I am trying to understand the functionalities of a batteries-isolator
and a batteries-combiner. Based on reading about this subject in books
and in this newsgroup, I have these understandings. I would like
people to check if my understandings are correct or not:

- They both prevent a weak battery from draining the strong battery
when those two batteries are in parallel (such as when we switch the
battery selector to BOTH).

- They both have to do with charging by an alternator.

- They both have nothing to do with from which battery that we get the
power from (the battery selector controls this). This means regardless
which device that I use I still need to remember to turn the battery
selector to the house battery when I have stopped the motor; otherwise,
I still may run down both the starting battery and the house battery.

- The isolator costs a 0.7 volt loss of charge that significantly
increases the charging time. That's unless we have something called a
remote regulator that we normally don't use in an outboard motor. The
combiner doesn't have this problem.

- The isolator generates a lot of heat (coming from the loss of 0.7
volt), and need good ventilation around the isolator. The combiner
doesn't have this problem.

- The isolator is a simple device that doesn't tend to fail. The
combiner may not disconnect fast enough under some circumstances (that
I don't quite understand).

- The isolator is cheaper than the combiner.

Is my understanding correct? Thanks in advance.

Jay Chan

wrote in message
oups.com...
I am trying to understand the functionalities of a batteries-isolator
and a batteries-combiner. Based on reading about this subject in books
and in this newsgroup, I have these understandings. I would like
people to check if my understandings are correct or not:

- They both prevent a weak battery from draining the strong battery
when those two batteries are in parallel (such as when we switch the
battery selector to BOTH).

- They both have to do with charging by an alternator.

- They both have nothing to do with from which battery that we get the
power from (the battery selector controls this). This means regardless
which device that I use I still need to remember to turn the battery
selector to the house battery when I have stopped the motor; otherwise,
I still may run down both the starting battery and the house battery.

- The isolator costs a 0.7 volt loss of charge that significantly
increases the charging time. That's unless we have something called a
remote regulator that we normally don't use in an outboard motor. The
combiner doesn't have this problem.

- The isolator generates a lot of heat (coming from the loss of 0.7
volt), and need good ventilation around the isolator. The combiner
doesn't have this problem.

- The isolator is a simple device that doesn't tend to fail. The
combiner may not disconnect fast enough under some circumstances (that
I don't quite understand).

- The isolator is cheaper than the combiner.

Is my understanding correct? Thanks in advance.

Jay Chan


Understanding not quite correct. With an Isolator, is pretty much as you
state, but you just leave the battery switch on 1 or 2. Whichever you want
for starting. Same with the combiner, but the combiner is a relay, that
will stay engaged until the battery voltage on one of the batteries drops
below about 13.5V To start from the battery being charged by the combiner,
you still have to switch the dual battery switch. I run a combiner on my
boat, and run the electronics off the #2 battery. I had to add an extra
disconnect switch for the electronics, as they are wired direct to the #2
battery. The starter gets power from whichever battery the dual batterytch
points to. Normally #1.

wrote in message
oups.com...
I am trying to understand the functionalities of a batteries-isolator
and a batteries-combiner. Based on reading about this subject in books
and in this newsgroup, I have these understandings. I would like
people to check if my understandings are correct or not:

- They both prevent a weak battery from draining the strong battery
when those two batteries are in parallel (such as when we switch the
battery selector to BOTH).

- They both have to do with charging by an alternator.

- They both have nothing to do with from which battery that we get the
power from (the battery selector controls this). This means regardless
which device that I use I still need to remember to turn the battery
selector to the house battery when I have stopped the motor; otherwise,
I still may run down both the starting battery and the house battery.

- The isolator costs a 0.7 volt loss of charge that significantly
increases the charging time. That's unless we have something called a
remote regulator that we normally don't use in an outboard motor. The
combiner doesn't have this problem.

- The isolator generates a lot of heat (coming from the loss of 0.7
volt), and need good ventilation around the isolator. The combiner
doesn't have this problem.

- The isolator is a simple device that doesn't tend to fail. The
combiner may not disconnect fast enough under some circumstances (that
I don't quite understand).

- The isolator is cheaper than the combiner.

Is my understanding correct? Thanks in advance.

