Bay Star 2022, model 3408 house battery connections

[SteveG]

Our rig has four 6 VDC batteries mounted in a tray located on the driver’s side. Two more 6VDC batteries are mounted in the engine compartment. These six batteries are electrically connected and are considered together to be the “house” batteries. However, I cannot determine the location where the wiring physically connects the six batteries together.

When I checked on the battery fluid levels (1) The four batteries required a lot of water. (2) the two batteries did not require much water. I have no battery problem that I am aware of. Because the two batteries do not seem to be working as hard as the four batteries, I am trying to determine a way to know that the two batteries are still electrically apart of the house battery circuit.

 

[SteveG]

More information.

About four months ago when I checked the fluid levels of the two front batteries, when I removed the positive battery protective covering of one of the two batteries, I discovered that the cable was not physically connected to the battery. The nut was gone, and the cable was floating off the battery lug. These two batteries had been out of the six-battery circuit for “X” time period. Because the batteries were not working, no additional battery water was required for either battery.

At no time during “X” period did I sense that there was a battery problem. This included when I pre-trip cooled the refrigerator overnight using the inverter. We only have a portion of a 20 AC amp circuit to charge the batteries with a trickle charger. We arrive in storage fully charged and trickle charging will maintain the full charge. This means that there were only four batteries being used by the inverter and not four.

 

[Sealyn]

Just a FYI, when flooded batteries start using more and more water it's time to consider replacement. I would recommend replacing all 6 with AGM batteries.

 

[SteveG]

I agree about the water use. The mystery is why are six batteries not using the same amount of water.

 

[Sealyn]

You said the front two were disconnected.

 

[osuallen]

I used to have a Canyon Star with the same battery arrangement. It was not uncommon for the two battery banks to not require the same amount of water. I used a battery water system so could not comment on each individual battery.

 

[SteveG]

At one time I did find the front batteries were disconnected. I mention that as a reference for water use. Would not be using water if not used. And now, with all six batteries connected into the circuit, the front two still not using water. I squeezed into the four batteries with a bulb squeezer system a little over a quart of water. With the front two batteries which I can easily see and access I used a hand bulb and added not more than 2-3 oz. into each battery. I will call Newmar to see if they will tell me where the two batteries and the four batteries are physically wired together to be sure they are in fact operating as a six battery circuit.

 

[Sealyn]

Batteries use more and more water as they age, depending on how long the front batteries were disconnected there could be a big in use age difference in your batteries. Also the long cable run between the banks will effect the charging rates. When you decide to replace them, be sure to replace all 6 with the same type/size.

 

[SteveG]

Yes, I agree. And factually I do not know for how long the front batteries were disconnected. But I do know when I reconnected them and so when I went to add water this last time, I was surprised to see how little water they took. It was on the order of about the same amount I added when they were disconnected. Thus, my inquiry.

Doing some internet research, I found some information about how the batteries are connected to the inverter. This is the link, pages one and two: Bay Star Battery Monitor Install - iRV2 Forums

According to the above link, the inverter is connected across the four-battery bank instead of off the entire battery bank of six 6VDC batteries wired in series / parallel creating a battery bank grouped as three 12VDC batteries. If our batteries were assembled in one tray, then the load would be shared by all the batteries. But we have four batteries in one place and two batteries in another place. If my battery knowledge is correct, because of where the inverter / converter is connected to the four batteries, the four batteries will be discharged faster and charge faster than the front two batteries. The four batteries are working harder and thus they gas more which causes water loss. Thus, the four batteries need more water than the front two batteries.

I am also in agreement about the length of wiring that connects the front and rear batteries causing some resistance imbalance which also contributes to some degree the rear batteries working harder. I think the science of “imbalance” would also be affected by the wire size: the larger the wire the less resistance. But I will let that sleeping dog alone.

I have called Newmar and asked them to confirm where the inverter is connected to the batteries. They did not know but said they would attempt to find out. All in all, I think the “water” mystery has been solved.

 

[SteveG]

I will add one more observation. In preparation for our trips, we power on the refrigerator using the inverter (only four amps of shared power available where we park) at about 1900 hrs the night before departure. By about 0830 the next morning the inverter event usually draws down the batteries to about 12.2 VDC. Sometimes not even that, if the air temperature is not hot.

What got my attention, and how I found the front batteries disconnected, is when I arrived after the typical “inverter event” and found the batteries at about 11.9 VDC. So, after that trip I went poking around, thinking I may need water and maybe I had a loose or corroded connection. That’s when I found the missing nut and the positive battery cable not connected to one of the front batteries. The reason the loose cable was not observable is because I wrap the positive posts to help protect against a short to ground.

As it turns out, this “disconnected cable” became evidence that even though the front two batteries are not connected to provide the most efficient solution, they are contributing when the inverter is operating.

 

[Kevin D Pem]

Batteries use more and more water as they age, depending on how long the front batteries were disconnected there could be a big in use age difference in your batteries. Also the long cable run between the banks will effect the charging rates. When you decide to replace them, be sure to replace all 6 with the same type/size.

Adding to this!

Shelf life is not the same as active life. The batteries should have a manufacturing date on the top in the form of a sticker.

It is recommended the dates should not be more than 6 months different, nor should they be in service with anymore than 6 months differents.

This may, or is likely why the batteries are disconnected. What happens when connecting old to new?

The new complete top off before the old due to less resistance. When fully charged any battery will create heat ultimately destroying the battery that was the better battery.

The same can be said for different length cables.

It should be noted that with the system able to charge with the set disconnected, best practice for connection of charging connection has not been adhered to, or likely not adhered to.

You would be advised to verify the charging system connections. These have been talked about in former threads. Search other threads, or look for information on charging banks of batteries.