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Where to put two to four 6 volt batteries in Sunrader motorhome??


Stevo

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I would like to have the two 6 volts batteries (and maybe even 4 later) in a metal box located just aft of the differential kind of like this https://www.vanspecialties.com/gallery_van/yota-4x4/ (see last few photos). Instead of a bracket that requires one to crawl around underneath like they did, I would prefer to access the batteries through a flush hatch in the floor. There's no way I could hang all that weight off the floor so it will require a metal box that's welded to the frame underneath. I was wondering if anyone has done something like that?

Edited by Stevo
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Enjoyed your site.   You will be the first one I know of that is going to do that with batteries.  It is unlikely it has not been done before but not archived anywhere

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  • 2 weeks later...

Interesting, I wasn't getting notifications from this thread...

So you don't think 124 pounds concentrated in such a small area wouldn't be too much weight on the flimsy floor of a Sunrader?

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The best place for that sort of weight is between the axles. Distribute the weight and use large battery cables to make up for the distance.

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Well would you let a 124 lb girl stand on the floor? Bet so. But there are tons of metal boxes on EBay for cheap and I know I could attach it to the frame maybe where a cross member is so that it would be solidly attached. Drill some holes in it and voila it's vented. Or a plastic battery box that fits both batteries held in place with some steel straps like the ones that hold your holding tanks, wrapped around the frame. There's always a way

Linda S

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16 hours ago, WME said:

The best place for that sort of weight is between the axles. Distribute the weight and use large battery cables to make up for the distance.

Between the axles would be ideal but there's no room because the muffler and gas tank are in the way (18' Sunrader). 

There's space behind the differential that's very roughly 13" x 25" though. What do you guys think about a steel bracket there with a trap door cut into the floor so I can service them?

 

16 hours ago, linda s said:

Well would you let a 124 lb girl stand on the floor? Bet so. But there are tons of metal boxes on EBay for cheap and I know I could attach it to the frame maybe where a cross member is so that it would be solidly attached. Drill some holes in it and voila it's vented. Or a plastic battery box that fits both batteries held in place with some steel straps like the ones that hold your holding tanks, wrapped around the frame. There's always a way

Linda S

Hah hah, good point about the girl, but what if I eventually have four 6 volt batteries?

 

NOTE: I'm not getting email notifications when someone replies to a thread I'm subscribed to and I'm pretty sure I have all the right boxes checked for that. Can you please tell me who I should contact about this?

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The space between the differential and the spare tire is about 13" x 25. I know I can put two there and maybe just maybe four. They did that in the last 4 photos on this page: https://www.vanspecialties.com/gallery_van/yota-4x4/

In the case of that rig, the bracket is bolted to the frame so they can drop it to change batteries. They used sealed AGM's so there was no need to service them. I'm thinking of making the bracket fixed so I can service the batteries from the top through a trap door.

Yes, I would appreciate it if you could let me know who I should contact about not getting notifications. They aren't in spam either. Thank you.

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I checked and only you can change your notification settings. On the other hand mine were set to send me an email every time new content was posted and thank god that never happened. It seems to be just the way this system is working. You need to login to see content of threads your following. You did mark the thread as following right?

Linda S

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The default is set to "Notify me of replies" on each page because that's what I have selected in my Settings but I'm not getting email notifications when someone responds to a thread I'm subscribed to - like this one, for example. I used to get them a couple years ago.

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  • 4 weeks later...
On 3/21/2017 at 4:49 PM, linda s said:

Greg did have to change the system a while back for security reasons. It may be that this new system no longer does that. Sorry

Linda S

If the system no longer sends email notifications then he is losing a ton of traffic no doubt.

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Now, back to where I should put the house batteries...

Instead of spending the dough on a welded bracket behind the differential and the complications involved, I'm thinking about putting 2 to 4 batteries on top of the passenger side wheel well in my 83 Sunrader. I would build a plywood platform for them to sit on top of the wheel well with extensions on each side that would go to the floor and then I will epoxy everything in place. This battery compartment would be the bottom section of the galley cabinet that will have a sink, drawer and counterspace above it.

So, what do you think about putting 120 to 240 pounds of batteries there?

Thanks

 

IMG_0488.JPG

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OK so this post is back. Lets refresh things, why so much battery capacity? vs say 2 T-105s and a 200w solar setup.

 Also keep in mind the cargo carry capacity of the RV

Edited by WME
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Two T-105's might be enough or the Crown equivalent. I need to figure that out still. Either way, what do you think about putting them on top of the wheel well?

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We've done the lower and forward thing and it won't work, BUT its still the best thing so keep looking. However 2 batteries mounted on top the wheel wheel, how you suggest, in a completely sealed box vented to the outside should be OK. With everything installed how are you going to service them?

4 or 6 batteries NO WAY

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16 hours ago, WME said:

We've done the lower and forward thing and it won't work, BUT its still the best thing so keep looking. However 2 batteries mounted on top the wheel wheel, how you suggest, in a completely sealed box vented to the outside should be OK. With everything installed how are you going to service them?

4 or 6 batteries NO WAY

There's no more "looking" because there are only two places I can put the batteries inside. One is in a compartment under the dinette bench, but then the weight would be cantilevered too far back. The only other option is to put them on top of the fiberglass wheel well. Yes, I will vent the compartment to the outside and the access door inside would be totally sealed with a rubber gasket.

