Three months ago I replaced my 12 volt batteries (I had 2) with 2 6 volt golf cart batteries. I checked and re-checked to be sure that they were connected properly in serial. They have been sitting for 2 months, water level checked, and battery disconnect switch off.

Today I checked them and found that they are dead. One is reading 0.0. and the other a little over 10. one has developed an small bulge in the top of the case. Costco can't check them or put a charge on them but the good news is that they said if I bring them in they'll just replace them!

Before I put the new ones in I want to make sure I didn't do something wrong that caused this. Did I need to make other changes for this switch from dual 12 to dual 6? Am I wrong that a couple of months sitting (while disconnected) shouldn't be a problem?

While I know they are dead because I tested them with my multimeter and because when I turned the disconnect switch on the lights weren't working, but is there anything different about using my multimeter on these batteries than there was on my 12 volt (also connected in series)?

Thanks for the help  :)

I'll be interested to hear how this sorts out.  That's great about Costco replacing them!  From what you've said, I don't see the problem.  Two sixes in series is the same as 2 12s in parallel, as far as voltage is concerned.  Were the batteries totally disconnected or were they connected with a disconnect switch in the circuit?  Could be a bad switch.

TT

The batteries were connected and only "disconnected" via the disconnect switch, so if it is bad that would explain.  I expect I can test that by hooking the new batteries up, setting the disconnect switch to "off" and then checking to see if my interior lights work.  Right? If the switch is bad can it drain enough power to deplete the batteries while not enough for my lights to work?

I'll check that pin. These are good ideas but I can't check them out until at least Thursday.  I'll keep checking here to add to my list of things to check and I'll report back. Thanks so much for the help.

Great about Costco though, right? I bet they won't do it more than once though  ;)

But first  just to be sure you have the batteries connected up correctly. 

The dual battery 1-2-both-off switches are generally intended to switch between house and start batteries on a motorized RV or boat. You don't need that for a trailer with two paralleled 12v batteries, it's fine to just leave those connected to each other. If you want, you can get a simple isolator switch to disconnect the batteries from the house loads when the trailer is not in use, but then you need to consider that lead acid batteries cannot be left uncharged for long periods, which is likely what happened to the OP here.

 Alternatives (depending on your storage situation):

leave the trailer connected to shore power or connect to shore power for a day or so every few weeks and let the converter maintain battery charge.

install a small solar module and charge controller

remove the house batteries in the off season and maintain them at home on a small charger.

o

Originally posted by hogone Probably a goofy battery question but will ask anyway!!  When Im home, I leave the old pod plugged in 24/7.  Should I disconnect occassionally (maybe for a week or two) just to let the batterys drain a little?  jon

Though I remove batteries during winter I read of many who keep their pods plugged in 24/7 for long periods of time without any ill effects.  The only word of caution that could be added here would be to keep an eye on electrolyte levels (once/month) and fill with distilled water when needed.

1) They sat for just under two months

2) After a couple of years of reading about the 6 v batteries I never saw that they can discharger faster, I wish I had as I might not have done it because my camper is parked where I cannot plug it in.

3) I don't have an "off season" so I guess I'll try to get a solar tender.

3) I have this same kind of  disconnect switch and I keep it set on "off" or "both"

One day I'm going to make it to a rally in hopes of having someone teach me to use my multimeter. I only know how to test the charge on my batteries. This is way beyond my capabilities (honestly, with I can't even read this lol):

" Put your multimeter on the ohms scale and connect it across the switch terminals. You should get an open circuit (or very high ohms) reading with the switch open. Then with the switch still disconnected from the battery  close the switch and measure the ohms again. You should get a reading in the 0 to 1 or so ohms range." Just for fun I put the terms I don't understand in italics.  :)

Ohms scale:  On your meter, you should have a dial with various things like DCV (Direct Current Volts), ACV (Alternating Current Volts - your usual house plugs are 120V AC), DCA (DC Amperes), ACA (AC Amperes), Ohms (May be on the dial as a Greek letter Ω (Omega) which is the symbol for Ohms) and possibly battery test and transistor test functions. Ohms may be divided into 2000k, 200k, 20k, 2000, and 200 Ohms. Your meter may be different. Ohms is the symbol used to measure resistance.

Take the multimeter and put it on one of the Ohms settings. You should have a reading of 1, which indicates that there is no current flowing. Touch the tips together. The digital display should change to 0.00 for digital or the needle should move to 0 on the OHMS scale on a meter with a dial and needle. That is what indicates that there is a closed circuit and that current is flowing. If the reading is anything but zero, then that is the resistance of the circuit.

your battery switch should have three connections. One goes to one battery, one to the second battery, and the third to the load (the trailer wiring). With the batteries disconnected, turn the switch to Off. Put one probe on the terminal that leads to the load. Touch the other two terminals, one at a time with the other probe. The reading should stay at 1 (or very high on an analog meter). Turn the switch to battery 1. Again, one probe goes to the load, the other to the terminal for battery 1. The meter should move to 0 or very close to it. Touch 2 and it should stay at 1. Move the switch to battery 2. Again, one probe goes to the load and the other probe goes to the battery 2 terminal. The reading should be 0 or close to it. Then touch the Battery 1 terminal. The battery 1 terminal should remain at 1. Last, turn the switch to Off. Touch the Battery 1 and Battery 2 connections. The reading should remain at 1. If all these give you the results I mentioned, then your switch is functioning normally. 

