Maximum voltage for Minipulse rev D? Tool batteries?

[aeberbach]

Hi, I have a minipulse looking for a housing. I've been thinking about adding a charging/management circuit for some rechargeable batteries and making it a neat unit and then lately bought a battery powered line cutter for the garden and thought "why not use a tool battery system in the metal detector?" It has plenty of capacity, isn't heavy, I have multiple batteries and a charger already. So why not make a 3d-printed enclosure for the metal detector that accepts one of the tool batteries I already have? Some 3D design work for the housing obviously but this may still be the easier option.

What I am most concerned about is maximum voltage that can be tolerated by the minipulse power supply circuit. 18V should be OK, looking at the circuit - what do the rest of you think? 12V systems are available but I already have the 18V system from a couple of manufacturers and don't want three incompatible battery types.

[waltr]

I only have Rev E schematic so...
What chip does the rev D use for the Voltage inverter? LT1054 or a 555 and transistors?
Ensure it can handle the higher Voltage.

Also check ALL Cap that would see the battery Voltage and ensure they at rated higher then the battery.

Other wise should be fine.

[aeberbach]

Yeah I was just looking at LT1054, max 16V - I think the easiest thing would be a $10 18V->12V buck regulator before the input. Not so efficient, but hey, $10 and it's a very big battery.

edit: My bad - such a converter module is about $4. Looks like that is the answer.

[Qiaozhi]

Hi, I have a minipulse looking for a housing. I've been thinking about adding a charging/management circuit for some rechargeable batteries and making it a neat unit and then lately bought a battery powered line cutter for the garden and thought "why not use a tool battery system in the metal detector?" It has plenty of capacity, isn't heavy, I have multiple batteries and a charger already. So why not make a 3d-printed enclosure for the metal detector that accepts one of the tool batteries I already have? Some 3D design work for the housing obviously but this may still be the easier option.

What I am most concerned about is maximum voltage that can be tolerated by the minipulse power supply circuit. 18V should be OK, looking at the circuit - what do the rest of you think? 12V systems are available but I already have the 18V system from a couple of manufacturers and don't want three incompatible battery types.

The 79L05 typically has a maximum input voltage of -20V, although some manufacturers have versions that can go up to 35V.
The 555 timer (TX oscillator) is limited to 18V.
However, the LT1054 will be a problem, as its max input voltage is 16V.

[homefire]

Three 18650 3S 2600mAh does the job most well. Do it... Your arms will be finished before the batteries are. About a thousand ways you could charge the things. Solar if wanted.

[Tibuck19]

Three 18650 3S 2600mAh does the job most well. Do it... Your arms will be finished before the batteries are. About a thousand ways you could charge the things. Solar if wanted.

I like the tool battery idea, but they are heavy, even a small pack from a M18 are not very lite, If you going to print it! print a 3S 18650 pack as mentioned by homefire add a little 18650 BMS, and a plug, That way u can just charge the unit when battery power drops. I used a battery indicator like this one https://www.ebay.ca/itm/1S-2S-3S-4S-...ar=&hash=item0 And the BMS I used is this on, https://www.ebay.ca/itm/3S-20A-12-6V...item3634df86ec both items are dirt cheap and lets you use 18650's that you could get out of old laptop's .