Battery Recommenation?

[jscusmcvet]

Curious if you have a recommendation for a good battery choice for my camper project. This will live in a removable power box on the trailer. Primary charging is via the jeep while traveling and by 45w solar if needed in camp. Primary use is to run a few LED lights and an Indel B 50 q. Fridge. Secondary use is as a back up jump starter should that be needed. I saw an inexpensive 122 AH battery at Walmart. Numbers look good, but not sure on quality.

http://www.walmart.com/ip/EverStart-Maxx-Group-Size-29-Marine-Battery/20531539

I do not mind paying more if needed. Just not sure what to look for other than a high amp hour rating.

John

 

[tarditi]

I'm a fan of optima batteries

 

[unseenone]

45W solar will not be enough, you need at least a 100W.

That trailer living for the battery means you need something like the Optima or Deka AGM Intimidator to take the vibration and bouncing. It should be mounted fast, so it can't bounce around in your battery box.

 

[jscusmcvet]

I know 45w is low, but it is what I have for now, so figure it won't hurt to have it hooked up and providing some charge, even if not enough. I also like optima for the jeep itself, but if you investigate, even their blue top dual purpose is only 60 amp hours. I believe I need a minimum of 80 and should be higher.

 

[unseenone]

If you can swing it, and have the space, the Deka line I mentioned does 80 and larger Ah versions (I have two) one I replaced the Optima with and one I replaced the Interstate with. I'm tickled with them so far. A couple of photos here, you can click and see that particular one is 92Ah. The one I replaced the Optima with is here. Nothing particularly against the Optima, I have two, some folks have reported awesome results, some have experienced failures in 2 years or less.(for me it was 1 failure) They are made in MX now, the the Deka are made in Pennsylvania. I wanted a clean install without any other factors so I replaced them both at the same time.

I hope this helps.

 

[CaliMobber]

So optima are a good batteries, but for your setup i would look for a larger amp hour rating like your saying. Since its going to be on the trailer and not your starting battery I would go with a more traditional deep cycle battery. Crown batteries have a very good name and cost is fair.

http://www.solar-electric.com/batteries-meters-accessories/batteries/crdecyinba1/repose/12voba1.html

One of those would be great for your intended use. If you end up needing for a jump start just leave the cables on for a little while since they are not meant for instant cranking. That solar panel will be fine as a aux charger if your not parked for to long. Can always start up the jeep and connect some jumper cables for a faster recharge if needed.

 

[228B]

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This will live in a removable power box on the trailer.

CaliMobber (as does unseenone) offers good advice, but since you mention that the battery will live in a box presumably with other electronic components, may I suggest an AGM battery type. Deka, Lifeline, Odyssey... They're still a lead-acid battery, but they're sealed. They do require a certain charge profile, however; one that any name-brand "smart" charger has a profile for. An AGM does not outgas (unless blatantly overcharged then it's ruined as a "recombinant" battery), does not require venting, is non-spillable, can be mounted on it's side if necessary and with brands like Odyssey, deliver both engine cranking amperage as well as deep-cycle ability. Not many batteries on the market make that claim. For your proposed setup, yes; you should be looking at a minimum 100Ah capacity.
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An emerging rule of thumb now that AGM batteries are found in more and more solar power battery banks is, "100 watts panel for every 100 amp-hour battery capacity" and that is fast becoming a minimum recommendation. AGM batteries with all their advantages (and increased initial cost) like to be hit with as many amps as possible (within existing battery charger outputs) during the "bulk" charge phase (up to roughly an 80% state-of-charge), then they like a little more than the industry standard for flooded batteries' 14.4 volts for the "absorption" charge phase... more like 14.6 and in the case of Odyssey batteries, 14.7 volts for absorption, and for at least four hours... finalized with a 13.6V "float" charge indefinitely.
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I know 45w is low, but it is what I have for now, so figure it won't hurt to have it hooked up and providing some charge

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Indeed, it is better than nothing. You must be certain, however, to keep that panel in full sun (weather permitting) and care must be taken to see that it not fall under any partial hard shading. Panels when partially shaded are near-useless in output; they will function better than expected, though, during full cloud cover so you can continue to keep it connected in those conditions as well.
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Of further importance, since the 45W panel is all you have at the moment, is to ensure the necessary copper stranded wire sizes to prevent voltage drop. A battery that does not see the necessary voltage due to too-small wiring/cable will not become fully charged.
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Here's a decent Voltage Drop Calculator
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Since you're already on the edge regarding watts input, it is imperative you seek less than 3% losses. Choose "single phase", copper stranded (unless your solar rig uses aluminum wire), "overhead" for Installation, 12 for volts, 3% for minimum volt drop, and 3 amps (the best that panel might produce under absolute optimum conditions)

 

[jscusmcvet]

This is all great info guys. I really appreciate it. You all have given me lots to delve into, now and over time as I try to improve my system. For the most part when out camping, we move every couple days, but I want to have some level of insurance that the fridge stays cold (fridge set to arrive tomorrow... according to a tracking update) and that I can start the jeep. What I may have to do $ wise is cobble together a less than perfect system this time around and upgrade as $ allows.

