Combining a 6v bank with existing 12v bank

[McKenziek]

My new motorhome came equipped with two 12v deep cycle batteries rated at 160ah each that connect to a Xantrex ProWatt 1800 inverter as in the left side of the below diagram.

We dry camp quite a bit so I'm torn between removing the 2 twelves and going with a complete 4 battery 6 volt system at 460ah or combining the two battery banks as I've diagrammed below and have a total of 780ah.

First question is whether the combination is good for the batteries and if i build it like this will the 6volt bank be charged efficiently.

[MEXICOWANDERER]

RoyB,

Dang! That sure puts my Crayon® diagrams to shame.

[RoyB]

Mena - Thanks I used to be real patient in my younger years and always enjoyed playing with the drawings... Was pretty good with AUTOCAD at one time. Its neat to draw in real size on things... Then I retired and of course no one has enough monies to keep all of these programs updated... The older programs would continue to work without KEY ID etc.. Now as soon as your open up the program it checks who you is. When I retired I just left all the good stuff at work. I thought I had a copy of VISIO here but can't find it haha... Thats another arm and leg to get validated again.

I then found LibreOffice Ver 3.4 and it does pretty good working with objects being a FREEWARE program... I have added a bunch of library drawings fixed up around what I am drawing... Some one on here recently told me they have a newer version but I haven't gone out and looked for it yet to see what the changes might be...

I like the LibreOffice as it works great with PDF drawings. I also have the fancy Adobe Acrobat Pro 9 which allows you to dissect almost any PDF drawing program and use their object components any way you see fit... So the two work together pretty good... I save everything in PDF format which allows me to CUT and PASTE in JPG format any part of the drawing I want to send along...

Now that I am retired I need to start up again and get my library looking better now...

I will around looking for the parts drawings of electronic things that go with trailers like BLUE SEA or alot of these electrical drawings. I can usually dissect them real easy and adapt to my drawings without a lot of effort. This lets me use their drawings components haha...

I get on roll here sometimes and spend days working on them to make them look pretty hehe... One good sneeze and all those components will go flying away...

When you zoom in real close it doesnt look as pretty as these cheap freebie programs wont lock the ends together like autocad does...

I will download one of their object drawings and start breaking it down. Pretty soon I have bunches of objects all over the pages.. Then you can start using some their fancy art work. Of course the real big guys have all of that locked up...

Roy Ken

[mena661]

As always, your diagrams are awesome!

[RoyB]

This is my season to replace my aging battery bank. I am currently planning on using two groups of two each TROJAN T1275P 150AH 12VDC batteries. To spread out the weight of 82lbs per battery I am going to install two T1275P on the trailer tongue and two additional T1275P batteries in the bed of my truck. this will give me 300AHs capacit from each 12VDC bank. I have a requirement to use a battery bank with my Two way radios and well as when camping so having the two separate banks will work just fine for me.

When camping I will have the capability of combining the two battery banks together giving me 600AH battery capacity

My setup in the truck will look like this


My setup in the trailer will look something like this except only one battery bank will be used...


My OFF-ROAD POPUP floorplan will look something like this


I too may run out of monies as well and coulde possibly mix one bank being the cheaper GC2 6V batteries.

Just some of my planning
Roy Ken

[PaulD1]

jauguston wrote:
Hook them all together. Don't separate them into two banks. It will work just fine.

Jim

Hey Jim,

If you hook enough of them in series, you can make a model boat go over 100 mph! 🙂

It's been a few years.

PaulD

[HiTech]

Hmm I thought there were pretty serious consequences to mislabeling a battery. Might be worth a call. The might ship some real 160 AH batteries out, or a matching set of group 27s to get te amp hours up to meet or exceed the label?

Jim

[MEXICOWANDERER]

Harris battery northeast is clustered (coincidentally I'm sure) around the East Penn DEKA battery manufacturing factory in Pennsylvania.

Harris Battery west is clustered next town over (coincidentally I'm sure) from Corona home to U.S. Battery.

Another "Me Too" reseller

Truck batteries used to be "different". Now, even all but the rare and expensive true deep cycle 8-D are made with the exact same plate design as Wal-Mart group 29

[HiTech]

McKenziek wrote:

HiTech wrote:
The 12v 20 hour rate 160 amp hour batteries I can find are really nice units. I'd be inclined to get 1 or more of the exact same batteries, though they do cost more per amp hour than GC batteries. For example you could add just one more and be at a 480 Ah bank for maybe a little less than replacing the two you have with 4 golf cart batteries to get a smaller bank.

What model number are these big guys? 4D AGM true deep cycles maybe? If they are AGM, it will be hard to get a charger set up that will do what flooded golf cart batteries need AND give the AGMs what they want, without hurting either by under/over charging excessively.

Jim

They are model 27D170's from Harris Battery.http://www.harrisbattery.com/deep-cycle-batteries-harris-deep-cycle-marine-series-27d170

Any comment as to their quality?

Anyone familiar with Harris batteries?

Jim

[mena661]

McKenziek wrote:

Mena, just checked out your sliding battery tray setup. Nice. Did you have to reinforce the compartment below to handle the weight? All my compartments are cheap plastic bins suspended by sheet metal screws so I have some fabrication to do.

Thanks. 🙂 The compartment is steel but I did use two 1/4" pieces of plywood on the bottom of the compartment. Eventually I will probably get someone to weld a steel or aluminum plate on the bottom of the compartment cause I want to get longer slides (I want the batteries to slide all the way out).

McKenziek wrote:


False Advertising?

Hmmmm. Unless the info in the link is wrong. I would call the manufacturer and see what they say. Should be entertaining.

[HiTech]

You do find group 27's at 105 (interstate SRM-27B) and even 115 Ah at the 20 hour rate, but you see more and more listing the 1 amp rate instead.

Jim

[HiTech]

.

[wa8yxm]

Uh, Group 29's are around 105-110, Group 27 more like 95-100 (That is at the 20 hour rate)

NOTE: Some companies (Wal-Mart for example) rate the batteries at the 1 amp rate or some other rate. This is so they can show a bigger number on the amp hour rating,, Ignore it, all G-27's are about the same amp hour no matter if Flooded, Mantence Free or AGM, all the same, it's watts per pound after all.

[McKenziek]

mena661 wrote:
Those are not 160 Ah. The reserve capacity at 25A is 160 minutes. Typical group 27's are around 110 Ah.

False Advertising?

[McKenziek]

mena661 wrote:

McKenziek wrote:

So would this involve a different Charger? This sounds like a plan as I'm sure the one provided by Thor is some low budget Chinese converter/charger.

Depends. If the 12V and 6V have the same or similar charging and floating requirements it is probably ok to use the same charger. One of the members here, BFL, says that it was difficult getting his 12V's back to a real 100% versus the 6V's. The 6's were much easier to get back to 100%. IMO, I wouldn't charge them altogether BUT it's probably ok up till the converter goes into float (which is never really 100%), then I'd put them on separate chargers that have the ability to go to 15+V and top them off (Black and Decker VEC1093DBD equalize mode will perform this function).

Mena, just checked out your sliding battery tray setup. Nice. Did you have to reinforce the compartment below to handle the weight? All my compartments are cheap plastic bins suspended by sheet metal screws so I have some fabrication to do.