4 AA battery pack issues
 

I wish I could charge these batteries without taking them out of the holder. Do they make a charger that plugs into these kinds of battery holders?

Is there some other battery pack I could use with this light? I don't like having to remove the batteries from the holder in order to charge them.

I know I'm being picky but I like convenience and this set-up is not convenient. It's an older Dinotte 200L light.
TIA

Not that I am aware of, but I'll let others take the lead on that. I assume those batteries are wired in series which can cause problems charging that way. I for one greatly prefer to charge the individual cells, that way with a quality charger I can specify the exact charge current for each cell, refresh/analyze the cells, etc.

Charging packs all at once is problematic. Without the ability to monitor each cell, charging is prone to getting the cells way out of balance. This is because if you charge the whole pack as a unit, the cell that's the most discharged (even if only a tiny bit) will be the last one to take a charge, and the fastest to discharge when you put it under load. Over multiple charge cycles, this only gets worse.
On well designed power systems, if charging a whole pack there's a wire going to each cell and a circuit to monitor that cell's voltage, and if any cell's voltage goes over that of the other cells, the circuit drops a resistor across that cell to shunt charge power around it and into the other cells.

You can charge as a pack, but you can't fast charge. If you just trickle charge it, it would be fine as long as you don't leave it on there too long. I'd shoot for an 8 hour charge time if not longer. With nominal 2100 mah cells, there will be some losses, say over 8 hours you need to pass 3000 mah of charge current through those cells. 3000 mah over 8 hours = 375 ma charge current. Find a 7.5 or 9 volt adapter (charge voltage must be higher than nominal pack voltage), a 9v battery clip, and wire them in series with a resistor. You want 375 mah at 7.5 volts, that's 7.5/0.375 = 20 ohms, 7.5*0375 = 2.8, so find a 20 ohm, 3 watt (probably 5 watt would be easier to find) resistor.

It can be hard finding just one resistor in consumer sources. Amazon has them but $8 for 10 of them.

Still even just going to Amazon and throwing away 9 of the resistors, you could easily toss this together in a few minutes for < $20.

Bush & Muller Ixon IQ headlights can be bought with a Charger that plugs in to recharge the 4 AA batteries in them , or removed and Charged.

Busch & Müller: IXON IQ


REVIEW: Busch & Muller Ixon IQ Premium - Warning Photo Heavy

Look into a cheap r/c battery charger. Then you just need to make an adapter to whatever kind of plug that pack uses.

Here's one for example: Accucell S60 AC Charger (US Plug)

I was going to recommend a Hobby charger but seems someone beat me to the punch.
Regardless, you're better off charging all the cells separately but like you I understand how that is kind of a PITA. It's one of the reasons I always use standard battery packs rather than cell holders.
The thing is since you're using a cell holder it's just better to charge the cells separately. The metal contacts on cell holders will accumulate oxidized residue over time. Believe me it doesn't take long for this to happen and it isn't visible to the eye. If not cleaned regularly the residue builds up and small voltage drops begin to take place. While this isn't really that big an issue it does exist. More a problem with single cell applications than with cell holders. Still, NiMH cells are just 0.3 volts less than standard Lithium ( non-rechargeable ) AA's at 1.5 volts so the difference in a couple tenths of a volt will shorten the run time even if only for a couple of minutes. Even more an issue in colder temps if the lamp you use has automatic power-down circuits ( which the 200L does ).

I have one of those old 200L's. I used to use the same set-up as you do only back then they didn't sell the Low self-discharge NiMH cells. Eventually I bought a Li-ion ( 4 cell ) battery with a 6 volt regulator built into the pack and that worked great for the few times I used it. The Li-ion pack had almost twice the run time of the NiMH's but the downside was that the pack would self discharge in storage because the regulator circuit was always, "on". That meant I had to make sure I charged it right before every ride. The 200L , while a fine lamp is just obsolete now. If you're going to spend money you might just consider a better/brighter lamp. Besides if you buy a lamp that uses Li-ion cells the Li-ion cell just have larger capacity and handle colder temperatures better.