I hope this helps clarify for you what was meant.

+1 Same. I do have a reminder every 3 months to check the water.

When we stored our Rpod in a storage facility for a while, we pulled the batteries and kept them on a bench. That was a bit of a pain, as I would put them on a charger periodically. I guess you could also put them on a trickle charger, which is not an expensive proposition.

A terminal is a place where a wire attaches. The wire terminates there. Thus, terminal. If a wire does not attach to anything, nothing happens. I would like to help you understand. Thanks for letting me know that I left that part out of my previous reply. We all start from somewhere. There was a time when I did not know what a terminal was either or many other things.

Echogale, maybe try this video, see if that clears some of this up. Look particularly at the ohms and continuity sections. Checking a switch function is really a continuity check, either the switch is acting like a continuous piece of wire or its acting  like  two pieces of wire that are disconnected.

https://youtu.be/ciyWwcKmPC4

One thing that often helps electrical newbies is to think of your electric circuits as if they are water pipes. Voltage is like water pressure,  pushing electricity through the wire. Current (amps) is l

the rate the electricity flows through the pipes. Resistance (ohms) is the restriction of the wire (or load device)  resisting the flow of electricity - skinny wire = more resistance so less amps, just like a skinny pipe will flow less water.

 I suggest caution to start with when 

leaving your batteries on the on board converter continuously on charge. Check the water level in  them frequently (like once a week frequently) until you get a good feel for how much they are consuming. Don't just connect and leave them for a month or two.

When a flooded type lead acid  battery is floating on charge it is continuously converting water into oxygen and hydrogen (called electrolysis). You will see small bubbles in the cells when you look. That's good because the bubbles act to keep the acid mixed with the water in the cells. Otherwise the sulfuric acid,  being much heavier, settles to the bottom, eventually causing degradation to the lead plates in the battery.  But too much bubbling is bad, just consumes water needlessly and risks exposing the plates.

The amount of gassing (bubbling) is proportional to the amount of current being forced through the cells by the converter, and the higher the voltage setting of the converter the  more current.The gassing rate is also effected by temperature (hotter = higher) and the details of the chemistry used in the battery manufacture).  So it's hard to know in advance what your water consumption/gassing rate will be.

What happened to me was that my WFCO converter got stuck in it's "boost" stage  and set it's voltage way up around 15V. It probably will surprise no one here to know that FR hasn't necessarily selected the highest quality converter for their trailers... 

15V is way too high for continuous charging and consumed my battery water rapidly. In just a few weeks I went from completely full cells to barely covered plates. Caught it in time, no harm done as long as the plates aren't exposed . So the warning is, be cautious and check water level often till you have a feel for how fast you're consuming water. 

Re filling new batteries with acid instead of water, that is a one time thing only. Often lead acid batteries are filled with acid at the factory, fully charged, then the acid is drained and placed in a separate container. This is called dry charging a battery and is done to increase it's initial shelf life and to improve safety during shipment  There is no (well, very little) self discharge if the battery doesn't have electrolyte in it, if it it takes months before the end customer gets it installed there is no harm done.

But once you fill the battery one time with acid youre done. It won't consume acid over time, just water, so if you pour in more acid later you'll just be steadily increasing the acidity beyond what the battery is designed for. And that's bad because the higher acidity will cause more internal corrosion and result in shorter battery life. So, distilled water only please! 

In that case you might see your battery voltage look ok but if you put any kind of load on the battery it dies quickly.

One thing that sometimes works in that case is "desulfation". In desulfation you take the battery up to a high voltage, like around 16V, hold it there for a little  then cut off the charging for awhile, then repeat. That works to mechanically cycle the plates and might possibly break the sulfate loose,freeing up more plate area.

So you could try that if you have an old school battery charger that can be set to charge at a high voltage. I wouldn't hold out a lot of hope though after 3 years.

Jon, please keep us abreast of your battery situation.  Yes, as Offgrid points out, your batteries have been hurt due to the fact that the plates were exposed (for who knows how long) to air.

As I think about the electric carts we had at one of our 4 golf courses we went through a fair amount of distilled water!  Each 6 volt battery holds just north of 1.5 gallons of liquid.  Multiply that times 6 and you find yourself transporting over 9 gallons.  But that is old school.  Yamaha I believe was the first cart manufacturer to come out with the 48 volt system for golf carts; using six 8 volt batteries.  The 8 volt batteries (Trojan) weigh about 1-2 lbs more than their 6 volt brothers but I think the liquid capacity is about the same. 

Last year our oldest 12v Interstate (it was over 11 years old) was replaced with a Trojan T-1275, which is a 12v golf cart battery putting out 150aH, not light at 85 lbs, but has performed well so far with our nearly 12 year old original Interstate 12 volt.  Each is run separately from the other.

