Question for the Battery Experts

Do not mix batteries of different ages or constructions. The weak,old batttery will drag down the new battery. Keep what you have until your ready to change them. Install 4 at that time.

Don't mix batteries. Wait until getting to Dover, if there is a Sams there since there is no state sales tax. But beware, if there is a Sams there, not all Sams sell GC batteries and some even if they have the lower amp hour version don't stock the higher version. Just from what I have seen out in the West.

I would load test the 12v gel battery to see if it is worth even keeping at this point. May be it will give you an extra day or so of power if brought along and swapped into the system once the 6v's gave up the ghost, might not be worth it's weight to even bring it.

You don't say how much solar you have but if you can make it for the 5 day trip without much issue and the 10 day trip is the only real concern, maybe renting/borrowing a Honda 2000 for that trip to help your recharging efforts might be the ticket this year.

I'm in agreement that not buying additional until you can replace buy all four together is the right answer for the benefit of your system over the long haul.

One other option is if you have a camping friend that wants to upgrade to a bit more battery capacity, give them a deal on your used 6v batteries and then go out and buy your 4 new ones together.

Enjoy your trips, sound like great times.

Hi Fire,

Do nothing with the battery bank.

Don't bother to bring them "home" next winter. Just leave the Rogue doing its job.

Do beef up the charging path from the tow vehicle, if you have not already done so.

CincyGus wrote:
I would load test the 12v gel battery to see if it is worth even keeping at this point. May be it will give you an extra day or so of power if brought along and swapped into the system once the 6v's gave up the ghost, might not be worth it's weight to even bring it.

You don't say how much solar you have but if you can make it for the 5 day trip without much issue and the 10 day trip is the only real concern, maybe renting/borrowing a Honda 2000 for that trip to help your recharging efforts might be the ticket this year.

I'm in agreement that not buying additional until you can replace buy all four together is the right answer for the benefit of your system over the long haul.

One other option is if you have a camping friend that wants to upgrade to a bit more battery capacity, give them a deal on your used 6v batteries and then go out and buy your 4 new ones together.

Enjoy your trips, sound like great times.

Think that I'm gonna get the gel-cell load tested... it may be junk, it's so old...

As for how much solar, it's in my signature block - 300W. I own a Yamaha 2400, just don't like to start it unless I absolutely have to....

I HAVE a friend who wants the two 6v, but on his new TT, the battery (single) is "sunk" between a-frame at the hitch, and if he raises it to the top of the a-frame for a double battery box, it blocks his ability to get the propane cylinders in and out of their molded nose compartment. Still working on a solution for that, as he really needs twin 6v for nighttime use of a CPAP!

As for buying in DE, what a GREAT idea! Not only will we be in DE for the race, but we travel through DE to get to Assateague, plus wife also usually wants to go to the factory outlets in Rehoboth Beach while we are in Assateague. Now I will have something to shop for!

Hi,

Be careful with load testing gel cells. They can be destroyed by that process.

If a battery isn't holding a charge as well in terms of its voltage, then it's not a good idea to wire it in parallel with stronger batteries because the difference in voltage creates a differing potential which will cause current to flow from the stronger battery to the weaker one while the batteries are sitting.

However, you say that the older battery still holds a full charge, which I take to mean that it reaches a full charging voltage of around 12.6 volts. In that case, it does no harm to use the battery to increase your amp hour capacity during discharge. If it has different, maybe less, capacity then your CG's, the different sets of batteries will discharge in proportion to their differing capacities. I have several banks of batteries with differing capacities. I don't wire the batteries directly in parallel, however, they are in separate compartments.

Charging, however, may be a different story. The gel cell may have different charging voltage requirements than your CG's, so charging them together from the same converter may be a problem. The gel cell may also have a different resistance than the GCs, so it will grab a different proportion of the charging amperage. In other words the differing batteries may not charge evenly. I partly solve this problem by isolating my separate battery banks from each other during charging with relays. I use a separate charger for my AGMs.

The fact that you are also charging from solar panels adds another complication to using different batteries if all of them are tied in to the same circuit from a single controller.

But my main point is, if you have an additional battery available, why not use it? You can always charge it separately.

Miles

The more that I hear from others, the more that I research on my own, and the more that common sense sinks in, I'm inclined to just keep the two 6v GC batteries that I have until they start to die their natural death.... And THEN replace with a bank of four!

Thank you for all of the input, Guys! It's like a good diner or bar discussion, only without the virtually, without coffee or beer!

If you actually need the capacity just add the two more GC2 wet cell batteries.
Expect all 4 to age out together in 7 to 10 more years.

smkettner - Yours is one of the opinions that I was looking for, as I know that you are a bit of an SME. Repeatedly, folks post to replace all at once, but I know in fire apparatus, if a battery goes bad, we replace it. Most of the full-size apparatus, and many of the ambulances and smaller rigs have dual batteries, and changing one bad one is fairly common practice....Even if I only get four years out of the existing and the two new ones, I consider myself "ahead", because when was running one 12v marine battery I had to recharge almost daily, and I only got a couple of seasons out of them... three at best....

So, IYHO, adding another pair to the existing two won't cause problems?