Battery/boondocking Question

[kath]

We used to take the Chalet to many of our Forest Service campgrounds here in Oregon ($6 or $10 a nite in th most beautiful places - you can't beat it!). We had 2 batteries and never once ran out of juice. The longest we go is 5-7 days, with only basic needs (heater fan, lights, etc.)

My question is this:  The new 16DBS only has one battery (for now; photo below, hopefully). Are we likely to run out of juice?  Should I just go get the extra battery now and not be concerned?



https://www.flickr.com/photos/96992642@N04/shares/z4X8Po

[tinkeringtechie]

5-7 days is pushing it with one battery even if you're careful about how much electricity you use. Will the sites have sunlight? If so, you might be able to extend you trip with solar charging. You could also hook it up to your vehicle or a generator to charge periodically. But if you don't want to hassle with charging then you'll probably need to upgrade your battery to last a week.

[david]

If you are using the furnace it will really pull some DC amps to run the blower. Fans less so. Lights are trivial with LED and your unit doesn't have the DC hogging frame heater on the fridge. But you might be using 30 amp hours each day with extensive furnace use. Depends on how much you use the furnace.

That battery at the very best is 55 AHs. But notice that they don't give an AH capacity, only a starting CCA spec. That is an almost sure fire indication that it is not a true deep cycle battery. It is a starting battery with a BS sticker on it. Also I don't see filler caps, another sure fire indication.

But I digress. Even if it is a true deep cycle Group 24 battery one day of 30 AH use is all you can expect since you shouldn't run batteries down to less than 50% for best life (and almost no life if it is a BS starting battery).

With that much power use or even half of it for  5-7 days you need more battery capacity and maybe some recharging capability. The best bang for your buck is a pair of 6V golf cart batteries wired in series for 12V. That will give you 220 AHs, which may last for 7 days if your use is less than 15 AHs daily. Get some 1-1/2" aluminum angle and pop rivet two lengths crosswise to support a big battery box for two GC batteries.

So I would start with that. The batteries are about $100 each at Battteries Plus and less at a GC shop. You can do the whole installation for about $300. Then get a hydrometer and measure the specific gravity of the electrolyte as you camp to get an indication of how much you are using. The Trojan Users Guide is a great reference for SG or voltage as an indicator of state of charge: http://www.trojanbattery.com/pdf/TRJN0109_UsersGuide.pdf

Then if you need more, think about solar, a Honda generator or jumper cables to your TV to recharge your batteries. There are several threads that discuss these possibilities.

David

[kath]

Thanks for your thoughts, guys. You've confirmed what I suspected. Guess who'll be getting a new battery (or two)?  And solar may be in our future down the road as well. 

David, it seems odd for a dealer to put a less-than-useful battery in their new TTs. I assume it's just cheaper?

I've read everything on here and lots more on other sites about using 6v GC batteries. Why are they inherently better?  Some folks debunk this idea, but there's so much comflicting information, it's difficult to get the actual facts. It sounds like your experience bears this theory out. 

Another thought... That Trojan Battery Users Guide is helpful. It indicates that wiring batteries in both series and parallel will increase both voltage and capacity.  Why wouldn't we wire the 6v GC batteries in this way to get both the increased capacity as well as the increased (12) voltage?

I appreciate your experience sharing on this. 

[charliem]

Kath,

Let me answer some of your questions in David's absence. He's probably out getting a well deserved cup of coffee. My comments are in [font color="e63219"]red[/font] below:


[quote source="/post/11316/thread" timestamp="1432488900" author="@kath"]David, it seems odd for a dealer to put a less-than-useful battery in their new TTs. I assume it's just cheaper? [font color="e63219"][font size="3"]How do I put this diplomat[font color="e63219"]ically[font color="e63219"]? I can't so I won't. [/font][/font][font color="e63219"]The dealer installs the cheapest battery that will get the unit off his lot. In your case I could [font color="e63219"]not find any [font color="e63219"]definitive[/font] info on the Batteries Northwest [/font][/font]B24DC. [font color="e63219"]Batteries Northwest appears to be a generic [font color="e63219"]distributor[/font] and the battery is who [font color="e63219"]knows what.[/font] I agree with David that the lack of AH rating and filler caps probably means it's aimed at the trolling motor market or such.[font color="e63219"] [/font][/font]If I had to guess I go 65AH, but no more.[/font][/font]

