Tip & Trick: 235 AH Battery Upgrade

My little teardrop required power for lights, the water pump, and the 12v outlet that powered my Dometic fridge. That was pretty much all we used the batteries for other than charging our devices. My husband updated our battery package on the teardrop so I could go nearly a week without charging (depending on weather of course because the hotter the weather the more the fridge ran).

When we got the Airstream we were shocked with the number of batteries for the number of things that required power. We call my husband “More Power Mick” because he is good about making sure we have lots of battery power. We do not like generators and refuse to dry camp with them (NOBODY likes camping next to a big, loud box running for hours on end). He installed all new batteries replacing the 2 that came with the trailer and adding an additional two batteries. All of this paired up with the solar package we have installed means we have lots of battery power, which gives us several days between charging.

Here is how my super-amazing husband went about the install. Let us know if you have questions! He is happy to answer!

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235 AH Battery Upgrade on 2016 19’ Flying Cloud

I was happy to find out that our 2016 19’ flying cloud had the larger battery box easing the install of larger 6v batteries. Previous models have a smaller box and modifications have to be made to those boxes to enable the VMAX batteries I selected to install would fit. They are rated at 235 AH which is a significant upgrade from the stock batteries which were 80 AH.

IMG_0702-001If you wonder why I have 4, it’s because I actually installed two banks, one in the stock location and a second bank under the bed. They are installed as two separate banks, not directly connected. I’ll explain this in detail in a separate post but in summary, one bank is the main house batteries (stock location) and the second bank is for the inverters. My thought process is that if we use the luxury of the inverters I do not want to drain the important house batteries which power the fridge, furnace lights etc. However if for some reason we accidentally drain the house batteries, leave a light on or something, I can use the second bank to power the main house circuit. In addition, I have automatic charge relays which connect the banks when a charge voltage is sensed on the main lines. It’s cases like this that I am happy that I am a BEng with electrical and computer specialties.

The first thing I did was make a fused bus bar to connect the two 6 volt batteries together. The reason for a fuse between the batteries is two-fold. First as a safety backup – if for some reason the battery gets shorted the fuse between the two 6V will 2017-01-30_17-37-18_475pop. This fuse should be bigger than the max load expected. The second reason for the fuse and the reason that it’s a reset-able fuse, is to act as a battery disconnect if needed.

The bus bar, as seen on the left, is made out of copper bar and in this case a 2/0 welding cable wire.

IMG_0709-001To the right you can see why I couldn’t use two bits of copper for the bus bar – the battery tie down sits between them. On the second battery bank I was able to sit the batteries next to each other so use two copper bars with the fuse between them.

2017-01-31_13-05-53_359The batteries fit snugly in the battery box on the tongue of the trailer. Note I put a rubber hose over the threaded post and made a small plastic pad to help hold down the batteries. There is room on each side but I use 1.5” PVC pipe to ensure the batteries cannot move.

I wanted to measure the battery use so I installed a 500 amp shunt on the negative terminal.
2017-02-02_13-38-34_270This is the shunt that came the Xantrex linkLITE AH meter. I am sure you can get better equipment but I’ve had good luck with the Xantrex stuff which is why I selected it. This and the linkLITE meter is small and installs via a simple hole.

If you look at the photo to the right you can see that no negative cables go directly to the battery – they all go via the shunt. This way you can monitor amps used and amps charged.

In the picture you can also see the two 6V batteries in series making the 12V needed. I still have the direct inverter feed cables connected but they no longer power the inverters, instead, they now carry charge voltage to the second battery bank.

The blue and yellow cables are to enable me to plug in a portable solar charger, just in case the built in solar setup needs a helping hand.

2017-02-02_13-39-05_037I made a little plastic cover for peace of mind that nothing is going to touch the battery box lid.

Speaking of the lid, I drilled a couple of holes and installed locks. I know you can get a locking catch but I can tell you they are weak and easily broken with a screwdriver. This IMG_0694-001lock setup is not much better but will slow down a thief. We have had friends who came out to their trailer and found their batteries had all been stolen, so if we can discourage the act, it is worth it to us.

IMG_0738-001Finally, inside the trailer I installed the Xantrex linkLITE meter. It’s under the couch which might not be the best
place for many, we don’t mind getting down to look at it.

The AH meter is the one on the left, the one on the right is the solar meter.

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