LectraScan Battery Usage
I have been experimenting with the new ET version and battery usage. For
instance a group 24 battery would appear to have about 75 amp hours of
capacity. The ET unit uses about 1.5 amp hours per flush. This would
provide about 50 flushes and the battery would be stone dead.
As a practical matter it would appear that there are about 30 flushes
from such a battery leaving about 50% battery capacity left. My tests
have been with a group 24 unit and at 15 flush cycles the battery
voltage is around 95% at start of treatment and shows about 93% during
treatment.
The ET unit will shut down at 83% of nominal voltage, which would be
very near stone dead. I assume this is to protect not only the battery
but the motors and equipment in the ET.
Peggie Hall says that the ET unit should be used for not more than 2-3
cycles in rapid sequence without a pause for the motors to cool. The new
ET controlled unit senses temperature but it is not clear if the unit
will shut down if the temperature goes beyond acceptable limits.
This temperature problem will be a bigger one in a warm climate and less
in a cold one.
The LectraSan/Scan units are not designed for continuous usage, but
expect breaks between users. Breaks between users also allows the
battery to recover. There are more flushes from a battery that is
allowed some time between flushes. A group 24 used a few times a day may
hold out for more than 50 flushes and still not be anywhere near stone dead.
In summary, battery size should be calculated not only by the nominal
capacity numbers from the battery specs but also in regards to the
frequency with which the head will be flushed. Higher frequency usage
will require a larger battery, a good rough estimate is the next group
size up.
A few suggestions for boats with limited battery capacity. Don't use the
head to urinate in. Use a bottle and dump several in at one time. If
several people want to urinate, one after the other, do so in the head
but only flush once.
These remarks do not cover all the possibilities and I have not tested
all of this thoroughly, but they will give you some added insight into
how all this works.
Mike
Mike, I don't understand the concept of using a battery for your LectraSan
that does NOT get recharged throughout the day. Can you elaborate?
Thanks, Bob Peterson
-----Original Message-----
From: trawlers-and-trawlering-bounces@lists.samurai.com
[mailto:trawlers-and-trawlering-bounces@lists.samurai.com] On Behalf Of Mike
Maurice
Sent: Friday, July 27, 2007 11:03 AM
To: TT
Subject: T&T: LectraScan Battery Usage
I have been experimenting with the new ET version and battery usage. For
instance a group 24 battery would appear to have about 75 amp hours of
capacity. The ET unit uses about 1.5 amp hours per flush. This would provide
about 50 flushes and the battery would be stone dead.
As a practical matter it would appear that there are about 30 flushes from
such a battery leaving about 50% battery capacity left. My tests have been
with a group 24 unit and at 15 flush cycles the battery voltage is around
95% at start of treatment and shows about 93% during treatment.
The ET unit will shut down at 83% of nominal voltage, which would be very
near stone dead. I assume this is to protect not only the battery but the
motors and equipment in the ET.
Peggie Hall says that the ET unit should be used for not more than 2-3
cycles in rapid sequence without a pause for the motors to cool. The new ET
controlled unit senses temperature but it is not clear if the unit will shut
down if the temperature goes beyond acceptable limits.
This temperature problem will be a bigger one in a warm climate and less in
a cold one.
The LectraSan/Scan units are not designed for continuous usage, but expect
breaks between users. Breaks between users also allows the battery to
recover. There are more flushes from a battery that is allowed some time
between flushes. A group 24 used a few times a day may hold out for more
than 50 flushes and still not be anywhere near stone dead.
In summary, battery size should be calculated not only by the nominal
capacity numbers from the battery specs but also in regards to the frequency
with which the head will be flushed. Higher frequency usage will require a
larger battery, a good rough estimate is the next group size up.
A few suggestions for boats with limited battery capacity. Don't use the
head to urinate in. Use a bottle and dump several in at one time. If several
people want to urinate, one after the other, do so in the head but only
flush once.
These remarks do not cover all the possibilities and I have not tested all
of this thoroughly, but they will give you some added insight into how all
this works.
