RTIII
1 kW
I'm planning to add a DC-DC converter to at least one if not both my TSDZ2 48v bikes so that I can add robust 12v lighting for night riding - including lighting for my trailer - and after spending hours looking at options, it looks like I've got really two options that financially make sense, but they have trade-offs and so I'd like the opinion of those of you with 48v systems. (I spent a lot of time looking here on ES for a good answer to this, but haven't found it so far, so please forgive if this is "asked and answered" and point me to it!)
The better one I like because: better packaging (ie how it would mount / looks, etc), a better (published) efficiency of 90%+, AND, shipping from the USA - I can have it by Monday if I order today. Only down side: published cut-off input voltage of 40V.
The second (and third and fourth, all share these characteristics) has only ONE possible advantage: a published cut-off voltage of 36V. The down sides are dorky looking packaging, non-published efficiency - which tells me it has to be low - AND delivery dates that are off into November / December!
I'd like to go with the first option but I'm concerned that I might loose my lighting if the pack ever drops below 40v. And here's where I have no experience! I have NEVER taken my pack below 50v (at rest), much less 40! However, I have read the specification sheet for my brand of 18650 cells and a "48V" pack (13S) should be "officially in need of a recharge" at 36.4v. ... Yes, I know it's REALLY bad to bring your pack down that low all the time for longevity reasons, but you never know what the future may hold, so... It'd be REALLY bad to lose lighting because the pack dipped below 40V (but wasn't yet to 36).
Another thing to consider I don't (yet) have any direct experience with but know to be concerned about: I know (from other experience) that the resting voltage of a battery and the in-service, during load voltage are two very different things! And since I don't have a meter on my system (yet), I have no idea what the pack voltage is actually like when I'm using it full bore when its at-rest voltage is, say 50. BUT, my system is only rated at 18A, and other users of the TSDZ2 say the actual usage is very modest. So MAYBE the difference between rest voltage and full load voltage isn't so great - but it's an unknown to me at this time.
Please share your insights!
The better one I like because: better packaging (ie how it would mount / looks, etc), a better (published) efficiency of 90%+, AND, shipping from the USA - I can have it by Monday if I order today. Only down side: published cut-off input voltage of 40V.
The second (and third and fourth, all share these characteristics) has only ONE possible advantage: a published cut-off voltage of 36V. The down sides are dorky looking packaging, non-published efficiency - which tells me it has to be low - AND delivery dates that are off into November / December!
I'd like to go with the first option but I'm concerned that I might loose my lighting if the pack ever drops below 40v. And here's where I have no experience! I have NEVER taken my pack below 50v (at rest), much less 40! However, I have read the specification sheet for my brand of 18650 cells and a "48V" pack (13S) should be "officially in need of a recharge" at 36.4v. ... Yes, I know it's REALLY bad to bring your pack down that low all the time for longevity reasons, but you never know what the future may hold, so... It'd be REALLY bad to lose lighting because the pack dipped below 40V (but wasn't yet to 36).
Another thing to consider I don't (yet) have any direct experience with but know to be concerned about: I know (from other experience) that the resting voltage of a battery and the in-service, during load voltage are two very different things! And since I don't have a meter on my system (yet), I have no idea what the pack voltage is actually like when I'm using it full bore when its at-rest voltage is, say 50. BUT, my system is only rated at 18A, and other users of the TSDZ2 say the actual usage is very modest. So MAYBE the difference between rest voltage and full load voltage isn't so great - but it's an unknown to me at this time.
Please share your insights!