Home » Public Forums » GMCnet » how to wire extra house batteries in front
| how to wire extra house batteries in front [message #360478] |
Wed, 02 December 2020 15:42  |
KB
Messages: 1262
Registered: September 2009
Karma: 0
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Senior Member |
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Hi all, our neighbor gave us some good 6-volt batteries, so I'm considering adding a couple of them to the front of the coach in a 3-battery tray as many have done.
So now I'm trying to figure out what else I would need to buy/do to make it work to see if it's worth doing. Something like a wiring diagram and/or parts list would be really helpful. I *know* this must have been covered extensively, but I'm having a hard time finding the info. This is for a '75 26' coach.
Does anybody have a pointer or links handy?
thanks much,
Karen
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| Re: [GMCnet] how to wire extra house batteries in front [message #360481 is a reply to message #360478] |
Wed, 02 December 2020 19:22  |
mercdave
Messages: 45
Registered: May 2014
Karma: 2
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I have some ideas on this but first, does your battery charger/power supply already have capability to manage two battery banks?
> On 12/02/2020 1:42 PM KB via Gmclist wrote:
>
>
> Hi all, our neighbor gave us some good 6-volt batteries, so I'm considering adding a couple of them to the front of the coach in a 3-battery tray as
> many have done.
> So now I'm trying to figure out what else I would need to buy/do to make it work to see if it's worth doing. Something like a wiring diagram and/or
> parts list would be really helpful. I *know* this must have been covered extensively, but I'm having a hard time finding the info. This is for a
> '75 26' coach.
> Does anybody have a pointer or links handy?
>
> thanks much,
> Karen
>
>
> _______________________________________________
> GMCnet mailing list
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Dave L
Lynnwood, Wa.
1976 GMC 26' Edgemonte Rear Twin
1973 GMC 23' Rear-Ended, Totaled
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| Re: how to wire extra house batteries in front [message #360495 is a reply to message #360478] |
Thu, 03 December 2020 13:14 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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A suggestion Karen when you install the batteries . I installed them on the passenger side as the air pump was on the driver side. Put the 2 golf cart batteries toward the front and the starting battery nearest the tire. When you install or remove the batteries it is much easier to remove them by taking off the wheel liner and sliding them out the bottom those golf cart batteries are heavy and awkward coming out the top. I used to do it out the top but as I got older they got heavier. A short lip on the tray is helpful also.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: how to wire extra house batteries in front [message #360497 is a reply to message #360496] |
Thu, 03 December 2020 15:03 |
Bill Van Vlack
Messages: 419
Registered: September 2015
Location: Guemes Island, Washington
Karma: 14
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Senior Member |
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The main issue with adding the new front house battery set is that they shouldn't be connected in parallel with the rear house set due to charging issues..
https://batteryguy.com/kb/knowledge-base/connecting-batteries-in-parallel/
One way to address this issue is with a battery isolator between the two sets; this would be in addition to a house/engine battery isolator if already fitted.
https://www.bluesea.com/products/7611/BatteryLink_Automatic_Charging_Relay_-_12V_24V_DC_120A
Along with a three-position battery switch (1-2-both) that selects which set is providing house power and allows combining them when boondocking.
https://www.bluesea.com/products/11001/e-Series_Selector_3_Position_Battery_Switch_with_AFD
That way, only one set is connected to the house panel at a time, but both are being charged by either the engine or converter.
Another issue is that when the sets are connected in parallel, the cable running front-to-back should have a circuit breaker at both ends to protect the cable from a short on either end.
One way to connect these are:
Front house set
Ground to closest frame member.
Positive to position 1 on the battery switch.
Selector Switch
Position 1 - Front house set positive
Position 2 - Rear house set positive via circuit breaker
Common - House side of Boost Solenoid.
Front circuit breaker
Between cable from Rear house set to selector switch position 2.
Rear/Front House combiner
One side to Front house position 1 terminal
Other side to Rear house cable at selector switch position 2 terminal.
Engine/House battery combiner
One side to Boost switch Engine terminal
One side to Boost switch House terminal.
Batteries at rest are at about 12.7 volts, so only the alternator, convertor, or a solar controller can raise the voltage at a combiner. The Engine/House Combiner will combine when either the engine or the connected house battery reaches 13.7 volts. The Rear/Front House Combiner will combine when either the Rear or the Front house batteries reach 13.7 volts. When the engine is running, the alternator voltage causes the Engine/House Combiner to combine. Then the Rear/Front House Combiner senses the alternator voltage and combines the rear and front house batteries.
