House Batteries - 6V vs 12V

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JeffatJacks
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Joined: Tue Jan 05, 2016 10:38 pm

House Batteries - 6V vs 12V

Post by JeffatJacks »

We purchased our 2004 26RB in March and enjoyed our trip back from PA to TX. One of the last upgrades I have planned are the house batteries. I've searched and read everything I can find on this wonderful forum but I'm still confused on a few things.

I was thinking that a couple of AGMs would be the way to go but to make that work I believe I need to upgrade to a 3-stage charger akin to the information posted here: http://www.bornfreervclub.org/bulletin_ ... =14&t=2482 by Bill Hemme. I don't mind the upgrade if the AGMs are indeed superior in someway.

We won't be doing any long-term boondocking in the near term but would like enough battery power to cut down on generator use as much as possible during 2-3 day outings. I've converted all our interior lighting to LED to help in that regard. Our only other critical use for battery power would be for the TV and running the furnace during the cold times we are out. We'd like for the batteries to get us through a complete night of furnace use. In the future it would be nice to be able to run the microwave for short uses but that might not be realistic with only two house batteries driving the inverter that would be required. We might also want to try out a portable solar panel setup when all other needs and wants are taken car off.

All that being said, I still don't know whether or not to go with two 6V in series or two 12V in parallel. I can get AGMs both ways and if AGMs aren't the way to go I'm sure I can get other deep cycle batteries both ways. I'm hoping Bill Hemme or another equally knowledgeable Born Free Expert can enlighten me a little bit. I realize I haven't asked any direct questions. I just wanted to cover our setup and possible requirements.

I appreciate any input that is provided.

Jeff
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CuJo's Pride
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Re: House Batteries - 6V vs 12V

Post by CuJo's Pride »

I have no advise but we have a 26' RB as well. How are you liking it?

Jo
Curt and Jo
Our Springer Spaniels - Betsy and Moxie
Member of The Born Free Leap'n Lions
"BeMo" is our 2004 26'RB
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whemme
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Re: House Batteries - 6V vs 12V

Post by whemme »

Jeff,

What you want is a house battery pack system with the highest amp-hour rating whether accomplished with deep cycle lead-acid or AGM batteries or with two 6 v batteries in parallel or two 12 v batteries in series. I personally use a pair of Interstate SRM-29 batteries which are rated at 106 amp-hrs each for a total of 212 amp-hrs. The standard batteries installed by the factory were Interstate SRM-27 batteries rated at 94.5 amp-hrs each but the larger SRM-29 will fit the battery carrier.

Your Suburban furnace will be the major drain on those batteries - the fan in the furnace draws about 6 amps. My experience is that you can barely get two days of battery life with extensive running of the furnace and that is with the SRM-29s installed.

The reason to replace your existing Parallax 7345 Charger/Converter is that it is really slow at recharging your depleted house batteries whether plugged into shore power or by running your generator. If you want much quicker recharge times, you need to replace that charger/converter with a modern 3-stage unit such as the Progressive Dynamics PD4655 unit that I recommend.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
JeffatJacks
Posts: 44
Joined: Tue Jan 05, 2016 10:38 pm

Re: House Batteries - 6V vs 12V

Post by JeffatJacks »

CuJo's Pride wrote:I have no advise but we have a 26' RB as well. How are you liking it?

Jo
We have only done the 3.5 day trip back to Texas. We loved the coach for our trip back. I have been buried at work so my preps and upgrades are taking longer than anticipated so we haven't had the opportunity for another trip. We were fortunate to find a 26RB with an immaculate interior. I've only had to focus on things like tires, new shocks, exterior cleanup and gel coast restoration. The rig is really looking nice after hours on the buffer.

Once I get the house battery project nailed down, I will finish the preps to get the Jeep ready for 4 down towing and we'll finally get to take our first trip. We really wanted to attend the homecoming this year but it wasn't possible with work commitments but we are really looking forward to next year. We also joined the BF Club.
2004 Born Free 26 RB
Towing a 2014 Jeep Wrangler Unlimited
JeffatJacks
Posts: 44
Joined: Tue Jan 05, 2016 10:38 pm

Re: House Batteries - 6V vs 12V

Post by JeffatJacks »

Bill,

I really appreciate your input. I've been looking at the Progressive Dynamics 3-stage charger based on your recommendation. I'm pretty confident I can install it myself. I have also looked at the SRM-29s and a couple of other lead acid deep cycle batteries. Please correct me if I'm wrong but when you put 2 6volt batteries in series to get 12 volts it doesn't double the amp hour rating like when you did your 12volt batteries. If that is true what is the appeal for the 6 volt batteries? Do they have overall more capacity, charge better, last longer? It seems everything I read is about 50-50 between going two 12v or two 6v.

