OT- Need to adapt 7.4 volt lithium 115vac battery charger to existing cradle...

West Marine VHF85 handheld vhf radio where the unit works as new but the 12 volt input cigarette lighter charger crapped out (internal fuse is good, no replacement 12 vdc chargers available for this model..discontinued)

Really rather have an AC input charger, so wondering if I could simply adapt an existing generic 115 vac/ 7.4 vdc charger wiring to the unique charging cradle of this unit ? The possible catch is the 12 volt charger has 4 wires on the board and 4 terminals on the cradle and the 115 vac chargers seem to only have 2 wire output.

I'm guessing 2 of the VHF85 terminals are voltage in and 2 are voltage out ? (for monitoring when to taper the charge ?) If so how do the generic 115 vac to 7.4 vdc chargers "get away" with using just 2 wires ?

(and yes I know ultimately it would be cheaper to throw the works in the trash and buy a current model VHF....but, but.. )

https://uedata.amazon.com/West-Marine-VHF85-Handheld-Transceiver/dp/B00VVPU7BK

The only reason I could see for the extra wires is that the charger has the charging electronics, where most newer devices have the charging electronics internal.

you could wire in some random 12 volt supply to the old one and see if it works, but....

You need to study the charging characteristics of the battery. Then if you have the confidence to continue, get lots of fire insurance for each location that radio goes for recharging. Don't take the battery apart to see what it's made of. The one's we use in our product emit a gas that will instantly blind you and in short order kill you. Hope this helps you make an educated and safe decision.

The 4 wires are probably main charge power and temperature feedback.

The charger is usually high current until battery warms up and some device changes some state to indicate this then charger reduces current.

Can make a charger..

If you are lucky you may find a wall wart close.

Or in a higher voltage in multiples of 0.6 volts higher.

A diode drops 0.6 vdc, adding a diode drops voltage 0.6 vdc.

You can determine which wires connect to battery main and connect to wall wart.

Only use a low current unit as they make good rockets when they blow.

A charger for other device of same voltage may be used for source as well.

Or ebay...

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Some lithium batteries have integral protection. A common size is 18650, 18mm by 65mm, google the number and you’ll find all sorts of DIY projects for drones, RC toys, and robotics.

Install a proper jack to match one of the plugs on a multipurpose charger used by enthusiasts?

Why not buy a new unit, for less than 200 bucks it seems worth it rather than spending all this effort on outdated technology...I should follow my own advice, I'm still using a yaesu vx5 lol.