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| Seeking Battery Systems Advice [message #245976] |
Mon, 31 March 2014 23:33  |
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SteveW
Messages: 538
Registered: June 2005
Location: Southern California - Ora...
Karma: 1
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Greetings all - and THANK YOU in advance for any advice.
1973 23 footer. 455. Canyon Lands (pretty sure about that)...
As configured by a Previous Owner, it has three house batteries and one chassis battery. Two 12V Group 24 batteries in parallel back by the Onan, and one house battery up next to the chassis battery (passenger side). The batteries up front are clearly connected to the booster. I assume that the two rear batteries are wired in via connection to the 12V distribution panel in the electrical compartment. All have cut off switches. There's a single combiner between the two up-front batteries.
Two topics : one house battery fried and can I wire some 6V batteries into this configuration.
A battery fried. One of the two back by the Onan. Maybe both actually - but one was seriously hot. Sticker says ship date of 9/06. I knew they were old and needed replacement... But - the coach spent today plugged in (first time for quite a while) and when I went to work on it in the afternoon it stunk like crazy. I thought it was my black tank - but thanks to the recent thread about failed batteries stinking - I discovered that it was a battery. So... should I be worried about my Progressive Dynamics 9260 cooking it or was it doomed anyway. And how can i verify that my PD9260 is working properly ??
Replacement Batteries. Can I wire in two 6V batteries (in series of course) back by the Onan or will this confuse the other 12V battery, confuse the booster, or confuse the PD9260 ??
Comments appreciated and additional questions welcomed.
Steve W
Southern California
Steve W
1973 : 23'
Southern California
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| Re: Seeking Battery Systems Advice [message #245979 is a reply to message #245976] |
Tue, 01 April 2014 01:36  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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| SteveW wrote on Mon, 31 March 2014 23:33 |
Greetings all - and THANK YOU in advance for any advice.
1973 23 footer. 455. Canyon Lands (pretty sure about that)...
As configured by a Previous Owner, it has three house batteries and one chassis battery. Two 12V Group 24 batteries in parallel back by the Onan, and one house battery up next to the chassis battery (passenger side). The batteries up front are clearly connected to the booster. I assume that the two rear batteries are wired in via connection to the 12V distribution panel in the electrical compartment. All have cut off switches. There's a single combiner between the two up-front batteries.
Two topics : one house battery fried and can I wire some 6V batteries into this configuration.
A battery fried. One of the two back by the Onan. Maybe both actually - but one was seriously hot. Sticker says ship date of 9/06. I knew they were old and needed replacement... But - the coach spent today plugged in (first time for quite a while) and when I went to work on it in the afternoon it stunk like crazy. I thought it was my black tank - but thanks to the recent thread about failed batteries stinking - I discovered that it was a battery. So... should I be worried about my Progressive Dynamics 9260 cooking it or was it doomed anyway. And how can i verify that my PD9260 is working properly ??
Replacement Batteries. Can I wire in two 6V batteries (in series of course) back by the Onan or will this confuse the other 12V battery, confuse the booster, or confuse the PD9260 ??
Comments appreciated and additional questions welcomed.
Steve W
Southern California
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A few thoughts
Batteries directly wired together in parallel is a big no-no to me. Many people get by with it but I have seen my share of battery explosions over the years from parallel batteries. So I would keep that in mind when redesigning your house batteries.
I thought that 23' coaches and all 1973 coaches had their house battery(s) in front. I'm looking at the 0ctober 1973 house wiring diagram. It shows one 12 volt battery, that appears to be up front, with a 10 Ga. wire and a 50 amp CB going to the house distribution fuse panel. So I'm assuming that the rear pair of batteries are PO add-ons.
Also not mentioned in your posting is if there is one additional Onan starting battery in the rear. OEM had small battery near the Onan in the rear for Onan starting. A PO could have changed Onan starting to be that pair in the rear.
I think you need to re-think whether you need one or two or three house batteries. We can design several solutions for multiple batteries depending on what you want to accomplish.