Your input on the furnace is actually kind of encouraging. I knew the current house batteries probably weren't perfect and we weren't even getting a whole night of furnace use. What was odd is the fan was still blowing but the heater wasn't heating. This is after 4 hours or so. I assumed the batteries were too low to ignite the heater but weren't weak enough for the blower to die yet. If I cranked up the generator then everything was fine. Was my thinking correct on that?

Jeff
2004 Born Free 26 RB
Towing a 2014 Jeep Wrangler Unlimited
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whemme
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Re: House Batteries - 6V vs 12V

Post by whemme »

JeffatJacks wrote:Bill,

I really appreciate your input. I've been looking at the Progressive Dynamics 3-stage charger based on your recommendation. I'm pretty confident I can install it myself. I have also looked at the SRM-29s and a couple of other lead acid deep cycle batteries. Please correct me if I'm wrong but when you put 2 6volt batteries in series to get 12 volts it doesn't double the amp hour rating like when you did your 12volt batteries. If that is true what is the appeal for the 6 volt batteries? Do they have overall more capacity, charge better, last longer? It seems everything I read is about 50-50 between going two 12v or two 6v.

Your input on the furnace is actually kind of encouraging. I knew the current house batteries probably weren't perfect and we weren't even getting a whole night of furnace use. What was odd is the fan was still blowing but the heater wasn't heating. This is after 4 hours or so. I assumed the batteries were too low to ignite the heater but weren't weak enough for the blower to die yet. If I cranked up the generator then everything was fine. Was my thinking correct on that?

Jeff
You are correct in that when you connect two identical 6 v batteries in series, the amp-hr rating is not doubled, it stays the same as one of the batteries. However, a 6 v battery of the same physical size as a 12 v battery will have an amp-hr rating that is approximately twice as much as the 12 v battery. So what this means is that for a given physical size of a battery, two 6 v batteries in series will have the same amp-hr rating as two 12 v batteries in parallel.

Probably the highest amp-hr rating batteries you could install in your Born Free would be a pair of Trojan T-125 6 v deep cycle batteries. This company makes batteries for golf cars that are generally considered the 'cream of the crop' batteries that you can buy. Two problems: 1) they are expensive and 2) their physical form factor is not a real good fit for your Born Free's existing battery carrier. I think the T-125 has an amp-hr rating of 240 whereas a pair of Interstate SRM-29 batteries in parallel are rated at 212 amp hours.

Maybe someone who has converted to 6 v Trojans can chime in with their experience. Click on the following link to go to Trojan's website for their T-125 battery: http://www.trojanbattery.com/product/t-125/

If you do a search on this forum for the word Trojan you will find several posts about Born Free owners who have installed Trojan T-105 or T-125 6v deep cycle batteries.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
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Mike Jean Bandfield
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Re: House Batteries - 6V vs 12V

Post by Mike Jean Bandfield »

The problem with batteries connected in parallel is that unless they are perfectly matched (and they can never be perfectly matched) they will set-up parasitic currents that will always be flowing back and forth. Over time this will result in a slight drain and a gradual deterioration. Obviously, batteries dissimilar in size or brand will be mismatched and sooner or later they will destroy each other; and even the most perfectly match batteries can haves a slightly different temperature when sitting side by side or have slight differences in materials or construction. Matched 12v batteries will usually not have severe performance issues and generally perform well for a long time. I don't wish to overstate the problem and would not replace a working parallel 12v batteries until their EOL. The point is, with 2 6v's in series you'll never have to worry about it and should 1 battery fail it won't take out the other. And, if one does fail 6 mos down the road you will only have to replace the one that failed. So, if you only need 2 batteries this option makes sense. -Mike
randallrae
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Re: House Batteries - 6V vs 12V

Post by randallrae »

My first BF had room for the trojan golf cart batteries . The advantages in wet cell golf cart batteries are, no parasitic drain between batteries, golf cart batteries are constructed to handle at least 2 hundred deep cycle recharges which is much better than standard deep cycle batteries. Disadvantages physical size, wet cell construction, price (but worth it compared to 12 volt deep cycles).

My current BF did not have room for the trojans so I opted for 12 volt group 31 AGM's. These are really expensive, still can have parasitic drain, can be mounted in all positions, maintenance free, high capacity, and careful measurements required because there are many different configurations, but also good for close to 2 hundred deep cycles. (discharges of 11.9 to 12 volts)
https://www.batteriesplus.com/productde ... li31agmdpm
2012 25' rb
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cmeadows
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Re: House Batteries - 6V vs 12V

Post by cmeadows »

We have a diesel with 2 chassis batteries. The second battery is located under the passenger side bolted to the frame making it difficult to check the water. I replaced both chassis batteries with Duracell 65AGM batteries.

For the coach batteries, we have T-105 batteries bought at a local golf car company. Compared to the T-125, they have a higher charge cycle rating and were 40% less cost.

