3.7 is a little high for most LiMPO4, even single cell. Straight LiFePO4 is usually rated 3.65+/-0.03. LiFePO4 is much more tolorant of overvolting due to super lown internal resistance. I'd be more concerned about if the charge profile and termination current is correct for the other chemistry. I think it is designed as a storage charge as explicitly stated for other chargers.
Mike
That 3.7v number is just a label and as we see from unit to unit, these chargers are all over the map when it comes to hard numbers.
First question is, why put that switch there and cover it up?
Secondly, the 4.35 label and the 4.20 label target specific voltages that we commonly encounter, so why not include the third 3.6v-3.7v (3.0v/3.2) voltage?
We have 3 voltages and they seem to address that with the switch. Xtar doesn't use their 3.2v setting for storage, or market it that way. They make no mention of it in fact. The end result is more happenstance than a dedicated storage feature IMO, but that's just speculation on my part.
What is the margin of error with that 3.7v number you're getting? 10% tolerance?
I'm not trying to argue, just pointing out some contrarian observations.
I've got four 25Rs here that have been discharged down and I'm going to put them on charge with the 3.7v setting and see what I see, as I've not toyed with 'storage settings', but for doing in manually in my lights.
Chris
ETA:
My four 25Rs terminated at 3.7v and then settled on the charger to 3.69v after a few minutes, on the 3.7v setting, so that perhaps might be a bit high for LiFePO4, so I don't know what's up?