it.. so I haven't tried it yet. I've always kept my model-related electronic gear in the house. I could see how an un-insulated garage/out-building might not be the best place for storage.

Stepping-down voltage with a diode (as you mentioned, Peter..) sounds familiar. You may have mentioned it previously in another thread. I posted a while back, about putting together a lightweight 1/2A RC flight-pack. I bought a 2S (6.6V) 200mAh LiFe Rx pack that is a tiny 1" x 1" x 1/2" and weighs just 15gr. and is planned to power x4 nano-servos and the Rx.

See below.. the whole system-weight in grams. Hobbico does mention the possibility of needing a voltage-regulator in the battery-circuit to protect the servos/Rx. The fully-charged voltage of a LiFe cell is 3.6V. The 2S pack would have a fully-charged voltage of 7.2V. which is too high for my system as configured. I'd feel much more comfortable with a 1V step-down.. however that can be achieved.

Too lazy to look all of them up but because of the voltages with the new batteries vs Alkaline/NICD (OK,not so new now)...there are lots of different step down add ons (some very small and cheap) or even built into to many ESC along with some newer TX/RX and servos accepting the 6/7vdc ranges

HK stuff is hard to find for me but I would look there first