Replacing batteries..

[Flapper]

So, we learned last fall on the LT 26.5 RLS that it was a bad thing to run the battery all the way down. 5th is off site, in storage where I can't easily get to it currently. Stock Jayco supplied battery box in the front compartment. I'm not even sure what size battery is in the box. Whatever it is, it won't hold a charge. Now looking to upgrade. Costco is featuring their 6v Golf Cart batteries. Can anyone share the dimensions of the battery compartment, to determine whether the GC batteries might fit, and a suitable battery box I can use to put them in? Or, if you've done something else better for your 26.5 to boost the available battery amps, I'd love to hear about it!
Someday I'd love to add solar, but that someday is a ways off....

[Jmooney]

Many of the PWM type chargers say that they can bring a battery back after heavy discharge.

[Ela1948]

Recommend you to put a disconnect on your batteries. There is a pretty significant battery drain even when you think that you are not operational! They are not expensive and they will solve your problem.. Even golf cart batteries will drain down if left hooked up long enough. Most things in your camper are 12 volt powered and things like refrigerator electronics, smoke detectors & propane detectors are using some power all the time. A battery disconnect will eliminate that drain!!

[Flapper]

I wish - the current one is definitely a gonner. 'Tis a bad thing for one to leave a couple of lights on for several weeks in the driveway. Twice! It does have a disconnect, which I think my DW now understands needs to be turned on and OFF every time she does something in the camper when it is in the drive....

[Ela1948]

Originally Posted by Flapper

I wish - the current one is definitely a gonner. 'Tis a bad thing for one to leave a couple of lights on for several weeks in the driveway. Twice! It does have a disconnect, which I think my DW now understands needs to be turned on and OFF every time she does something in the camper when it is in the drive....

Most education comes with a price tag!!!

[msturtz]

If you choose to go to 2 GC2 6VDC batteries you may wish to keep in mind that the absorption charge voltage is 7.75 VDC per battery which equals 15.5 VDC. This is a much higher voltage than most RV converters can provide. This means that you will need to provide separate charging system from your RVs converter. I built a setup for my JayFlight 29BHS and had to add additional charging because I was constantly undercharging the batteries.

[Jmooney]

Originally Posted by msturtz

If you choose to go to 2 GC2 6VDC batteries you may wish to keep in mind that the absorption charge voltage is 7.75 VDC per battery which equals 15.5 VDC. This is a much higher voltage than most RV converters can provide. This means that you will need to provide separate charging system from your RVs converter. I built a setup for my JayFlight 29BHS and had to add additional charging because I was constantly undercharging the batteries.

What Michael wrote is very important . The best batteries in the world will only be as good as the charge method you use.

[Mustang65]

Originally Posted by msturtz

If you choose to go to 2 GC2 6VDC batteries you may wish to keep in mind that the absorption charge voltage is 7.75 VDC per battery which equals 15.5 VDC. This is a much higher voltage than most RV converters can provide. This means that you will need to provide separate charging system from your RVs converter.

If you have the 2 - 6VDC batteries in series to equal 12VDC for the TT, you do not use the 6VDC recommended battery specifications X2. You need to use the 12VDC specifications. If your TT is a late model will handle the requirements easily. The TT's battery charger's microcontroller determines the amount of amperage that the batteries need. You can Google your battery controller mfr to see what your controller specifications are.

Most battery TT controllers do not use the 15 – 15.5VDC Equalization mode, they use 14.6VDC “Boost mode”. The TT's battery controllers "Absorption" mode should be close to 13.6VDC, and “Float” mode around 13.2VDC.

With 15-15.5 volts comes a lot of battery heat, and the well designed (aftermarket) controller should have a temperature/voltage sensor connected to the batteries terminal (post), so the controller knows when to drop the voltage. If not monitored, there is a chance that the batteries may explode, if overcharged. TT battery controllers are not that sophisticated, hence only about 14.6VDC, to play it safe.

The PD4000 battery charge controller in our 2013 Eagle 284BHS, has the capability of putting out 45Amps at 13.6 volts (14.4 volts in burst mode), and I never had an issue of undercharging (2 - 6VDC Trojan T145 260Ah batteries in series). I have since added SOLAR and I have turned the TT's charge controller's 120VAC breaker off (wired to its own breaker). Normally the batteries only need about 1.5 amps when in Absorption mode each day.

The only time my voltage hits 15 - 15.5VDC is when I manually switch to "Equalization" mode on the solar charge controller. I only do this once every few months. One last thing, it is not a good idea to have your TT's electronics online when the voltage is in the 15VDC range. A lot of nasty things can happen to electronics in that range.

If you are encountering undercharging, there are a few areas to look at: The size of your batteries may not meet your DC power demands, the batteries may have been discharged to a voltage that is to low multiple times and can no longer maintain a charge. One of the batteries may have a bad cell. The age of the batteries (cycles). The TT's battery controller may not be operating properly. Another area to look at is the possibility that the cable connections may not be clean or the gauge of wire used may be to small.
Don

[msturtz]

Originally Posted by Mustang65

If you have the 2 - 6VDC batteries in series to equal 12VDC for the TT, you do not use the 6VDC recommended battery specifications X2. You need to use the 12VDC specifications. If your TT is a late model will handle the requirements easily. The TT's battery charger's microcontroller determines the amount of amperage that the batteries need. You can Google your battery controller mfr to see what your controller specifications are.

Most battery TT controllers do not use the 15 – 15.5VDC Equalization mode, they use 14.6VDC “Boost mode”. The TT's battery controllers "Absorption" mode should be close to 13.6VDC, and “Float” mode around 13.2VDC.

