Coach Batteries

[Dennis Belfils]

Hello
Getting ready to replace Coach batteries, Chassis' were just done. Currently have 4 Trojan 6volt that were not well maintained. We are full-timers, but don't do a lot of dry camping for now. Considering deep cycle 12 volt that can be had @ Costco for about $90ea. What are the pros & cons? There is so much info out there & would like this forums' expertise for a final decision. Thank you

[Edward Buker]

Dennis,

Not sure if you are considering 4 -12V batteries now or fewer. If you go from 6 to 12V batteries, the tray dimensions or the existing cables may not fit properly requiring some expensive modifications.

In general the 6V golf cart batteries are very robustly made and may last 8-10 years or more with reasonable care and fewer deep cycles. They are typically less then $100 in a store like Costco, so if you are planning on 4 batteries, the 6V are a much better choice. The 12V deep cycle batteries are not as robust and will typically give 3-5 years of service which means the 6V versions are a better buy.

I also do not dry camp much and thought about a smaller battery bank but there have been several times due to weather or campsite availability that we have ended up off the grid and we were happy to have the extra battery capacity....one thing about RVing, sometimes things do not go according to plans.

Later Ed

[Dennis Belfils]

Thank you Ed. I will go with the 6 volt. Any thoughts on AGM vs Wet?

[Dick Simonis]

For what's it worth I had looked into the Costco batteries awhile back and found it interesting that they didn't list the AH capacity just CCA.  When I dug a bit deeper it appears they are/were built by Interstate but the AH capacity was quite a bit less than the standard golf cart battery by Interstate.  The difference in capacity may not make any difference to you but just realize that it may exist.

[Steve Huber]

Dennis,
Last time I checked, AGMs were 2x+ the cost of wet cells. However, they don't outgas which can cause corrosion of the cables and the battery tray. Plus you don't have to add water. If one takes reasonable care of wet cell house batteries they should last 5-7 years or more and corrosion can be kept to a minimum. I'm not sure AGMS will last twice that long. IMHO, if one wants the convenience of AGMs you pay for that convenience but gain little if any in performance over wet cells. That said, my neighbor has had AGMs in his coach (non-Beaver) and says he wouldn't go back to wet cells because of the convenience. If you do switch, be sure to change your battery charger setting to AGMs.
Steve

[Edward Buker]

Ditto to Steve's comments. I check my batteries every couple of months, add about a quart or so of distilled water using a jug with a spout that shuts down when the water level is correct, it is made for that purpose. It takes about 15 minutes if your cables are arranged not to be in the way and you have a pull out battery tray. I like the idea of AGM but not the price.

Later Ed

[Joel Ashley]

This issue regularly comes up since I began motor homing 31+ years ago, and I certainly made my share of mistakes early on with batteries.  I grew up on a farm with many unsealed wet cell batteries, so using up 15 minutes and adding distilled water to them (plus a little longer once in a while for cable/post maintenance you have to do on any batteries, regardless) every few months is not a problem.  Whether it is an issue for you is your call.  But I would get the Costco 6 volt ones. 

Our Interstates are over 10 years old and original to the coach.  That includes the two 12v high cca chassis batteries.  It's accepted knowledge that 6v deep-cycles supply more reserve than the 12v deep-cycles, wherever reserve capacity is more important than cold cranking amp (cca)capacity.  The main value in 12v deep cycles is their using minimal space - think electric trolling motors or very small camping units, etc., where there is room for only 1 battery.  Where there's room for 2 or more batteries, 6v's larger reserve is best.  As for your penchant for dry camping or not, I think Ed has the right attitude.

As to the Costco 6v's, after I think Keith Moffett mentioned in a prior thread the info he'd been given by someone at Costco, I did some checking because it didn't sound right that that battery had relatively low reserve.  I don't recall the numbers off the top of my head, but concluded from my research that those batteries should be quite adequate, and the person at Costco was not correct.  Dick may choose to dispute me on this point, but my research at the time convinced me that the Costco 6v Interstates should be just fine in our application.  You may wish to do your own sleuthing on the matter, Dennis;  or do a search of this Forum for the previous thread.

Joel

[Rick Vyncke]

I recently replaced the wet cell batteries in our coach with the more-costly maintenance free versions.  While I cannot tell you whether or not they will last longer or be more cost effective, I Can tell you that the reduced maintenance has been greatly appreciated.  It seemed that the old batteries would gas and cause a tremendous amount of corrosion that I was constantly fighting.  No such problems with the maintenance free batteries.