I've read everything on here and lots more on other sites about using 6v GC batteries. Why are they inherently better?  [font color="e63219" size="3"]Let me compare a popular and available set of batteries, where data is available: The Interstate SRM-24 (~70 AH @ 12V) and the Interstate GC2 (233 AH @ 6V). Many dealers supply the SRM-24 on new trailers. When the need to upgrade comes the easiest and cheapest (not recommended) is to add a second SRM-24 in parallel for 140 AH @ 12V. Double the AH at the same 12V. A better option is to replace the original battery with a pair of GC2s in series to obtain 233AH @ 12V for 3.3 times the original single battery capacity in about the same two battery space. This is by far the most popular battery upgrade in the RV community and the GC2a are designed for this application. [font color="e63219"]A[/font]s to why series, not parallel, and other technical goodies I refer you to:[/font]

[a href="http://www.marxrv.com/12volt/12volt.htm"]http://www.marxrv.com/12volt/12volt.htm[/a]

[font color="e61942" size="3"]You could start with two GC2s in series, then add a second pair in parallel (4 batteries) for a whopping 466 AH @ 12V, but now we're talking serious cost, size, and weight (including the bigger truck to haul them) so let's not go there yet[/font]  


[font color="1979e6" size="3"]PS: The B24DC is not entirely useless. If you never need a battery the present battery is quite adequate. IOW, if you only camp with full hookups and tow connected to the TV charging system the B24DC will meet the need completely and probably last forever. [/font]

[/quote]

[peislander]

If I think about the typical RV trailers sold in my local market they would be 27-foot plus units sold to people who will take them to a relatively close full-service RV park and park them for the summer. These buyers will use them as cottage substitutes. They will build wood decks covered in astroturf and put up flagpoles. Their trailers will be moved at most twice a year --- at the beginning & end of the season. Some will stay parked at the rv park for years.  It is for these people I'd suggest the RV dealers install the 55ah batteries. Those customers don't really need any more and if they thought they would, they're the same kind of folks who'd be happy to buy a generator and disturb the peace. IMHO the RV dealers are just serving their typical customer's needs. Adequate cheap batteries for people who don't want to spend anymore than necessary.

In contrast I'd suggest most Livin' Lite purchasers really are atypical of the broader Rv market. (We are special?) Most of us actually "camp" rather than "cottage". A dealer who sells lots of pop-ups probably understands our needs far better than average dealer selling big fifth-wheelers & motorhome palaces on wheels. So unfortunately when a 'camper' buyer goes into a big RV dealership they get the same basic commodity battery as the full-service-rv-park-cottagers. Almost everyone is happy.

[david]

Charlie said it well before I could. BTW I am hanging out on our boat doing boat camping. Beautiful pm here on the ct river.

One other point of understanding. 6v GC batteries are typically 220 ah each. But when you hook up two in series to get 12v you still have 220 ah for the pair.

David

[sidecarmike]

http://www.batteriesnorthwest.com/batteryschool.cfm?TID=9

[charliem]

[font size="3"]Thanks, Sidecar.

The BNW spec is a bit better than I expected, 80 AH @ 20Hr rate, but it is consistent with other manufacturer's batteries of similar weight. Battery capacity is strongly correlated to the weight of the lead  contained. That said, I stand by my recommendation to upgrade to two GC2s.  

Camp on!
[/font]

[kath]

Charlie, thanks for answering my questions. And the MarxRV site you provided has a ton of great information. I've learned a lot today and you all saved me hours more of research. Much appreciated.