GMC Electrical FAQ Part II
Q: Is there much of a difference between the TrueCharge 40 and 40 plus? The
only major difference I can find is the ability to charge three banks (40+)
A: The internal circuitry is also different. In theory the 40+ should be a bit
more reliable than the 40, but an individual is NOT likely to see the
difference in a MH use.
Q: Can our configuration use the 3 bank capability of the TrueCharge 40+?
A: You can hook up the 40+ to 1,2,or 3 battery banks. Unless you add a second
house bank the third output will not be used.
Q: I found a remote control panel, is it worth installing?
A: I did. It's a great addition. Keep in mind that the panel is really a
remote
monitor since you can't turn the charger off from it. It does let you see how
much current is being supplied to the battery banks (and coach 12V circuits),
so when using the genset to recharge. Monitoring the charge rate allows you to
shutdown the genset when the charge rate is too low (the banks are nearly
charged). This saves significant time and gas.
Q: My buzz box works but I am concerned for the safety of my batteries and
also
the sound level.
A: The TrueCharge definitely has better battery protection built in.
There's no
need to disconnect from shore power like there is with the buzz box to avoid
damaging your batteries. Do keep in mind that the Statpower units have a fan
that will periodically turn on when the unit is running. They are used to cool
the electronics. Mine runs pretty continuously at 40 amp charge rate, some of
the time at 20 amps, and sometimes at the lower rates. Air temp and how you
mount the unit will influence how much the fan runs. FWIW, the fan makes about
the same amount of noise as one of the older PC fans. (Not much impact during
the day, but can be annoying at night if it's really quiet).
Q: My Statpower charger turns a fan on and off, often in response to me
turning
on a light. Why does it happen?
A: The fan is used to cool the electronics when higher currents pass through
the charger. Fan turn on/off is determined by many factors including the
ambient air temp. In general the fan will come on for less time and less
frequently when it is cool than when it is hot inside the compartment where
the
charger is located. When you turn on a light it draws more current from the
TrueCharge. Sometimes this additional draw is enough to cause the fan to come
on. Likewise, when you turn off the light it reduces current so that the
fan is
no longer needed.
Q: My TrueCharge works fine when connected to shore power, but stops charging
when using the genset. The lights on the status panel blink.
A: Your Onan genset has a small 2 amp charger that feeds through a voltage
regulator to the house battery. Remove the wires from the regulator. There
should be two terminals - one with a single wire and one with two wires.
Remove
the single wire and tape the connector at the end of the wire to guard against
shorts. Keep the two wires that are connected to one terminal connected to
each
other. Duane Simmons indicates that failure of the regulator is one
significant
cause for genset failure. Removing the wires doesn't interfere with the genset
operation and makes the unit ignore any regulator failures.
Q: I've heard that the Statpower chargers sometimes catch fire.
A: All battery chargers have components that fail. Power circuits tend to fail
with smoke and fire. The Statpower cases are designed to contain any
flames. In
UL tests, the Statpower cases contained ALL flames so that materials in
contact
with the unit would not catch fire.
Q: Is there a multistage regulator for my automotive regulator?
A: Yes. West Marine offers several. They range in price up to several hundred
dollars. These regulators replace the automotive regulator with the multistage
capability. The full output of the alternator is managed by the regulator.
Like
the statpower charger, these automotive multistage regulators permit the
fastest possible battery recharge.
Q: How much of an advantage is an automotive multistage regulator?
A; If you are driving very long distances there is little advantage since the
tapered charge from the OEM regulator will fully charge most battery banks in
about 20 hours. If your drive distance is shorter, say 3 hours and you move
often, the multistage regulator will fully recharge your battery bank without
running the genset.
Q: The wire from my alternator to the isolator sometimes gets hot. What's
happening?
A: The wire is undersized for the maximum possible current flow. The OEM
Alternator is capable of a sustained 85 amp output. When the coach is
drawing a
heavy load the wire will get hot. The problem is compounded if you have a
higher amperage after market alternator. The solution is to replace the OEM
wire with a heavier gauge wire. I recommend using a marine engine environment
chart for selecting wire sizes in the engine compartment of the GMC. These
charts provide a greater safety margin than standard automotive charts. Also,
be cautious of the additional heat generated in the GMC engine compartment.
Q: Is there a product that does all of these, charges, inverts and converts?
A: Yes. The Statpower ProSine 2500 and 3500 both provide all functions in one
unit.
Q: Why do I need to double the wire length from the battery to my appliance
when choosing the hookup wire size?
A: The 12V path is actually the positive line and the ground return. So,
resistance for the wire loop needs to accommodate the wire plus the chassis
ground. Note: you do not need to use a separate ground wire from your
device to
the battery bank. The ground may be supplied by the chassis itself. However,
you will still need to calculate wire size for the positive wire using the
positive plus ground length. It's easiest to just double the positive wire
length.
Q: My dash gauges change readings, and they remain changed, when I turn on my
headlights. Why?
