Home » Public Forums » GMCnet » Batteries in Parallel for charging
Batteries in Parallel for charging [message #271600] |
Tue, 10 February 2015 09:08 |
Chris Tyler
Messages: 458 Registered: September 2013 Location: Odessa FL
Karma: 7
|
Senior Member |
|
|
Assuming I have Disconnects that will be off when not charging or on shore power, will it cause any problems to have the house [front] and Onan start batteries in parallel for charging?
Thinking that since the charging voltage is higher than the batteries and no load on them they will not draw from each other. They are two different types and capacity though.
Recently had a short in the heavy gauge cable to the rear battery. I had thought that it was hot only on the boost switch. Turns out it was paralleled to the front and there was a curcuit breaker. That heavy cable is also the only line to the house battery.
The short melted the neg terminal to the front battery. Lucky It didnt cause more problems...happened at 2AM while camping. Replaced the battery, fixed and insuated the cable, and had to replace the buzz box with an Intelecharger as it was only outputin 8.52 volts after the short. I also placed a disconect switch as a safety device. I will also be placing a cuircuit breaker to the house battery
Got Allen Hendersons 17" wiring diagrams [highy recomended BTW] and see the original configuration was with the house battery in the rear. I may return to this with 2 6V GC batteries in the future. THe coach had been used by the PO for ~10 years in the configuration I bought it in, and I ran it this way for over a year without a problem.
For now though, the rear battery is only connected to the boost solenoid. Problem is, the rear battery is not charging as the Onan alternator is either not working or has been disconnected so no tag line back to charge it while running. [Onan runs /works great otherwise]The large cable is hot when on shore power, but that is also not charging since the line from the circuit breaker is disconected.The battery would hold a charge for quite some time only being used for onan starting but will run down at some pont.
So, my question is, if I use the disconnects to sparate the batteries when not on shore power or being charged, is there any potential problem in paralleling them to charge the rear battery when it is? I would place another disconect switch in line with the circuit breaker in the rear.
76 Glenbrook
|
|
|
Re: Batteries in Parallel for charging [message #271613 is a reply to message #271600] |
Tue, 10 February 2015 10:36 |
jhbridges
Messages: 8412 Registered: May 2011 Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
If they aren't identical batteries, I don't think I'd do that. Paralleling different batteries can lead to problems.
--johnny
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
|
|
|
|
Re: Batteries in Parallel for charging [message #271620 is a reply to message #271600] |
Tue, 10 February 2015 11:38 |
|
Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
Chris Tyler wrote on Tue, 10 February 2015 10:08Assuming I have Disconnects that will be off when not charging or on shore power, will it cause any problems to have the house [front] and Onan start batteries in parallel for charging?
Thinking that since the charging voltage is higher than the batteries and no load on them they will not draw from each other. They are two different types and capacity though.
Recently had a short in the heavy gauge cable to the rear battery. I had thought that it was hot only on the boost switch. Turns out it was paralleled to the front and there was a curcuit breaker. That heavy cable is also the only line to the house battery.
The short melted the neg terminal to the front battery. Lucky It didnt cause more problems...happened at 2AM while camping. Replaced the battery, fixed and insuated the cable, and had to replace the buzz box with an Intelecharger as it was only outputin 8.52 volts after the short. I also placed a disconect switch as a safety device. I will also be placing a cuircuit breaker to the house battery
Got Allen Hendersons 17" wiring diagrams [highy recomended BTW] and see the original configuration was with the house battery in the rear. I may return to this with 2 6V GC batteries in the future. THe coach had been used by the PO for ~10 years in the configuration I bought it in, and I ran it this way for over a year without a problem.
For now though, the rear battery is only connected to the boost solenoid. Problem is, the rear battery is not charging as the Onan alternator is either not working or has been disconnected so no tag line back to charge it while running. [Onan runs /works great otherwise]The large cable is hot when on shore power, but that is also not charging since the line from the circuit breaker is disconected.The battery would hold a charge for quite some time only being used for onan starting but will run down at some pont.
So, my question is, if I use the disconnects to sparate the batteries when not on shore power or being charged, is there any potential problem in paralleling them to charge the rear battery when it is? I would place another disconect switch in line with the circuit breaker in the rear.
Chris,
It would seem that the coach has been seriously re-muddled. If you have a house bank in the front, that is a hang-on or copy from the '73~4 models. The later models do not have the separate APU and house batteries. This being the case, the APU's battery charging regulator was disconnected. But the intent was that the converter would change the house bank that also starts the APU.
I can tell that GC2 is a good idea. If you plan to put them in the back, get the sliding battery tray that pulls far enough to see both.
