Tdi Pro 18v + Battery Pack. 5 X 18650 With Dedicated Charger

[karelian]

Now that White's is gone, pays to nurse the machines. I keep the SL machines well under 16 volts, just peace of mind.

My standard Tdi Pro had standard battery packs that are 16.8 volts hot off the charger, no problems there. The modified Tdi Pro is the machine that gets the hotter  5 x 18650 battery pack, in for a penny in for a pound.. Hot off the charger it has 21.5 volts if I let it. I use a timer and try and keep it at 20 volts max or just a bit under.

Just started a discharge experiment, battery was in the machine for a month after being charged to 20 volts.

Starting voltage was 19.53 and I'll check it every hour after that to see how much run time if provides. I am looking to go down to roughly 3.2 volts per cell or 16 volts for the pack.  So maximum charge of 20 volts and maximum discharge to 16 volts. We have to draw our lines somewhere. That leave run times. I'll have the answer to that shortly.

Ok so after one hour or run time starting at 19.53 volts it is down to 18.47 volts.  . no outward signs of heat issues. Removed battery and checked the machine for warm spots etc. Have used this setup on the beach for many hours and the Tdi Pro seems to work without any issues at the higher voltages. Long term wear or strain on components is another issue, so far so good.

 

[karelian]

Results of the battery endurance test. No surprises here, I've used the battery enough to know that a full charge will see you to 4 hours. From 21.5 volts to 16 volts is 4 hours. Today I used the speaker and started at a lower voltage, just over three hours and twenty minutes runtime. The PCB will cut the power at 16 volts so you cannot overly discharge the cells. No warning the machine just turns OFF. That is a good thing.

Started at 19.53 volts, an hour later 18.47 volts. An hour later 17.74 volts , an hour later 16.76 volts and twenty minutes later it cut out at 15.97 volts. Three hours and twenty minutes, use a set of headphones and you will get extra runtime.

Ok maybe I need three battery packs for a full days detecting...? All for now, all the best.

[Tony]

Or you could get really serious and just get a very long extension cable and plug into the 240v.....?

[karelian]

I tend to play it safe with my machines, but the modified Tdi Pro has been the exception. I've pushed that baby hard, like driving a rental.. Since it was already modified I just wanted to see how much the higher voltage battery could push things. Baby steps all the way, just that bit extra depth every time.  The Tdi Pro just hits hard all the way, maximum performance until the PCB kicks in at 16 volts.  I agree Tony that it is not worth pushing safety margins for a few extra centimeters, plan on enjoying my machines for some time yet. Who knows a few years from now I might cast an eye on a second hand GPX 6000. Until then I'll have at least one Tdi Pro to swing on the beaches and the goldfields.

Last trip with this machine will be to a less well known mining area, I'll work around the edges where I know there was large gold.  Large nuggets found between two and three feet.  I'll mount the larger 14 x 8 Digger coil and run her hot until the PCB spoils the party at 16 volts.... All the best.

[Joe Beechnut OBN]

On 3/23/2021 at 1:20 AM, Tony said:

And here’s me going back to a stock battery......well not quite....it’s a 3 x 18650 setup @ 11.1v. In another thread, I mentioned the super hotspot on my TDIBH board when running the 14.4v battery which got me worried. Being sealed up, there's probably less opportunity for the heat to dissipate. Even when opened, the hotspot was severe.....couldn’t touch it for more than a second or so without burning a finger. 
My depth results were a maximum increase of 2” over the stock battery. In fact, my current 11.1v Lithium setup sits in the middle (depth wise) between the stock battery and my retired 14.4v battery so I’m more than okay with just the 1” drop.

Regards,

Tony

Tony did I see one of your batteries with a LED volt meter? If so I was wondering how it held up.

[Tony]

Not mine Joe.....must have been another setup somewhere.

[karelian]

I've been using my brothers smart charger with this power pack, had to replace the dedicated chargers connector which plugs into the male 2.1mm plug. A faulty female plug needs to be replaced, still waiting for the post man..  When the charger arrived it came with a male 2.1mm plug, which I swapped over for the female connector, which worked great for a couple times and then failed. Maybe I was a bit rough or it was too delicate, not complaining about a part that cost one dollar..

Ordered a different brand female plug, looks a bit more robust.. just like to get the parts right before final parts list and review.. Again the dedicated charger works with the 5 x 18650 battery pack and is the better option for those of us who don't have expensive smart hobby chargers..

More to follow, all the best.

 

[Jim in Idaho]

You don't need an expensive "smart" charger. You can buy a buck converter on Ebay, that allows setting the max charge voltage, for about $30.00. I've been using mine for several years. I can use it for both my 16volt 4-cell packs, and my 3 cell 12volt pack. I can use it for any pack from 1.5v to 30v. https://www.ebay.com/itm/DROK-DC-3-5V-15V-to-DC-0-6V-30V-Buck-Boost-Converter-5v-to-3v-12v-24v-2A-15W/333937403216?hash=item4dc0386550:g:aCgAAOSwjRlgYAxb

Jim

[karelian]

They say the devil is in the detail. If you are handy with an soldering iron and have young eyes then it does not really matter which style of pug you go for. The big chunky ones have the plus and minus connectors labels on them, are much easier to connect and for anyone with arthritis or poor eyes are recommended. Small and finicky vs large and practical, my opinions and experiences only...