If you want to replace the two in the rear that are fried. I would definitely replace those two with two 6 volt batteries in series. Series batteries do not present the explosion hazard the parallel ones do. Your PD unit will maintain those two 6 volt ones just fine.
Let's address the 12 volt battery up front. If you keep the rear ones, I would eliminate the front house battery if at practical. Keep in mind, that doing so will eliminate the battery boost capability because you only have a 10 ga. wire running to the rear.
So decide what you want or need and we will engineer a safe solution for you.
I like the disconnect switches that you have on all batteries. I had an engine fire in mine one time and the disconnect switch is what saved my coach from burning to the ground.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Seeking Battery Systems Advice [message #246006 is a reply to message #245993] |
Tue, 01 April 2014 10:22 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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OK,
Thinking this through, the obvious first change is to put two 6 volt batteries wired in series in the rear. I'm ignoring the engine starting battery as it is a different system and should be just fine the way it is.
What we are then dealing with is two parallel 12 volt batteries rather than three. One is up front and the other one is now a large capacity one in the rear.
We are also dealing with 2 charging sources. One up front which is the engine driven alternator and one in rear (or where ever it is mounted) which is the PD unit.
I would love to see the two house batteries kept separated except when charging to minimize explosion potential and also to eliminate the self discharging problem inherent with parallel batteries. This is easy enough to do with a combiner.
So that leaves one final problem. That problem is how to use both the front and rear batteries for the 12 volt house loads and how switch between the batteries either manually or preferably automatically.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Seeking Battery Systems Advice [message #246007 is a reply to message #246006] |
Tue, 01 April 2014 10:38 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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It sounds to me like the biggest load will be the 12 volt refrigerator. The combiner has a lead that can be toggled to force combining even though charging is not happening on either side.
Here is a thought. How about combining only when the heavy load is present and leaving the batteries separate the rest of the time (except when charging). All smaller loads like lighting would be on the big rear battery.
This automatic combining using the manual combiner lead can be accomplished by adding one lead to the combiner from the refrigerator.
That is my thought for the day.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Seeking Battery Systems Advice [message #246059 is a reply to message #245976] |
Tue, 01 April 2014 14:20 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Steve,
You are very lucky that you got KenB's attention. Take what he has written as fact. Paralleled Lead/Acid banks are bad news. The very first thing is that all the paralleled have to be identical in every respect, and close won't do. There are ways that this can be done, but the battery explosion will always be part of the equation.
I also have a '73-23. For there to be two 12V batteries back there, they have to be tiny. I happen to really like the tiny battery in the back as it has allowed me to crank up the APU when everything else was down. (It would also help I were to replace some batteries that much deserve replacement.)
As to your 12/120 reefer. I can tell you from personal experience that if it is t-shirt weather, the pair of GC2s will run it for a bit longer than two days if you are careful with power use. Mine went TU and I replaced it with a dorm reefer and a cheap inverter. It works, but it is far from satisfactory. It is even worse as we got caught at a hot music festival last year and I think I lost 30% of the house bank capacity.
To test your PD9260, go to their website and read what it is supposed to do. Then, get out a meter and watch it. If it looks like it is doing what they say it will. If it does, it works.
Another thing you should know and you will learn if you read PD's site. The size of the converter/charger only matters for the first half of an hour of recharging, after that the bank will limit the charge rate to what it can do.
If you have other questions or need clarification, both KenB and I are here a lot. Just do us one big favor. ASK US before you spend money.
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: Seeking Battery Systems Advice [message #246067 is a reply to message #246059] |
Tue, 01 April 2014 15:08 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Matt, I was operating under the assumption that he had 2 full size batteries in the rear. Are you saying that it is physically impossible in a 1973 23 foot coach?
