Hi,
this is my first car with 2-batteries system where one is for starting another for accessories (btw - which is for what?)
question is:

a) how to charge this batteries if needed (is there any algoritthm like - from one, and + from the other? or other options??)
b) is it ok to keep charger always on (which will go to keep-a-live mode) when eg. I am not going to use the car for X days (what is the moment i should do this? when stop for 3 days? 5 days? more?)
c) what is the procedure of changing broken batteries? to not introduce unnecessary resets or defaultings, or maybe to not break somethig?
d) i remember that sometimes when I went to a car-service with my previous cars, for some of the services the had to disconnect the batteries - they answered 'JUST IN CASE' - how to approach now, when smb will want to disconnect battery? allow it? dont allow?

note: i remember once in another car I break off the hook holding exhaust and the service-guy wanted to weld this hook to the car under-body, so he disconnected batteries.

 

I would highly recommend an owner's manual. I know you are looking for one. I ended up getting mine off eBay. I waited for a good deal and got a slightly beat up set of books. They were still rather expensive, but have been well worth it. I found the manuals free online, but they wanted all of my information first. I would rather buy books... I learned a ton of stuff about my car from the manuals. Part of that learning was how to charge the car batteries.

You will need to charge both batteries at the same time. It has been a long time, but I think the manual says to put the positive cable on the left battery and the negative cable on the right battery.
On my car, the batteries go low enough not to start in about 10 to12 days. Using a charger got it going again with no trouble.
If I remember right, the battery on the right is the one that starts the car. I tried to charge this battery by itself to get the car started. It would not work. In my experience you need to charge them together.
I don't think the batteries are anything special. I think you change them like you would in any other car. I have two different brands of battery in mine. Looks like previous owners probably replaced them at different times.

I have trickle chargers on 2 of my other cars. They are single battery, so it was super simple. I can't tell you how to do it with 2 batteries, but I can tell you it is well worth figuring out and getting in place if you do not plan to drive the car often.

 

after studying some data on internet - for sure when you are doing emerg start with wires connected to other car you need to connect - from the left and + from the right battery.

but - it looks like that charging is done separatelly cause one of the batteries - left - is agm and the second ist standard acid.

the charger need to auto-switch to appropriate charging mode.

correct me anyone if i am wrong

 

I did not jump the car, I used a charger. I hooked the charger up to 1 battery, did a full charge, and was unable to start the car. I read the manual, hooked the charger up to both batteries and everything worked.

I see where you are coming from, because I had the same train of thought. Fully charge the starter battery and I should be good to go. The car tried to start once. I got some bells and whistles. Then it would not turn over again. Hook up the starter battery and give it a full charge. All that resulted in the car not turning over. Hooked the charger to both batteries as suggested in the book. Gave it a full charge and everything worked perfectly.

I cannot say for sure if you can add a trickle charger to just one side, or use one on each battery and have good results. I just know that when using a battery charger in the garage, I had to hook up both batteries.

 

@sazam ,
You would be correct, you do not charge both batteries with the same charger at the same time by hooking up the charger in the manner one would as shown in the "Jump Start" procedure, you hook the battery tender up to the house battery (left side) posts /terminals +/-, the vehicle has a built-in battery control module that switches between charging each battery, I believe that you posted a picture of a battery tender plug harness on the top of your house battery, purchase a C-TEK battery tender to match that plug, or install the plug and terminals that come with a new C-TEK on your house battery.

I will say, to me, the jump start procedure shown in the service manual (attached picture and written description) is somewhat not accurate, and or is just for safety reasons as to have the person keeping the positive and negative jumper cable ends as far apart from each other as possible when they are hooking them up, BECAUSE, one might think that by hooking up the positive (+) to the starter battery (right side) and the negative (-) to the house battery (left side), that you actually have both batteries joined together, when in actuality, you are only jumping the starter battery (rs), that is unless you turn the ignition switch to the left for the emergency start procedure, which engages the parallel solenoid switch to join each positive cable from each battery, because, each negative cable from each battery only goes right to the body panel in the area of each battery, no where else, very short cable, so when you hook up the positive at the starter battery, it doesn't know if you hooked up it's negative right at it's post, or on the house battery negative, or anywhere on the body for that matter, it only see the power, whereas the house battery sees nothing from the jumpers, again, unless the key is turned to the left.

I will also add that when I first hooked up the jumpers as per the instructions on my 05 rebuild, I had no power inside, I then put the jumpers or charger on the house battery and I had power to the dash, I didn't know about the turning to the left at that moment, but once did, I could have the starter battery in place, turn the ignition to the left and have power over to the house power distribution board, so be careful or that, if you are ever going to remove either battery, it is best to disconnect both negative cables first, if you are worried about memory settings of seats and windows, use the C-TEK in it's power supply mode on the house battery terminals before disconnecting and removing the house battery.

One other thing I have noticed a few times, I rebuilt my GT with late 06 early 07 wiring harness and certain electronics, being the ignition switch, push button start, KESSY module, battery control module, parallel solenoid, other items go up to the 2014 year, but as to the 06-07 items, I have never had to turn my key to the left to engage the emergency start/parallel solenoid when my house battery is low, and I have left the vehicle in the cold and forgot to plug in the tender, leading to a low house battery, but the vehicle gives me a warning in the dash and I can hear the parallel solenoid switching on, the dash brightens a bit and I start the engine, so I have wondered if Bentley made it automatic after the 2005 model year.

Johnny

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you are right - looks like they just wanted to separate + and - as much as possible ... in fact the jump start was for the starter battery (+ is there).

ive just purchased ctek mxs 7 - hope it is the right choice.

 

I think the parallel solenoid is triggered when the starter battery is low as I heard it in my '09 and now in my '16 if the car's been sitting awhile without the tender. However, when the battery on the '09 was actually dead, I had to turn the key to the left to get it to start. One terrific feature on the '16 is the CTEK connection. It's a round magnetic disk with two contacts in the center that slips into a pocket under the edge of the boot lid on the left side so it doesn't have to be opened at all. If one were to forget to remove it and drive away it just pops right off no harm no foul. I back into the garage so that's a concern for me. I always hang a "Remove Before Flight" tag on the door handle as a reminder. You can see a picture of the connector here: https://www.juicemyride.com/products...a-adapter-only