Just about the time I thought I had a good handle on all things GMC, here I=
go climbing the learning curve getting to know this Prevost Country Coach =
conversion. It is interesting to me that the GMC experience is so much mor=
e helpful in this process than our previous full timing in a large diesel p=
usher. One would think it would be the other way around. The answer is th=
at owning our two GMCs, and driving them so extensively, put me in a hands =
on position with nearly every system. With our diesel pusher that was not =
the case. Most of the Prevost systems are similar to the GMC, only sca=
led way larger and often with more redundancy. As an example, the roof mou=
nted heat pumps are very much the same as on our GMCs, only there are three=
of them, each zone controlled, and they are commonly ducted. The way they=
are implemented they are way quieter than in either of our two GMCs (neith=
er of which had heat pumps, just AC with small electric heat strips). But,=
in addition to that there are two large engine driven AC compressors that =
supply evaporators located throughout the coach, each zone controlled by a =
thermostat, so the whole coach stays at set temp no matter how hot it is ou=
tside. As luxury tour busses it was imperative to keep all your passengers=
comfortable after all! Interior heat is a very different in the Prevo=
st from the GMC. In the Prevost the engine cooling fluid is also pumped th=
roughout the coach, including the bay storage areas, where fan assisted rad=
iators provide three zone even heat control even in very cold temperatures.=
Yes, the GMCs do that but only for the driver and passenger unless you ad=
d additional radiators and fans elsewhere. In addition, the Prevost has a =
diesel fired boiler (Webasto) that also heats that same fluid when needed l=
ike when you are parked so the even and controlled heat remains moving or n=
ot. The Webasto heating the engine cooling fluid means the engine is alway=
s warm started, even in cold weather. Finally, that same fluid passes thro=
ugh the water to water heat exchangers in two domestic water heaters (both =
about double the size of the GMC water heater) so you have continuous hot w=
ater whether plugged into shore power or not. Slick. Both our GMC and=
the Prevost use air bags and auto ride height controllers. Both have abou=
t 4=E2=80=9D up and 4=E2=80=9D down travel for leveling while parked. The =
Prevost uses air bags all around while the GMCs obviously use air just in t=
he rear. In the Prevost the air compressor is engine driven and of very hi=
gh CMF output, but there is also a 120vac (Thomas in this case) air compres=
sor to power such things as air doors and toilet flushing while parked. Th=
e Prevost also uses air to tension the belts that drive the huge side mount=
ed fan (which itself uses a much larger version of the viscous coupled fan =
clutch employed in our GMCs) and the second AC compressor. One set of belt=
s goes from the crank pulley to a 90 degree power take off unit and a secon=
d set of belts goes from that unit to the fan clutch. A third set of belts=
goes from that unit to the second AC compressor. With the engine running =
air pressure keeps all those belts properly tensioned. If a belt ever brea=
ks, with the engine shut down you can release the air pressure and change b=
elts by hand - no tools required. The biggest difference between the s=
ystems on our GMCs and the systems in this Prevost is in the electrical sys=
tems. Our GMCs use 12vdc for both the chassis and house batteries and for =
starting the generator so it is easy to use combiners or isolators to make =
sure all batteries are charged from any charge source. Not so the Prevost.=
There the chassis uses 24vdc for most things (like starting) and also tap=
s off 12vdc for things like the fluid recirculation pumps and light bulbs w=
hich are more widely available in 12vdc form than in 24vdc form. The house=
battery bank is all 12vdc as is the generator starting battery bank. The =
house and chassis batteries are completely isolated one from the other and =
each has its own independent charging systems. When the engine is running =
there is a belt driven, water cooled, 300 amp alternator that takes care of=
the 24vdc and 12vdc chassis battery bank. There also is a second belt dri=
ven air cooled alternator that charges the house and gen start batteries. =
When plugged in, the 50 amp main cord supplies power to the house, the hous=
