Sparrow >> Modifications >> Other Charger >> Manzanita Micro PFC
Replacement with a Manzanita Micro PFC-20 or PFC-30
There are many possible replacements for the Zivan, but one option stands out, mostly since it's the most popular. Manzanita Micro (http://www.manzanitamicro.com) sells the "PFC" line of chargers.
It has these advantages over the Zivan:
- PFC stands for "Power Factor Corrected" and a power supply or battery charger that is "PFC" is more efficient. This means that more of the power that you paid for actually ends up in your batteries. It also means that you can more closely approach the maximum current the plug can deliver, shortening your charging time.
- These chargers have an adjustable current limit. You can set it to draw no more than 5A (for example) from an A/C outlet or you can set it to draw the maximum possible current (20A for a PFC-20 or 30A for a PFC-30.) Ultimately, this means that you can switch modes, charging as fast as you possibly can at home and being polite and not blowing circuit breakers when you're charging away from home.
- These chargers take feedback from the Manzanita Micro battery regulators, throttling back their current when any battery's voltage goes over a pre-set limit, usually 14.8V. Charging effectively ends when all the batteries hit their limit.
- PFC chargers can run on any input voltage, allowing the user to switch between 220V outlets and 110V outlets on the fly, just by using different extension cords. This can dramatically lower charging time in your garage while preserving the ability to plug in anywhere while traveling.
- PFC chargers are easily adjustable for different pack voltages. If, for instance, you decide to add one more battery to your Sparrow, you can just twiddle the set screw on the PFC and you'll be ready to charge your pack. A Zivan charger requires a new EPROM from Zivan for this sort of change.
Disadvantages over a Zivan:
- It costs more, particularly when you already own a Zivan. At this writing, the cost of a PFC-20 is about $1600 and a PFC-30 is about $2000.
- You need to install regulators, which cost a lot by themselves. The simpler (Mk2B) regs cost $45 apiece, or about $600 for the entire pack. The more complex (Mk3) regs cost $75 apiece for about $1000 for the entire pack. The Mk3's, however, can provide excellent data about the health of your battery pack. Again, installing regulators is something that you'd probably want to do anyhow. But Manzanita Micro's regulators are more expensive than other regulators. And these chargers require Manzanitas.
- Manzanita Micro chargers are not isolated. This means that the battery negative terminal is attached to the A/C outlet's neutral wire during charging. Rich Rudman and Joe Smalley, the principals of Manzanita Micro, seem to believe that isolation is not necessary because there should already be many safeguards against shock hazard, including that your battery pack should be isolated from the car's chassis ground. Most electric vehicles have this sort of battery pack isolation. Sparrows from the factory do not. So, before you install a PFC charger, you must isolate the battery pack, which also involves isolating the Link-10 E-Meter. This process is useful in and of itself and it's usually referred to as "Defanging" by the Sparrownaut community. Once your Sparrow has been de-fanged, installation of a PFC charger isn't very difficult.
All in all, people switch to PFC chargers when they want to be able to charge quickly with minimal damage to their batteries. Charging quickly means that you can, for example, get home from work and almost immediately use the Sparrow for going somewhere in the evening. It also increases the likelihood that you can travel further during the day by "opportunity charging" at outlets at your destinations.
Jake Oshins
