[T2] Help to enhance my AUX battery diagram before we burn alive !

[accessys at smart.net]

I have twin batteries but both wired in parallel so both are always 
working, but have a boat selector switch in the engine compartment (MUST 
be a make before break type) and when camping or whatever I just switch 
from both batteries to just one of them. then when is time to go I switch 
the other back into the circuit.

Bob



On Wed, 3 Jun 2015, Christophe Guilbert wrote:

> Date: Wed, 03 Jun 2015 14:49:44 -0700
> From: Christophe Guilbert <cguilbert at picasso.ucsf.edu>
> To: "TYPE2 at type2.com" <TYPE2 at type2.com>
> Subject: [T2] Help to enhance my AUX battery diagram before we burn alive !
> 
> Hi,
>
> I am adding a new Aux battery and draw a diagram to do so.  I really would 
> appreciate if someone review it to see if I am doing something dangerous, 
> enhance the safety or if it could be done differently (and more elegantly)
>
> Here is the diagram:
> http://mondale.ucsf.edu/download/secondary_batt2.pdf
>
> The feature of rewiring is to select which battery and I to use for all my 
> appliances and I can start the fridge on the AUX battery when the van is not 
> running.
>
> Basically , I have my Aux battery wire going to the dash board to provide the 
> interior light , cigarette lighter and radio.  The interior lights, cigarette 
> lighter wires was "repossessed and diverted" from the main fuse panel S8. The 
> Aux battery wire (in the dashboard) is going back to the Aux battery 
> compartment trough the regular fridge/LED panel relay (C in my drawing).
> I have a switch S1 which control the relay B , relay B can select if the 
> current flowing to the fridge/LED and appliances panel is coming from the 
> main or the AUX battery. This way I can select which battery I want to use 
> for my appliances. Note that the AUX battery is used by default.
> Switch S2 is here to override relay C (fridge relay ) to have the fridge 
> working on the Aux battery when the engine is not running , it is also light 
> up a strong red light in the dashboard to remind me that the fridge is 
> running on the aux battery. This is practical if you are doing grocery and 
> don't want to switch to gaz. the trick is that when the fridge is not working 
> , the LED panel is (that's the design of relay C),  so I use the +12V out of 
> the LED panel post to energized relay A 86 terminal.  I trigger it by the 
> switch S2 through Tem 85. Note that the S2 switch is using ground line.
>
> If any one could be kind enough to tell the weakness of my design and how to 
> fix it. I especially would like to emphasized where to add more fuse to make 
> it safer.
>
> Thanks and sorry for any eventual headache following my diagram.
>
> Chris
>
>
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