Home » Public Forums » GMCnet » Battery Isolater / Combiner & Generator Question
Battery Isolater / Combiner & Generator Question [message #189775] |
Fri, 09 November 2012 21:56 |
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SteveW
Messages: 538 Registered: June 2005 Location: Southern California - Ora...
Karma: 1
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First of all, THANK YOU for this tremendous resource. Really.
I'm exploring and considering replacement of my current (stock) battery isolator with a combiner. Actually two combiners as I'll include the generator battery too.
Here's the question :
If the engine and the generator are running simultaneously, how do the combiners handle these multiple charging sources ??
On a related note - it is OK to run the engine and the generator simultaneously - correct ?? (I envision driving with the generator on occasionally to use the roof air.)
1973 23' Painted Desert (probably - not confirmed yet)
Chassis and House batteries up front, Generator battery in back
Thanks again,
Steve W
Southern California
Steve W
1973 : 23'
Southern California
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Re: Battery Isolater / Combiner & Generator Question [message #189777 is a reply to message #189775] |
Fri, 09 November 2012 22:21 |
Dennis S
Messages: 3046 Registered: November 2005
Karma: 2
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SteveW wrote on Fri, 09 November 2012 21:56 | First of all, THANK YOU for this tremendous resource. Really.
I'm exploring and considering replacement of my current (stock) battery isolator with a combiner. Actually two combiners as I'll include the generator battery too.
Here's the question :
If the engine and the generator are running simultaneously, how do the combiners handle these multiple charging sources ??
On a related note - it is OK to run the engine and the generator simultaneously - correct ?? (I envision driving with the generator on occasionally to use the roof air.)
1973 23' Painted Desert (probably - not confirmed yet)
Chassis and House batteries up front, Generator battery in back
Thanks again,
Steve W
Southern California
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Steve,
Here is a link to an article by Rick D on the GMC electrical system and he covers installing two combiners.
http://www.gmceast.com/technical/Denney_GMC_Electrical_Sys.pdf
Yes, it is ok to run the generator while the coach engine is running. But, early coaches, like your 73, only had a plywood box with a small sheet metal panel over the generator. Be sure you do not have an exhaust leak that might overheat the generator -- harder to notice when driving down the road.
Dennis
Dennis S
73 Painted Desert 230
Memphis TN Metro
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Re: Battery Isolater / Combiner & Generator Question [message #189787 is a reply to message #189775] |
Sat, 10 November 2012 07:59 |
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Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
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SteveW wrote on Fri, 09 November 2012 22:56 | First of all, THANK YOU for this tremendous resource. Really.
I'm exploring and considering replacement of my current (stock) battery isolator with a combiner. Actually two combiners as I'll include the generator battery too.
Here's the question :
If the engine and the generator are running simultaneously, how do the combiners handle these multiple charging sources ??
On a related note - it is OK to run the engine and the generator simultaneously - correct ?? (I envision driving with the generator on occasionally to use the roof air.)
1973 23' Painted Desert (probably - not confirmed yet)
Chassis and House batteries up front, Generator battery in back
Thanks again,
Steve W
Southern California
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Steve,
Short answers:
1 - Just like they handle anything else. Adequately
2 - Sure, many of us do.
Denny's write up is a good read and you should take it on, but the actual answer to your question is easier than you might think.
Combiners are relatively stupid. What they know is that one of the attached banks is at or above a charging potential (it does not know or care which), and therefore, it should close and connect the other bank.
The whole situation is, in the case you describe, that you have two stupid chargers and one intelligent system (I hope - your converter - powered up bu the APU), and just like any other time this case exists, the stupids will keep doing what they want the intelligent one will just step back because he knows he can't change those others. (This is not a political rant.) Then, you will be charging three different banks in parallel. While this may not be very desirable for charging, but it does work (for the larger part).
The thing that I find gets missed a lot, is that an Onan of our series needs the +12V power just to run. It uses it for the ignition, the fuel pump and the fuel solenoid (if so equipped). This is a problem for us 73~4 23s. You kind of need the battery back there. It can be really small. I last chose for price alone. As motorcycle and garden tractor batteries were more expensive, I used a really small car battery. Sometimes I actually bother to connect a charger to it during the winter lay-up. Most times, I do not and it has lasted six years.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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Re: Battery Isolater / Combiner & Generator Question [message #189800 is a reply to message #189787] |
Sat, 10 November 2012 11:06 |
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mike miller
Messages: 3576 Registered: February 2004 Location: Hillsboro, Oregon
Karma: 0
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Matt Colie wrote on Sat, 10 November 2012 05:59 |
SteveW wrote on Fri, 09 November 2012 22:56 | ...
