Best AGM battery for RV

[Mike Curran]

I have a Scamp 13' RV whose 12 volt battery has long since died. I'm looking to replace it, and I'm also looking to supplement charging with a surplus MX60 and a couple of 275 watt panels I have on hand. My question is what is the best battery for this application? I'm thinking 100Ah (since that's the spec I'm seeing when I Google "RV battery") but I don't know if that's the 20 hour rate, or what. I also would supplement charging with a small portable generator so I'm not worried about load vs battery capacity.

Note I'd prefer not lithium-based, thinking AGM. Battery case is sized for a group 27, I believe.

Any suggestions? Thanks in advance.

[EA6LE-ONE]

Maybe EnergyCell 106NC will be best fit.
http://www.outbackpower.com/downloads/d ... csheet.pdf

[Mike Curran]

Thanks EA6LE-ONE. That looks like a good choice.

[raysun]

I used the big brother of the 106NC (200NC) as my home system battery for years. The NC is a good battery design, but is optimized for a somewhat specialized niche - Partial State of Charge (PSoC) operation between 80% and 50% SoC. Cycled between 100% - 50% SoC, it behaves more like a normal high-end VRLA battery.

Note that Outback has discontinued offering this battery, though the documentation is still published. There may be stock available, but it may be difficult to get warranty replacements down the road.

Outback offers two new batteries that may be well suited for your use: Northstar NSB Blue and NSB Red. The NSB Red 90TT looks to be a reasonable form factor for installation in a trailer. The top terminals take a 10mm threaded bolt so a 3/8" ring terminal would be required on the battery cable, as opposed to the standard lead automotive battery clamp.

This battery will have very fast charging, almost rivaling lithium, very high output, and high storage capacity for its physical size. About 2000 cycles if discharged to 50%, then recharged. Discharge as low as 80% would be permitted in a pinch.

It would be a good match to an MX60 and 550W of panels.

The nanocarbon enhanced anode technology is finding its way into this class of high-end AGM batteries. It does improve battery life at partial state of charge. This would be a generation 2 nanocarbon design.

https://www.outbackpower.com/products-m ... gy-storage

[Mike Curran]

Note that Outback has discontinued offering this battery, though the documentation is still published. There may be stock available, but it may be difficult to get warranty replacements down the road.

Thanks for those alternatives, Raysun. I went looking for the 106NC at Northern Arizona Wind and Sun, and they didn't have them, but they did have those you suggested.

Now I've got to figure how to mount those somewhat massive (compared to my trailer) panels. I'd like to put them on a hinge that would make them a sun canopy over the side of the trailer when parked, but I'm a bit concerned they may be too fragile for this (folded against the trailer while moving). Suggestions welcome.

[raysun]

Do the panels have tempered glass? If so, probably no bueno for mobile installation.

There are many later model panels that replaced tempered glass with a thin, tough, polymer coating that is quite rugged. (I've tested it, testing method not disclosed. )

I'd think the ones that rate their snow loading at figures like 6000 kpa (870 psi) would stand up to the rigors of a well fashioned hinged framework. I think solar panels can make an attractive awning. The trick is fabricating said framework.

[grmaryp]

I would suggest checking Optima batteries for RV uses because it has high respect on the market. But I'm not sure it has AGM or SLA battery.

[Mike Curran]

Thanks. Optima offers both AGM and FLA type batteries, but I'm leaning toward a lithium type like this https://discoverbattery.com/products/li ... LB-G24-12V.

Now if only I had a starting battery for this project.

[sbrownian]

I gotta say, I'm impressed with the Optimas..

The ones in the F-250 6.9 diesel finally crapped out after some +22 years of service. (Optima RED.)
(No, I didn't put new ones in... Not spending $500 on a truck that will be gone in the next year..)

[JRHill]

I get a 'new posts' feed from an RV forum. I subscribed to it because of some of the RV battery questions, rooftop solar, etc. Its entertaining for sure. And I had an interest from the past: when we were camping and planning the future on our 'lil bit of heaven I had a box of 4 semi deep cycle batteries in the pickup box. At home I charged them with a std battery charger. When we got to our spot the batteries ran lights, the cell booster and phones, battery packs, etc. I thought as the bank ran down I'd just plug it into the RV connector and back charge them off the pickup's 12v system. Ahh, not. The pickup would pump a few amp/hrs into them but certainly not recharge them.

It seems like a few folks knowledgeable on auto electrical nailed the issue: on a nominal 12vdc system the voltage drop from the front of the vehicle to the point of need is substantial enough that ya just can't charge sufficiently unless the rig is 'on' for a long time. On our F250 the hot blade on the 12v RV plug is 10ga - factory wiring. That's a long run of wire and connections and then more into the RV.

So, any charge contribution from the tow rig, regardless of battery type, is going to be negligible. So its going to be your panels, camp ground power or on site generator that will have to sustain things. I wish I had known this during those times.

But I really want to wish you HAPPY CAMPING for the season!

[sbrownian]

I've seen DC-DC converters built especially for that issue.
They will take an input of 12 - 14v and output 14.4 or so.

I would imagine that someone somewhere has built one that would use "12v" and act as a 'battery charger' for 'x' chemistry and not just be a "power supply."

[JRHill]

I've seen DC-DC converters built especially for that issue.
They will take an input of 12 - 14v and output 14.4 or so.

I would imagine that someone somewhere has built one that would use "12v" and act as a 'battery charger' for 'x' chemistry and not just be a "power supply."

Yup, on that same forum there have been mentions of a DC-DC converter for this purpose. But it was also said that the wiring, front to back, has to be upgraded to support the load. The point being that only so much 12v can be pulled from the factory 10ga wire. BTW, for any RVers: does your rig's factory RV plug have bigger than 10ga coming in? My new pickup has 10ga to the factory RV plug. Just like the 'ol 2000 F250.

BTW, in the camping days I had added a heavy connector (fork lift type) to the battery and mated it to the 12v inverter. The inverter was so darned inefficient that the idea was a bust too.

[sbrownian]

I usually scavenge the smaller gauge versions of the 'fork lift connector' out of the SOHO UPS boxes that go poof. They're good for a minimum of 50 to 75 amps or so and are used to connect the battery pack to the guts of the inverter, allowing the two 12v batteries used as a 'pack' to be easily swapped out.

Of course, they don't bother telling you on some of the units, you have to use a special serial cable and enter a few cryptic commands to 'reset' the clock / countdown register in the box so it 'knows' the battery pack has been changed...

[daltonbourne]

I am like a lot of people wanting to save a few bucks. Optima batteries are top-of-the-line and the difference in power and run-time increase with these batteries is amazing. These are AGM batteries and they must be charged with a charger programmed for AGM batteries. You can mount AGM batteries at any angle because there is no possibility of losing acid from the battery. The acid is soaked into fiberglass pads inside the battery. They were fully charged when I received them and I fished 2 long days with them before charging them for the first time.