How long should I charge my Excalibur II?

LawrencetheMDer

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Feb 22, 2014
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Ohio and Florida
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Detector(s) used
Minelab Manticore, Minelab CTX3030 w 11" and 17" DD coils,
Minelab Excalibur II w 10" coil, Equinox 800 (4) w 11" and 15" coils,
Troy Shadow x2 w 7" coil, Pointers; Garrett Carrot, Pro Find 35,
Primary Interest:
Beach & Shallow Water Hunting
Since the Excal doesn’t have a full-charge indicator, it is often a guessing game to fully charge the battery but not overcharge it and decrease battery life. For a while, I was charging my Excal 1hr per 1hr use (i.e., 1:1). After getting stuck with a low battery on a lonely stretch of beach, I started to charge my Excal 2hr per 1hr use (i.e., 2:1) which worked well (or at least as far as I could tell). In Pauln’s video on the sounds of the Excal(http://www.treasurenet.com/forums/b...calibur-2-metal-detector-sounds-settings.html) , he notes that voltage of the Excal battery's working range is from 14v, at full charge, to 11.2v.

To better estimate the required charge time for the Excal, w/o constantly measuring battery voltage with a voltmeter, I compared discharge of the battery with general beach use to voltage over time during charging. In a nutshell, the (3 yr old) Excal battery discharged at a rate of 0.3v/hr, suggesting a run time of about 10hrs; given a voltage range of about 3v. The Excal battery charged at a rate of about 0.2v/hr. Assuming that the Excal is fully charged at 14v; you should recharge the battery for 1 1/2hrs per 1 hour of use (i.e., 1.5:1) to maintain a full charge.

On a related topic, while looking at Excal voltage in other situations, I found that Excal battery voltage ranged up to 14.66v. This may reflect an overcharged battery, but also may lead to 2hrs of additional detecting. For my current 3 yr old Excal my best estimate of working battery life, on a single charge, is 12hrs.

One other tidbit of information is noteworthy; while gathering data on my Excal, I found that one hunt had a particularly long estimated battery life of 20hrs! The only thing that separated this hunt from that other 12 was that I set threshold volume to just below detection. I usually set threshold slightly above detection, where you hear the constant hum of the Excal. Could setting threshold below detection reduce battery drain and prolong battery life? (What about volume level?) Since this observation was seen only once and not investigated, I don’t know. It is possible, however, that individual Excal settings may affect battery life. Then again, the 20 hr estimate of battery life could just be an outlier – just like the Platinum ring I recently found in a sea of pull-tabs.
 

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Charge it for 10-12 hours before using it on a depleted battery or just buy the smart charger. It gives full charge in 3 hours and then switches to trickle charger so no danger if left on charger. It also has indicator light for when battery is fully charged...
 

Where can you get the smart chargers for the excalII?
 

An excal is fully charged at 13 volts. You can buy a voltmeter for less than $10. When it reads 13 volts it's fully charged.
 

An excal is fully charged at 13 volts. You can buy a voltmeter for less than $10. When it reads 13 volts it's fully charged.

Not exactly true, a fully charged battery will read between 13.7 to 14.5 volts, the charger should read 18 volts measuring out of the adapter that plugs into the battery. You can take the ikelite gasket off and read voltage with the detector on to see what it is drawing as it is running. A battery going bad can read in the 13's but when it is installed on excal and turned on will suddenly drop down to less volts. Once it gets to around 10 volts or less it will cause problems....
 

I read it in the manual.
 

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I don't think you can overcharge them. I plug mine in in the evening and unplug in the AM after 2-3 hunts. Maybe 12-15 hours of use. And I hunt very trashy areas mostly.
 

Last year I bought a rechargeable Excalibur battery last year.The charging instructions stated that it should be charged no longer than than 8 hours.That is what I do.
 

I read it in the manual.
I'm giving actual battery readings..........I have been taking battery readings on my excal batteries for years. .[emoji3]
 

I charge from whenever time I hook it up... / overnight / till I take it off the charger in morn...
Ussually at least 12 hour shots.
And have forgotten many times till late morns.
Never had a prob since X2 era bats...
Rarely use backup AAA pack.

On my third X2... no bat probs... ***AARC knocks on wood***
Never replaced one.
BUT>>>>
I did loose 2 couplers to the first X2's... rolled off the boat somewhere between Feather sound and Desoto area...
IF you find them THEY ARE MINE ! :P
I had to go buy 2 new ones from Bill Jacksons... TO THE TUNE OF $75 EACH... at the time.
Just because I wanted to hunt THAT day.
 

I'm giving actual battery readings..........I have been taking battery readings on my excal batteries for years. .[emoji3]

I go by the manufacturers manual. If the manufacturer says that 13 volts is fully charged and you are charging to 13.7-14.5 then you are overcharging the battery.