When plugged in at a campground, the convertor will provide 13.7 volts to the rear house batteries and the Selector Switch position 2 via the rear/front cable and circuit breaker. The Rear/Front House Combiner combines the house batteries. Then the Engine/House Combiner sense 13.7 volts at the Selector Switch common and combines the house and engine batteries.
When boondocking, the Selector Switch is set to 1, 2, or Both depending on load and whether it's desired to keep one house battery in reserve. For mostly dead batteries all around, the selector switch can be set to Both and the boost solenoid to Boost to squeeze every bit of power from all the batteries in the coach to start the engine.
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid November 2015.
[Updated on: Thu, 03 December 2020 15:04] Report message to a moderator |
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| Re: [GMCnet] how to wire extra house batteries in front [message #360501 is a reply to message #360495] |
Thu, 03 December 2020 19:00 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Karen,
I agree with Roy's arrangement and R&R. In fact, I've got a special "ramp"
used to slide the batteries from the Ragusa tray back toward the upper
A-arm that makes R&R MUCH easier.
Ken H.
On Thu, Dec 3, 2020 at 2:15 PM roy keen via Gmclist
wrote:
> A suggestion Karen when you install the batteries . I installed them on
> the passenger side as the air pump was on the driver side. Put the 2 golf
> cart
> batteries toward the front and the starting battery nearest the tire. When
> you install or remove the batteries it is much easier to remove them by
> taking off the wheel liner and sliding them out the bottom those golf cart
> batteries are heavy and awkward coming out the top. I used to do it out the
> top but as I got older they got heavier. A short lip on the tray is
> helpful also.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] how to wire extra house batteries in front [message #360516 is a reply to message #360513] |
Fri, 04 December 2020 17:43 |
stu@97381.com, Emery
Messages: 232
Registered: June 2020
Karma: 2
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Check your manual. If you don’t have it you can likely find it free on line.
My Xantrex 40 amp has three separate terminals so I could charge independently 3 separate battery banks. I am only using two - the house bank and the front engine battery. No other isolators needed as the circuits are kept independent internally in the converter (charger)
Emery Stora
> On Dec 4, 2020, at 2:42 PM, KB via Gmclist wrote:
>
> Thanks all. I appreciate your insights. Our current setup has a stock isolator in front, and in place of the buzz box, an Iota DCS-55 converter.
> We also have a couple solar panels and a Xantrex/Schneider C40 charge controller. Since it's a '75, it's got whatever
> gauge that big wire is running from the front to the back. It'd be nice not to have to run another big wire.
>
> I confess putting the extra weight up front for traction is part of the appeal. We live up a big hill, and of
> course are out west where the land is a lot more wrinkled than other parts of the country. Don't think I'd buy
> batteries in just for that, but hey, free batteries... :)
>
> Sounds like we'd have to manually switch between banks with a 3-position battery switch, yes?
>
> thank you,
> Karen
>
>
>
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| Re: how to wire extra house batteries in front [message #360525 is a reply to message #360478] |
Fri, 04 December 2020 20:19 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I suggest that there are lots of ways and choices to make when designing your wiring solution once you have decided where and how you want to mount the the new battery bank.
You want to make the system as simple and as automatic as possible both for charging and later usage. You also need to consider the ground side when you design this. So I would first look at how am I going to charge them.
I can not tell you how confusing it is when someone asks me to look at an electrical problem on their coach and when I open the hood I find all kinds of added switches, devices, and wiring there. You may know what you think you did but no one else will be able to troubleshoot or modify it in the future without some very detailed diagrams and labeling on any added or changed wiring. One of the best at labeling I know is Colonel Ken. Check out his coach if you ever have the opportunity.
You have three banks to charge from the engine driven alternator.
I suggest that the easiest way to do this is to remove the two position isolator and install a 3 position one. This maintains the original GM wiring design and simply adds on new wire to the new house bank.
An alternate design would be to leave the original isolator and add a combiner between the original house bank and the new house bank. Either will work.
Next comes charging from the Converter. If a combiner were used in the previous step then I would take care of combining the same way and charging the front added house set to the OEM rear house set of batteries. This solution would not charge the engine battery but you have not had this added function for 40 years so you probably do not to need it now.