Jay Chan

Bill McKee wrote:
Understanding not quite correct. With an Isolator, is pretty much as you
state, but you just leave the battery switch on 1 or 2. Whichever you want
for starting. Same with the combiner, but the combiner is a relay, that
will stay engaged until the battery voltage on one of the batteries drops
below about 13.5V To start from the battery being charged by the combiner,
you still have to switch the dual battery switch. I run a combiner on my
boat, and run the electronics off the #2 battery. I had to add an extra
disconnect switch for the electronics, as they are wired direct to the #2
battery. The starter gets power from whichever battery the dual batterytch
points to. Normally #1.

Seem like my understanding of the way a combiner works is not quite
correct. I am trying to understand what you are telling me.

You said "Same with the combiner, but the combiner is a relay, that
will stay engaged until the battery voltage on one of the batteries
drops below about 13.5V." If I understand you correctly, you are
saying that a combiner will get the power from both batteries if both
are strong, and will not get the power from a weak battery if one if
strong and another one is weak; I assume you are talking about when we
have switched the battery selector to "BOTH". Thanks for pointing this
out.

You also said "To start from the battery being charged by the combiner,
you still have to switch the dual battery switch." If I understand you
correctly, you are saying that we can use the power from a weak battery
that is being recharged by the combiner if we switch the battery
selector to only use that battery. Thanks for pointing this out. I
assume this is to force the electronic devices to use the house
battery, and to keep the starting battery (that has been fully charged)
from being used.

You said "I had to add an extra disconnect switch for the electronics,
as they are wired direct to the #2 battery." Why do you need to do
this? If what my understanding in the last paragraph is correct, you
can simpy turn the battery selector to the #2 battery, right? Why do
you need another disconnect switch?

You said "The starter gets power from whichever battery the dual
batterytch points to. Normally #1." Seem like you are saying that the
combiner will be smart enough to direct power to the starter from the
strongest battery if we have switched the battery selector to BOTH.
This is a good feature.

Seem like I didn't quite understand the fact that a combiner not only
direct the charging current from the alternator but also provides power
to the loads on the boat. Thanks for the correction. I hope I
understand this correctly this time around.

Jay Chan

wrote in message
ups.com...
wrote in message
oups.com...
I am trying to understand the functionalities of a batteries-isolator
and a batteries-combiner. Based on reading about this subject in books
and in this newsgroup, I have these understandings. I would like
people to check if my understandings are correct or not:

- They both prevent a weak battery from draining the strong battery
when those two batteries are in parallel (such as when we switch the
battery selector to BOTH).

- They both have to do with charging by an alternator.

- They both have nothing to do with from which battery that we get the
power from (the battery selector controls this). This means regardless
which device that I use I still need to remember to turn the battery
selector to the house battery when I have stopped the motor; otherwise,
I still may run down both the starting battery and the house battery.

- The isolator costs a 0.7 volt loss of charge that significantly
increases the charging time. That's unless we have something called a
remote regulator that we normally don't use in an outboard motor. The
combiner doesn't have this problem.

- The isolator generates a lot of heat (coming from the loss of 0.7
volt), and need good ventilation around the isolator. The combiner
doesn't have this problem.

- The isolator is a simple device that doesn't tend to fail. The
combiner may not disconnect fast enough under some circumstances (that
I don't quite understand).

- The isolator is cheaper than the combiner.

Is my understanding correct? Thanks in advance.

Jay Chan

Bill McKee wrote:
Understanding not quite correct. With an Isolator, is pretty much as you
state, but you just leave the battery switch on 1 or 2. Whichever you
want
for starting. Same with the combiner, but the combiner is a relay, that
will stay engaged until the battery voltage on one of the batteries drops
below about 13.5V To start from the battery being charged by the
combiner,
you still have to switch the dual battery switch. I run a combiner on my
boat, and run the electronics off the #2 battery. I had to add an extra
disconnect switch for the electronics, as they are wired direct to the #2
battery. The starter gets power from whichever battery the dual
batterytch
points to. Normally #1.

Seem like my understanding of the way a combiner works is not quite
correct. I am trying to understand what you are telling me.

You said "Same with the combiner, but the combiner is a relay, that
will stay engaged until the battery voltage on one of the batteries
drops below about 13.5V." If I understand you correctly, you are
saying that a combiner will get the power from both batteries if both
are strong, and will not get the power from a weak battery if one if
strong and another one is weak; I assume you are talking about when we
have switched the battery selector to "BOTH". Thanks for pointing this
out.