I'm exploring and considering replacement of my current (stock) battery isolator with a combiner. Actually two combiners as I'll include the generator battery too. ...
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... an Onan of our series needs the +12V power just to run. It uses it for the ignition, the fuel pump and the fuel solenoid (if so equipped). This is a problem for us 73~4 23s. You kind of need the battery back there. It can be really small. ...
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-- I would keep the isolator. (Even if bad.) Use it as a terminal strip to connect your stuff. My 26 foot (1973) has three battery banks (House/engine/Onan), two combiners and an isolator. All batteries can be charged by the 60 amp smart converter/charger, main engine alternator OR the Onan flywheel alternator.
-- I have two 23 foot coaches without ANY battery in the rear. (Granted not 73 or 74.) They were set-up by Coachman to start the Onan from the house battery (mounted up front) through a large cable. The question would be, Is it cheaper to buy and maintain a small battery in the rear or buy and install the large cable?
-- For info: 1973/74 coaches and most (but not all) transmodes have boost switches that are NOT spring loaded. I have been told you can take apart the switch and put a spring (from a pen???) inside.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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Re: Battery Isolater / Combiner & Generator Question [message #189835 is a reply to message #189800] |
Sat, 10 November 2012 18:57 |
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Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
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Mike Miller wrote on Sat, 10 November 2012 12:06 |
-- I would keep the isolator. (Even if bad.) Use it as a terminal strip to connect your stuff. My 26 foot (1973) has three battery banks (House/engine/Onan), two combiners and an isolator. All batteries can be charged by the 60 amp smart converter/charger, main engine alternator OR the Onan flywheel alternator.
-- I have two 23 foot coaches without ANY battery in the rear. (Granted not 73 or 74.) They were set-up by Coachman to start the Onan from the house battery (mounted up front) through a large cable. The question would be, Is it cheaper to buy and maintain a small battery in the rear or buy and install the large cable?
-- For info: 1973/74 coaches and most (but not all) transmodes have boost switches that are NOT spring loaded. I have been told you can take apart the switch and put a spring (from a pen???) inside.
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Mike,
The flywheel alternator on the Onan is good for about 10 amps total and the Onan takes about three amps just to run. So, don't count of charging anything but the APU start battery with that. Besides, if you have the APU running, your converter will bring up the house and engine battery much faster.
Would it be cheaper to buy the cable and start the Onan from the house battery?
That has two issues:
1 - Have you tried to run anything the length of that coach? Speaker and Cat cable can run in that over head molding, but I wouldn't plan on bending a 2AWG (what should be for that length and current) up and through there. That leaves underneath. Lots of luck.
2 - Have you priced copper recently? And, it is going up.
You can add a spring, but it is far better to add it to your check list. If Steve's radio killed the batteries (house and starting) over night, then he has much bigger problems than the boost switch. I accidentally left mine playing a CD at reasonable volume for three days (maybe more) and the house battery would still run the reefer when I turned it on.
If you add the spring, also put a jumper clip in your kit so you can make the boost contactor on solid when you need it.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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Re: [GMCnet] Battery Isolater / Combiner & Generator Question [message #189839 is a reply to message #189831] |
Sat, 10 November 2012 19:17 |
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USAussie
Messages: 15912 Registered: July 2007 Location: Sydney, Australia
Karma: 6
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Matt,
I trust you're having me on with this reply and that's OK!
You're right, I just pulled the one out of The Blue Streak and am going to set it up with a step down transformer (240vac/120/vac)
so I can use it here in Oz.
Water almost killed me, when I was about 12 I was playing with a friend of mine down at the Holland America Line docks where my
family had the food concession.
There was this long plank sitting on two cross braces above the water, I walked out on it and when I reached the end that was
hanging off the second cross brace I upset the balance and it tilted up rapidly, I slipped off hitting my head on the way down and
hit the water unconscious.
My friend ran to get help and my Uncle came back (my Dad wasn't there at the time), dove in and pulled me out saving me from
drowning.
Regards,
Rob M.