An alternate solution is some companies make a converter with multiple outputs. If this is the kind of converter you have, then running one wire probably no larger that 10 ga from the converter forward to the new battery bank will take care of your charging requirements while maintaining isolation from the original house battery bank.
A side note on negative battery post connections on house battery banks. The negative connections should be connected to the aluminum frame of the body and NOT to the steel frame of the coach.
Now what to do with the positive side of the new battery bank. What do you want to power with it? Answer this question and we can decide how much of what size wiring and maybe some switches or relays we need to add it's use in to the house system.
Be very careful with this as we do not want to put the two battery banks in parallel for electrical safety and mutual discharge reasons.
I can visualize one circuit that could be added with two heavy relays and one wire that would allow the battery switching from inside the coach. I have have not posted it because I have no idea what you want to do here.
There are other possible solutions.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: how to wire extra house batteries in front [message #360538 is a reply to message #360525] |
Sat, 05 December 2020 11:54 |
Bill Van Vlack
Messages: 419
Registered: September 2015
Location: Guemes Island, Washington
Karma: 14
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Senior Member |
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Ken,
In my '76 Royale, the house ground was factory wired from the buzz box to the frame. There may be a steel frame to aluminum frame bonding jumper but I haven't come across it.
Given that some arrangement of isolators and combiners will accomplish the charging requirements, I think the next step - as you mentioned - would be to decide what the second set of house batteries would be used for.
Assuming that it was desired to use the second set for an alternate source for house power plus boost backup, and that the cable to the rear serves both the house panel/converter and the rear house battery, a fairly simple arrangement would be to provide a battery disconnect for both house sets and alternate their use, say, after each trip. The rear house battery disconnect would be at the rear. That way, either of the house sets could power the house panel and boost solenoid, and they could both be paralleled if needed for boost.
Add a power post at the front similar to the engine system V+ post and terminate the front house set positive from the disconnect, the large rear cable, and a jumper to the boost solenoid.
https://www.bluesea.com/products/category/28/3/PowerPost_Connectors/PowerPost
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid November 2015.
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| Re: how to wire extra house batteries in front [message #360542 is a reply to message #360540] |
Sat, 05 December 2020 13:22 |
Bill Van Vlack
Messages: 419
Registered: September 2015
Location: Guemes Island, Washington
Karma: 14
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Senior Member |
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One way to use the capacity of both banks while boondocking without paralleling the sets is to add a house panel for the front set and swap over some circuits. Let the combiner or converter take care of charging. Add a disconnect or swap over wires if one or the other set dies.
Bill Van Vlack
'76 Royale; Guemes Island, Washington; Twin bed, full (DS) side bath, Brazilian Redwood counter and settee tops,455, 6KW generator; new owner a/o mid November 2015.
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| Re: [GMCnet] how to wire extra house batteries in front [message #360581 is a reply to message #360551] |
Sun, 06 December 2020 19:24 |
KB
Messages: 1262
Registered: September 2009
Karma: 0
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Senior Member |
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ljdavick wrote on Sat, 05 December 2020 14:44
I had a similar thought early on with my coach - an extra deep cycle battery - and thought that a yandina combiner would keep it charged and I’d use it exclusively for an inverter circuit for microwave or television, computer, coffee pot, etc.
Hmmm, that's a thought. I do have an inverter installed, which runs off a huge honkin' overkill cable from the rear batteries.
We use it to power the fridge when driving, and the TV, etc, when parked.
thanks,
Karen
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| Re: [GMCnet] how to wire extra house batteries in front [message #360590 is a reply to message #360581] |
Mon, 07 December 2020 07:51 |
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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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Karen,
I have had all kinds of experience with combining multiple battery banks and most of what is here is good, but I will add some cautions.
If there is a single cable that connects the two banks, plan to put a BIG Honkin fuse in that line. If a cell fails in either bank, the good bank will feel obligated to dump all the power it can into the failed bank and you don't want to clean up when that happens.
Buy all the copper you think you might need. Copper may not be cheap, but you only have to buy it once. If you don't buy enough, you will pay for it forever.
Lead/Acid batteries do not play well in parallel. One want to be either the hero or the boss so less less you charge both to full density separately, they will never both be at full density (charge) at the same time.
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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