With 15-15.5 volts comes a lot of battery heat, and the well designed (aftermarket) controller should have a temperature/voltage sensor connected to the batteries terminal (post), so the controller knows when to drop the voltage. If not monitored, there is a chance that the batteries may explode, if overcharged. TT battery controllers are not that sophisticated, hence only about 14.6VDC, to play it safe.

The PD4000 battery charge controller in our 2013 Eagle 284BHS, has the capability of putting out 45Amps at 13.6 volts (14.4 volts in burst mode), and I never had an issue of undercharging (2 - 6VDC Trojan T145 260Ah batteries in series). I have since added SOLAR and I have turned the TT's charge controller's 120VAC breaker off (wired to its own breaker). Normally the batteries only need about 1.5 amps when in Absorption mode each day.

The only time my voltage hits 15 - 15.5VDC is when I manually switch to "Equalization" mode on the solar charge controller. I only do this once every few months. One last thing, it is not a good idea to have your TT's electronics online when the voltage is in the 15VDC range. A lot of nasty things can happen to electronics in that range.

If you are encountering undercharging, there are a few areas to look at: The size of your batteries may not meet your DC power demands, the batteries may have been discharged to a voltage that is to low multiple times and can no longer maintain a charge. One of the batteries may have a bad cell. The age of the batteries (cycles). The TT's battery controller may not be operating properly. Another area to look at is the possibility that the cable connections may not be clean or the gauge of wire used may be to small.
Don

I had GC2 golf cart batteries in my JayFlight 29BHS installed by the dealer. I had major problems with undercharging. Even when I had a 3 stage Progressive Dynamics converter installed the batteries were constantly undercharged by the converter. To resolve this issue I had to install two separate 6VDC automatic chargers to each battery. The chargers were isolated from each other. Following the directions from the battery manufacturer as to charging voltage is important. There are specific instructions for paralleling situations. Do your research and ensure you are not under or overcharging your batteries. I chose the option of using separate isolated 6VDC automatic chargers to keep my GC2 batteries up because of the issues of the higher 12 VDC charging voltage. GC2 batteries are a great way to go if you understand the limitations. There are other issues with paralleling batteries including how you connect the charger(s) and load(s). http://www.batteries-faq.com/activek...p?questionid=1

[Seann45]

In 6 years with my solar system I have never seen voltages in the 15.5 area. mine charge to 100% at 14.6. IF you camp off grid (boondock) pairs of 6's is the way to go.. IF you always stay in RV parks with electrical hookups then dont waste your money on 6's

[msturtz]

Originally Posted by Seann45

In 6 years with my solar system I have never seen voltages in the 15.5 area. mine charge to 100% at 14.6. IF you camp off grid (boondock) pairs of 6's is the way to go.. IF you always stay in RV parks with electrical hookups then dont waste your money on 6's

I would be very curious to hear how you are determining 100% charge. A volt meter showing full charge for a 12vdc system is not full charge for a series 6 VDC to 12 VDC system.

[Flapper]

Oh my... more homework!
Someday the dream will be solar, but until we have some more boondocking time under our belts, and I can get some real world experience with what we actually need for power....
I had thought about just a big Group 31 AGM, but started down the GC road after doing some more investigation. Guess the prudent thing to do is to wait till I can get it out of storage, so I can directly evaluate available space, current wiring, and review what I may/may not have for charging capability. Thank you all for the detailed answers!

[Mustang65]

""""Oh my... more homework!""""


Don't forget the most important thing.... How long your batteries will last based on your camping lifestyle. Odds are that will have to be modified.. Depending on your system size, Lots of LEDS, turn it off if your not using it, charging your things during the day, watching your battery output.... but it all becomes second natured after awhile.
Would not be with out SOLAR!!!!
Don

[Mustang65]

Originally Posted by msturtz

A volt meter showing full charge for a 12vdc system is not full charge for a series 6 VDC to 12 VDC system.

Actually it is the same.

The cell voltage for each battery cell is 2.1VDC. So for a single 12volt battery or (2) 6volt batteries in series or (3) 4volt batteries in series, each battery cell is 2.1VDC. Here is the math...

(1) 12VDC Battery = 6 cells * 2.1VDC = 12.6VDC

(2) 6VDC Batteries in SERIES = (Bat#1.. 3 cells * 2.1VDC=6.3VDC) + ( Bat#2.. 3 cells * 2.1VDC=6.3VDC) = 12.6VDC

(3) 4VDC Batteries in SERIES = (Bat#1.. 2cells * 2.1VDC=4.2VDC) + ( Bat#2.. 2 cells * 2.1VDC=4.2VDC) + Bat#3.. 2 cells * 2.1VDC=4.2VDC)= 12.6VDC


The charge controller see a demand for 12.6 VDC and knows what to do!!

Everything works out.

Don

[wwsmith111]

Usually battery boxes for TT are either standard size series 24 or larger size series 27. Series 24 are typically around 9.6 x 14.2 x 10.7 inches while series 27 are 9.5 x 16.8 x 11 inches in size. My Jayco Eagle 338 rlts has room for one series 24 box and one series 27 box. The dealer installed a series 24 box and battery and I added a larger series 27 box and battery in parallel using #2 cables.

[msturtz]

I opted to purchase two group 31 VMTANKS http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1 batteries. Each battery is rated to 120 AH so two in parallel produces 240 AH. The notable difference is AGM batteries do not have the nearly the issues with the Peukert’s Law that flooded batteries do. Flooded batteries have a really bad problem with losing capacity the higher the amp draw. The VM Charge tanks battery I bought will fit in a the group 27 / 29 battery location in my Greyhawk. The VM Charge Tank batteries are slightly taller and longer and wider than the group 27 battery.

[Mustang65]

Nice!!
Let us know how they perform.

Don