I could build a 3/4" plywood platform for the batteries to sit on top of the wheel well. Another option would be to build a steel frame that the batteries would sit on. The point is that I wouldn't just put the two to four 6 volt batteries directly on top of the fiberglass. So now that I have explained that, do you still think 4 batteries would be too much there?

Thanks again.

Edited by Stevo
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Two batteries yes, four no. The mount your planning on is glassed to the floor, the floor on Sunrader is a known weak point. The complete weight of the shell is carried by the edge of the light ply/foam floor and you want to add 120 - 240 lbs right at the edge. You need to spread the weight out as much as possible. A 3/4×8 piece of ply isn't enough area. The floor on a Sunrader is NOT supported full width and is known for buckling around the edge

The only way I would consider four batteries is if there was a steel sub frame under the floor that was welded to the truck frame. Crawl around under your rig and look how the house is attached to the frame.

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On 4/12/2017 at 7:04 PM, Stevo said:

Now, back to where I should put the house batteries...

Instead of spending the dough on a welded bracket behind the differential and the complications involved, I'm thinking about putting 2 to 4 batteries on top of the passenger side wheel well in my 83 Sunrader. I would build a plywood platform for them to sit on top of the wheel well with extensions on each side that would go to the floor and then I will epoxy everything in place. This battery compartment would be the bottom section of the galley cabinet that will have a sink, drawer and counterspace above it.

So, what do you think about putting 120 to 240 pounds of batteries there?

Thanks

 

IMG_0488.JPG

Remember that the batteries might weigh a certain weight but when you encounter ruff road conditions, pot holes, dips etc there will be some G-Force applied amplifying the weight considerably. My question why so many batteries? Two group 24 agm, solar panels and a small backup generator. 

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i would get a used lifepo4 (lithium ion) battery pack on ebay from a donor prius or tesla or the chevy volt.

save all that lead weight for the golf cart and get into the new technology. Once you go lithium you never go back./ No need for venting 3 times the amp Hours per density and the best part they charge in less than half the time.

They can be had in the junkyard at pick a parts from wrecks believe it or not. Chevy banks are 48 Volts and can be put into parallel.

If you decide to do it and it works I will copy you.

 

 

Edited by Totem
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On 4/21/2017 at 2:06 PM, Totem said:

i would get a used lifepo4 (lithium ion) battery pack on ebay from a donor prius or tesla or the chevy volt.

save all that lead weight for the golf cart and get into the new technology. Once you go lithium you never go back./ No need for venting 3 times the amp Hours per density and the best part they charge in less than half the time.

They can be had in the junkyard at pick a parts from wrecks believe it or not. Chevy banks are 48 Volts and can be put into parallel.

If you decide to do it and it works I will copy you.

You inspired me to look into using lithium batteries instead of lead acid and so far they look amazing. Lighter, smaller, no venting, thousands of cycles, can be deep discharged, charge fast, etc.

Are you saying I should look into buying them from junk yards out of wrecked hybrid cars like Prius's and Volts?

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LiPo batteries are awesome but require very special charging. Also a basic LiPo single cell has a nomial voltage of 3.2v and a cut off voltage of 2.5v  so your looking at a battery of 12.8  to 10 v. Most of the hybrid battery packs are 24, 48, or 96 v.

http://www.ebay.com/sch/Electric-Vehicle-Batteries/177703/i.html

Have fun

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the only special thing they require to charge is a BMS module; but there are chargers out there on ebay that can handle any LifePo4 (they are programmable and have pin out wires to attach to multiple banks individual cells etc.

Finally, do not let a 24 volt setup discourage you... there are many out there and many more to come in 48 and higher; its becoming the new automotive standard, and 24 volt is standard on commercial vehicles in many many applications. In fact 24 volt and othe inverters are easy to find on ebay also to run common 110 household appliances. :)

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OK so we're talking about a 20 year old  RV with a 12v system.  How do you charge a 24 or 48v battery under way.

This is a long slog to read but it has the right answers...https://www.victronenergy.com/blog/2015/03/30/batteries-lithium-ion-vs-agm/

 

 

 

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  • 1 month later...

I have had the same thought about using the underfloor area aft of the differential for a battery bank with an access hatch. It is a large area. Others have made a good point though, that it is best to keep large weight additions as far forward as possible as our rigs are already tailheavy. I am likely going to go to a dual battery setup and have considered the area above the wheel well.

I would still like to utilize that area behind the axle. for bulky but light items such as folding chairs, bedding, empty water containers, etc. I would make a fairly good sized hatch in the floor. This would work very well for my rear dinette layout. I would also keep the spare tire there. This would free up the rear bumper for another storage project, an enclosed bike storage.

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On 5/2/2017 at 11:29 PM, WME said:

OK so we're talking about a 20 year old  RV with a 12v system.  How do you charge a 24 or 48v battery under way.

This is a long slog to read but it has the right answers...https://www.victronenergy.com/blog/2015/03/30/batteries-lithium-ion-vs-agm/

 

 

 

ironically this would easily be accomplished with a charger plugged into a 12 volt inverter, case closed; you wouldn't want to hook it up direct to the alternator. I charge my 36 volt Lifepo4 scooter banks while driving all the time; off of a dinky small 800 watt HF inverter. I have had an eyeball on 36 volt to 120 inverter that I saw on ebay a few times.. I should have bought it when I had the chance, it was Japanese and I havent seen it since. I could have used my scooters AS my house battery bank and ditched another Marine lead brick from the rig.

Edited by Totem
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