NiMH dislikes overcharge: Charging Nickel-Metal-Hydride Batteries ? Battery University

The most common cause of premature battery failure is overcharging: NiMH Battery Charger FAQ
 

So your saying you are monitoring your battery while it charges so you stop it exactly at 13 volts?

I'm telling you what a fully charged battery is, don't believe me charge yours then read the voltage.
 

So your saying you are monitoring your battery while it charges so you stop it exactly at 13 volts?

I'm telling you what a fully charged battery is, don't believe me charge yours then read the voltage.

The manual says that the battery is fully charged at 13 volts.

A nimh battery gets warm just before being fully charged. Thats how I monitor. When its warm I check the voltage. It's always close to 13 volts so I stop charging. A little undercharged is better than decreasing battery life by overcharging.

Search this page for... Warm

Charging Nickel-Metal-Hydride Batteries ? Battery University
 

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Cb, I have read batteries hundreds of times over the years.. Manual tells you to charge for 12-14 hours, charge your battery for that time period them take a voltage reading of your battery and see what it reads....Do same thing with a new battery...

The excal is deeper in pinpoint/all metal than it is in discriminate, that is why we hunt in pp. When we hit a target we use thumb switch to switch to desc, if it is good tone we continue to dig. Here is where the advantage is, we get targets in pp that discriminate doesn't see at all....
 

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Thanks for the info Lawrence et all! I charge for eight hours or until the battery starts to feel warm. This last summer I ran out of juice right after finding back to back gold and silver rings. Its a tough way to cool off. If you are going for a long hunt its best to be charged and not assume. I have two appropriate wattage bulbs in series with leads to check but I'll try the volt meter as it will be more accurate. Anybody doing anything on the east coast? I see guys all over the beach on the cams but no ones posted anything yet.
 

Those manual charge reading are under load. TH is right most will read around 14.6 dcv with a multi meter. BUT..... once its turned on it quickly drops to 13 dcv. Those quick chargers are the best. I use the Maxxpack one in most cases will charge my battery in around an hour then shut down. The only problem i saw with them is the light is green when plugged in..... if your battery is DEAD it can still show green and fool you. Also...... the smart charger states for 1000 MA and above. The ole blues are only 750..... if they are weak from age, they can get hot from charging an crack a cap.
 

Those manual charge reading are under load. TH is right most will read around 14.6 dcv with a multi meter. BUT..... once its turned on it quickly drops to 13 dcv. Those quick chargers are the best. I use the Maxxpack one in most cases will charge my battery in around an hour then shut down. The only problem i saw with them is the light is green when plugged in..... if your battery is DEAD it can still show green and fool you. Also...... the smart charger states for 1000 MA and above. The ole blues are only 750..... if they are weak from age, they can get hot from charging an crack a cap.

I bought the quick smart charger, it is nice because it gives such a fast charge and switches to a trickle charge once it is fully charged. I have seen batteries measure 13+ volts but put it under load it instantly drops to 12 volts or less, a good sign the battery is going bad... I am currently using 3 1600 mah batteries, one for each of my 2 excals and one spare.

The blue batteries are all old and as Dew says are less than 1000 mah, the new 1600s will last far past 12 hours of constant hunting...I have hunted from 5am till 7pm almost non stop using them and they still had power left...
 

I believe you're right on both counts. The Excal battery typically charges to 14-14.6v fully charged. If this range is overcharged than so be it. My 3-yr old Excal battery still provides at least 12 hrs of hunting. I would not trust my battery for a full (8-10 hr) day of hunting if I started at 13v.
I estimate that PP is about 1-2" deeper than Discriminate. For deep targets, based on sound level, if I detect in PP and switch to Discriminate and don't hear anything I'll remove a few inches of sand then be able to detect and evaluate further in Discriminate. However, I have found that for some deep targets Discrimination will sometimes give a false reading/unreliable reading and you'll need to remove more sand to get a better signal to evaluate in Discrimination. This is also why I don't hunt in Discriminate - you'll miss to much gold...and sinkers.
 

If you're referring to the east coast of Florida, I hunted there for a month last yr and rumors had it that pirate gold was washing up on the beaches of Indialantic - just north of Melbourne Beach! Best hunt time is low tide since many of the beaches in the area, including Melbourne beach, have been recently rejuvenated with virgin sand making beach hunting less productive. MDing in the surf is a real challenge in the area because of the constant breaking waves; seem to average 3 ft constantly. Lots of sharks also in the area AND they're close to shore. [FYI, Two yrs ago I was swimming down the coast along Melbourne Beach, and when I got out a fisherman asked if I knew a shark was following me? I had no idea. The guy said an 8-foot, black-tipped shark followed 12 feet behind me for about 50 yrs. The shark disappeared when I turned toward shore. Have not swam in the area since.]
 

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