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
|
|
|
Re: [GMCnet] Batteries in Parallel for charging [message #271628 is a reply to message #271600] |
Tue, 10 February 2015 12:40 |
|
ljdavick
Messages: 3548 Registered: March 2007 Location: Fremont, CA
Karma: -3
|
Senior Member |
|
|
I believe, from the bit I’ve read, that when charging - batteries can be in parallel without issue if the charging source is sufficient for the task. Gary Bunzer’s article about batteries was very informative . My preference would be to install a combiner, like the Yandina Jim K sells for $60. This connects both batteries, in parallel, when the voltage is higher than (13.3v???) so that they can all charge - then disconnects when the voltage drops below that to a normal battery voltage. It’s an automatic way to do what you are looking to do, and it’s proven. Installation is a snap - all the connectors are already under the passenger side hood where the boost solenoid is.
Mr. ERF posted this great “10 minute combiner installation"
Seems like an inexpensive solution to your problem.
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, CA
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
|
|
|
Re: [GMCnet] Batteries in Parallel for charging [message #271629 is a reply to message #271614] |
Tue, 10 February 2015 13:08 |
Chris Tyler
Messages: 458 Registered: September 2013 Location: Odessa FL
Karma: 7
|
Senior Member |
|
|
[quote title=Mr ERFisher wrote on Tue, 10 February 2015 10:50]Use a combiner to solve this delima
My understanding was that the PD Intelechager acts somewhat like a combiner in charge mode.
I actually have a Yandina combiner but don't see where it could be placed in this configuation to solve the problem.
Only thing I can think of is using it in addition to the isolator as in the photo side writeup referenced on GMC info but it would only charge while running the engine
I do think the 2GC bank is the best solution long term but not in the buget right now. Hence my question. In the interim, and under the conditions I mentioned, is there a potential problem I am overlooking?
Mind you it was functional the way it was [paralelled] for many years and the batteries althogh 3 and 4 yrs old charge and load test fine. The short was a frealk accident that exposed a flaw.
Matt: I seem to recall that many coaches back in the day had the Onan alternator disconnected due to some sort of feedback problem to the board and was charged by either the converter or the engine alternator. Getting that to work might be an option, but not if is a potential issue with the board. The Onan [knock on wood] is doing great and I almost hate to mess with it. I was looking at adding an electronic ignition to it but havent for the same reason.
76 Glenbrook
|
|
|
Re: [GMCnet] Batteries in Parallel for charging [message #271642 is a reply to message #271629] |
Tue, 10 February 2015 17:19 |
|
Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
Chris Tyler wrote on Tue, 10 February 2015 14:08My understanding was that the PD Intelechager acts somewhat like a combiner in charge mode.
I actually have a Yandina combiner but don't see where it could be placed in this configuation to solve the problem.
Only thing I can think of is using it in addition to the isolator as in the photo side writeup referenced on GMC info but it would only charge while running the engine
I do think the 2GC bank is the best solution long term but not in the buget right now. Hence my question. In the interim, and under the conditions I mentioned, is there a potential problem I am overlooking?
Mind you it was functional the way it was [paralelled] for many years and the batteries althogh 3 and 4 yrs old charge and load test fine. The short was a frealk accident that exposed a flaw.
Matt: I seem to recall that many coaches back in the day had the Onan alternator disconnected due to some sort of feedback problem to the board and was charged by either the converter or the engine alternator. Getting that to work might be an option, but not if is a potential issue with the board. The Onan [knock on wood] is doing great and I almost hate to mess with it. I was looking at adding an electronic ignition to it but havent for the same reason.
Chris,
PD units have no internal combiner capability.
As soon as the the house bank was moved to the rear and the APU start battery eliminated, The Onan charging circuit was disconnected, Most were not removed, but they were disconnected. I heard it was a warranty issue, but I never got any specifics. I could easily believe that there was a conflict between the original freo-resonant "buzz box" and the strange SCR trigger of the Prestolite. If you have three banks (main engine, house and APU start) and your APU still has the Prestolite brick on it, you might as well hook it up.
In the mean time, get both the '73~4 and '76 diagrams and see which is closer. You said you have a good set, well print a junk set and mark it up. If you can provide us with enough information, we can make this work right.
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
|
|
|
Re: Batteries in Parallel for charging [message #271661 is a reply to message #271600] |
Tue, 10 February 2015 21:03 |
roy1
Messages: 2126 Registered: July 2004 Location: Minden nevada
Karma: 6
|
Senior Member |
|
|
I removed the rear 6d battery from my76 glenbrook and installed 2 golf cart batteries up front with the starting battery to gain storage in the rear compartment . I also moved the 50 amp circuit breaker and bypass relay up front also. Actually with the 50 amp breaker up front it would protect you better with the short you had. You should get rid of the generator starting battery in the rear you don't need it. There is only a fraction of a volt drop in that big cable with the Onan cranking. You also should disable the Onan factory charge circuit if it is still connected you don't need it. I made this modification 20 years ago it it works real well for me.
Roy Keen
Minden,NV
76 X Glenbrook
|
|
|
Re: Batteries in Parallel for charging [message #271663 is a reply to message #271600] |
Tue, 10 February 2015 22:01 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
Charging of batteries in parallel is not a problem. It is done all the time.
