The powerbank charger outputs 5V and as the cells get near to charge, stops at 4.1V. So a little low but acceptable for long term longevity.
My airsoft buddy has an iMax charger and you're right, once the lipo-automotive pack proves like it can handle an hour of driving at night. Then adding the tiny bms wires, would keep everything at the same voltage and capacity as the pack ages.
Though right now, before going for it, it's wise to do some cursory maths to determine if it will fulfill the needs of the car.
Do we have any data on Watt-hours of draw a typical small car like the metro draws over an hour journey, with head lights on?
I'm guessing the lights are 20A. Though what is the draw per hour, to provide thousands/millions of sparks?
Strangely not something my search engine skills can uncover.
The best, as ever resource is the founders of the site, looking at his estimate of 530 watts, though conservatively you can read 700 W from the list, under dark, cold and raining conditions.
That's W/V =A. Which in this case is 700/
14V = 50 A on rounding. For one hour of night driving in the rain with the hair dryers on throughout. You conservatively need a battery with 50 A.h capacity for an hour of worst case driving. With each 4 in series under a 13 amp load(a draw more than within the continuous run time of Sony VTC5A cells, in fact the higher 3Ah capacity samsung 30Q starts becoming more appealing in this continuous drain role, than the higher cold cranking amp rated, Sony cells in this calculation)
A 4s4p lipo pack, with each cell at the VTC5A, nominal capacity of 2.5A.h. That means with 4 in parallel, the capacity is 10 A.h.(12 A.h with the samsung cells)
So that comes out to be 12 to 15 mins of run time . Not the needed 60 mins of run time.
For complete alternator deletion, a 4s
16p pack is needed. Is this accurate?
That thing will be as large as a typical lead acid battery and cost near 150 dollars easily in batteries/cells alone, with 64 cells.
Still, might get away with close to half that size, a 12 parallel pack, instead of the 16, as realistically Ireland doesn't have the assumed monsoon weather. Though good to know 16 would just do and no more.
Anyone recommend a non Iron phosphate, Li-ion recreational vehicle, battery in the 50 Ah range?
On looking on amazon, for "12V lithium" which are all Iron phosphate based, as far as I can tell, this DIY route, actually starts looking pretty decent price wise.
Darin's metro mpg page on alternator optional in his Firefly