Mike
On Jul 27, 2007, at 11:03 AM, Mike Maurice wrote:
The ET unit uses about 1.5 amp hours per flush
I think there is something wrong with this statement, It implies that
for the 10 seconds to flush the ET it will uses 540 amps-!!?? 1.5 Ah
x 60 min/hour x 60 sec/min x 10 flush/sec = 540A/flush.
An amp-hours is a capacity measurement, that is 1 amp used over one
hour.
If it is 1.5 Amps during the flush cycle (say 10 sec) then it will
use 1.5/60/6= 0.0042 Amp-hours and take about 17,850 flushes...
math symbols wrong, but answer is correct, should have been
1.5 Ah x 60 min/hour x 60 sec/min / 10 sec/flush = 540A/flush.
On Jul 27, 2007, at 12:39 PM, Jerry Berndt wrote:
I think there is something wrong with this statement, It implies that
for the 10 seconds to flush the ET it will uses 540 amps-!!?? 1.5 Ah
x 60 min/hour x 60 sec/min x 10 flush/sec = 540A/flush.
He's not just talking the flush itself...
Electra Sans electrically treat the waste in a unit seperate from the
toilet after the flush.
CUAgain,
Daniel Meyer
http://lifeisaroad.com/boat.html
On Jul 27, 2007, at 11:03 AM, Mike Maurice wrote:
The ET unit uses about 1.5 amp hours per flush
I think there is something wrong with this statement, It implies that
for the 10 seconds to flush the ET it will uses 540 amps-!!?? 1.5 Ah
x 60 min/hour x 60 sec/min x 10 flush/sec = 540A/flush.
Mike, I don't understand the concept of using a battery for your LectraSan
that does NOT get recharged throughout the day. Can you elaborate?
If I told someone that they should charge the battery constantly when
using the LectraSan I would get someone wanting to know why it has to be
charged constantly. So, I describe a test where the battery is not
getting charged at all and naturally...
I specifically stated that I was describing some testing. Which by the
way I may not have added the 1.5 amp (hours) as the consumption number.
But it should have been obvious from the 50 times 1.5 equaling 75, what
was going on. The batteries being rated in AMP HOURS.
What anyone does in terms of battery charging is beyond the scope of my
tests or comments. In effect, battery charging is a whole separate issue
and I was trying to separate that from the issues of battery usage and
life. I have no intention of delving into battery charging technique,
except perhaps as a completely separate thread.
One of the problems with the forum is that a topic tends to become so
diluted by it being taken in every direction except that which started
it. This does a disservice to the original poster, which causes very
little damage at the time. But, what it does do is make it difficult,
not impossible, for folks who come along later to find the material in
the archives.
One other thing, don't go reading into my comments or tests things which
I have not written. For instance, don't draw conclusions about my
opinions about the LectraSsan/Scan units. If I have an opinion and I
think it's important, you can be !@#$ sure that I will not hide it under
20 feet of water.
On the other hand, if you want to know my opinion and if it will be of
interest to the forum, just ask.
Regards,
Mike
+++++++++++++++
Capt. Mike Maurice
Beaverton Oregon(near Portland).
The LectraSan/Scan units use about 50 amps for about 2.5 minutes. This
works out to about 1.5 amp hours. A 60 amp circuit breaker is required
and #2 to #4 wire is needed.
A 75 amp hour battery has about 50 flushes in it, based on simple
arithmetic. The actual flushes to be gotten is more complicated.
A good installation is fairly complicate,d it is easy to make some small
mistakes when doing it.
In many cases a LectraSan/Scan unit beats the tar out of a holding tank
system. But the installation must be thought out very carefully.
Mike
+++++++++++++++
Capt. Mike Maurice
Beaverton Oregon(near Portland).
Thanks, now I understand..
On Jul 27, 2007, at 4:15 PM, Mike Maurice wrote:
The LectraSan/Scan units use about 50 amps for about 2.5 minutes.
Jerry and Sharon Berndt
1-A 87th Ave. NE
Everett, Wa. 98205
Ph 425 335 4020