You also said "To start from the battery being charged by the combiner,
you still have to switch the dual battery switch." If I understand you
correctly, you are saying that we can use the power from a weak battery
that is being recharged by the combiner if we switch the battery
selector to only use that battery. Thanks for pointing this out. I
assume this is to force the electronic devices to use the house
battery, and to keep the starting battery (that has been fully charged)
from being used.

You said "I had to add an extra disconnect switch for the electronics,
as they are wired direct to the #2 battery." Why do you need to do
this? If what my understanding in the last paragraph is correct, you
can simpy turn the battery selector to the #2 battery, right? Why do
you need another disconnect switch?

You said "The starter gets power from whichever battery the dual
batterytch points to. Normally #1." Seem like you are saying that the
combiner will be smart enough to direct power to the starter from the
strongest battery if we have switched the battery selector to BOTH.
This is a good feature.

Seem like I didn't quite understand the fact that a combiner not only
direct the charging current from the alternator but also provides power
to the loads on the boat. Thanks for the correction. I hope I
understand this correctly this time around.

Jay Chan


The combiner is a relay that connects the 2 bats together. It is a voltage
sensing relay. If either battery is above 13.5 volts, then the relay will
energize. connecting the 2 batteries together. The only time that the
voltage is that high is when a battery is being charged, or shortly
thereafter. I run all my eletronics on #2 battery. It is charged via the
combiner when the main #1 battery that runs the starter / engine is being
charged. Motor running. If #1 battery fails or is low, I can change the
dual battery switch to #2 or both, to start the main motor.

The 50 amp Combiner from West Marine is the cat's pajamas for smaller 2
battery boats. Mine works perfectly. The .7 V loss through an isolator's
diodes is a major drop in charging voltage to the batteries.
wrote:

I am trying to understand the functionalities of a batteries-isolator
and a batteries-combiner. Based on reading about this subject in books
and in this newsgroup, I have these understandings. I would like
people to check if my understandings are correct or not:

- They both prevent a weak battery from draining the strong battery
when those two batteries are in parallel (such as when we switch the
battery selector to BOTH).

- They both have to do with charging by an alternator.

- They both have nothing to do with from which battery that we get the
power from (the battery selector controls this). This means regardless
which device that I use I still need to remember to turn the battery
selector to the house battery when I have stopped the motor; otherwise,
I still may run down both the starting battery and the house battery.

- The isolator costs a 0.7 volt loss of charge that significantly
increases the charging time. That's unless we have something called a
remote regulator that we normally don't use in an outboard motor. The
combiner doesn't have this problem.

- The isolator generates a lot of heat (coming from the loss of 0.7
volt), and need good ventilation around the isolator. The combiner
doesn't have this problem.

- The isolator is a simple device that doesn't tend to fail. The
combiner may not disconnect fast enough under some circumstances (that
I don't quite understand).

- The isolator is cheaper than the combiner.

Is my understanding correct? Thanks in advance.

Jay Chan



--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth

JR North wrote:
The 50 amp Combiner from West Marine is the cat's pajamas for smaller 2
battery boats. Mine works perfectly. The .7 V loss through an isolator's
diodes is a major drop in charging voltage to the batteries.
wrote:

I am trying to understand the functionalities of a batteries-isolator
and a batteries-combiner. Based on reading about this subject in books
and in this newsgroup, I have these understandings. I would like
people to check if my understandings are correct or not:

- They both prevent a weak battery from draining the strong battery
when those two batteries are in parallel (such as when we switch the
battery selector to BOTH).

- They both have to do with charging by an alternator.

- They both have nothing to do with from which battery that we get the
power from (the battery selector controls this). This means regardless
which device that I use I still need to remember to turn the battery
selector to the house battery when I have stopped the motor; otherwise,
I still may run down both the starting battery and the house battery.

- The isolator costs a 0.7 volt loss of charge that significantly
increases the charging time. That's unless we have something called a
remote regulator that we normally don't use in an outboard motor. The
combiner doesn't have this problem.

- The isolator generates a lot of heat (coming from the loss of 0.7
volt), and need good ventilation around the isolator. The combiner
doesn't have this problem.

- The isolator is a simple device that doesn't tend to fail. The
combiner may not disconnect fast enough under some circumstances (that
I don't quite understand).

- The isolator is cheaper than the combiner.

Is my understanding correct? Thanks in advance.

