Mornignstar SunSaverDuo Field Testing Instructions

SunSaver Duo Field Test Document
Morningstar Corporation
5 v1.0
FAQ
Q: The SunSaver Duo seems to be working but my battery does not recharge (or recharges
very slowly). Why?
A: The recharge time depends on several factors:
1. Amount of current produced by the solar panel(s) –vs- the amount of power
drained from the battery daily - If more power is drained from the battery by system
loads than can be replaced by the solar panel, the battery will be at a constant state
of discharge.
2. Size of the battery bank – If the capacity of the battery bank is large compared to
the amount of current produced by the solar panel(s), charging time will be slow.
Your solar system designer/installer should properly “size” the PV system.
3. Health and age of the battery bank- If the battery is old or has been abused, it may
not accept or hold a charge.
Q: Why is the SunSaver Duo under-charging or over-charging my battery?
A: If the SunSaver Duo Status LED is not indicating a red error condition, the most likely
reason is temperature compensation. If a Remote Temperature Sensor or the internal
temperature sensor is being used for temperature compensation (see manual), then the
regulation voltage will be higher in cooler ambient temperatures and lower in warmer ambient
temperatures. The SunKeeper adjusts the regulation voltage to compensate for changes in
battery chemistry which varies with temperature.Also, double-check the system wiring. Be
sure that the Solar + and Battery + lines are not inadvertently wired together.
Other charging sources in the system such as the vehicle alternator or shore power charger
may be responsible for over-charging the battery.
Q: Should I use a Remote Temperature Sensor?
A: The Remote Temperature Sensor allows precise temperature measurement at the battery
so that the SunKeeper can more accurately adjust regulation voltage with temperature. If the
battery is stored in significantly different ambient temperature than the SunKeeper, the
Remote Temperature Sensor may be required.
Q: Will I damage the SunSaver Duo if I disconnect one or both batteries during operation?
A: No. Batteries can be connected or removed at anytime during operation without risk of
damage. Be careful with live circuits and always fuse battery power cables. The SunSaver
Duo will detect connected and missing batteries. If only one battery is connected, 100% of the
charge current will be used to charge the battery.
Q: Does the connection order of the batteries and solar input matter?
A: No. The connection order provided in the manual is only a suggestion. The SunSaver Duo
will not be damaged if the connection order is not followed.
Q: Can I disable temperature compensation?
A: Yes. There are two (2) ways to fix the SunSaver Duo to 25C regulation. The easiest way is
to insert a through-hole 10K resistor across the Remote Temperature Sensor terminals. The