If this is true, then we may have to re-think what the best solution is for him.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
[Updated on: Thu, 03 April 2014 01:50] Report message to a moderator |
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| Re: Seeking Battery Systems Advice [message #246126 is a reply to message #245976] |
Wed, 02 April 2014 00:43 |
Luvn737s
Messages: 1106
Registered: June 2007
Karma: 2
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I have 2 6V GC batt in the front (house) along with a 12 V starting battery and in the back I have a 12V deep cycle for starting the genset. Combiner, boost switch (non-momentary) and PD smart charger allow any DC power source to supply any other DC power source. Alternator charges Starting battery and house batteries (isolator), Genset charges house and starting (combiner), house battery substitutes for starting battery (boost sw), engine alternator charges genset battery (combiner - unfortunately my genset doesn't have a battery charger feature). I really like the combiner and PD unit working together. I think I finally have a reliable power distribution network on my coach. I just wish my GC batteries from Costco would hold up better. I remove them and keep them inside in the off season, but they still don't come up to full charge on the Smart Charger at home.
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
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| Re: Seeking Battery Systems Advice [message #246129 is a reply to message #246121] |
Wed, 02 April 2014 01:52 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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| SteveW wrote on Tue, 01 April 2014 22:52 |
Thank you Ken, Matt, and Mike !!
Surprisingly I do have two batteries back there... I also couldn't believe it when I discovered them. they're stuffed in forward of the generator and aft of the wheel well. They butt right up to the drivers side hanging closet. Yea... I know... pics would serve well here. I'll take some tomorrow.
I've decided to go with two six volters back there, and retain the house and chassis batteries up front.
I have a Yandina combiner on two front batteries. Sure would like to install same between the rear house battery bank (2 x 6V) and the front house 12V. But how do I do that when they both connect to the same house distribution panel ??
To be continued,
Steve W
1973 23'
Southern California
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You can install the second combiner in series with the power lead going to from the front battery to the distribution panel. The will allow charging of both the front and rear batteries from either the engine alternator or the PD unit. All loads on the distribution panel will normally be powered by the rear batteries which are your largest storage bank. If you deplete the rears you can manually turn on the combiner and it will allow the loads to draw from the front battery. Leave the OEM 50 amp circuit breaker installed for additional safety. I would also install an additional 50 Circuit breaker in the line going to the rear battery bank.
This arrangement has several advantages:
1. The front (smaller battery) is always held in reserve.
2. The front battery can still be used with the battery boost function.
3. Normal operation will keep the dissimilar batteries from discharging each other. This is what Matt was referring to.
4. Normal operation will not allow a shorted cell from one battery to absorb a large amount of current from the other parallel battery and explode. This is not a common thing but does occur on occasion especially on older batteries.
After you install this, please resist the temptation to leave the combiner manually combined all of the time. If you do this item 3 and 4 above will not happen. Explosions while semi-rare can be a catastrophic event. I have seen several in automotive applications as has Matt in automotive and marine applications.
The most catastrophic one I saw was in a UPS room for a major international corporation HQ Data Center. The design specs for the room was concrete walls, floor, and ceiling. There was climate control, proper ventilation, and air quality monitoring. The three UPS battery banks were designed for no parallel cells.
The contractor for the battery equipment in the room did not follow the design specs and the client never realized it. He installed a combination of series and parallel batteries instead of series only. These are large batteries where individual cells that are about 5 gallons each all built in square glass sealed containers so they can be visually inspected. All had over pressure vent valves on each cell hooked to a gas (Hydrogen and oxygen) collection / ventilation system.
This was a 3 phase UPS designed for 10 minute back up while the two diesel generators outside came up to speed and temperature in the case of a commercial power failure.
Well one day one of the cells shorted internally and blew up due to the high current available from the parallel cells. Had the parallel cell not been there this would just have been a low voltage situation requiring the replacement of the bad cell. Needless to say it was a real mess and the repair cost was in the tens of thousand of dollars.
While our application is much, much, much smaller, I hope I have scared you enough not to parallel batteries without some safety devices, which the combiner and CB's are giving you.
I know the above was more detail than you asked for, but others reading this may also take notice.
Good Luck with your project.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Seeking Battery Systems Advice [message #246153 is a reply to message #246121] |
Wed, 02 April 2014 09:57 |
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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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| SteveW wrote on Tue, 01 April 2014 23:52 |
Thank you Ken, Matt, and Mike !!