A: You have a poor gauge cluster ground. Clean all connections between the
instruments and the panel, the ground wire in the dash, and add at least one
more ground between the chassis and the dash. This should eliminate your
problem.
Q: I turned off my Onan and now it starts but doesn't create 110V AC. What's
wrong?
A: The Onan failure is probably a Bridge Rectifier failure. They typically
fail
while turning off the Onan while the AC (or some other heavy duty AC motor) is
running. A voltage transit (called inductive kickback) usually causes the
failure. The OEM Bridge rectifiers are operating very near to their Peak
Inverse Voltage (PIV) rating. A simple solution is to replace the bridge
rectifier with one having a much higher rating.
Q: How do I replace my OEM bridge rectifier?
A: (Courtesy of Duane Simmons)You have two choices - replace with an exact pin
compatible device having the same low PIV, or use one that is higher. After
market bridge rectifiers with the same OEM pin-outs have PIV limitations. To
avoid the limitations you have to modify the Onan.. A 1/4" hole in the base
for
each wire allows you to install a heavy duty bridge rectifier. To remove the
OEM bridge rectifier, slide out the Onan as far as you can & remove the BR
mounting screw which is located aft of the Control Board on the rear Generator
Housing (1/4" screw head). Remove the plastic cover on the side of the
generator housing & the BR can be moved to where you can ID the terminal from
the side of the BR. Carefully transfer the terminal ID to each wire (i.e. +
, -
, AC , AC). Transferring the proper ID is very important since the Onan will
not operate with crossed wires & the wires are very hard to trace for ID. Now
individually remove the wires from the base (relive tab on each wire terminal
from the front/BR engagement side & push terminals out the rear). Now drill
1/4" holes for each wire. Slide the wires through the proper hole &
attach/slide on the 4 wires to the BR. Slide the BR & wire terminals back down
through the base to where the Original mounting screw will secure the BR to
it's original position on the housing. An after market BR w/1,000 volt (PIV)
rating is available from many Electronics stores at less than $10. The PIV is
greater than 3 times the OEM BR & should never fail (well almost never). NTE #
5328 is the after market BR that Duane uses.
You can see how to change the bridge rectifier at Scott Nehoda's site:
http://members.aol.com/adohen2/page/newpage3.htm http://members.aol.com/ad
ohen2/page/newpage3.htm
Henry Davis Consulting, Inc / new product consulting
PO Box 1270 / product readiness reviews
Soquel, Ca 95073 / IP reviews
ph: (831) 462-5199 / full service marketing
fax: (831) 462-5198
http://www.henry-davis.com/ http://www.henry-davis.com
Q: Is there much of a difference between the TrueCharge 40 and 40 plus? The
only major difference I can find is the ability to charge three banks (40+)
A: The internal circuitry is also different. In theory the 40+ should be a bit
more reliable than the 40, but an individual is NOT likely to see the
difference in a MH use.
Q: Can our configuration use the 3 bank capability of the TrueCharge 40+?
A: You can hook up the 40+ to 1,2,or 3 battery banks. Unless you add a second
house bank the third output will not be used.
Q: I found a remote control panel, is it worth installing?
A: I did. It's a great addition. Keep in mind that the panel is really a
remote
monitor since you can't turn the charger off from it. It does let you see how
much current is being supplied to the battery banks (and coach 12V circuits),
so when using the genset to recharge. Monitoring the charge rate allows you to
shutdown the genset when the charge rate is too low (the banks are nearly
charged). This saves significant time and gas.
Q: My buzz box works but I am concerned for the safety of my batteries and
also
the sound level.
A: The TrueCharge definitely has better battery protection built in.
There's no
need to disconnect from shore power like there is with the buzz box to avoid
damaging your batteries. Do keep in mind that the Statpower units have a fan
that will periodically turn on when the unit is running. They are used to cool
the electronics. Mine runs pretty continuously at 40 amp charge rate, some of
the time at 20 amps, and sometimes at the lower rates. Air temp and how you
mount the unit will influence how much the fan runs. FWIW, the fan makes about
the same amount of noise as one of the older PC fans. (Not much impact during
the day, but can be annoying at night if it's really quiet).
Q: My Statpower charger turns a fan on and off, often in response to me
turning
on a light. Why does it happen?
A: The fan is used to cool the electronics when higher currents pass through
the charger. Fan turn on/off is determined by many factors including the
ambient air temp. In general the fan will come on for less time and less
frequently when it is cool than when it is hot inside the compartment where
the
charger is located. When you turn on a light it draws more current from the
TrueCharge. Sometimes this additional draw is enough to cause the fan to come
on. Likewise, when you turn off the light it reduces current so that the
fan is
no longer needed.
Q: My TrueCharge works fine when connected to shore power, but stops charging
when using the genset. The lights on the status panel blink.
A: Your Onan genset has a small 2 amp charger that feeds through a voltage
regulator to the house battery. Remove the wires from the regulator. There
should be two terminals - one with a single wire and one with two wires.