USAussie - Downunder
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Matt Colie
Sent: Sunday, November 11, 2012 11:36 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Battery Isolater / Combiner & Generator Question
Robert Mueller wrote on Sat, 10 November 2012 17:18
> As far as the buzz box goes it makes a good boat anchor, most of "us" install one of these:
> <snip>
> Regards,
> Rob M.
No Rob, It will not be a good boat anchor.
It will be a good bench power supply for testing 12V stuff if it still works.
(And, what did that water ever do to you that you would ant to throw that in it??)
Matt
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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Re: [GMCnet] Battery Isolater / Combiner & Generator Question [message #189843 is a reply to message #189839] |
Sat, 10 November 2012 19:33 |
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Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
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Robert Mueller wrote on Sat, 10 November 2012 20:17 | Matt,
I trust you're having me on with this reply and that's OK!
You're right, I just pulled the one out of The Blue Streak and am going to set it up with a step down transformer (240vac/120/vac) so I can use it here in Oz.
Water almost killed me, when I was about 12 I was playing with a friend of mine down at the Holland America Line docks where my
family had the food concession.
There was this long plank sitting on two cross braces above the water, I walked out on it and when I reached the end that was
hanging off the second cross brace I upset the balance and it tilted up rapidly, I slipped off hitting my head on the way down and
hit the water unconscious.
My friend ran to get help and my Uncle came back (my Dad wasn't there at the time), dove in and pulled me out saving me from
drowning.
Regards,
Rob M.
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Well,
I sounds to me like the plank was what got you.....
The water just cushioned your fall so your uncle could drag your wet ass out. (
It's all a matter of point of view.
And, don't bother with a step-down transformer, the buzzbox won't work on 50Hz power that you have. They only work because they use the 60Hz to control the output.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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Re: [GMCnet] Battery Isolater / Combiner & Generator Question [message #189866 is a reply to message #189792] |
Sun, 11 November 2012 09:21 |
jhbridges
Messages: 8412 Registered: May 2011 Location: Braselton ga
Karma: -74
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Senior Member |
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Steve -
Transmode have the non-momentary switch. GM upfits haver the momentary. Interestingly, most transmodes including mine power the turn signals even when the key is off. Maybe some of theex GM types can give us the thinking behind these differences.
--johnny
'76 23 transmode norris
'76 palm beach
From: Steve Weinstock <steve.weinstock@cox.net>
To: gmclist@temp.gmcnet.org
Sent: Saturday, November 10, 2012 11:08 AM
Subject: Re: [GMCnet] Battery Isolater / Combiner & Generator Question
Thank you Dennis and Matt.
I did locate and read Rick Denny's write-up prior to my post. It's a great explanation. I was just looking deeper to discover how the specific electronic devices actually operate...
Here's an interesting discovery - the Battery Boost switch on my coach is not a momentary switch. It can actually be switched to boos position and it stays there!! I accidently left it in that position overnight - with the radio on (no volume) - and yep - no battery juice in the morning.
Just about everything on the coach is original... I think that a buzz box replacement is one of the first things I'll do. And I'll do that mostly to gain the smart / stepped charging capability 'cause it seems to work otherwise and certainly isn't buzzing.
Steve W
Southern California
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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Re: [GMCnet] Battery Isolater / Combiner & Generator Question [message #189867 is a reply to message #189815] |
Sun, 11 November 2012 09:39 |
jhbridges
Messages: 8412 Registered: May 2011 Location: Braselton ga
Karma: -74
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Keep the buzz box. It's a good heavy current 12v bench supply.
--johnny
'76 23' transmode norris
'76 palm beach
From: Rob Mueller <robmueller@iinet.net.au>
To: gmclist@temp.gmcnet.org
Sent: Saturday, November 10, 2012 5:18 PM
Subject: Re: [GMCnet] Battery Isolater / Combiner & Generator Question
Steve,
I am electrically challenged and when I was at Emery's home last summer he helped me install a combiner as per GeneF's instructions.
Piece of cake!
http://www.gmcmhphotos.com/photos/combiner-to-diode-isolator/p24994-adding-a-combiner-to-a-stock-diode-isolator.html
As far as the buzz box goes it makes a good boat anchor, most of "us" install one of these:
eBay item 220999465789
Regards,
Rob M.
USAussie - Downunder
-----Original Message-----
From: Steve Weinstock
Thank you Dennis and Matt.
I did locate and read Rick Denny's write-up prior to my post. It's a great explanation. I was just looking deeper to discover how
the specific electronic devices actually operate...