I have been checking the water level and have needed to add water a good bit more than with my old batteries so I think that likely was the problem.

there is an extra wire with both positive and negative connections it's thin. I bought my rpod used and its been there all along and have assumed it was the zamp wiring and I don't use it.  Wouldn't mind alternatve guesses if you have any.

Heading out Sunday for a couple of weeks; thanks again for all the help.

That is exactly what they are. If you are not using the Zamp connector, you can leave them disconnected.

And yes, flooded deep cycle golf cart batteries have a higher self discharge rate and consume more water. That is the tradeoff you make for better ability to handle deep cycling compared to SLI (starter, lights, ignition) auto batteries, or dual use marine type batteries.. 

I've been all over Florida in the last couple of weeks including almost a week of dry camping with very little power discharge. FWIW, since I can only stay out as long as the house batteries last-- or are successfully recharged with my solar panel--I'm very careful about power usage and many of my little things have their own rechargeable/replaceable batteries.

I think with my new batteries I can stay out for weeks.  :)

I think the problem was the water level as I had not understood that my maintenance routine needed to be modified from the old 12v batteries.

Thanks again for the tutoring.  :)

Originally posted by EchoGale Thanks, no I don't mean complete discharge. I was, however, under the impression that the 6V golf cart batteries could be discharged down more than that though. Am I mistaken?

A single 6v battery can safely be taken down to 6.1v (50% S.O.C.) without damaging it.  If you are reading the meter with both batteries hooked together than what offgrid states (12.2v) is correct. 

Yes, please keep an eye on the electrolyte levels, keep filled with distilled water only.  My oldest 12v battery (Interstate deep cycle group size 24) will turn 12 years old in 3 months.  Proper care and maintenance is key with battery life/longevity.

That being said, since you live in a hot climate your battery life will be relatively shorter because what's called shelf life (aka corrosion life). This is just inherent in lead acid batteries because the sufuric acid is constantly corroding the lead plates, and the hotter it is the faster the corrosion rate. So you won't get Jato's Michigan climate battery longevity in FL. Plus deep cycle batteries usually corrode faster than SLI batteries because the chemistry is optimized for cycling rather than shelf life. It's a trade off like most things in life. 

Probably you won't get more than about 4 years out of your golf cart batteries where you live even if you're really careful about cycle depth. 

Long story short, don't be afraid to cycle the batteries you have now when you need to, while avoiding going  below about 50% as you can. Hope that's clear. 

So, don't 

1) SLI and dual use "marine" batteries have a different chemistries from deep cycle lead acid batteries. IIRC the deep cycle batteries use a lead antimony alloy which makes the plates more phyically robust (so they can handle the mechanical effects of deep cycling which consumes and redeposits the lead on the plates). But the antimony makes for higher self discharge  rates. Also deep cycle batteries usually use higher specific gravity sulfuric acid (so that there is more acid there to be consumed during discharge).  Both those chemistry differences increase deep cycle battery internal corrosion rates vs SLIs so shorten their shelf life.

2) There is a rule of thumb chemists use to assess the effect of temperature on reaction rates. That is roughly, to assume a doubling of reaction rate for every 10C temp rise. Internal corrosion in a battery is just another chemical reaction  so if a battery in Michigan  is 10C colder than a battery in FL it should last twice as long  everything else being equal. And looking at annual average temp is misleading because the doubling corrosion rate factor is an exponential function, meaning that the extreme temps high and low will tend to dominate lifetime,  not the averages. 

3, jato is clearly an expert on how to manage batteries  from his  long experience with golf cart maintenance, plus he is very careful in monitoring hus battery system state of charge. 

4) And yes he has a shorter use season than EchoGale does.

So he is able to extract more life from his batteries than pretty much anyone. Including me, I'm not anywhere near as careful as jato is and live in a warmer climate, and run deep cycle golf cart batteries not SLIs or "marine" batts. So I've always hitting the 4 or 5 year lifetimes too.  The way I look at it golf cart batteries are kind of an insurance policy for those of us who aren't going to be perfect in our battery management techniques and will wind up deep cycling them more than we'd like from time to time. 

Of course  Li batteries blow away PbA's in all these areas and theyre so cheap now that for those of us who are a bit electrically handy they have become a almost a compelling upgrade. And since it's mandatory that Li's have a BMS for safety, you do t need to be a super conscientious operator as much with them. The BMS provides that last line of defense fircyou automatically.  

The price has dropped tremendously if you don't go for the big names such as the one that has two of the letter B in its name. Even it has come down below $900 but it is still on the high end for 100Ah LiFePO4 batteries.

 Being lithium about 80% of that capacity is useable so 280ah is roughly equivalent to 2 series (edit) x 2 parallel 220ah golf cart batteries used down to 50% SOC, which will set you back about (edit) $600-700. So lithium batteries are really now (edit) about the same cost as low cost flooded lead acid. Not (edit) even considering all the benefits. 

The weight factor is critical if you want a high power system to run a/cs or other big loads.  As an example, right now I'm planning a 48V 280ah system for my new to me RV, that's the equivalent of 16 GC2 batteries but will weight in under 200lbs vs half a ton of lead acid batts, which would of course be impossible.