Good Question about a Bad Battery

ScottG

Through ignorance and inattention, I killed the original battery that came with my T@B. Well, it's definitely dead, but I'm wondering if it was really all that healthy to start with.

When we first got the T@B it sat in the yard with the battery connected for two (maybe three) weeks. Everything in the camper went dead, and the battery measured a whopping 1.5V across the terminals before I charged it up and hit the road. This happened two (maybe three) times before I wised up and started disconnecting the battery between trips. Despite the early insult, the battery still performed for a couple of late-season, four-day boondocking trips (though it was down to 10-11V when we broke camp). Over the winter, I've disconnected the battery and kept it on a float charger, but it drops to below 12V within a day or two of being removed.

While I have plenty of experience with starting batteries, I'm new to this deep cycle business. Does what I've described sound like a normal death spiral for an abused battery? I know there is phantom drain, but I'm a bit suspicious of the degree to which the battery discharged, and the time it took to do it.

Our camping buddies have an R-Pod that's several years old and still enjoys the services of its original battery. Though they camp frequently, they have never disconnected the battery outside of winter storage.

Battery gurus, any wise thoughts?

Ratkity

Yes, it sounds like you killed a cell or two when you dropped the voltage of your original battery below 11.5V (that's a dead battery) and then dropped the voltage below that level several more times. Most people recommend 12.1 - 12.2V as a 50% depletion voltage as a rule of thumb to discharge a deep cycle battery. A fully charged battery is 12.8V. You can do a search on this forum and find battery meters and color-coded charts to help. Simple plug in meters have been used successfully to monitor general battery health. Other people have installed complex meters and like more detailed information due to different power needs.

Float maintainers usually don't charge a depleted battery. They maintain a charge to a battery when it is sitting with no huge parasitic loads. I found my float charger could not keep up with the parasitic load of the T@Bitha. I keep a float charger on the motorcycle, but that battery also has a parasitic load that the float maintainer eventually will lose the battle against if I don't ride the bike more than short distances on a regular basis. 

Many people have installed cut-off switches because of the parasitic loads. AGM batteries (since you have to get a new one anyway) lose so much less charge when idle (and disconnected) than a lead acid (flooded) battery. I'd recommend spending the extra money for AGM.

jkjenn

I am beginning to think it's a rite of passage to kill your first RV battery. I killed mine. Yes, that first drain probably did it in. I am really glad that LG has started including a battery monitor so people can see their status but it seems as though no dealers are doing a thorough battery education. 

ScottG

Thanks Ratkity and Jenn. I've absorbed your battery wisdom over many past posts. I've learned a lot and will be implementing many upgrades this season--including a cut-off switch, basic monitor, solar panel, and a larger capacity battery. Might even go with the AGM, though I'm inclined to give myself the opportunity to kill another flooded cell before dropping extra coin on that. :-)

Per Jenn's data, I know the T@B's phantom drain can be pretty significant. I think I was just surprised that the battery went all the down way to 1.5V. I've played with lots of dying batteries, but have never seen one get that depleted. Wasn't even sure if it was possible!

ScottG

Ratkity's comment about motorcycle batteries led me to a related question. Does anyone buy their batteries "dry" so they can fill them and perform the initial charge themselves?

I do this routinely with motorcycle batteries. It's been alleged that when dealers prep a new battery they often perform the initial charge too quickly, and that this compromises the battery right from the start. When I prep my own, I do a low slow charge (as recommended by the manufacturer) and I seem to get exceptional life from those batteries.

I wonder if this might also apply to our larger RV/deep cycle batteries.

Ratkity

For a minute there, I thought you were talking about adding fluid to a dry cell.. d'oh. You are talking about that quick and dirty charge dealers do.  I have a big automotive charger that has that quick charge option when in a pinch, but I believe it's only listed for lead acid types.

I read somewhere that because AGMs lose so little charge while sitting idle, that they are shipped with a full charge. An automotive store that has a high sale rate of batteries would be constantly getting freshly and fully charged AGM batteries on a regular basis. Disclaimer: Just because I read this in passing, doesn't mean it's true. I believed for years that concrete sucked the life out of any battery!! (myth). 