[Keith Moffett Co-Admin]

There seems to be alot of falderal about batteries. 
The best I can do is to pass on what was explained to me.
Johnson controls makes most of the batteries in America.  This includes Interstate, Napa, Costco, Walmart and all the others.  The only difference is the specs required by the people who are going to put their label on it.
The dept. Mgr. At Costco wrote by hand in the book describing those 6 volt batteries saying they were rated at 115 AHr.  Trojan #105 and #115 are both rated at well over 200AHr.  Deka #GC10 and GC15 are both over 200Ahr as well.
AGM batteries are best for use in closed spaces like basement compartments because they off gas less but they are almost double the cost.
In short, 4 costco 6V batteries equal 230 AHr. At 12 Volts
4 - 6Volt batteries from Trojan etc. Equals 440 to 520 AHr at 12 VOLT.

I still dont have it all straight but this is my take on it.

[Edward Buker]

Kieth,

I think these Costco 6V golf cart batteries by Interstate are normally rated at 220ah at 20 amps where the Trojans T105 are 225 ah at 20 amps. There are cranking specs in minutes as well as various other discharge capacities at various minutes, like reserve capacity at 75 amps is 100 minutes, and this all gets very confusing when comparing batteries. They may only give one spec and it is many times not comparable to another type capacity spec for another battery. Sometimes the box stores could push the price spec and may get a different capacity version but it could not be half and compete for that application. Too many dead golf carts cluttering the 9th hole :-)

The capacity is very much related to the amount of surface of lead plate in the battery and that is a good way to tell if you are getting the capacity that you want, by just using the weight which I think is 63 lbs. That is similar to others like Trojans. You can do this because the case plastic and plate separators weigh about the same between batteries. So I think the Interstate 6V golf cart batteries are a good cost effective choice but bottom line, check the weight before you buy.

Later Ed

[Keith Moffett Co-Admin]

Thanks Ed
I would like to see a universal understanding on the important issues in our house batteries.  Like so many things
in these coaches everyone has had their experiences or has been told something bg a trusted source and it isnt always  right, or wrong. 
As you said the stores often use different stats to promote their batteries intentionaly making it difficult to compare directly between brands.  Lowes has an ad for Deka 6 volt batteries at 435 Ah.  Deka makes no such claim.  Those Costco batteries at least atmour Costco seemed way lighter than a Trojan or other common unit.  Might be just me but that is what prompted me to ask them about the specks.
I am thinking that this would be a good seminar at a rally.

[Edward Buker]

Good points Keith, I would not be above wandering into a Costco and borrowing a display bathroom scale and weighing one battery if there was a question. It is not unheard of to make a cheap version for a better price but I think Costco would not stray too far here. If they are 60+lbs I would not worry.

Later Ed

[Dale Walker]

I just replaced my 4 coach batteries, because of my own stupidity, I forgot they were being charged by the solar charger and they ran dry. Well, the batteries that I replaced were Duracell's, which are sold buy batteries plus. I went to the website, and checked them out, and bought 4 more. They had a very good price, and the core charge from the previous batteries made them quite reasonable, I thought.
https://www.batteriesplus.com/

[Stan Simpson]

Ditto to Steve's comments. I check my batteries every couple of months, add about a quart or so of distilled water using a jug with a spout that shuts down when the water level is correct, it is made for that purpose. It takes about 15 minutes if your cables are arranged not to be in the way and you have a pull out battery tray. I like the idea of AGM but not the price.

Later Ed

I just got 4 new wet cell 6V Interstates. Can you give a brand name and source for that water jug that you mention above? Thank you.

[Edward Buker]

Stan,

Mine is two quart and shaped like this but a different color. Basically the nozzle releases water only after you push it down in the cell opening and when the fluid in the cell reaches the level of the tip it stops the flow. Any golf cart place or an automotive place like NAPA should have one. Also here..

https://www.amazon.com/Plews-75-030-Capacity-Plastic-Battery/dp/B000RFUF12

Use distilled water. On my Marquis there is enough clearance over the batteries with the tray pulled out and to get all the cells with some attention paid to how the wires are routed. Check your clearance, most battery installs are designed to allow for one of these but the RV world does make exceptions at times.

Cell addition of water becomes a quick job with this jug, a light and a mirror to check the cell level. The only other thing to be aware of is that the electrolyte level rises in a fully charged battery, so only add water when the batteries are fully charged or you can have them overflow. Hope this helps.

Later Ed