Update on my AA rechargeable pack for older Sovereigns.

[Ron from Michigan]

I thought building a rechargeable AA pack for the Sovereign would be a lot easier than it was.I guess it kinda of reminded of the movie October Sky's,just when everything was figured out Holmer was back to the drawing board.Example I saw on You Tube a AA pack being made where the positive tip was grinded off for a better connection but when mine was filed off it leaked.One bad connection and the whole pack would die.Any way the pack is built with 10 X 2600 batteries soldered together and wrapped in tape.Not hi tech and ugly but works.To test the battery pack duration I turned the volume to the max with a threshold a little louder than what I hunt with in the field the Sovereign had the BBS 800 coil installed also for the controlled conditions.This procedure was done three different times and on an average lasted 7 hrs and 41 minutes.Note I used a Minelab Charger for 12 hrs and noticed the battery pack was warm.Overall I was pleased with the results and will make a second pack with 3000 batteries.HH Ron

 

[kered]

The minelab charger for the sovereign XS2a, 1, is for charging nicads not nimh(although it will charge them) and 2, puts out maximum 65ma in an hour, for 2600mah thats a 40+ hour charge to full 2600/65=40(in theory but is slightly more)

The sov GT charger is for nimh and puts out a charge of 100ma max therfore it would take minimum 26 hours to charge the same 2600mah.

In use the sov XS2apro/GT consumes on average 47-55ma per hour on the speaker and slightly less on the phones, my 1450 lipos will give over 28 hours of use on a charge, if you are only getting 7 hours on 2600mah something is drastically wrong.

The original XS2apro battery is only 700mah and lasts well over your 7 hours, the GT one is 1000mah and also lasts well over that time too.

Critterhunter with 450mah batteries is also getting 7 hours + per charge.

Batteries getting slightly warm during charge is normal as long as they don't get hot to the touch.

In the positive tip of the battery is a small safety valve for letting of gas during charge, by grinding the end you have probably distroyed the valve and hence the leak, you also have to be carefull soldering normal rechargables so as not to block the valve, this is why batteries for making up soldered packs come with a manufacturer soldered tab(apart from making things easier)

 

[Critterhunter]

Good info for him, but my lipos in my GT are 750ma, not 450ma.

 

[kered]

Good info for him, but my lipos in my GT are 750ma, not 450ma.

oops i thought you had 450's too

 

[Ron from Michigan]

Kered maybe I should go a couple more hours on the charger to see if the duration could be increased.So you are suggesting to go down to AA batteries a lot less than 2600s to get much better results, faster charging time and longer duration? Thanks

 

[Critterhunter]

Ron, while stock charger is hooked up put a volt meter on the two battery leads. Write down voltage. Come back an hour later and write down voltage again. Is it higher? Then it's still charging, even if it's only several millivolts higher. When the voltage stays the same or has dropped over say two hours the pack has peaked.

 

[Critterhunter]

In use the sov XS2apro/GT consumes on average 47-55ma per hour on the speaker and slightly less on the phones, my 1450 lipos will give over 28 hours of use on a charge, if you are only getting 7 hours on 2600mah something is drastically wrong.

750ma / 55ma worse case with speaker = 13.6 hours on my lipos. Not bad. Hadn't timed them well yet in the field. Yea, before i was using some 450ma lipos a friend gave me and i think i was getting about 7 hours.

 

[Ron from Michigan]

Critterhunter,thanks.I probably have cabin fever.I order a Cen Tech Meter going to see if I can make the thing work for a digital meter for the Sovereign.Heck for 3 bucks its at least entertaining.I 'm curious to see how well it would work.Later Ron

 

[kered]

Sorry for the delay, been busy.

Ron, the AA pack you have made should be ok(if its built properly)and as long as you charge it properly, smaller mah will charge faster(time wise) but still only give you the 7 hours if you charge them for the same length of time on the same charger, a 50 gallon gas tank half full will give the same milage as a 25gallon full, the bigger the better takes longer to fill but you are then set for a longer time.

If possible i suggest you get a better charger if you are still using the minelab stock one as its rubbish, you don't realize untill you have tried another how bad it is. There are many options available.
I use the Accucel6(i've now got 2 as i'd hate to be without it once i tried it) but there are many other good options, errik has a good one, there is also the one from onlybatteriesareus, no meter but a red led for charging and a green for charged, simple, only takes 2 hours from flat too on the excalibur 1450mah i put in. All you need with it is the pigtail relevent for the battery.

 

[Ron from Michigan]

Kered,thanks for the information I have an excal in need of a battery also which is for another post.Thanks again.

 

[Willee - Texas]

Lithium battery packs are a bit more dangerous to charge than regular Ni-Cads.
Most Lithium Ion packs will have a small electronic board in there that controls the charge and monitors the temperature of the pack.
Charging them with out that electronic board has the possibility of exploding one or more of the cells.
You dont want that!
Even the top engineers get it wrong sometimes and some laptop computer Li-On packs had to be recalled due to meltdowns.

Willee

 

[kered]

I had a meltdown with a rechargable 9v transistor battery, put it in my pocket and it shorted on my keyring , anything is dangerous if you don't follow the instructions, or do things you shouldn't:blush: other than that things are much safer nowadays than when they came out

 

[Critterhunter]

No, most lipos DO NOT have a circuit in them to balance the cells, monitor temperture, control the charge, or avoid going past low voltage cut off. They just contain a simple parallel charging port that gives individual access to each cell. Most lipo chargers contain the balancing/charging hardware these days to control that aspect, and it's usually up to the device it's being used in to monitor LVC.

Back in the day when lipos first came out none had balance ports or chargers that could balance the cells while charging. that is what made things unsafe. Not an issue today. Back in the day some of the first balancing lipos had safety electronics in them until they figured out that it made no sense to put the same electronics in each and every lipo when it could be done just once in the charger. Those types with any kind of electronics in the lipo are the rare exception to the rule these days and often need a very specific charger that is designed to work with their internal electronic circuits. With the advent of the universal balancing port using a molex plug just about all lipos work with all lipo chargers these days and they contain no internal electronics, which was rare even back in the day when some were using internal electronics.

The balance issue is what made lipos unsafe back in the day. These days i'd say nimhs or nicads are more unsafe because they don't have balance ports, yet individual cells CAN be overcharged and cause fires. that's why it's a good idea to drain a nimh or nicad all the way dead several times a year to get them all in balance, along with exercising the cells for more capacity.