ScottG

The bike batteries I buy are Yuasa AGMs. (You are right about them being able to hold a charge--at least when they are young and healthy!) They are shipped empty with a separate pre-measured electrolyte pack to fill them when you're ready to activate them. In addition to being able to perform the initial low and slow charge yourself, another advantage is that they can sit unfilled on the shelf indefinitely without any degradation. I always assumed the dealer did the same, but that was just an assumption.

Not sure if any of this applies to the much larger RV batteries (AGM or otherwise). 

Ratkity

No clue, Scott. Since an AGM battery is sealed and under pressure, I'm not sure where or how that packet can be added. Part of the chemical reaction is driven by internal gas pressure in the sealed box.  Unless one of the posts screws off and you can reseal it that way. The chemicals would provide their own gas and pressure if re-sealed quickly after adding to the liquid inside. I would think it would take a bit of mixing so the electrolytes wouldn't layer and the mats get infused with the identical amount of electrolyte solution for optimal reaction. A clump of dry chemical could cause one area of the battery to get overheated. I'm sure there's specific instructions for those types of AGMs where you can do that. Just never knew they existed. 

Tabaz

Bob - My battery box will allow this 125AH battery to fit.  It's $100 more than the 100AH you link to above. Is this a better way to go?

http://www.amazon.com/Vmaxtanks-Vmaxslr125-rechargeable-Solar-Inverters/dp/B00ACNO2AO/ref=pd_sim_sbs_23_2?ie=UTF8&dpID=518ODfMs33L&dpSrc=sims&preST=_AC_UL160_SR152,160_&refRID=1X8PMCFK8RZNVXPCFH8Z#Ask

Nomad

ST_Bob - The std battery that came with my T@B was a 24, not a 27.

Nomad

Yes, the battery is installed by the dealer but the frame for the battery box is too small on mine (and others) for a 27 without mods.

Tabaz

Bob - this 155AH will also fit in the plastic battery box in the metal Outback propane tub (my current dealer-installed battery is a Group 27).  Is the extra 30 AH "Umph" worth the extra $50?

http://www.amazon.com/Vmaxtanks-VMAX-Rechargeable-Solar-Inverters/dp/B00DDYM1UC/ref=pd_cp_23_3?ie=UTF8&refRID=17ZATB7A4FVK7MDAF01C#Ask

Nomad

Hey Frank - We'll teach you how to cook so you won't need to keep upgrading your battery to keep up with your microwave dinner needs :-)

Tabaz

PXLated - that might be a better solution - the 155AH battery weights 90lbs.!

Tabaz

I'm going to go with the 125AH model.  Was going to replace the stock battery anyway.

ScottG

Yuasa claims the small bike batteries I mentioned are AGM. They are "sealed" (after you add the pre-measured electrolyte), but beyond that they don't sound anything like what Ratkity and ST_Bob described with regard to the the big deep cycles. In a roundabout way I guess that answers my question about self-activating a new battery--at least with regard to AGM's. I still wonder if it's possible (and marginally advantageous) to do this with a regular flooded cell battery.

I'd also echo what Bob said about the relative "worth" of a bigger/more expensive battery (or any other gizmo, for that matter). The only short answer is it depends. I spent the first camping season with the T@B (including multi-day boondocking trips) without investing in any accessories or upgrades. I killed my original battery in the process, but experience and research (including participation on this forum) have given me a much better sense of what I need to improve and how much I'm willing to spend to do it!

Nomad

This forum is great but if I paid 100% attention to the recommendations/advice I would never have dreamed I'd have survived 18 months with a wimpy 24 battery. Will probably up to a 27 at some point but it's definetly not a throw out the old while it's still working situation. :-)

mickietucs

PXLated said:

Yes, the battery is installed by the dealer but the frame for the battery box is too small on mine (and others) for a 27 without mods.

My group 29 fit (but is at an angle and one of the reasons I took out that pvc in the front).

Nomad

Michele - Not saying you can't fit a different size in the tub, just that the frame that holds the battery box will have to be modified in some way.

Emy

I did it. I killed the battery.  The tab was plugged into home power over the winter, so I believed it was charging as needed. Nope.  I wanted to blame the converter, nope. Blame it on the fuses? Nope.  I used a battery charger for 2 days, got it up and running, only to have it wipe out almost before my (voltmeter) eyes.  I also would like to blame the junk Dorka brand of battery the dealer gave me.

Can anyone recommend an AGM brand?  (I probably will not do solar anytime soon).  

BTW, I miss ST_Bob's posts, where did he go?

