I have access to avaition ni-cad batteries 28v New outback fm 80 question

Himins

Can I dial this outback fm80 charge controller to the correct voltages to maintain avaition nicad batterys...Don't attempt to explain exactly how its done on this forum, I'm willing to read more on the topic if it is practical. I havn't pulled the trigger on the batt's yet. There is a charger available for these battries and that would surely be an infinately time consuming way to test, assemble and then charge these battery packs...the problem and question is this...after these batterys are completely tested and reassembled...can I set the outback fm80 to safely charge these batterys with out some termendious expense in additional equipment?

westbranch

Re: I have access to avaition ni-cad batteries 28v New outback fm 80 question

got a model ?

Nicds are 1.2 v / cell... 28/1.2 = 23.3???

Cariboocoot

Re: I have access to avaition ni-cad batteries 28v New outback fm 80 question

That would depend on exactly what the batteries need for a charging profile. The FM80 (like all high-end controllers) can be programmed for all sorts of Absorb & Float Voltages, as well as current limits.

But without knowing what the NiCads expect there's no way to know for sure. They might require Voltage limits during bulk or cell management or some other function which the FM80 can not duplicate.

inetdog

Re: I have access to avaition ni-cad batteries 28v New outback fm 80 question

Cariboocoot wrote: »

That would depend on exactly what the batteries need for a charging profile. The FM80 (like all high-end controllers) can be programmed for all sorts of Absorb & Float Voltages, as well as current limits.

But without knowing what the NiCads expect there's no way to know for sure. They might require Voltage limits during bulk or cell management or some other function which the FM80 can not duplicate.

Unlike LiIon cells, NiCads are relatively forgiving of overcharge (similar to AGM lead acid, in that they recombine any evolved gas but vent if severely overcharged), and are not damaged particularly by complete discharge as long as individual cells in the series string do not get reversed during the discharge.

They generally do not need cell-to-cell balancing circuitry, nor do they have the incendiary potential of Lithium chemistry from thermal runaway. They do have a high enough energy density and low enough internal resistance that they can self-destruct when short circuited.

As for the charging profile, you really need to get information from the manufacturer if possible, or at least get a count of the number of cells in series. The nominal voltage of 28 is similar in accuracy to the nominal 12 volts for Lead-Acid. The exact numbers are what is needed. They you can ask whether the Outback can be programmed to deliver a high enough voltage.

FWIW, the typical end-of-charge voltage used for a sealed cell is 1.45 volts and for a vented cell 1.55 volts.
However it is important to have a temperature sensor to stop charging if the pack overheats, as well as a voltage-rate-of-rise sensor if you will be doing high rate charging, which you probably will not!

Himins

Re: I have access to avaition ni-cad batteries 28v New outback fm 80 question

Still researching this battery westbranch, the internal cells look like the cells on this link
http://www.saftbatteries.com/MarketSegments/Aircraft/tabid/362/MarketSegments/Aircraft/Technology/Cellsrange/tabid/374/Default.aspx
They are installed into a Stainless Steel box not unlike an ammo box, except the odd shaped plug showing on the exterior, the box looks like the one shown on this link
http://www.changhongbattery.com/Aircraft_Ni-Cd_Rechargeable_Battery_p49_m3.1.html
scroll down half page...
My customer showed me his batterys yesterday, he is a pilot, and these batterys were salvaged as a safety of flight measure every so many cycles, he has 5 of them.
I am not sure but I believe the nominal voltage is 24(ish) These batterys have no history of failure, simply a part of the maintainance process every so many cycles on the aircraft(or batts)...Some of these are used to start an aircraft when on the ground...but also used in flight. I know he flies a multi engine jet aircraft for a local factory

westbranch

Re: I have access to avaition ni-cad batteries 28v New outback fm 80 question

what about the box that shows in the vid clip on this page? labeled Aviation batteries.

http://www.saftbatteries.com/MarketSegments/Aircraft/tabid/362/Language/en-US/Default.aspx

It looks a lot like the Chinese one, except the handles are at 90* to the SAFT.


this doc may help http://www.saftbatteries.com/doc/Documents/stationary/Cube780/tm_bb_en_0407.6f92351c-93f1-4404-b97d-bc4669140ace.pdf

note the section on how to charge.

Himins

Re: I have access to avaition ni-cad batteries 28v New outback fm 80 question

Yes, the photo in the link you provided is what my customer has been storing in his hangar. The photo I provided is depicting a much squater overall size, basicly shorter. I've read the entire pdf file you linked here, the individual cells appear different inside the stainless steel case, more like the cells in the link I provided...from memory. I should take photos...I was servicing his computer last night and didn't want to dissasemble the things to photograph them. Had camera with too!! I do all sorts of specialty photography and have tens of thousands of dollars of lens's and equipment including video and sound applications.

westbranch

Re: I have access to avaition ni-cad batteries 28v New outback fm 80 question

It is not so much the difference in the case etc, the internal chemistry is the same, just the amperage and possibly the charging regime that may differ. the difference may be subtle though.

side comment, if these are anything like the 30+ year old NiCd's I have, they are rock solid ( long life they are' said Yoda) and recover well. If they fit the application , go for it.

stephendv

Re: I have access to avaition ni-cad batteries 28v New outback fm 80 question

The battery technology handbook describes charging 2 types of NiCd, firstly just plain old "NiCd":
Attachment not found.

And secondly gas tight NiCd, which they say should not be charged using the IU characteristic (Bulk-Absorb)
Attachment not found.