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TDI SL Factory Battery Pack Vdc Differences

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Hey All, Measured White's TDI SL factory battery packs and discovered the following differences. 


NiMh Battery - HD #802-5321, 2200 mAh.

  1. After full a charge, one day later..........................................10.99 VDC

AA Battery Holder - #802-7150, 8 cell.

  1. With Nuon Industrial Alkaline from White's Factory............12.94 VDC
  2. With Member's Mark Alkaline from Sam's Club...................12.96 VDC
  3. With Energizer Ultimate Lithium...........................................14.46 VDC


Was very surprised that with Alkaline batteries, the tested voltage was higher than with the NiMh battery pack.

Also, the NiMh battery pack seems to drop about 0.05 VDC a day.

But the clear winner are the Energizer Ultimate Lithium batteries at 14.46 VDC!

Stay Safe!




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The non-rechargeable lithiums lose voltage quickly, but still plateau pretty well.  Of course you pay $ for that extra voltage....

Some of the White's TDI's (note, apparently not all of them) are unusual in that they don't have voltage regulators, which almost all modern electronics, including most metal detectors have.  Voltage regulation just results in the voltage delivered not being relevant until it gets very low.

For most detectors, the battery's charge capacity (typically shown in mAh = milli-amp hours) is the more relevant quantity since that determines how long the detector will operate.  PI's are particularly charge hungry.  IB/VLF's tend to run a long time, just like the Energizer Bunny.




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Thanks!  So the RnB Innovations LI-ion battery pack putting out 3,100 mAh would be a large improvement over the factory battery pack?  It's about $149. 

My detector was just shipped from White's factory about a month ago with the 12"x8" Hi-Q and 7.5" coils...I just wish it already had the latest battery power technology.

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RnB makes a solid product, have one of their battery packs for my Garrett and have no complaints.

Does that 14 volts give you more depth?

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If the NiMh is only 10.99 and the Lithium at 14.46 is 3.47 VDC higher, I'd think so, but I can't say for certain because I haven't done any tests.

GB_Amateur says that Lithiums lose that peak voltage quickly.  But if the RnB has 14 VDC, I'll order one tomorrow.  🙂

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RNB makes several lithium ion battery packs for Whites detectors. The latest one that actually fits in the TDI SL without any kind of modification is 3100 mah but it only puts out 12V........ They do make a 14.8 volt for other Whites detectors but it would need some serious modifications to work either inside you TDI SL, strapped to the outside or wired to a hip mount. Most of us who own or have owned TDI SLs have either gone with the RNB 3100, used the supplied Whites Nimh rechargeable, used throw away alkaline or the high voltage lithiums, or built our own 14.8 to 16 volt lithium ion battery pack. It is not hard to mod the throw away blue label battery pack into a 4 cell lithium ion pack and buy four Panasonic 18650s and a good charger. I made mine for less than $60. So before you order the $149 RNB 3100 12 volt pack, consider your options.

This forum has tons of info on building a lithium ion battery pack for the TDI SL.

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When looking at the  White's  rechargeable factory packs you cannot but be dissapointed. Barely adequate for stock Vlf machines and completely inadequate for the Tdi Sl.  We are forced to go elsewhere in search of voltage and depth.

I quickly tried the Rnb battery pack, it has three 18650  cells, max voltage is about 12.5. Great for my White's Vlf machines, not the

Tdi Sl. Moved on to try the disposable lithium cells, good voltage and decent improvement in performance. Cost was and is an issue.

Tried the 3 x 18650 Ukranian orange pack. Same as the RnB, just a lot cheaper. Use your own cells and charger. Great and used on all my White's  VLF machines now.

Finally ended up converting a battery tray and going with the 4 x 18650 rig. Loving it. End of the road.

Tdi Sl battery packs..jpg

4 x 18650 voltage.jpg

Energizer Lithium.jpg

Orange voltage..jpg

open tray orange.jpg

3 x 18650.jpg

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Yup, best thing is to build your own 4-cell li-ion pack. It's not that hard to do. Also get a charger that can control the max voltage. Best life of the pack is attained by only charging to about 80% capacity, or 16.0v. That also gives a bit of safety margin for your TDI SL. I use a $30 buck converter to charge mine. I can set the charge current, and the max charge voltage, and forget about it. Go to bed, and in the morning the pack is at whatever voltage I set as the max....ready to go. I can power the buck converter from a wall wart, too, or plug it into a 12v socket in the pickup, or camper. It will handle DC  input voltages from 8-60, and recharge both 3 and 4-cell li-ion packs. Just have to make the appropriate adjustments.

 The only bone I have to pick with the RNB 3-cell pack is the connection points are recessed too deep. It only works intermittently with my DFX. in fact, it quit working completely on the desert the other day. It had quit before, but always turned back on. This time, I couldn't get to restart, but it restarted fine with the NIMH pack. I'll have to modify those contact points to keep using it.


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11 hours ago, LStart219 said:

GB_Amateur says that Lithiums lose that peak voltage quickly.

I was referring to the non-rechargeable lithiums.  I don't know the decay curve for the rechargeables.  Here's a plot from the Energizer L91 datasheet which shows the decay:


Notice that the voltage plateaus around 1.4 V for these fairly heavy current draw applications.  But the TDI/SL current draw is similar, I think.  The numbers you show in your original post (average ~1.80 V per AA battery) are consistent with the leftmost part of the curve -- fresh battery.  8 x 1.4V = 11.2 V which is about what you'll get at 3-4 hours into operation, as shown above.  That's still better than the NiMH pack will be putting out at that time.


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9 hours ago, Jim in Idaho said:

The only bone I have to pick with the RNB 3-cell pack is the connection points are recessed too deep. It only works intermittently with my DFX. in fact, it quit working completely on the desert the other day. It had quit before, but always turned back on. This time, I couldn't get to restart, but it restarted fine with the NIMH pack. I'll have to modify those contact points to keep using it.

Jim, would it help to just shim the back end of the battery pack to push it forward in the housing and cause better contact?  That would be a lot easier (safer and also reversible) than playing around with the business end of the pack.  Or have you already tried that?


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