I was thinking about getting the Midland LTX440, but I read elsewhere that the charge does not turn off the RED charge light & can overcharge causing battery damage or short battery life.
Is this the case?
A Midland or all mfg’s. problem?
Similar mfg, features & price that does not have this issue?
That’s correct. The charger continues to charge the batteries after they are fully charged. The good news is that the Midland rechargeable battery pack seems to retain its full 6-volt output for some time after charging. To prevent damage or “overcharging,” you can either remove the plug of the AC adapter from the rear of the charger or remove the two radios from the charger – both methods are inconvenient. I solved the problem in a different way. I use the Midland AVP-4 charger with a pair of GXT710 radios. I purchased a double-pole double-throw (DPDT) micromini toggle switch from Radio Shack (#275-626), drilled a 1/4" hole in the front of the charger (just above the two LEDs), and wired the switch into the charging circuit. Now, after 12 hours, I just switch off the charger, allowing the radios to remain in their seats until ready for use and without having to unplug the AC adapter.
Sorry that I did not see this posting sooner, if I had I would have recommended that you modify the charging base in a different way.
I had a look inside both my Cobra and Midland chargers and noticed that they were essentially the same electronically but the resister value in the Cobra has about twice the resistance of that of the Midland charger. This difference would reduce your charge current to approximately ½ as in the Cobra model that I never turn off and that the manufacture indicated is safe to remain on continuous charge.
See my post on this issue. CLICK>
I forgot the exact resister values (one for each bay) but if you like I could open both units up again and give them to you. This modification would have allowed you to remove and restore back like original without adding the hole and switch and also the resisters would have costed only about $1.
In your case now, if I were you, I would have both resisters values connected to the DPDT switch so as to have a rapid charger OR a trickle holding charger.
This type of modifying is beyond the scope of most users and would void any warranty. Midland has a 3 year now.
Almost all of the manufacturers choose to go with the “dumb” chargers. Maybe to seel more battery packs… or cut costs.
Really, if you charge according to instructions, you ought to be okay. Those Midland packs really are pretty good, and surprisingly give good performance over a decent amount of time.
I took another look inside both the Cobra and the Midland chargers this week and found the value of the charging current limiting resisters were 34 Ohms for the Midland and 680 Ohms for the Cobra.
For making the Midland a dual function charger, and if you wanted to make another modification to the DPDT switch that you added, you could re-wire the switch function to select either the original 34 Ohm resister for the rapid charging or a higher resistance, I would recommend ~1000 to 5000 Ohms for the floating charging function.
In the float mode, the LED will now glow very dimly as apposed to normal brightness when normal charging current is flowing.
With that modification, after the Midland recommended charge time, you could switch over to the floating current and keep the batteries safely at a full, toped off charge indefinitely.
Again, this modification would void the manufactures warranty, but then you already did that when you added the switch.