e battery bank via two 2500 watt inverter/chargers and the gen start batter=
ies via a combiner. But, it does not supply power to charge the chassis ba=
tteries. The idea was that as a luxury tour bus, the Prevost would be driv=
en most every day so the large 300 amp alternator would take care of that d=
uty. Country Coach did include a separate 10 amp 24vdc trickle charger, bu=
t it has to be plugged in separately from the 50 amp cord. What was =
news to me is that the generator does not power the chassis battery charger=
unless you plug it into one of the dedicated shore/gen plugs that bypass t=
he inverters. As an all electric coach, nearly everything runs off the inv=
erters powered by a massive 1800 amp hour AGM battery bank. The exceptions=
are one of the roof heat pump units and the 220vac stove top. They only r=
un if you are plugged into a 50 amp shore power plug or are running the 17.=
5kw four cylinder turbo charged Kabota generator which can supply as much a=
s 145 amps (about the output of three of our GMC generators). That int=
eresting 24v/12v chassis electrical system requires the use of a device I d=
id not know about called a battery equalizer. The 24vdc is achieved by usi=
ng four 12vdc AGM batteries wired series/parallel. The two series wired gr=
oups make the 24vdc while tapping off of just one paralleled group provides=
the 12vdc. The battery equalizer makes sure that both groups carry the 12=
vdc load so they do not see significantly different amps while charging. =
Some owners and some converters did add a dedicated 120vac plug in the e=
ngine compartment which is powered only by shore power or generator power b=
ut not by inverter power so the 24v charger would come on automatically but=
so far I have not found such a plug in this Country Coach conversion. =
Having been so hands on with all the systems in our two GMCs has really =
helped speed up what otherwise would have been a much longer learning curve=
trying to figure out the systems in the Prevost. Not that it has been eas=
y or fast, but just a lot easier and a lot faster because of that experienc=
e. Jerry Jerry Work The Dovetail Joint Fine furniture designed a=
nd hand crafted in the 1907 former Masonic Temple building in historic Kerb=
y, OR glwork http://jerrywork.com =
go climbing the learning curve getting to know this Prevost Country Coach =
conversion. It is interesting to me that the GMC experience is so much mor=
e helpful in this process than our previous full timing in a large diesel p=
usher. One would think it would be the other way around. The answer is th=
at owning our two GMCs, and driving them so extensively, put me in a hands =
on position with nearly every system. With our diesel pusher that was not =
the case. Most of the Prevost systems are similar to the GMC, only sca=
led way larger and often with more redundancy. As an example, the roof mou=
nted heat pumps are very much the same as on our GMCs, only there are three=
of them, each zone controlled, and they are commonly ducted. The way they=
are implemented they are way quieter than in either of our two GMCs (neith=
er of which had heat pumps, just AC with small electric heat strips). But,=
in addition to that there are two large engine driven AC compressors that =
supply evaporators located throughout the coach, each zone controlled by a =
thermostat, so the whole coach stays at set temp no matter how hot it is ou=
tside. As luxury tour busses it was imperative to keep all your passengers=
comfortable after all! Interior heat is a very different in the Prevo=
st from the GMC. In the Prevost the engine cooling fluid is also pumped th=
roughout the coach, including the bay storage areas, where fan assisted rad=
iators provide three zone even heat control even in very cold temperatures.=
Yes, the GMCs do that but only for the driver and passenger unless you ad=
d additional radiators and fans elsewhere. In addition, the Prevost has a =
diesel fired boiler (Webasto) that also heats that same fluid when needed l=
ike when you are parked so the even and controlled heat remains moving or n=
ot. The Webasto heating the engine cooling fluid means the engine is alway=
s warm started, even in cold weather. Finally, that same fluid passes thro=
ugh the water to water heat exchangers in two domestic water heaters (both =
about double the size of the GMC water heater) so you have continuous hot w=
ater whether plugged into shore power or not. Slick. Both our GMC and=