Here's an interesting discovery - the Battery Boost switch on my coach is not a momentary switch. It can actually be switched to
boos position and it stays there!! I accidently left it in that position overnight - with the radio on (no volume) - and yep - no
battery juice in the morning.
Just about everything on the coach is original... I think that a buzz box replacement is one of the first things I'll do. And I'll
do that mostly to gain the smart / stepped charging capability 'cause it seems to work otherwise and certainly isn't buzzing.
Steve
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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Re: [GMCnet] Battery Isolater / Combiner & Generator Question [message #189887 is a reply to message #189866] |
Sun, 11 November 2012 15:19 |
Don A
Messages: 895 Registered: October 2008 Location: Dallas, TX
Karma: 0
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<<< most transmodes including mine power the turn signals even when the key is off >>>
My Glenbrook also, sure does make it convient to check the lights on coach and towd walk around before driving off. Just reach in drivers window to change.
Don Adams Dallas, TX
'76 26' Glenbrook, '90 Sidekick
rebuilt by R Archer, powered by J Bounds, Koba [IMG]http://www.gmcmhphotos.com/photos/data/6109/G2.jpg[/IMG]
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Re: [GMCnet] Battery Isolater / Combiner & Generator Question [message #189894 is a reply to message #189843] |
Sun, 11 November 2012 16:19 |
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USAussie
Messages: 15912 Registered: July 2007 Location: Sydney, Australia
Karma: 6
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Senior Member |
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Matt,
Good point re the plank!
Thanks for the info on the buzzbox, the PO had it connected to a transformer and I guess he never noticed that it didn't charge the
batteries!
Regards,
Rob M.
USAussie - Downunder
-----Original Message-----
From: Matt Colie
Well,
I sounds to me like the plank was what got you.....
The water just cushioned your fall so your uncle could drag your wet ass out. (;)
It's all a matter of point of view.
And, don't bother with a step-down transformer, the buzzbox won't work on 50Hz power that you have. They only work because they use
the 60Hz to control the output.
Matt
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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Re: [GMCnet] Battery Isolater / Combiner & Generator Question [message #189917 is a reply to message #189866] |
Sun, 11 November 2012 19:22 |
Adrien G.
Messages: 474 Registered: May 2008 Location: Burns Flat, OK 73624
Karma: 1
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Johnny,
The power for the turn signal appears to be fused from the battery side instead of the ignition side in the fuse block, so they're never really off.
If a person is hard of hearing, and the turn signal gets activated at night before going to bed. Maybe a dead battery?
Just a thought.
-----------------------------------
>>>>> Transmode have the non-momentary switch. GM upfits haver the momentary. Interestingly, most transmodes including mine power the turn signals even when the key is off. Maybe some of theex GM types can give us the thinking behind these differences.
--johnny
'76 23 transmode norris
'76 palm beach <<<<<<<
Adrien & Jenny Genesoto
75 Glenbrook (26-3) Mods LS3.70 FD / Reaction Sys / 80mm Front&Intermidiate / Hydroboost / 16" Tires / Frame Rebuild / Interior Rebuild
Yuba City,Ca. Text 530-nine-3-three-3-nine-nine-6
[Updated on: Sun, 11 November 2012 19:30] Report message to a moderator
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Re: Battery Isolater / Combiner & Generator Question [message #189921 is a reply to message #189775] |
Sun, 11 November 2012 21:21 |
Luvn737s
Messages: 1106 Registered: June 2007
Karma: 2
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So Why do you need 2 combiners? Aren't you just combining the gen start battery and the house battery? The alternator keep the engine starting battery up.
My combiner is tied to the PD power converter, which is only charging the gen starting battery and the house bank of 2 golf cart batteries. I've tried standard batteries, deep cycle and garden tractor batteries and found that the deep cycle seemed to work best. I depend on the genset too much and it often has to crank a while to start (separate issue) that I need the higher reserve of power in a bigger battery to do the job.
If the genset starts, it can charge the house which in turn will boost the starting battery and get me home. Without an APU, I rely on house batteries which are often depleted at the end of a couple of days of dry camping.
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
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Re: [GMCnet] Battery Isolater / Combiner & Generator Question [message #189937 is a reply to message #189917] |
Mon, 12 November 2012 01:00 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Adrien G. wrote on Sun, 11 November 2012 19:22 | Johnny,
The power for the turn signal appears to be fused from the battery side instead of the ignition side in the fuse block, so they're never really off.