Surprisingly I do have two batteries back there... I also couldn't believe it when I discovered them. they're stuffed in forward of the generator and aft of the wheel well. They butt right up to the drivers side hanging closet. Yea... I know... pics would serve well here. I'll take some tomorrow.
I've decided to go with two six volters back there, and retain the house and chassis batteries up front.
I have a Yandina combiner on two front batteries. Sure would like to install same between the rear house battery bank (2 x 6V) and the front house 12V. But how do I do that when they both connect to the same house distribution panel ??
To be continued,
Steve W
1973 23'
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Steve,
Before you spend any money, make careful measurements. I think you will be hard pressed to fit 2ea GC2 in the back. If you think you can, cut and tape a pair of corrugated cardboard replica and try to get them in there. (This is something I used to do when fitting more house bank in client's boats.) You may find out that this is not something you care to deal with.
I just looked at mine. I did not measure anything. It might be possible to get 2ea - GC2 in there, but it will be tight. Be sure to let us know what you find. If I did that, I would lose my back up lube oil storage. Several bottles are stuffed along the sides of the single (grp22?) APU battery.
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: Seeking Battery Systems Advice [message #246195 is a reply to message #246118] |
Wed, 02 April 2014 15:41 |
mikethebike
Messages: 331
Registered: January 2014
Karma: 0
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There is a very good write up by a British Electrical Engineer with lab data to back up his claims. I will agree that 2 batteries in parallel most likely will not be a problem but if you start stringing 4 or 5 (as you would in a solar array) it just gets worse and worse the farther from the load the battery is. I'll try and find the article and post a link.
Diagram 5 is in essence the same thing as using a Buss-Bar. The Buss-Bar just makes it easier.
| A Hamilto wrote on Tue, 01 April 2014 21:34 |
| mikethebike wrote on Tue, 01 April 2014 20:44 |
Batteries don't explode because you parallel them, they explode because they give off hydrogen gas. But if you do parallel them do it with buss bars and do not wire them one to the other. If you do the latter the battery closest to the load will drain faster due to minute resistance in the connections at each battery.
If you want to upgrade your house battery go to Odyssey battery and choose one.
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No need for bus bars. Read here:
http://www.gmcmhphotos.com/photos/data/5945/battery_balance_jan2012.pdf
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[Updated on: Wed, 02 April 2014 15:53] Report message to a moderator |
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| Re: Seeking Battery Systems Advice [message #246252 is a reply to message #246146] |
Thu, 03 April 2014 02:00 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| Matt Colie wrote on Wed, 02 April 2014 09:01 |
| Ken Burton wrote on Tue, 01 April 2014 16:08 |
Matt, I was operating under the assumption that he had 2 full size batteries in the rear. Are you saying that is physically impossible in a 1973 23 foot coach?
If this is true, then we may have to re-think what the best solution is for him.
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Ken,
It is not like a 26 at all. There is barely room for a group 24 in there. If one were so inclined, you might be able to stuff two Grp 24s in there. But making connections would be a bear and maintenance would not be practical. Plus, there are no deep cycle available in the little sizes.
I should show you mine next time we are close.
Matt
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If we are still on for Pennsylvania this summer or Hamilton in late spring, I'll take a look at yours then. I'll also be at BS. If you come to BS this year I do NOT expect you will work the whole rally on your coach. That was a bit much last year. You and your wife need to spend some time for recreation at BS this year.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Seeking Battery Systems Advice [message #246257 is a reply to message #246255] |
Thu, 03 April 2014 03:17 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Loffen,
Here is my suggestion.
Work on wiring in that coach as two separate and isolated systems.
One system is for the engine and everything run off of the engine. That includes all exterior lights, the heater / AC blower, anything in the dash, and the two overhead lights above the driver and the passenger.
The second system is everything else inside the coach plus the outside entry light neat the door.
There should be no inner connection between the two systems so if you disconnect the house battery(s) nothing inside the coach should work while everything run by the engine battery should be operational.
I have the schematics for the 1973 coach stored on my PC. If you want them, send me a PM with your email address and I'll forward them to you.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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