here is my small Accu:Originally Posted by zvi
Usually DC - AC-DC will introduce line noise and other unwanted noises.
A 9Ah is way overkill, all you need is 1Ah if anything.
Also, assuming you have a Z, you probably take turns like I do, and I autocross. So a 9Ah battery placed in the car is just not ideal...
How do you have it wired up and mounted?
Yes, I know, whole my system will use a bit of it, but this accu was easiest to find here (and cheapest), so let it beOriginally Posted by LESLIEx317537
Well I dont autocross, only if I am in hurry to somewhere , it's just a peaceful, family car
I have wired it up as Ricky327 proposed in his first post, just only I have four of 1N5822 diodes (in place of one, total - 8) in paralel. I have 120watt PSU, so I assumed, that current coming from accu might be 10 amps, so I put four of 3 amp diodes, total can pass 12, besides: these diodes drop less voltage on less amps, so 4 of them drop less volts. Now, with no load, it drops 0.25v only
I have 12.35 with engine off, and 12.10v when cranking.
I have used 15 ohm Resistor, impedance I calculated also from Ricky's first post: 9ah Accu needs 0.9 amp for charging -> I have 14v with engine on-> as V=I*R -> R=14/0.9=15.5 ohm, so I found 15 ohm resistor.
The backup baterry just fits next to my main baterry
let me draw a circuit and pcb I have used...
the green colored is a copper on the back side of the PCB
Nice neat layout zvi...If you gonna drain that much current you might be better off using a diode with higher current capability...but then I guess it depend on the availability and price at your place.
Let us know how your version work for you. The original circuit I have posted was only intended for low power laptop. Look like you are the first person to attempt a high current version of it. I cant see any reason why it cant work, as long as the right components are used it should be fine.
That's a very nice drawing. What you use to make it?
I used CorelDraw 11, just jumped to my office today and had some 5 minutes to draw it
Only high current diode I could find here is BYV133 (18 A), this is like MBR6035, dual diode inside, but it Forward Voltage drop is 0.6v, for 1N5822 it is 0,5v, 1N5820 is not available here, so I better go with many diodes, which give me less Voltage drop, than one diode with more Voltage drop.
Tomorrow I will test it on a real load, so let's see, thank you for wishing good luck
zvi, as I tested in another post, yes running the smaller diodes in parrallel is good since it has a lower foward voltage drop. FS on Ebay 12VDC 5.1Ah Ignition Backup Battery
I thought you had a Nissan Z..lol my bad...
What battery and ps setup are you using?
I have 46Ah main Battery, 9 Ah Backup SLA Battery, AudioForge PW120a (or maybe ITuner PW70a, it's a same I think), no ITPS, i dont have any 12v device.Originally Posted by LESLIEx317537
look at my pictures from the link in my signature