If a person is hard of hearing, and the turn signal gets activated at night before going to bed. Maybe a dead battery?
Just a thought.
-----------------------------------
>>>>> Transmode have the non-momentary switch. GM upfits haver the momentary. Interestingly, most transmodes including mine power the turn signals even when the key is off. Maybe some of theex GM types can give us the thinking behind these differences.
--johnny
'76 23 transmode norris
'76 palm beach <<<<<<<
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It is no different from leaving the 4 way flasher lights or headlights on all night.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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Re: [GMCnet] Battery Isolater / Combiner & Generator Question [message #189942 is a reply to message #189917] |
Mon, 12 November 2012 07:01 |
jhbridges
Messages: 8412 Registered: May 2011 Location: Braselton ga
Karma: -74
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Senior Member |
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Probably - but like someone posted, it sure makes it easy to check the lights on the toad. You pays your money and you takes your pick....
--johnny
'76 23' transmode norris
'76 palm beach
From: Adrien Genesoto <fixman54@syix.com>
To: gmclist@temp.gmcnet.org
Sent: Sunday, November 11, 2012 8:22 PM
Subject: Re: [GMCnet] Battery Isolater / Combiner & Generator Question
Johnny,
The power for the turn signal appears to be fused from the battery side instead of the ignition side in the fuse block, so they're never really off. If a person is hard of hearing, and the turn signal gets activated at night before going to bed. Maybe a dead battery?
Just a thought.
-----------------------------------
>>>>> Transmode have the non-momentary switch. GM upfits haver the momentary. Interestingly, most transmodes including mine power the turn signals even when the key is off. Maybe some of theex GM types can give us the thinking behind these differences.
--johnny
'76 23 transmode norris
'76 palm beach <<<<<<<
--
”When we avoid the mistakes we might have made, we sometimes make the mistakes that we might have avoided.”
Adrien & Jenny
75 Glenbrook
Yuba City,Ca.
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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Re: Battery Isolater / Combiner & Generator Question [message #189947 is a reply to message #189921] |
Mon, 12 November 2012 08:02 |
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Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
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Senior Member |
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Luvn737s wrote on Sun, 11 November 2012 22:21 | So Why do you need 2 combiners? Aren't you just combining the gen start battery and the house battery? The alternator keep the engine starting battery up.
My combiner is tied to the PD power converter, which is only charging the gen starting battery and the house bank of 2 golf cart batteries. I've tried standard batteries, deep cycle and garden tractor batteries and found that the deep cycle seemed to work best. I depend on the genset too much and it often has to crank a while to start (separate issue) that I need the higher reserve of power in a bigger battery to do the job.
If the genset starts, it can charge the house which in turn will boost the starting battery and get me home. Without an APU, I rely on house batteries which are often depleted at the end of a couple of days of dry camping.
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Randy,
If your APU has to crank a while, then add the primer switch that has been frequently discussed.
You are also making a mistake common to pilots and such. You are forgetting that the rest of the world avoids check lists and standard procedures. (This mostly to their own detriment.) If I had a coach that started the APU on the house bank, I'd look for a way to hand start the APU as a back-up. I like redundancy.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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Re: Battery Isolater / Combiner & Generator Question [message #189948 is a reply to message #189921] |
Mon, 12 November 2012 08:14 |
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mike miller
Messages: 3576 Registered: February 2004 Location: Hillsboro, Oregon
Karma: 0
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Senior Member |
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Luvn737s wrote on Sun, 11 November 2012 19:21 | So Why do you need 2 combiners? Aren't you just combining the gen start battery and the house battery? The alternator keep the engine starting battery up. ...
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Using your logic most of us would not need a combiner at all, as we only have two batteries and both are connected to the engine alternator through the isolator. (1975 on) BUT just like most classic cars/trucks, not everyone gets to drive the coach enough for "the alternator keep the engine starting battery up." A combiner between these each side of the isolator allows a single smart charger/converter to maintain the starting battery along with the house battery.
The Onan is a bit different. As delivered from the factory, none of the coaches had anyway to maintain the charge on the generator other than running the generator. If it was used often enough, you wouldn't need to have a combiner there... but most GMC'ers do not. That was one reason that GM made the battery changes in 1975.
SO with any year coach, if you use it often enough. Yes, you do not NEED any combiners.
.
..
...
.... Most of us "need" the combiner(s).
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
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