I am a member of the 12v boating group on Facebook. They are a group of knowledgable and very helpful individuals who are happy to help with good and detailed advice.
The mantra of the group when it comes to batteries is know how to care for them - first and foremost. There are many many types of batteries, charging systems and installs but it all comes back to knowing your batteries and what is going in and going out. The other message constantly made is know the power demands - do a power audit ....
So one thing I am looking at now from my recent learning it how many amps are going into the batteries as part of the charging process - this gives a good idea of the state of charge of the batteries. I do have a Smartgauge and this has been very helpful on Waterlily and Percy in helping me manage my batteries - the % SOC is, I have read around, the 'best' way to know when to charge. This I understand is because the system is doing many calculations on charge and discharge over the batteries life so it adjusts the SOC % to account for the natural 'ageing' of the batteries. Many ask for the banks combined AH and use that as the starting point for calculations, not ever changing so not allowing for the reduction of AH capacity over time = incorrect information ( my understanding)
However I'd still like to see that amps in and out.
Now my understanding from this group - thanks Brian, is I need a (at least) a DC clamp meter to read the amps on the main cable to the batteries to see what is going in at any point - and I guess on the same cable to the 12v side to see what is going out etc. £20 - £35 so not too much but very manual.
Now I could fit a BM2 or Victon or Phil meter ...... all three do what I am looking for - I'm less fussed about the % remaining as I have the Smartgauge which I trust for that. I guess it could be down to the install ease and also the ability to get the information... meaning the Victron with its Bluetooth is best here as i can be around the boat and get the info I need = lazy man
So I guess the two questions I need to resolve is can I fit either the BM2 or Victon alongside the Smartgauge and should I cut my costs and just buy a cheapish clamp meter and take occasions readings (meaning opening up the batter cover - not a big job to be honest? )
I did have this post scheduled for automatic posting on Friday.... however I have just got into some deep reading of an excellent thread on CanalWorld forums about this subject. So now I have volt meters and ammeters to think about.... I may yet edit this post again before it's posted....
Here is the link to the post I am reading - its long !