not good enough for you
here it is again off optima's US web site.... optima.com.......they obviously think its a common enough issue to put in their FAQ.
Oh and what about a similar statement from sonnenschein...hmm isnt that a manufacturer.
seriously I didn't have to look far.
Can I hook up an OPTIMA battery in parallel with my other battery?
No, when hooking batteries together in parallel they should be of identical make, model and of similar age.
Back to top Can I use an isolator with an OPTIMA battery?
Yes, most any type of battery separator or solenoid can be used with an OPTIMA. The important thing to remember is that the charging voltage must be within the limits suggested by OPTIMA Batteries. If you are using an OPTIMA and a conventional battery, your system must charge each battery independently. Remember, some isolators cause a voltage drop, so make sure your charging voltage AT THE BATTERY is sufficient. Continued undercharging of a battery will lead to premature failure and a drop in capacity.
There is a solution.
As I have posted earlier
lots of people do install dissimilar batteries and get away with it, with possibly some reduced Battery performance and Battery Life....... but they get satisfactory service in their view.
simple relay bassed dual battery systems will at least let the main start battery charge to a reasonable point before connecting the auxiluary battery and disconnect at some point after the motor is turned off......................there are thousands of these out there, both packaged as marine and 4WD products............they are known as voltage sensitive relays.
you can get one of these for arround $140... from a marine supplier...( bep or blue sea brabd).........it isnt the be all but its better than nothing and they seem to work
you could install a proportional charging device, that charges the batteries in turn or proportionaly......these will cost you a lot more but will also provide a charge monitoring display for bothe batteries and possibly other stuff.
or to run a dual alternator system.
using similar batteries would not be a bad idea either
As for ambulances... they frown on leaving them running because it can fill the cabin with exhaust fumes.
They leave fire engines running because they need the motor to drive the pumps.
Hmm .....so where do you recon you stand with your warranty on a optima battery in a mixed charging situation.
cheers