 

[unseenone]

Just a tip on extra solar. I see those pop up on craigslist for dirt cheap regularly, try a bigger city.

 

[zelatore]

I want to know where you found the specs that say that Walmart battery is 122Ah. That would be a huge number for a group 29. I usually see around 100-105 in a group 31 deep cycle. The web link doesn't show anything but MCA, which isn't really all that important in a deep cycle anyway.

 

[jscusmcvet]

I want to know where you found the specs that say that Walmart battery is 122Ah. That would be a huge number for a group 29. I usually see around 100-105 in a group 31 deep cycle. The web link doesn't show anything but MCA, which isn't really all that important in a deep cycle anyway.

This is right on the label on the battery in the store. Not sure if it shows on line. On their 27DC they say 109AH I believe. They are made by Johnson controls. I wonder if it is because they are old style wet cell and not gel or AGM. Have no idea, just had the thought.

 

[Bigunit]

Group 31 Lifeline battery...tried, true and 100% reliable..screw the Optima...just speaking from experience.

 

[4x4junkie]

Very doubtful that Walmart battery is 122Ah with a shipping weight of 61lbs. My guess is it's real Ah figure is between 90-100.
I suspect it's also made by Exide, judging by the recessed vent caps and ribbing on it's case (JC puts the caps sticking up above the top). Whether thats actually better or not, I don't know... Both Exide and JC do leave something to be desired in their batteries.

My opinion about AGM batteries is they are not the same amount "better" than flooded batts as they are more expensive. True, they are more vibration-resistant, and their IR tends to be a slight bit lower, however unless you're running it the Baja 1000 or KOH, or are competing in a decibel (stereo) competition, their much-higher cost is nearly entirely wasted $$$ when all you're doing is powering a 12V fridge and some LED lights off it. Unless that trailer has a rigid axle (no suspension), you aren't going to hurt a flooded battery mounted in it either, especially if it's up near the trailer tongue.

The only occasional issue I've experienced with certain FL batts (usually those from JC) is minor acid seepage from underneath the vent caps. Two turns of teflon thread sealant tape wrapped around each of the three plugs on each cap is usually effective in stopping this seepage.

If you have a Costco card, I suspect their batteries are some of the best values around at the moment. They have a group-27 made by JC (Interstate) that is in that same neighborhood of 90-100Ah for around $80 (not sure, they might have some grp-29 & 31 offerings too).

 

[jscusmcvet]

Good info 4x4 Junkie, thanks.

*** Edit - I saw the Johnson Controls on a post that turned out to be several years old, and then comments from people that the current Walmart 29DC is not the same as the old one... So have to think you are on the right track there.

John

 

[jscusmcvet]

Stumbled across this online decription of the term "Reserve Capacity". Should I be paying more attention to this rating that "Amp Hours"?

3) RESERVE CAPACITY
What does the Reserve Capacity rating mean and how does it apply to deep cycle batteries?

ANSWER:
Reserve capacity is the number of minutes a battery can maintain a useful voltage under a 25 ampere discharge. The higher the minute rating, the greater the battery's ability to run lights, pumps, inverters, and electronics for a longer period before recharging is necessary. The 25 Amp. Reserve Capacity Rating is more realistic than Amp-Hour or CCA as a measurement of capacity for deep cycle service. Batteries promoted on their high Cold Cranking Ratings are easy and inexpensive to build. The market is flooded with them, however their Reserve Capacity, Cycle Life (the number of discharges and charges the battery can deliver) and Service life are poor. Reserve Capacity is difficult and costly to engineer into a battery and requires higher quality cell materials.

For instance, Rolls, Surrette and Lifeline use thicker lead grids (the plate's skeletal structure) to support additional positive plate oxides which are compressed into a denser form in order to add battery reactive material for greater Reserve Capacity and Cycling Performance. In addition, these plates are separated by indestructible separators. These mats hold the active oxides tightly in place during the cubical plate expansion which occurs during deep discharging, instead of allowing the oxides to shed off and precipitate to the bottom of the battery. Construction materials such as those raise the Reserve Capacity of a battery and increase the battery's Cycle Life.