the Prevost use air bags and auto ride height controllers. Both have abou=
t 4=E2=80=9D up and 4=E2=80=9D down travel for leveling while parked. The =
Prevost uses air bags all around while the GMCs obviously use air just in t=
he rear. In the Prevost the air compressor is engine driven and of very hi=
gh CMF output, but there is also a 120vac (Thomas in this case) air compres=
sor to power such things as air doors and toilet flushing while parked. Th=
e Prevost also uses air to tension the belts that drive the huge side mount=
ed fan (which itself uses a much larger version of the viscous coupled fan =
clutch employed in our GMCs) and the second AC compressor. One set of belt=
s goes from the crank pulley to a 90 degree power take off unit and a secon=
d set of belts goes from that unit to the fan clutch. A third set of belts=
goes from that unit to the second AC compressor. With the engine running =
air pressure keeps all those belts properly tensioned. If a belt ever brea=
ks, with the engine shut down you can release the air pressure and change b=
elts by hand - no tools required. The biggest difference between the s=
ystems on our GMCs and the systems in this Prevost is in the electrical sys=
tems. Our GMCs use 12vdc for both the chassis and house batteries and for =
starting the generator so it is easy to use combiners or isolators to make =
sure all batteries are charged from any charge source. Not so the Prevost.=
There the chassis uses 24vdc for most things (like starting) and also tap=
s off 12vdc for things like the fluid recirculation pumps and light bulbs w=
hich are more widely available in 12vdc form than in 24vdc form. The house=
battery bank is all 12vdc as is the generator starting battery bank. The =
house and chassis batteries are completely isolated one from the other and =
each has its own independent charging systems. When the engine is running =
there is a belt driven, water cooled, 300 amp alternator that takes care of=
the 24vdc and 12vdc chassis battery bank. There also is a second belt dri=
ven air cooled alternator that charges the house and gen start batteries. =
When plugged in, the 50 amp main cord supplies power to the house, the hous=
e battery bank via two 2500 watt inverter/chargers and the gen start batter=
ies via a combiner. But, it does not supply power to charge the chassis ba=
tteries. The idea was that as a luxury tour bus, the Prevost would be driv=
en most every day so the large 300 amp alternator would take care of that d=
uty. Country Coach did include a separate 10 amp 24vdc trickle charger, bu=
t it has to be plugged in separately from the 50 amp cord. What was =
news to me is that the generator does not power the chassis battery charger=
unless you plug it into one of the dedicated shore/gen plugs that bypass t=
he inverters. As an all electric coach, nearly everything runs off the inv=
erters powered by a massive 1800 amp hour AGM battery bank. The exceptions=
are one of the roof heat pump units and the 220vac stove top. They only r=
un if you are plugged into a 50 amp shore power plug or are running the 17.=
5kw four cylinder turbo charged Kabota generator which can supply as much a=
s 145 amps (about the output of three of our GMC generators). That int=
eresting 24v/12v chassis electrical system requires the use of a device I d=
id not know about called a battery equalizer. The 24vdc is achieved by usi=
ng four 12vdc AGM batteries wired series/parallel. The two series wired gr=
oups make the 24vdc while tapping off of just one paralleled group provides=
the 12vdc. The battery equalizer makes sure that both groups carry the 12=
vdc load so they do not see significantly different amps while charging. =
Some owners and some converters did add a dedicated 120vac plug in the e=
ngine compartment which is powered only by shore power or generator power b=
ut not by inverter power so the 24v charger would come on automatically but=
so far I have not found such a plug in this Country Coach conversion. =
Having been so hands on with all the systems in our two GMCs has really =
helped speed up what otherwise would have been a much longer learning curve=
trying to figure out the systems in the Prevost. Not that it has been eas=
y or fast, but just a lot easier and a lot faster because of that experienc=
e. Jerry Jerry Work The Dovetail Joint Fine furniture designed a=
nd hand crafted in the 1907 former Masonic Temple building in historic Kerb=
y, OR glwork http://jerrywork.com =