ScottG

Emy, I favor removing my various batteries and taking them inside in the winter where I can monitor and charge them as needed. When I did this last winter with my already compromised T@b battery I noticed that it constantly "boiled" when left connected to a high-quality float charger. It lost quite a bit of water, and afterward behaved just as you described (even after being refilled).

While what you did theoretically should have been fine, I wonder if your battery was already headed south. Apparent performance alone is not a good indicator--mine worked fine for my needs on several multi-day dry camping trips, but careful monitoring of the voltage told me it was on its last leg and I knew I'd be replacing it this season.

You didn't mention how you use your battery. If you intend to do much dry camping (no hookups) then you might consider moving the solar panel up on your priority list. As I learned the hard way, even a deep cycle battery will die quickly if it is routinely discharged below a certain point. A solar panel will help maintain a healthy charge to prevent such damage. (On the other hand, if you are always hooked up to shore power, the convertor takes over the 12V needs and the battery becomes superfluous for camping purposes.)

Disconnecting the battery when not in use is also highly recommended. A healthy battery will retain its charge a long time in a static state.

I do realize I haven't answered your specific question. I replaced my battery with a similar (but larger) flooded cell. Being a scientist, I didn't want to manipulate too many variables at once. Being a cheapskate, I opted to drop coin on the solar panel rather than an AGM. I will probably switch to an AGM at some point, after growing my knowledge and experience. Lots of people here use them and can hopefully make a recommendation if you want to go that route.

Mouseketab

My latest battery purchase was a Optima Blue Top AGM. Pricey and HEAVY, but works great. I bought this one.

http://www.ebay.com/itm/Optima-Blue-Top-Deep-Cycle-Starting-Marine-Battery-D31M-8052-161-/131843824020?hash=item1eb2811994:g:52UAAOSwuhhXWkcQ&vxp=mtr

Caveat, I have no clue how it will fit in the front tub of a T@B. My battery box is under my front closet on a 2007 Dutchmen Clamshell. Different size box, and it fits in there fine.

JacobyO

I just purchased the VMAX SLR155 AGM battery from Amazon but now I am worried that it will be too much battery for a Zamp 120 panel. Anybody have experience with that size battery and solar? I might try to have them switch me out to the 125 just to be safe. We plan on doing a lot of boondocking and want the best possible solution.

jkjenn

JacobyO said:

I just purchased the VMAX SLR155 AGM battery from Amazon but now I am worried that it will be too much battery for a Zamp 120 panel. Anybody have experience with that size battery and solar? I might try to have them switch me out to the 125 just to be safe. We plan on doing a lot of boondocking and want the best possible solution.

You should be fine. I use 200 watts of solar to recharge my batteries and they are 225ah capacity.

Nomad

Biggest thing with solar is how many good rays you get during the day. Here in the summer with early light, I'm fully recharged by 10 in the morning. You should be fine.

Emy

I opted for an AGM.  I like the sealed technology, and my Genius smart charger has AGM settings.  I justify the heavy price because I am old, and I deserve it, my Dad would let me buy it, and it fits in the same box. Thanks, guys!

Floridaloha

I swung by my RV dealer today to visit my 2016 Outback ;-) and to ask about a couple of things, one being whether the battery would be installed with a cutoff switch. There was no battery on the RV, the dealer said they don't install them until they are ready to deliver because the ones stored outside tend to "disappear." I told him about the 2016 supposedly having the cutoff switch, and he suggested I get this in writing so that their service department installs the right battery. I've seen some people mention here that the 2016 models have the cutoff switch. How can I get "proof" of this to take to the dealer with my punch list? They seem very nice and cooperative but they've already told me some things that contradict what I've read here about other topics, so I want to be sure to do the right thing.  Hope it's OK to ask this here, I thought it was a better thread to put it in rather than start a whole new one.

Photomom

My trailer came with the propane cover and and a battery cutoff switch inside the trailer, ready to install. Have you looked inside to see what's there?

Floridaloha

Yeah, I did. There was no battery, but there was an empty propane tank. The dealer says they install the battery when they deliver. I don't take delivery until the beginning of August and I want to make sure they install one with the battery cutoff switch.

Nomad

Did you look inside the propane tank cover (tub) to see if the switch was mouted inside?

Floridaloha

Yes, like I said above, there was no battery there. It's on the showroom floor.