I was trying to figure out which was the house and which was the starter battery, my concern is that im somewhere at sea and i run down the starter battery and need to start the motor, so its normal for everything to work on either 1 or 2? My motor cranks on either but i did notice it cranked a bit faster on one than the other, another question if im anchored which battery should i be using for power, either of them as long as not switched on both?My guess - I'm not an electrician.
From the drawing , looking at the voltage readings, my guess is all bats are 12v and the readings were taken with the switch in the BOTH position. If true, the 2 bat bank is wired in series and should be in parallel.
WILF, the normal way to wire is so that either bank (or both together) will supply power to everything - engine, lights, etc. Using one to start eng and the other for house requires you to switch between position 1 and 2 as appropriate.
Mainsail has the best recmendation for this arrangement - use the larger "house" bank for everything, keep the "start battery" as an emergency backup - make sure you check it and keep it charged. I believe if the combiner is properly wired it will ensure the start is kept charged.
I am going to try to trace them today and see where they go, i only got the boat a month ago and everything is as it was when i got it so maybe its been wired wrong by the PO. ?The 2 6v GC batteries are wired in Series, that gives you the 13 v (remember batteries voltages are nominal, i.e., a 12 V battery is really about 12.5 when charged and at rest) and then the 12v battery is wired in series with the 2 6v batteries. That's how you get to 28v.
The question then, is how did the 2 banks end up in series? I think part of the problem is that the negative cables are connected together at a battery post. Break that connection and check the voltages. The other problem is going to be at the positive end. Somehow, the positive wire is connecting to the negative to make a series connection between the 2 banks.
Time to trace the other end of the circuit. It could be at the switch or the refrigerator or starter. How are the negative cables connected to the engine block? Where do the positive cables go?
Heres a diagram showing where each cable is positioned and also showing the volts between the different terminals, does this configuration of the batteries look correct ?
I Will do that,Some of these readings are as close to an impossibility as there is. For instance you can not read 28.5V across the positive post & negative post of a 12V battery, the DC24N, without the battery having already exploded. If you are reading 28.5V across the pos & neg terminals on the 12V battery that means the battery is at 28.5V and that is simply not going to happen without some rather explosive results and LOTS of current......
I would check your DVM then check all your wiring...
Sometimes it is the simplest thing that does us in.Well As i said earlier i know nothing about electrics but i have figured out one thing, i must have had the voltmeter on the wrong setting! (dumb arse ha ha) because i tested it now and the new 12v battery shows around 14v and the 2 others show 6.2v each or 12.4v combined,
whats the reason for having 2x 6v batteries instead of 1 or even 2 x 12v batteries? The 6v ones are 9 years old but still show 6.2v so should they be changed?
This is why I said your readings were near impossible..Well As i said earlier i know nothing about electrics but i have figured out one thing, i must have had the voltmeter on the wrong setting! (dumb arse ha ha) because i tested it now and the new 12v battery shows around 14v and the 2 others show 6.2v each or 12.4v combined,
Because they are actually a "deep cycle" battery not just a dual purpose battery with a deep cycle sticker..whats the reason for having 2x 6v batteries instead of 1 or even 2 x 12v batteries?
You just answered your question from above. This is why you want to use actual deep cycle batteries not just dual purpose batteries with a "deep cycle" sticker.. Read the below article for a bit more information on deep cycle vs. light cycling batteries....The 6v ones are 9 years old
6.2 + 6.2 = 12.4V and without knowing how that reading was taken, loaded, unloaded, unloaded and rested for 12+ hours etc. it is impossible to comment on state of health. Based on that voltage I would charge them to full, and if you have the equipment, equalize them.but still show 6.2v so should they be changed?