Jay Chan

Thanks for the suggestion of the West Marine combiner. Seem like it
costs just a little bit over an isolator. This really makes sense for
me to get a combiner instead of an isolator. Then, I can avoid the
0.7-volt loss of charge.

Jay Chan

Bill McKee wrote:
wrote in message
ups.com...
wrote in message
oups.com...
I am trying to understand the functionalities of a batteries-isolator
and a batteries-combiner. Based on reading about this subject in books
and in this newsgroup, I have these understandings. I would like
people to check if my understandings are correct or not:

- They both prevent a weak battery from draining the strong battery
when those two batteries are in parallel (such as when we switch the
battery selector to BOTH).

- They both have to do with charging by an alternator.

- They both have nothing to do with from which battery that we get the
power from (the battery selector controls this). This means regardless
which device that I use I still need to remember to turn the battery
selector to the house battery when I have stopped the motor; otherwise,
I still may run down both the starting battery and the house battery.

- The isolator costs a 0.7 volt loss of charge that significantly
increases the charging time. That's unless we have something called a
remote regulator that we normally don't use in an outboard motor. The
combiner doesn't have this problem.

- The isolator generates a lot of heat (coming from the loss of 0.7
volt), and need good ventilation around the isolator. The combiner
doesn't have this problem.

- The isolator is a simple device that doesn't tend to fail. The
combiner may not disconnect fast enough under some circumstances (that
I don't quite understand).

- The isolator is cheaper than the combiner.

Is my understanding correct? Thanks in advance.

Jay Chan

Bill McKee wrote:
Understanding not quite correct. With an Isolator, is pretty much as you
state, but you just leave the battery switch on 1 or 2. Whichever you
want
for starting. Same with the combiner, but the combiner is a relay, that
will stay engaged until the battery voltage on one of the batteries drops
below about 13.5V To start from the battery being charged by the
combiner,
you still have to switch the dual battery switch. I run a combiner on my
boat, and run the electronics off the #2 battery. I had to add an extra
disconnect switch for the electronics, as they are wired direct to the #2
battery. The starter gets power from whichever battery the dual
batterytch
points to. Normally #1.

Seem like my understanding of the way a combiner works is not quite
correct. I am trying to understand what you are telling me.

You said "Same with the combiner, but the combiner is a relay, that
will stay engaged until the battery voltage on one of the batteries
drops below about 13.5V." If I understand you correctly, you are
saying that a combiner will get the power from both batteries if both
are strong, and will not get the power from a weak battery if one if
strong and another one is weak; I assume you are talking about when we
have switched the battery selector to "BOTH". Thanks for pointing this
out.

You also said "To start from the battery being charged by the combiner,
you still have to switch the dual battery switch." If I understand you
correctly, you are saying that we can use the power from a weak battery
that is being recharged by the combiner if we switch the battery
selector to only use that battery. Thanks for pointing this out. I
assume this is to force the electronic devices to use the house
battery, and to keep the starting battery (that has been fully charged)
from being used.

You said "I had to add an extra disconnect switch for the electronics,
as they are wired direct to the #2 battery." Why do you need to do
this? If what my understanding in the last paragraph is correct, you
can simpy turn the battery selector to the #2 battery, right? Why do
you need another disconnect switch?

You said "The starter gets power from whichever battery the dual
batterytch points to. Normally #1." Seem like you are saying that the
combiner will be smart enough to direct power to the starter from the
strongest battery if we have switched the battery selector to BOTH.
This is a good feature.

Seem like I didn't quite understand the fact that a combiner not only
direct the charging current from the alternator but also provides power
to the loads on the boat. Thanks for the correction. I hope I
understand this correctly this time around.

Jay Chan


The combiner is a relay that connects the 2 bats together. It is a voltage
sensing relay. If either battery is above 13.5 volts, then the relay will
energize. connecting the 2 batteries together. The only time that the
voltage is that high is when a battery is being charged, or shortly
thereafter. I run all my eletronics on #2 battery. It is charged via the
combiner when the main #1 battery that runs the starter / engine is being
charged. Motor running. If #1 battery fails or is low, I can change the
dual battery switch to #2 or both, to start the main motor.

OK. This means a combiner has everything to do with "charging" and has
nothing to do with "using". And I can decide on which battery to use
by using the battery-selector. I think I finally understand the
difference between a combiner and an isolator. Thanks for your
explanation.

Jay Chan