Battery tales – upgrading batteries for boondocking Safari SE

[hshovic]

There was an old thread where I proposed upgrading battery capacity for boondocking in cool weather. See thread http://www.airforums.com/forums/f449...ity-38012.html

I won’t go into that again, but I figured out I needed 320 AH, and only had 160 AH available from the stock batteries. After months of hand wringing, beery engineering analyses, and communication with THOSE WHO KNOW (my wife), I chose the 6V method. Two GPL-6CT Lifelines with 300 AH. $900 for two! But they are tough (military air grade) and are real hogs (100 lbs apiece). Randy at bestconverters.com had a good price and good service. The dealer mechanic affirmed they would not break the box out (the old batteries were ½ that weight).

Here are some pictures.

First, the BATTERY, heavy but proud. Looks like it needs a stomach staple!

Second, the pre-install area.

Alright, so working conditions were not ideal. Hot toddies every fifteen minutes…

Third, the batteries after being dropped in (gently).

I was surprised at how easy that was. No hernias, no strain, but they did not require lifting up much. Another plus for building a lid, not building up the sides. There was about 2 inches spacing in back, and ½ inch on the sides.

The usable space in the box is 15 1/8 by 14 by 9 7/8”. The battery is 10.28 x 7 12.98”.

Fourth, the wiring in place.

They are hooked up in SERIES not in PARALLEL. Luck entered here, since the wires were just long enough, though I had to replace the clamps, as the Lifelines had screw holes, not posts, and readily-available screw-in posts did not fit the threads. I tried to silver solder the connections, but after a few minor blazes, decided not to try that at home.

Other wires are for battery temp, and battery voltage.

I put anti-corrosion felt rings on each one, though they are not likely to be needed.

I found a wooden handle type socket to tighten the copper bolts, so reducing chances of shorting against trailer side while working. This tool goes in the trailer.

So you noticed there are two jumpers, not one. Whatever… I had them from the old batteries, so more is better (see post http://www.airforums.com/forums/f464...ths-39422.html about more).

I eventually insulated the tops of the two jumpers with little rubber snap-ons.
I epoxied an extension on the center tie down stud to lengthen it enough for the tall batteries.

But these batteries are HEAVY, and I didn’t want them moving around or jumping out, so got a strap iron clamp down to supplement the screw down handle.

Also, note the security device. Lew Farber sold me these and gave me the scoop on use. It is a lockable surround. So it goes over an additional nyl nut just above the wide tie down nut. It is loose on there. Ok, it is not perfect, but then it might slow them down.

Fifth, the padding on the front.

To reduce vibration and chafing (the wife laughed at this one). Chafed batteries are worse in my opinion than chafed thighs…

Sixth, the engineering design.

I was worried about the batteries walking backwards and scrunching the wiring, so I added a threaded stud across the back. You can kind of see it. It’s the threaded stud showing inside the box. It is above the center of gravity. It rotates, to reduce chafing (see above), and is held on with two nyl nuts. It has about 2 mm of play.

Seventh, the completed install w/ lid.

It just so happened the batteries fit nicely into the battery compartment, with plenty of room in the back for wiring, but are too tall, so I had a galvanized sheet metal lid built. All connections are insulated inside, and the lid is tall enough to have at least 2 inches above any connection. Plus the lid itself has stick-on felt around the inside. So if I sit on it, or throw the torsion bars on it, I will not get a surprise. Two bolts secure the lid.

Is it hard to get access? Not so much, but you have to take the propane tanks off and take two bolts out. But then I don’t need to get in there. I have an open voltage reader on the solar, they don’t need water, and they are not supposed to drain fast (3% month), so I don’t need to take them out for the winter. I will monitor that, however to avoid deep discharge.


And what will I do with the old batteries? One is going to go into the truck engine compartment as a spare, just in case I messed up.

As always comments are welcome, as are obvious things I forgot, or engineering nightmares I could have…

[87MH]

Originally Posted by hshovic

....As always comments are welcome, as are obvious things I forgot, or engineering nightmares I could have…

Looks great, and first class documentation.

If you have room, you may want to consider a Master Battery Cut Off - switch off EVERYTHING for storage and not worry about what "might have been" left on. After investing as much as you have in batteries, I would think you may appreciate some extra insurance to prevent total battery discharge.

More discussion in this thread.

http://www.airforums.com/forums/f449...ect-37767.html

This is what I did...

[JackMac]

Hello there, Nice installation. If I might suggest, it would be a good idea to place a plastic or rubber hose onto the threaded rod. The movement of the batteries while towing will cause the threaded rod to eat into the battery case.

[lewster]

Hank,

Nice work and good choice for the batteries! I'm setting up a solar panel array for my ervice van that will use these behemoths! Great capacity for draw-down also.

A master battery disconnect is also a good idea, as there are parasitic loads on your batteries all the time.....even with the Intellitec solenoid in the 'store' position. I have on ready to go into my CCD in the Spring when work slows down.

[TitusLivy]

Very impressive!

In past discussions, some members have expressed concern that added weight from bigger batteries could create problems: poor handling or metal fatigue in the trailer's tongue, for example. So, please keep us posted about your experiences with the changes you've made.

