Trailer Battery Questions

[Olivia O]

Both batteries were dead this spring after being in storage, and one of them recharged and the other did not (Apparently a dead cell). I have three questions.

Should I buy on new one or is it best to start with two new ones?
One dealer suggested buying 2 6v golf cart batteries and hook them up in series. Is this a good solution?
Is a no maintenance, sealed battery or one that I add water to better?


I was a new no-experience trailer owner four years ago, and this forum has been invaluable to me. Thank you all.

[AC0GV]

Originally Posted by Olivia O

Both batteries were dead this spring after being in storage, and one of them recharged and the other did not (Apparently a dead cell). I have three questions.

Unless they are almost new, replace both. Were they two 12 volt or two six volt. Two sixes in series may have a slightly larger capacity than two 12s in parallel if they fit. You will need to do the math. I run Duracell ultras,but they are heavy and required modifications on my Scamp.

[CalCop]

A couple of years ago I transitioned to lithium batteries. I changed my fridge to a 12V system (no propane) and required more amp hours.
Lithium batteries, like anything else, have their pros and cons. They are more expensive than other batteries. But they tend to last longer. Lithium batteries allow you to draw them to near zero voltage. This means if the battery is rated at 100 amp hours, you can draw nearly all of those amps without damaging the battery. Lithium batteries are roughly half the weight of lead acid or AGM.
So now the cons. Lithium batteries don't like being charged in near freezing weather. Charging them at lower temps could damage the cells and reduce their compacity and longevity. That doesn't mean you can't draw power out, you just can't put power in. However, once the temps rise you can charge them as you normally would.
I suggest you do some research on the battery styles and brands available to you.

[parmm]

Originally Posted by Olivia O

Both batteries were dead this spring after being in storage,.

When you put your trailer in storage - you should disconnect or remove your batteries - unless you can leave your trailer plugged in. But if you leave it plugged, you have to check the fluid levels in the battery cells.

[Mike_L]

Originally Posted by Olivia O

Both batteries were dead this spring after being in storage, and one of them recharged and the other did not (Apparently a dead cell). I have three questions.

Should I buy on new one or is it best to start with two new ones?
One dealer suggested buying 2 6v golf cart batteries and hook them up in series. Is this a good solution?
Is a no maintenance, sealed battery or one that I add water to better?


I was a new no-experience trailer owner four years ago, and this forum has been invaluable to me. Thank you all.

The age old question; which battery is best?
When batteries are connected in parallel the voltage remains the same and the capacity in amp/hours is the sum of the individual batteries. If the voltages differ, the weaker (lower voltage) battery will draw down the stronger battery as the voltages of the batteries equalize. This allows an older battery to be paired with a new one as long as their voltages are the same.
When batteries are connected in series the voltage doubles and the amp/hour capacity will equal the capacity of the weaker battery, usually the older one. That's why batteries wired in series should be replaced in matched pairs.
I've used flooded lead acid batteries for up to 10 years, with proper maintenance. I never draw them below 60% charge, recharge as soon as possible and check the fluid level AFTER charging. These batteries are cheap and readily available but heavy and require regular maintenance.
AGMs have stabilized electrolyte so they don't spill if tipped but after a few years of use they do loose electrolyte (evaporation) and capacity diminishes. Adding water at this point helps but full capacity isn't recovered.
I always remove my batteries at the end of the season. Otherwise they will discharge over time. A charged lead acid battery won't freeze but a discharged one will. Freezing causes physical damage to the battery. Topping up the charge every month or two helps.
Some years ago I replaced my batteries with a pair of 100 amp/hr 12 volt FLA batteries. A camping buddy replaced his batteries with a pair of 200 amp/hr 6 volt FLA batteries connected in series. In theory we had the same capacity and that's pretty much how things worked out. The only difference, when his kids killed his battery he was done for the trip. When the kids killed my battery, I had a second one fully charged.
Otherwise I use only lithium batteries. I have recelled all my cordless tool batteries with 18650 cells. I have quite a few of these cells and may build an RV battery to see how it works,

[Olivia O]

Thanks to all. The batteries were disconnected, so it is a mystery! I will buy 2 new 12-volt ones like the ones I had, which were 3 years old.

[Mike_L]

Originally Posted by Olivia O

Thanks to all. The batteries were disconnected, so it is a mystery! I will buy 2 new 12-volt ones like the ones I had, which were 3 years old.

Batteries will self discharge over time. As this happens the concentration of acid in the electrolyte decreases to a point where it can freeze and physically damage the battery, sometimes causing distortion of the case. In some cases you can revive a dead battery by charging it in parallel with a good one.

[THene1713]

Originally Posted by AC0GV

Unless they are almost new, replace both. Were they two 12 volt or two six volt. Two sixes in series may have a slightly larger capacity than two 12s in parallel if they fit. You will need to do the math. I run Duracell ultras,but they are heavy and required modifications on my Scamp.

THINKING OUT LOUD HERE, MAYBE (SOMEDAY/ SOMEONE) WILL DESIGN A DUAL 12V BATTERY SYSTEM THAT simply uses 2nd battery as 2nd battery, that you (use/automatically switch to) when the first battery runs down? (like they do w/ dual portable LP tanks?)

[Steve Outlaw]

Originally Posted by Olivia O

...I was a new no-experience trailer owner four years ago, and this forum has been invaluable to me. Thank you all...

Olivia, are you aware that Oliver has its own forum that is specific to the Oliver travel trailer?

You really should be posting Oliver questions there.

[Dan Chapman]

Sealed Gelcell batteries are in my opinion the best of the bunch but they are the most expensive. I have a SGC battery in my Scamp that is over 20 years old and it is working fine. Also Amp/Hrs ratings are misleading. What you want to look at is Reserve Capacity in hours.. The higher the better.

[Mike_L]

Originally Posted by THene1713

THINKING OUT LOUD HERE, MAYBE (SOMEDAY/ SOMEONE) WILL DESIGN A DUAL 12V BATTERY SYSTEM THAT simply uses 2nd battery as 2nd battery, that you (use/automatically switch to) when the first battery runs down? (like they do w/ dual portable LP tanks?)

Terry, I suspect this already exists. I have seen some newer-than-mine trailers that have manual switching to access either or both batteries from inside the unit. I don't know if they will switch automatically when one battery depletes but voltage regulators have been around for a long time.
I installed a second battery on my unit to accommodate four day boondocking trips but I still had to manually connect the battery on the tongue of my trailer which was inconvenient, especially at night.
I grounded both batteries to the frame and ran the live from each battery through a toggle switch and then to the trailer's power inlet. That allows me to use either battery or both.
When I went solar I could charge either or both batteries using these switches.

[redbarron55]

For two batteries I prefer tow six volt batteries in series as the charging current has to go equally through each of them where two parallel batteries this is not the case.
However in parallel each battery does have the same applied voltage across it.
A little imbalance between the tow will result in one battery having higher charge rate and higher discharge rate as well.
Basically you pays your money and takes your choice.
If you have one dead battery and the other more or less OK that imbalance is probably the cause.

[jwcolby123]

Originally Posted by THene1713

THINKING OUT LOUD HERE, MAYBE (SOMEDAY/ SOMEONE) WILL DESIGN A DUAL 12V BATTERY SYSTEM THAT simply uses 2nd battery as 2nd battery, that you (use/automatically switch to) when the first battery runs down? (like they do w/ dual portable LP tanks?)

Standard on boats. There is even a switch for the purpose.