New Batteries for 2007 Serenity

Well, the batteries in the house have been going dead since I got the Serenity in January. On the drive across country the batteries would not last the night (like close to 5 hours only). I read a LOT on the interwebs about people recovering their supposedly dead batteries using a desulfator like the one from Battery Minder. Well, it's been since February and I have only lost capacity, so I will be returning my Battery Desulfator.

Today I traded the Group 31 Car Quest batteries that were in it when I bought it on a pair of those famous Costco 2-GCS 6 volt Golf Cart batteries. The group 31's were 13"L by 6.7"W by 9.5H. The Costco's are only 10.3"L by 7"W by 10"H. Went from a 59 lb. battery to a 63 lb. The Group 31's should have about the same capacity, but I have read many good things about the golf cart style batteries, the lead plates have more vertical space to keep out of the sulfate that settles to the bottom. Also more space above the plates so it won't run dry during charge.

Biggest problem with the change was the taller battery. I feared it might not even fit under the gas line running to the generator. In later model years they re-routed that line. Fortunately it turned out not to be a problem, the Trojan's are an inch taller, might be a tighter fit. When I went to tie the batteries down I discovered another problem: the stud that ties the batteries down is almost exactly as tall as the new batteries... Originally the stud was welded to the battery tray and rises between the two batteries and then feeds thru a metal plate that is held to the top of the batteries by a washer and nut.



I was hoping to find a stud extension that would bolt to the top of the stud and provide additional thread, but it was so close to the top of the current batteries I would have had to use LOTS of washers to get back down to the level of the top of the batteries. Fortunately I found screw bosses at the hardware store, these hammer into a predrilled hole in wood and give a place to screw things down, for me I just bent off the tips and it was a washer and a nut in one.







I have heard of the Costco's going for as little as $63, but I paid $90, likely the people writing about them have had them for several years so we will probably never see $63 again. Still the Trojan T105's that are similar capacity are almost twice as much. I have not gotten exact capacity. Several posters mention a 225 amp hour capacity but also mention a red and white enclosure, while mine is black.

I knew I needed new batteries as I use the Xantrex LinkLITE Battery Monitor. When I took the old batteries out I took the opportunity to screw mount the monitor's shunt to the underside of the floor above the battery compartment. Since I didn't need two cables to connect the two batteries in parallel anymore I reused one to connect the shunt in the series circuit. Much safer than the twist tie I was using to hold the shunt in place.



-Randy

Re: Battery compartment rust

I read a lot about people changing out their batteries before I changed out mine. Lots of people with these battery trays that were swiss cheese. I took my old batteries out and at first thought I was in great shape but started thinking, perhaps this is the last time I will be in here for 7 years.



There was not much rust on the tray but I now saw a large rusty area below the try in the box it rides in. After much scraping and polishing I finally got what I thought was a surface ready for some Rustoleum, but I was wrong. Happened to catch sight of the underside of the tray. I was inspired but unsure how I was gonna get under there.



Then I noticed the two screws at the end of the tray runs. Unscrewing them allowed me to pull the whole tray out. They are the square head screws that are used thru out, never owned such a screwdriver before the Serenity.



With all this rust I was sure I was glad I got started doing this. Just scraped with one of those paint scraper 3 in 1 tools down to the metal, then a plastic scrubber from the sink. When it dried it was all ready to go.



Now it is looking pretty good. The plastic wheels are just sitting there and can be removed or accidently knocked off. If you forget the bevel is toward the tray.



Looks like the only rust I have left is the top where the battery bay attaches to the bottom of the vehicle. This is a nice shot as it allows you to see that the battery easily clears the top of the bay.

-Randy

Thanks for the great write up and pictures! Your timing was really good for my interest.

Questions for you. Here's my issue with my 06 Freespirit, I've got two 12V house batteries located behind the rear wheels. When these two are charged full, they seem to drop to 12.4V rather quickly (with no draw except relays), withing 5 hours. Both batteries series 31 were new 14 months ago. I've checked voltages, the water levels and also using a hydrometer many times. The cells in both batteries check out okay. In my unit there is two relays, one for the propane valve and the main relay (next to hot water tank) that switches from converter to the DC (alternator) charging. I'd suspect a 4-5A draw for both??

I am not convinced that both of these batteries are equally charged, the series thing. Now you've gone to using 6V in parrallel, i've been debating that myself. Have you noticed any better performance from your new configuration? I keep thinking that they would be charged more equal. Any ideas or feedback would be appreciated.

The relays probably have a pretty significant draw 24/7, use a clamp on ammeter to measure and figure that into your load calcs.

