Tell us about yourself!
you want a lithium battery charge circuit,as LiPo batteries are charged it switches from Constant current, to constant voltage (and trickling current). LiPo's have a tendency to explode when charged incorrectly - so I would avoid doing so without a proper charging circuit. even if you have to build it yourself, it's better then just connecting a voltage and current regulator and hoping for the best.
I use Methanol (Methyl Hydrate) instead of Denatured Alcohol (it's actually whats used to denature ethanol). I avoid Lighter Fluid completely as it really only is useful for dissolving sticky residue (which Goo Gone does much better, and safer). and acetone is to be avoided, like all ketone solvents. useful for etching though.
"Obihai" confused me, but an Obihai, appears to be a brand name for a basic ATA (Analog Telephone Adapter), similar to a Cisco SPA112. these devices can even be configured to retrieve a setup config from a remote server (using protocol such as TR-069). this allows the devices to be shipped blank, and provisioned on site remotely. new boxes can be mass pre-provisioned. this works with basically any VOIP provider. you can also write a dial plan to block calls to specific numbers, even 911 service if wanted, or reroute 911 to a different gateway (such as a PSTN). Multiple place offer free SIP service, but typically just for Subscriber to Subscriber, or Canada/US calls.