I replaced the battery tray and used the plywood step plate to stagger the tops of the batteries, added a piece of wood on top of the lower battery to support the tie-down strap over the fill cap, and bolted a 4 gauge, 18 inch extension to the positive cables.

Fleming EZ-Glide 14.125 X 13.25 X 2
http://www.ebay.com/itm/221564534095

The batteries will fit as shown but they will not fit side-by-side in this particular tray. Grinding was required to remove the heads of the front 2 bolts holding the old tray—the nuts were not accessible from the underside.

Interesting reading . . . Car Battery Myths & Facts
http://ponderingfools.blogspot.com/
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Chuck & Laura Meadows
'99 24RB PSD
JeffatJacks
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Re: House Batteries - 6V vs 12V

Post by JeffatJacks »

Thanks to everyone for the great input so far. I ordered two Trojan 6V T-125 from the Golf Car vendor that we do work for so I think I'm getting a pretty good deal. I will be ordering the Progressive Dynamics 3-stage charger as recommended by Bill. Hopefully with his technical article and the instructions with the unit I can get this installed on my own.

That should get us up and running so we can actually start using our Born Free as intended.

I guess the last question I have for now is whether or not it is helpful and/or necessary to install a Battery Monitor like the Tri-Metric, etc. Can anyone give me some advice on that? Is the battery monitor on the range hood helpful at all in this regard?

Jeff
2004 Born Free 26 RB
Towing a 2014 Jeep Wrangler Unlimited
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bcope01
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Re: House Batteries - 6V vs 12V

Post by bcope01 »

I installed two 6v Trojan T-105 Plus batteries in series. Best thing I ever did with batteries. The Plus series have the individual hinged pop-up caps that I like - makes it easy to check water level. I also replaced the original battery tray with the EZ Glide unit that allows the batteries to come out far enough so you have access to all fill holes.

Bill
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Barb & Bill
2004 Born Free 22' Built for Two (Sold)
no longer towing a 2008 Smart ForTwo

Escondido, CA
JeffatJacks
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Re: House Batteries - 6V vs 12V

Post by JeffatJacks »

Bill,

Thank you for your input. I have been looking at your pictures in other threads all night. Do you know the model number for your specific EZ-Glide tray?
2004 Born Free 26 RB
Towing a 2014 Jeep Wrangler Unlimited
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bcope01
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Re: House Batteries - 6V vs 12V

Post by bcope01 »

Jeff, sorry, not sure of the model #. Kim in Customer Service at the BF factory sent it to me several years ago. You could give him a call and ask him what size he recommends for your year and model coach.

Bill
Barb & Bill
2004 Born Free 22' Built for Two (Sold)
no longer towing a 2008 Smart ForTwo

Escondido, CA
JeffatJacks
Posts: 44
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Re: House Batteries - 6V vs 12V

Post by JeffatJacks »

One more question for Mr. Hemme. Is the wiring in my 2004 26RB up to the additional load of the 55 Amp 3-stage charger over the 45 Amp original charger?

Thanks.
2004 Born Free 26 RB
Towing a 2014 Jeep Wrangler Unlimited
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whemme
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Re: House Batteries - 6V vs 12V

Post by whemme »

Jeff,

Yes your existing wiring will handle the initial 55-amp charge rate. By the way that high charge current will only last a few minutes before starting to trail off gradually to less & less charging current.

As to your question about the existing battery monitor in the panel on your stove hood, it can only show the approximate charge level of your house batteries. I designed and built my own monitor using two meters, one 10 to 15 vdc for battery voltage and the other meter 0 to 50 amps to show either battery charge current or battery current drain. A picture of that monitor is attached below. Building that was a rather complex job and I would not recommend trying to copy what I did unless you are handy with electronics. I would recommend the Tri-Metric unit if you want an accurate battery monitor system.

When you install the Progressive Dynamics PD4655 Charger/Converter 3-stage unit (which by the way should be relatively easy to install as it is a direct fit replacement for the Parallax 7345 being removed) you will get a charger/converter that automatically selects one of 3 modes. A) BOOST Mode 14.4 Volts - Rapidly brings RV battery up to 90% of full charge, B) NORMAL Mode 13.6 Volts - Safely completes the charge & C) STORAGE Mode 13.2 Volts - Maintains charge with minimal gassing or water loss. It will select on of these three modes based on the current condition of the house batteries.

However, as you will discover when you read my PD4655 installation post, there is an option that gives you manual override control over these three modes. If you want that manual override control feature, then I recommend that you also get the PD92201 Remote Control Pendant and modify it to interface with the PD4655. This remote control pendant is only necessary if you want optional manual mode control. The pendant also has a green monitor LED that shows you at any time which mode the PD4655 is currently in.
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Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
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