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Changing from 2 12V to 4 6V batteries


Steven P

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The PO of our Diplomat had 2 12V batteries for the house batteries.  I feel they have gone bad and am wanting to replace them with 4 6V batteries, wired series-parallel.  I'm looking at Sam's Club Duracell GC2 AGM batteries.  I have read a lot of opinions on batteries and Sam's is near me making it convenient. 

In doing this, I will need to buy new cables since I do not have the right amount of cables. Any recommendations w cables?  Would Advanced Auto be as good as any?  

I know I will need to change settings in my Magnum inverter/charger to AGM.  What other settings do I need to change?  

What is the lowest voltage to allow the batteries to get to before recharging?  

I plan on going through and cleaning  all connections in the bay and cleaning up and repainting my battery tray.  

Anything I'm missing?

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This is the setup I have.  I have 2 such banks for a total of 8 batteries.  Note that the bank is balanced with one set of batteries in series connected to the positive 4/0 cable and the other set connected to the 4/0 ground.  In between, 2/0 cables were used.

For crimping, I used a 16 ton hydraulic crimper from Amazon.

Cables, lugs, crimper and heat shrink tubing were all purchased from Amazon.  Be sure to get the marine grade sealing heat shrink tubing for a water tight seal.  I also included a picture of the 4/0 small connector cables I recently made for my chassis batteries to replace the 2/0 stock cables.

51OfrWATssL._AC_SL1500_.jpg

PXL_20201021_001324699.jpg

PXL_20201020_181352713.jpg

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26 minutes ago, Steven P said:

I plan on going through and cleaning  all connections in the bay and cleaning up and repainting my battery tray.  

I want to clean up the battery trays on our Signature.  Wondering what you planned on using for paint in this area?   I have used POR-15 on other restoration projects and have had good success but wondering what else is available.

 

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@Frank McElroyvery good info and pics.  Thank you!

@Mike Wahl I like Ospho, a rust remover i got from Ace Hardware.  Once I have the rust gone, I'll paint with a Rustoleum spray paint likely.  Nothing fancy in mind.  Changing to AGMs should help too. 

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8 hours ago, Frank McElroy said:

This is the setup I have.  I have 2 such banks for a total of 8 batteries.  Note that the bank is balanced with one set of batteries in series connected to the positive 4/0 cable and the other set connected to the 4/0 ground.  In between, 2/0 cables were used.

For crimping, I used a 16 ton hydraulic crimper from Amazon.

Cables, lugs, crimper and heat shrink tubing were all purchased from Amazon.  Be sure to get the marine grade sealing heat shrink tubing for a water tight seal.  I also included a picture of the 4/0 small connector cables I recently made for my chassis batteries to replace the 2/0 stock cables.

51OfrWATssL._AC_SL1500_.jpg

PXL_20201021_001324699.jpg

PXL_20201020_181352713.jpg

Frank,

Thanks for the help again.  It looks like you have roughly 2.5 feet of each red and black 2/0 SGX cables for your house connections?  I'm planning my order.  I'll need 8 lugs (at least) and heat shrinks.   Looks like copper is recommended.  Just confirming there is no need for 4/0 cables to connect the 4 house batteries?

Thanks,

Steven

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Steve           You are on the right track with copper SGX cable. If you have an electrician friend he will have the cutters and crimpers you need without putting out cash for once in a blue moon needed tools. (I was so fortunate). That being said there are plenty of outfits on line that will make custom cables for you not a lot more than buying the parts especially if you add in the cutter and crimper. I also had some left over red guard (kind of a liquid rubber) and coated everything even after all was hooked back together cable ends look as good as the day done and that was in 2014.

Roy  2003 Dynasty 

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Steven, I just measured mine and the two long ones are 12" of cable and the short ones are 5" of cable.  So a total of under 2' of red and 2' of black 2/0 cable.  For the house you don't have high draw like you do on the starting batteries.  So 2/0 cables are good.  Yes, all copper.

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Frank's pictures are fantastic! Pulled my trays out this spring and if you would have seen them you would have said get the torches ! I used the rust remover, pressure washer,used the proper steps for applying POR - 15 (brushed it on) after everything was dry I started to lubricate the slides on the trays for a week or so before I put the batteries back in. Looks like brand new! The hard finish with the POR - 15 is amazing. I also have the Duracell Batteries , will be four years coming up and have added distilled water twice. Coach is always plugged in.

