3 battery banks. Is it necesary?

[map40]

I was checking the Alfa that we are in the process of buying and found out that it has 2 batteries for the engine (no problem) but then 2 more banks:
2 6 volts for the coach
4 6 volts for the inverter
Any reason why cant the coach share the same batteries as the inverter? What am I missing?

[map40]

Thanks for all the info. Researching to merge into a single house bank.

[HadEnough]

That's poor design.

Using one large bank for house loads is more efficient and better on the batteries. We've known this for years on boats.

Of course the starting batteries should be separated from the house bank.

[valhalla360]

Assuming the 6v are two separate banks and not just a single bank separated physically but electrically one...

No, it does not make sense to have 3 banks. Two banks makes sense because if house loads run down the house bank, you can use the starting bank to start the engine (or generator) to get the house bank recharged (may not be the ideal charging scenario but at least you aren't dead in the water).

For the same total amp-hr rating, a single large bank will actually have higher amp-hr available due to the peurket effect. It will also be able to absorb more amperage when charging, so you can put amp-hr back in faster.

A third bank only adds complications with no real advantage.

[wa8yxm]

When I first put in an inverter I had it on it's own bank (AGM's they did not last long even though the inverter knew how to baby them)

Now I use one bank for all house functions

I DO NOT have a "Residential" Fridge

THere is no reason you can not combine them that I know of.. You may wish to disable one or the other charger/converter though..

[2oldman]

Big Katuna wrote:
I have a watering system but I forget to add water every month and keep letting the electrolyte level go down.

Sounds like you're a good candidate for AGMs, and selling the inverter! 🙂

[Big_Katuna]

It depends how you camp. I have four T105 CG batteries, 2000W inverter. But I NEVER use my RV without being connected.

I am going to replace them soon and I have pretty much talked myself into replacing them with two Group 27 dual purpose, sealed batteries.

Why? They are the same size, 31s wont fit, I converted all my lights to LED and I hardly ever use the inverter, maybe for tv and its LED, too.

I leave it plugged in all the time.

I have a watering system but I forget to add water every month and keep letting the electrolyte level go down.

[pigman1]

I had a 2008 Allegro Bus that I converted from a 6 battery coach electrical bus to a dual DC electrical bus on 4 additional 6V batteries. THe 4 additional batteries powered the 1 meter Hughes Net Internet system and the entire audio visual system. The rear 6 batteries powered the household refer and the main inverter. The system worked great. I was able to control which (or both) system charged and was able to keep the refer well supplied with power through a third dedicated inverter on the rear system.

[2oldman]

map40 wrote:
Any reason why cant the coach share the same batteries as the inverter?

Nope, assuming it's a 12v inverter.

[Tom_Barb]

map40 wrote:
I was checking the Alfa that we are in the process of buying and found out that it has 2 batteries for the engine (no problem) but then 2 more banks:
2 6 volts for the coach
4 6 volts for the inverter
Any reason why cant the coach share the same batteries as the inverter? What am I missing?

The way you have the written sounds like you have 6 six volt batteries?
We have 2, 12volt engine starting batteries, and 4 ,six volt house batteries, wired in 2 in series to 2 wired in series, and both pairs of batteries wried in parallel to the inverter / house.

[Community Alumni]

Map40

Go here and your question will be answered. Yes you can combine the banks. But wait there is more just go here Alfa Forum

Not trying to take away from this forum but the experts are at the link.

JimR

[ken1961]

My Alfa had the 6 batteries in the front and the control electrical components under the steps. There is a main fuse for the batteries in the front drivers side. The setup worked for me. If you have to replace batteries get the sealed no maintenance ones and just change the settings for charge.

[dougrainer]

I believe ALL 6 batteries supply the Coach and the Inverter. Alfa just did not have space to install all 6 in the same place. The 6 batteries are interconnected as they should be. Alfa did some goofy things. The first production models did NOT charge the Coach batteries when the Chassis engine was on by design. We never could get a decent answer on why. Later on they did connect a charge relay to charge both battery banks. Doug

[Gjac]

I have always thought if I needed more battery power 2 banks would be a good idea if you do mostly dry camping. I have not heard much discussion on here about splitting batteries into 2 banks, but I would think it would be a lot less generator time to recharge 2 batteries from 50-80 percent SOC than 4 or 6 batteries. I know everyone's electrical needs are different but for me 2 6 v battery banks(4 6v batteries) would last me 2 weeks before I would need to recharge I would run out of water and laundry well before then. Are there many appliances that run of of 120 v?

[Tom_M1]

It sounds like a good approach. You probably have a residential fridge and microwave as well as other devices running on 120 volt off the bank feeding the inverter. The other bank will be feeding all the 12 volt devices.