Here are some of the options considered:
- BRUSA options: http://www.brusa.biz/products/e_nlg5112.htm (isolated)
- Manzanita Micro PFC50: http://www.manzanitamicro.com/pfc50a.htm (non isolated)
Bang for buck the PFC50 is hard to go past, but safety is high on the priority list with this project. Not to say that non isolated chargers aren't safe, but isolated chargers provide another level of protection (Victor from Metricmind has a similar high standard attitude to safety and sums it up quite well here). Also with isolated chargers, we have the option of putting more chargers in parallel for a faster charge (although this assumes we can draw enough current. We may need the help of a friendly power company who is interested in being involved at the race track). Not going there now, but might be useful in the future.
A comparison of relevant BRUSA options here.
Will probably go with 3 NLG513-Sx. One for each of the three 247.5V sub battery packs (max charge voltage based on 3.6V per cell is 270V). Since the car will not be carrying the chargers on board, having three charges does not cause a weight/space issue. Also, because the charger(s) are not on board, we don't want the hassle of water cooling. Need to find out under what conditions the air cooling may not be sufficient to deliver 3.3kW.
This will give us a total of 9.9kW charging capacity, which will fully charge a 22kWh pack in a little over 2 hours (max mains current for single charger is 16 A with 240V supply, so we will require 48 amps to achieve full charge rate). This should be quick enough to get us back to full charge between races.
-- Main.PhilipCourt - 10 Jun 2008