Remove
the single wire and tape the connector at the end of the wire to guard against
shorts. Keep the two wires that are connected to one terminal connected to
each
other. Duane Simmons indicates that failure of the regulator is one
significant
cause for genset failure. Removing the wires doesn't interfere with the genset
operation and makes the unit ignore any regulator failures.
Q: I've heard that the Statpower chargers sometimes catch fire.
A: All battery chargers have components that fail. Power circuits tend to fail
with smoke and fire. The Statpower cases are designed to contain any
flames. In
UL tests, the Statpower cases contained ALL flames so that materials in
contact
with the unit would not catch fire.
Q: Is there a multistage regulator for my automotive regulator?
A: Yes. West Marine offers several. They range in price up to several hundred
dollars. These regulators replace the automotive regulator with the multistage
capability. The full output of the alternator is managed by the regulator.
Like
the statpower charger, these automotive multistage regulators permit the
fastest possible battery recharge.
Q: How much of an advantage is an automotive multistage regulator?
A; If you are driving very long distances there is little advantage since the
tapered charge from the OEM regulator will fully charge most battery banks in
about 20 hours. If your drive distance is shorter, say 3 hours and you move
often, the multistage regulator will fully recharge your battery bank without
running the genset.
Q: The wire from my alternator to the isolator sometimes gets hot. What's
happening?
A: The wire is undersized for the maximum possible current flow. The OEM
Alternator is capable of a sustained 85 amp output. When the coach is
drawing a
heavy load the wire will get hot. The problem is compounded if you have a
higher amperage after market alternator. The solution is to replace the OEM
wire with a heavier gauge wire. I recommend using a marine engine environment
chart for selecting wire sizes in the engine compartment of the GMC. These
charts provide a greater safety margin than standard automotive charts. Also,
be cautious of the additional heat generated in the GMC engine compartment.
Q: Is there a product that does all of these, charges, inverts and converts?
A: Yes. The Statpower ProSine 2500 and 3500 both provide all functions in one
unit.
Q: Why do I need to double the wire length from the battery to my appliance
when choosing the hookup wire size?
A: The 12V path is actually the positive line and the ground return. So,
resistance for the wire loop needs to accommodate the wire plus the chassis
ground. Note: you do not need to use a separate ground wire from your
device to
the battery bank. The ground may be supplied by the chassis itself. However,
you will still need to calculate wire size for the positive wire using the
positive plus ground length. It's easiest to just double the positive wire
length.
Q: My dash gauges change readings, and they remain changed, when I turn on my
headlights. Why?
A: You have a poor gauge cluster ground. Clean all connections between the
instruments and the panel, the ground wire in the dash, and add at least one
more ground between the chassis and the dash. This should eliminate your
problem.
Q: I turned off my Onan and now it starts but doesn't create 110V AC. What's
wrong?
A: The Onan failure is probably a Bridge Rectifier failure. They typically
fail
while turning off the Onan while the AC (or some other heavy duty AC motor) is
running. A voltage transit (called inductive kickback) usually causes the
failure. The OEM Bridge rectifiers are operating very near to their Peak
Inverse Voltage (PIV) rating. A simple solution is to replace the bridge
rectifier with one having a much higher rating.
Q: How do I replace my OEM bridge rectifier?
A: (Courtesy of Duane Simmons)You have two choices - replace with an exact pin
compatible device having the same low PIV, or use one that is higher. After
market bridge rectifiers with the same OEM pin-outs have PIV limitations. To
avoid the limitations you have to modify the Onan.. A 1/4" hole in the base
for
each wire allows you to install a heavy duty bridge rectifier. To remove the
OEM bridge rectifier, slide out the Onan as far as you can & remove the BR
mounting screw which is located aft of the Control Board on the rear Generator
Housing (1/4" screw head). Remove the plastic cover on the side of the
generator housing & the BR can be moved to where you can ID the terminal from
the side of the BR. Carefully transfer the terminal ID to each wire (i.e. +
, -
, AC , AC). Transferring the proper ID is very important since the Onan will
not operate with crossed wires & the wires are very hard to trace for ID. Now
individually remove the wires from the base (relive tab on each wire terminal
from the front/BR engagement side & push terminals out the rear). Now drill
1/4" holes for each wire. Slide the wires through the proper hole &
attach/slide on the 4 wires to the BR. Slide the BR & wire terminals back down
through the base to where the Original mounting screw will secure the BR to
it's original position on the housing. An after market BR w/1,000 volt (PIV)
rating is available from many Electronics stores at less than $10. The PIV is
greater than 3 times the OEM BR & should never fail (well almost never). NTE #
5328 is the after market BR that Duane uses.
You can see how to change the bridge rectifier at Scott Nehoda's site:
http://members.aol.com/adohen2/page/newpage3.htm http://members.aol.com/ad
ohen2/page/newpage3.htm
Henry Davis Consulting, Inc / new product consulting
PO Box 1270 / product readiness reviews
Soquel, Ca 95073 / IP reviews
ph: (831) 462-5199 / full service marketing
fax: (831) 462-5198
http://www.henry-davis.com/ http://www.henry-davis.com