What is a problem is protecting against self discharge when the two or multiple batteries are left in parallel after the charging voltage is removed. Using a combiner or isolated resolves that issue. In this case I would use a combiner between the house and Onan starting batteries.
A second problem is the potential for explosion or fire if one of the batteries were to fail in a shorted cell condition. The combiner will not protect from that problem because of it's delay in both combining and un-combining. So, I would also insert a fuse or or a Circuit Breaker in line with the charging line between the combiner and the Onan battery.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
Re: [GMCnet] Batteries in Parallel for charging [message #271695 is a reply to message #271642] |
Wed, 11 February 2015 11:52 |
Emery Stora
Messages: 959 Registered: January 2011
Karma: 4
|
Senior Member |
|
|
Matt
When I installed my Statpower Trucharge a few years back the instructions indicated that it would not charge any battery that had another charging source. So, I removed the small charger that was on the Onan and everything has been working fine.
Emery Stora
> On Feb 10, 2015, at 4:19 PM, Matt Colie wrote:
>
> Chris Tyler wrote on Tue, 10 February 2015 14:08
>> My understanding was that the PD Intelechager acts somewhat like a combiner in charge mode.
>>
>> I actually have a Yandina combiner but don't see where it could be placed in this configuation to solve the problem.
>> Only thing I can think of is using it in addition to the isolator as in the photo side writeup referenced on GMC info but it would only charge
>> while running the engine
>>
>> I do think the 2GC bank is the best solution long term but not in the buget right now. Hence my question. In the interim, and under the conditions
>> I mentioned, is there a potential problem I am overlooking?
>> Mind you it was functional the way it was [paralelled] for many years and the batteries althogh 3 and 4 yrs old charge and load test fine. The
>> short was a frealk accident that exposed a flaw.
>>
>> Matt: I seem to recall that many coaches back in the day had the Onan alternator disconnected due to some sort of feedback problem to the board
>> and was charged by either the converter or the engine alternator. Getting that to work might be an option, but not if is a potential issue with the
>> board. The Onan [knock on wood] is doing great and I almost hate to mess with it. I was looking at adding an electronic ignition to it but havent
>> for the same reason.
>
> Chris,
>
> PD units have no internal combiner capability.
>
> As soon as the the house bank was moved to the rear and the APU start battery eliminated, The Onan charging circuit was disconnected, Most were not
> removed, but they were disconnected. I heard it was a warranty issue, but I never got any specifics. I could easily believe that there was a
> conflict between the original freo-resonant "buzz box" and the strange SCR trigger of the Prestolite. If you have three banks (main engine, house and
> APU start) and your APU still has the Prestolite brick on it, you might as well hook it up.
>
> In the mean time, get both the '73~4 and '76 diagrams and see which is closer. You said you have a good set, well print a junk set and mark it up.
> If you can provide us with enough information, we can make this work right.
>
> Matt
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
Re: Batteries in Parallel for charging [message #271715 is a reply to message #271661] |
Wed, 11 February 2015 16:46 |
Chris Tyler
Messages: 458 Registered: September 2013 Location: Odessa FL
Karma: 7
|
Senior Member |
|
|
roy1 wrote on Tue, 10 February 2015 21:03I removed the rear 6d battery from my76 glenbrook and installed 2 golf cart batteries up front with the starting battery to gain storage in the rear compartment . I also moved the 50 amp circuit breaker and bypass relay up front also. Actually with the 50 amp breaker up front it would protect you better with the short you had. You should get rid of the generator starting battery in the rear you don't need it. There is only a fraction of a volt drop in that big cable with the Onan cranking. You also should disable the Onan factory charge circuit if it is still connected you don't need it. I made this modification 20 years ago it it works real well for me.
Did you place them all on the passenger side? My measurements would seem they wouldnt fit. From a weight distribtion standpoint is this an improvement?
76 Glenbrook
|
|
|
|
Re: Batteries in Parallel for charging [message #271728 is a reply to message #271600] |
Wed, 11 February 2015 18:56 |
Chr$
Messages: 2690 Registered: January 2004 Location: Scottsdale, AZ
Karma: 1
|
Senior Member |
|
|
Chris, Don't try to charge two dissimilar batteries in parallel. The weaker battery will affect the charge of the stronger one, and if you have a bad cell in one, it will really screw things up.
Let the engine charge the coach battery, and if you want more house battery capacity, get two GC2 6V golf car batteries and wire them in series. You will get much better performance and life out of them. I have two that are 5 years old, and still take charge and run strong. Use shore power, the onan, or solar to charge the house batteries. (I have 390W solar on my rig.)
-Chr$: Perpetual SmartAss
Scottsdale, AZ
77 Ex-Kingsley 455 SOLD!
2010 Nomad 24 Ft TT 390W PV W/MPPT, EV4010 and custom cargo door.
Photosite: Chrisc GMC:"It has Begun" TT: "The Other Woman"
|
|
|
Goto Forum:
Current Time: Mon Sep 30 11:27:05 CDT 2024
Total time taken to generate the page: 0.01573 seconds
|