Wayne 1999 signature 

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Thanks Wayne.  The picture of the batteries is recent.  Batteries were replaced about 4 years ago and what you see is basically road dust on them.  The battery water miser caps do a great job of keeping the battery compartment corrosion free.

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I'm having trouble finding small amounts of 2/0 SGX cables, especially on Amazon.  I found these, but not SGX.  Anyone know of other sources?  

Screenshot_20201118-211106_Amazon Shopping.jpg

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6 hours ago, Steven P said:

I'm having trouble finding small amounts of 2/0 SGX cables, especially on Amazon.  I found these, but not SGX.  Anyone know of other sources?  

Screenshot_20201118-211106_Amazon Shopping.jpg

Steven,

Over the years I have ordered a lot of stuff from McMaster-Carr in small quantities for personal use. You can use a credit card to pay. Here is a link 2-0 battery cable. I ordered cable, crimp connectors, and a crimping tool to fabricate new cables for our motorhome from them.

https://www.mcmaster.com/standard-electrical-wire/wire-gauge~2-0/

 

 

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  • 2 months later...

Update:  finally got my batteries.  Got 4 of the Trojan 6v T105 AGM Reliant.   Wired up and am setting my Magnum inverter up.  Currently I am set for 400ah, 80% charge rate,  AGM type.  Once I installed, everything looks OK.  Seeing 14.6V on absorb charge.  23A. I'm hooked to 110v and running a couple lights and fridge.  Can someone explain amp hours for me?  Battery label shows 171ah at 5 hours each and 115min at 75amps.  I'm wired in series parallel.  Thanks. 

20210215_181858.jpg

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Here's an explanation.

What is Amp Hour Capacity? : Technical Support (rollsbattery.com)

The label means if you discharge the battery at a rate of about 34amps, it'll do that for 5 hours before the voltage falls below 10.5v. 5hr x 34.2 amps = 171 ah.

If you discharge the battery at 5 amps, you'll get more than 171 ah out of it,

If you discharge it at 75 amps, it'll do that for 115 min and you'll get about 144 ah out of it.

if you discharge at 100a, you'll get a lot less than that.

Cheers,

Walter

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Referring to my Magnum inverter and remote, I downloaded a more current manual from Magnum and it helped explain the settings a lot.  Having 4 Trojan T105s wired in series parallel puts me at 400ah of capacity.  That calculates to 80% charge rate from Trojan's spec sheet.  Per the Magnum instructions,  I set to AGM2 which is for Trojan, Deka, and some other batteries.  AGM is for lifeline (if I remember correctly).  Is there a way to update firmware on these?  I would imagine that would be something done at rallies...if they come back.  Thank you all. 

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I

On 2/21/2021 at 10:04 AM, Steven P said:

... Is there a way to update firmware on these?  I would imagine that would be something done at rallies...if they come back.  Thank you all. 

 I don't think they're built for that. Probably not without swapping out a circuit board. But I don't think there are any significant new 'features' in later versions of the inverter anyway.

Maybe they have some additional preconfigured charge profiles, but those are nothing but a preconfigured set of charge parameters that can easily be duplicated in the custom settings. Nothing magic about them. 

Don't be afraid to set up a custom charge profile to match whatever Trojan recommends.

Cheers,

Walter 

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I take it back... There are a fair number of new features that would be nice.

"If your inverter does not have the required compatibility level for a feature/setting you want, contact Magnum Energy to determine if there is a software upgrade option for your inverter."

I suspect the 'upgrade' comes in the form of a new circuit board...

Here's the ME-ARC compatibility matrix. Apparently I don't have 'level 4'. It would be nice to have the Rebulk setting in Final Charge Setting

Features are determined by the combination of ME-ARC and inverter revision. Apparently I have a 'Level 4' inverter, but need ME-ARC version 4 to see those additional charger features (my ME-ARC is version 3.01) 😞

Magnum Remote Compatibility | Magnum Dimensions (magnum-dimensions.com)

Cheers,

Walter

 

me-arc.jpg

Edited by wamcneil
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