Also,, read these links:

http://www.windsun.com/Batteries/Battery_FAQ.htm#Lifespan of Batteries

http://www.batteryfaq.org/

Icarus

brassarl said:

Now you've gone to using 6V in parrallel

Click to expand...

Don't hook up 6v in Parallel, you'll get... 6 volts. Just like a flashlight, one feeds the next, don't run cables along all the batteries in parallel unless they are 12v batteries.

-Randy

Randy, I,ve been using a product called Fluid Filim. You can getit on amazon or ebay. Its pure majic in a can. Wil kill all rust As soon as you spray it on you can see it start working. Tth next day it looks like a black rubber coating, can be used on electrical contacts also. Really great for those hard to get at areas. My freind has been using it on all his farm equipment for years. He has a house on the gulf which gets flooded every hurricane. He has been using it on the electrical box contacts for 20+ years and still using original breakers.

Randy

Your old batteries what was their output (when new) and how does that compare to the new ones you put in. What can you run off your batteries, comfortably?
Do you have the 600 W inverter?

SHane

The old ones were Group 24 or 27. It would be just under 200, very similar to what I have with the Costco batts, but not designed for deep cycle. The Costco batts are also CHEAP. Should be getting about 220 Amp Hours now. I can go days on the batteries if I don't run the fridge, but in my day to day I will run the fridge between parking. It kills the charge so fast I am hoping to get solar to keep it running. When I boondock I run the fridge on propane and I have a HUGE tank so I can go for a LONG time. I have two inverters currently, but am shopping for another. One each for the two, now, TVs (less than 100W each) and one eventually that will power the microwave and Keurig when the engine is running so I don't have to run the genset at 6 am.

-Randy

Were you talking about running the fridge on the batteries? Impossible with these large fridges. I quickly learned that if I put the Fridge on battery when I was driving, there was literally nothing going to charge the batteries. The batteries would give about the same reading before driving all day as after. Not a great thing if one is overnighting in boondock mode. The factory told me to NEVER even bother to try to run the fridge with batteries. The fridge only uses one amp of electric if you are running it on propane. (or so people have told me)

Mumkin
2011 LTV Libero

Perhaps the newer fridge, and yes, the fridge does bring down the volts available for charging. I was thinking of getting a Xantrex 3 stage charger for the alternator to fix this issue, but I run the fridge after being plugged in to save propane, I go 6 months between fills as I use shore or batt most of the time. When coming off shore your batteries are full so you don't need the alternator, if you stop for the night, flip to propane to keep the batteries full, but during the day with the engine running I keep it on 12v to save the propane. I wish I had an auto fridge like you, but I don't. I have to select by hand. Probably why I have been using it this way. On 12v I can leave it when I plug into shore power. Takes longer to charge the batteries, but it's done in the morning.

I am about to put solar on the roof JUST to goose the fridge along, gonna hook into the fridge's circuit and whatever the fridge doesn't use will help charge the batteries.

-Randy

These big fridges in the newer models are just not made to run on 12v. My experience was that I had been plugged in over night... so batteries should be have been fully charged in the morning. This was at my dealer and they worked on it for a couple hours and the fridge was on propane when I got in to leave. I put it on 12v manually and drove for 3-4 hours to the Wal-Mart. When I got there... put it on propane... and after shopping a bit, the battery read only 12.3. That is only about 70%. I was shocked assuming that I had started with nearly 100%... drove those hours... they should have been still near 100%. But the fridge alone pulled it down that much. Brad at the factory said that his advice is to never try to run these fridges on 12v as they just pull too darn much out of the batteries.

I too have never figured out why someone would want to pull out that freezer to make more fridge space. But that might be because I buy neither beer nor soft drinks.

Mumkin
2011 LTV Libero

Wow, that is good to know, now I am glad I have the crappy old fridge I have. Even the new 2014 still has that fridge you have. I think the old Sprinter style I have is the only year that used the two door fridge/freezer. I have not seen a lot of 2008/2009 Serenitys so not sure. Actually only saw my first Libero in the wild (my neighborhood) this last week.



-Randy

Two nice looking rigs... sisters (different father... shhhh...)

My Libero is the dark gray rather than silver...

Back to the fridge. They switched to the model I have because for awhile there wasn't a 3 way-two/door fridge available. But there is now again... wonder if they will eventually switch to it. The only other problem that I have had with this model is that if you put too much weight in the door (like half gallons of milk/juice), the door starts not wanting to close properly. No problem if I put the light stuff in the door. But then maybe that is a common problem in RV fridges.