The ACR keeps the starting battery separated from the house bank, when it senses the alternator is charging the batteries or the Solar panels are above a certain output it closes and combines the battery banks while the charging current is detected. It will also separate them if one side is too low.
You can think of it as an intelligent 1, 2, all off switch. I just leave my switch on 2, my house bank. Then the Solar panels and ACR take care of the batteries.
In my case my alternator and solar charger are both single line chargers. I do have a dual output battery charger but have not used in in 3 years.
I have two group 31 batteries under the starboard berth and the group 24 starter battery under the port berth. I can see space would be an issue if you you are fitting 4 batteries under one berth.
I am not sure I understand why you need two batteries in your starting bank.
A 200 ah lithium battery will give you at least 160 ah of usable capacity. 4 100 ah AGMs wold only give you a crushing capacity of about 133 ah (remember that only about 30% of a lead acid battery capacity is useable when you are relying on the alternator for charging). Your solar panel could change that ratio if you are getting the sun).
Given the height restrictions, golf cart batteries are probably out. If you want to keep costs down I would go with either one or two group 27 or 31 deep cycle AGMs installed on the starboard side to act as a house bank and a group 24 Optima starting battery installed on the port side if it won’t fit in the starboard side. That size of bank with the solar panel and your limited demand should give you several days on anchor without the need to run the engine for charging. I suspect your holding tank will run out of capacity before the batteries do, unless you install a composting toilet.
Use some type of isolator/combiner to allow charging both batteries from the alternator and a single bank charger with out having to change the battery switch selector.
Here is a web site with a lot of good articles in these issues
I I ever buy another Nonsuch, I will be looking for one that has nothing on it. The money I save I will put toward getting exactly what I want rather tag paying for what someone else wanted or thought was a good idea.
Do you have a photo of your batteries in place? I have 2 group 31 AGM for my house (plus a starter batter) under the starboard settee. I’d like to add a third house battery but I wasn’t sure there was room.
I will have to get you a picture hopefully this weekend..
It is tight. The trick is to put short jumpers on one of the batteries and then push it all the way forward as far it will go.
That tucks it up under the openning about 3/4 of the way. Than drop the other batteries in place and connect it up as part of the house bank.
I have one large piece of 3/4 marine plywood under the 4 batteries and oak straps over the top to hold them down.
In the ACR article, about 2/3 of the way down, under the sub-heading Connecting Other Charging Sources, there is a very good wiring diagram that is easy to follow and covers all common 12v devices connected to your batteries. I downloaded the image and enlarged and printed. Used this to install new batteries, bus, 12V wires, fuses, etc, last summer.
Also a note of caution, I found that my the location of the terminals on the back of my main battery switch do not directly correspond with the graphics (1/both/2/off) on the front of the switch. I tested mine and wrote on back with felt pen. Later found it is embossed in the plastic housing, but very difficult to see. Yours maybe different.
Victron also makes a low voltage cutoff switch, somewhat cheaper than Blue Sea depending on the amperage, comes in 3 sizes, 65/100/200 amps.
I know the Balmer volt meter is considered somewhat better than the Victron, but when you add the optional Bluetooth unit, it is a lot more expensive than the Victron. Plus the Victron networks to my Victron Bluetooth solar controller. The Victron can monitor two battery banks, mine is set up to firstly monitor the house bank, with all the battery data Victron offers. Secondary, it monitors the starter battery, but only displays voltage. If you aren’t using your start battery for other devices, I don’t know that you need any more info than the voltage.
It should be pointed out that Peter Farley has AGM batteries which may be installed without leak proof battery boxes. If his batteries were regular flooded lead acid batteries, the batteries would need to be in battery boxes. With the addition of battery boxes the four batteries would likely not fit into the available space.
I guess I did not tell Mark I do not have a Victron battery monitor.
I bought one but did not install it. I read RC Collins notes in Marine How To and decided I did not want to worry about resetting it to keep it accurate.
Like Paul Millar I have just installed a Balmar SG 200 with the bluetooth dongle.
So far I am pleased.
I have 2 Firefly carbon foam batteries, group 31. They fit length wise under the rear portion of the starboard quarter berth.
Expensive but given that they can be depleted to more than 50% without harm I think I have the same usable capacity as 3 group 31 AGMs.
Like Mark I have the spiral AGM 24 for starting. Still works great after 13 years.
I do have a smart external regulator on the Beta 20 with a 70 amp alternator.
Speaking of house systems, batteries, chargers, etc. I have a Xantrex XC Pro Marine 3000 Inverter Charger and Freedom X remote Panel that are like brand new if you’re interested.
I sold the Victron new in the box and installed the first Balmar Smart Gauge. It gave me % of charge but did not give me amps in or out or state of health. I just took that out and installed the SG 200 which show amps going in or out, state of charge and state of health. Easy install and highly rated.
Anyone considering a monitor should read the marinehowto.com article by RC Collins.