Gotta admit, I'm inspired by your example, so I hope to hear that you're completely satisfied even after you've put a few thousand miles on your modified rig.

Hundreds of amp-hours available for use while boondocking? It boggles the mind!

Thanks!

Titus

[CanoeStream]

Originally Posted by TitusLivy

....concern that added weight from bigger batteries could create problems: poor handling or metal fatigue in the trailer's tongue, for example.

I shouldn't make an absolute statement without checking but I'm thinking the A-frame steel is the same all the way up to a slideout or triaxle; ie, plenty of margin for overall strength. The point loading may be a separate factor.

Interesting project, excellent thread! Thanks

[68 Overlander]

Nice job Hank. Man that looks heavy!

[ROBERTSUNRUS]

Hi, Hank. Nice job on the battery conversion; And I hope it does what you want or expect it to do. And I look foreward to future reports on this set up. Still, for myself, I think for this amount of money, should I buy a 100 watt solar system and keep my cheap batteries. Or should I buy a 2000 watt portable generator. Or maybe buy or make a wind generator? Or just leave it as it is since our boon docking, so far, has only been at rest stops or an occassional park. Decisions, decisions? I think your decision to go with two large 6 volts is probably better than four 12 volts. Waiting to hear more.

[Ahab]

First, nice job, but then I think spending big bucks on batteries and solar is not my bag. We primarily boon dock and did well for 5-6 days on one 29 battery. With our new rig and it's luxuries, a Honda EU2000i does just fine with a lot less expense and weight.

[lewster]

Originally Posted by ROBERTSUNRUS

Hi, Hank. Nice job on the battery conversion; And I hope it does what you want or expect it to do. And I look foreward to future reports on this set up. Still, for myself, I think for this amount of money, should I buy a 100 watt solar system and keep my cheap batteries. Or should I buy a 2000 watt portable generator. Or maybe buy or make a wind generator? Or just leave it as it is since our boon docking, so far, has only been at rest stops or an occassional park. Decisions, decisions? I think your decision to go with two large 6 volts is probably better than four 12 volts. Waiting to hear more.

You won't really get the full benefit of a solar charging system with older batteries. We use AGMs exclusively on new solar installations because they have a super low internal resistance and are easily re-chargd by the solar equipment. Liquid cells have a much higher resistance which must be overcome before the solar begins to work.

IMHO, if you aren't going to do the full monte for a solar charging package AND AGM battreries, you're probably better off with a genny. And while on the subject, you can get a Yamaha already converted to LP use and run off your existing tanks without worrying about gas and the associated fumes, spillage and the like!!!!

[hshovic]

Thanks for the input, as always.

* Master cutoff? I see. I thought the solenoid would do that after checking the wiring, it looks like no drains are downstream from the solenoid. But then, the solenoid may be the drain itself, since it does not work without power. So I will check out a cutoff like Lewster's.

* rod chafing! Good engineering call. I will put a plastic wire loom on that rod. Holddown stud chafing? Not so much. There is a solid 2 inch nut out of sight between the batteries, that has flat sides up against the batteries. The threaded stud will not contact them. I don't see a way to isolate that, so will monitor.

* tongue weight? I think, using the capacity spreadsheet and the dealer mechanic opinion, and jumping up and down on the battery box when empty, that weight is ok. It's only a total of 100 lbs more, but on a long moment arm. Time will tell.

* Generator instead? Good choice too. Solar and batteries vs generator... I like the former, because of the silence, ease of maintenance, less hookup... But the generator would solve a bunch of problems. But a 2000 is much more expensive... But it could be stored in the truck... But we'll see how this works.

[TitusLivy]

Hank, when you refer to a solenoid as an alternative to a master cutoff are you referring to an Intellitec Battery Disconnect Relay? If so...and if your trailer is wired as mine is (which I strongly suspect, since they are of similar vintages), then it really does completely disconnect the battery's positive terminal from any and all downstream devices. And once it's been placed in the "disconnect" mode, it draws zero current. That's because it's a latching relay, which uses current only when its state is changed from "connected" to "disconnected".

There are two caveats:

1. In the "connected" state, the relay draws a very small current that's used to illuminate the LED that tells you the switch is "ON".

2. In the "disconnected" state, the following "upstream devices" are still connected to +12VDC, because they're on the "battery side" of the relay: LPG Gas Detector, +12VDC line from the 7-way connector (umbilical), and one arm of the breakaway switch. In ordinary circumstances, the LPG Detector (which is, of course, a safety device) is the only one of these devices that's drawing current, and it does so at a very low rate. Finally, the electric tongue jack is also connected directly to the battery's positive terminal, regardless of the latching relay's state, but it obviously draws current only when you use it.

Here's a link to Intellitec's website and a product brochure that describes the mechanical and electrical operation in detail:
100Amp Disconnect Relay

I hope this info is helpful.

Regards,

Titus

[ostream]

Looks great and I bet off the grid performance is fantatsic! Couple of quick questions:

- what material is the lid made of? what is the thickness?
- how did you extend the battery hold down screw to accomodate taller batteries?
- what lid opening solution did you use? (don't see a hinge on front?)

Thanks!