db8
Well Known Member
I have a semi-unique situation/question. I'd appreciate any input (especially from Dan (Horton) that all know about as I have done so many of his recommendations). I designed my electrical system about 15yrs ago using Bob's Z-13 wiring diagram (with some changes) for my 8. Please see attachment. Was basically running a 680 battery, SD-8 backup and dual Plasma I (like Plasma III) electronic ignitions. One of the major changes I did was connected the ignition wires directly to/from the battery (with fuselink to the breakers) without going through any buses as I wanted the most direct simple path for the ignition in the event of any electrical problems.
Fast forward to about five years ago when I replaced the 680 with a lithium battery from Aerovoltz (love their batteries). I used that battery for 4 1/2 years with no problems; but that was when they first came out and didn't have all of the internal protections that they have now. About 7 months ago I switched to their updated/upgraded battery (AVAI-480), which has all the bells and whistles as far as protection goes. I thought that would be better than having no protection and thought, though nothing wrong with the old battery, probably time for a change.
Getting ready to do my annual and there are couple things I have thought about, but haven't "fixed" yet to have a good reliable backup in case something happens to the battery. Since doing the annual, now is the time to get er done, and should have done it when installed the nice high feature battery!
Several of my concerns are if I get a low voltage warning from my voltage regulator from B&C, it is set to 12.7 volts. That's ok for a lead acid battery, but very bad for a lithium battery as there will be very little stored power at 12.7V (something different between the two batteries). B&C has said no problem for them to adjust that higher on the VR. Maybe 13.2 or 13.3V -- whatever I want. Not sure what I want? I do know that sometimes when I land and pull the power back to idle, I will get the low voltage warning. I just turn off the fuel pump and wig wags and it goes away. Don't really want to have that warning come on on short final because the warning has been changed/bumped higher. Normally not at idle on final, but think you get what I mean.
A bigger concern is if the battery has an auto shutdown for some reason, I wouldn't be able to excite the SD-8 (switch must be turned on) because once that battery turns off, it won't accept power (from the SD-8) or deliver power (to the ignitions since connected directly to the battery) -- not good! It depends on which gate it gets turned off for as to whether it will turn back on once the condition goes away. Low voltage it won't get turned back on until it's reset on ground (or I can make a pushbutton reset for in air, but not imperative if I have a good backup).
Have read a lot of info on the forums. The TCW seems like a good option, but I also like Dan's thought of almost a regular sized battery (though space is very limited in the 8 as he and we all know). Doesn't matter how it's mounted and very, very light in weight, so I would be able to make that happen.
Just trying to figure out the easiest and most reliable way of doing this given the SD-8, dual EI and ignition wires connected directly to the battery. Was very comfortable with this set-up with a lead acid battery, but am very uncomfortable now with the newer lithium batteries and their auto shutdown features. I believe the EarthX batteries are the same?
I wonder if maybe the easiest thing to do is add a same size battery with a battery switch or some kind of rigged up automatic switch over feature so no interruption (if that's even possible)? Have to probably do something with those directly connected ignition wires to the main battery also.
Thoughts? Thanks guys (and Dan I hope)
Fast forward to about five years ago when I replaced the 680 with a lithium battery from Aerovoltz (love their batteries). I used that battery for 4 1/2 years with no problems; but that was when they first came out and didn't have all of the internal protections that they have now. About 7 months ago I switched to their updated/upgraded battery (AVAI-480), which has all the bells and whistles as far as protection goes. I thought that would be better than having no protection and thought, though nothing wrong with the old battery, probably time for a change.
Getting ready to do my annual and there are couple things I have thought about, but haven't "fixed" yet to have a good reliable backup in case something happens to the battery. Since doing the annual, now is the time to get er done, and should have done it when installed the nice high feature battery!
Several of my concerns are if I get a low voltage warning from my voltage regulator from B&C, it is set to 12.7 volts. That's ok for a lead acid battery, but very bad for a lithium battery as there will be very little stored power at 12.7V (something different between the two batteries). B&C has said no problem for them to adjust that higher on the VR. Maybe 13.2 or 13.3V -- whatever I want. Not sure what I want? I do know that sometimes when I land and pull the power back to idle, I will get the low voltage warning. I just turn off the fuel pump and wig wags and it goes away. Don't really want to have that warning come on on short final because the warning has been changed/bumped higher. Normally not at idle on final, but think you get what I mean.
A bigger concern is if the battery has an auto shutdown for some reason, I wouldn't be able to excite the SD-8 (switch must be turned on) because once that battery turns off, it won't accept power (from the SD-8) or deliver power (to the ignitions since connected directly to the battery) -- not good! It depends on which gate it gets turned off for as to whether it will turn back on once the condition goes away. Low voltage it won't get turned back on until it's reset on ground (or I can make a pushbutton reset for in air, but not imperative if I have a good backup).
Have read a lot of info on the forums. The TCW seems like a good option, but I also like Dan's thought of almost a regular sized battery (though space is very limited in the 8 as he and we all know). Doesn't matter how it's mounted and very, very light in weight, so I would be able to make that happen.
Just trying to figure out the easiest and most reliable way of doing this given the SD-8, dual EI and ignition wires connected directly to the battery. Was very comfortable with this set-up with a lead acid battery, but am very uncomfortable now with the newer lithium batteries and their auto shutdown features. I believe the EarthX batteries are the same?
I wonder if maybe the easiest thing to do is add a same size battery with a battery switch or some kind of rigged up automatic switch over feature so no interruption (if that's even possible)? Have to probably do something with those directly connected ignition wires to the main battery also.
Thoughts? Thanks guys (and Dan I hope)