hello folks,
I am new here and have a project i am a little perplexed about.
I have a Acer Revo in my car that i use with a 12 inch touch screen, the computer is powered by 12 volt inverter that puts out the required 19 volts for the computer.
my problem is that unlike a lap top this computer doesnt have its own battery to rely on.
When I start the car from time to time the resulting temporary drop in battery voltage exceeds the inverters treshold and causes the inverter to clip thus i get a hard power loss at the computer. this is not good.
a plan to rectify this has been forming in my brain for a few weeks now, and has visited ULTRA Caps, a large electrolytic diode isolated Cap bank, but has finally landed on a 12 volt 7 amp sealed lead acid battery, cost and simplicity seem to wind back to this solution consistantly.
the battery works great, its isolated from the rest of the autos powersystem with i large diode and with this fully charged backup battery in the car, i dont have shut down problems any longer.
this is where i run into the snag that spawns this post, I have visited many options for charging my backup battery but nothing seems to be able to charge a 12volt battery from a 12 volt battery safely while the car is not running.
currently i use a large 2 ohm 5 watt resistor and i am content that I am not going to damage the battery and that it is safe but...the battery eventually dies because i have not calulated the chargeing requirements of the battery or the total load of the computer, the 2 ohm resistor was more of a safety precaution then anything else.
no one wants a lead acid electron containment device sealed or not to be overcharging spuing hot acidic steam while your driving down the road.
while a new battery may not do this right away I am thinking a few years down the road when battery is not much good anymore and is forgotten in the dash.
I need some kind of regulation circuit that will charge the AUX battery, power down when its fully charged and also supply the amperage for the computer when its running. the battery is basically to fill in the starting load and to keep the computer in sleep mode when im not using the car.
i guess this amounts to some kind of a slight "boost" circuit to keep the charge voltage slightly above the at rest car battery voltage of 12 volts and a current limiting stage that will throttle back the amperage when the load is nominal but prevent it from frying the battery should it be completely discharged for some unforseen reason, while STILL providing the computers inverter with happy power.
the computer inverter is not isolated from the AUX battery.
I have already considered augmenting the capacitors in the inverter as a last resort.
the Aux battery is isolated from back feeding the car battery voltage coming from the automotive fused circuits.
any thoughts or ideas how i can simply do this, would be very appriciated.
I have a large wealth of surplus power parts to choose from so i am open to any circuit design as long as it is resonably simply, robust and SAFE.
I dont want my car to leave a black sticky spot on the side of I95
I really want to KNOW why any system i may choose works because current regulation has always been a dynamic In which i sorely lack experiance, and i have a bunch of laser diodes i want to play with when i finally understand it enough to be dangerious with them.
Thank you again for your attention.
Jeff
I am new here and have a project i am a little perplexed about.
I have a Acer Revo in my car that i use with a 12 inch touch screen, the computer is powered by 12 volt inverter that puts out the required 19 volts for the computer.
my problem is that unlike a lap top this computer doesnt have its own battery to rely on.
When I start the car from time to time the resulting temporary drop in battery voltage exceeds the inverters treshold and causes the inverter to clip thus i get a hard power loss at the computer. this is not good.
a plan to rectify this has been forming in my brain for a few weeks now, and has visited ULTRA Caps, a large electrolytic diode isolated Cap bank, but has finally landed on a 12 volt 7 amp sealed lead acid battery, cost and simplicity seem to wind back to this solution consistantly.
the battery works great, its isolated from the rest of the autos powersystem with i large diode and with this fully charged backup battery in the car, i dont have shut down problems any longer.
this is where i run into the snag that spawns this post, I have visited many options for charging my backup battery but nothing seems to be able to charge a 12volt battery from a 12 volt battery safely while the car is not running.
currently i use a large 2 ohm 5 watt resistor and i am content that I am not going to damage the battery and that it is safe but...the battery eventually dies because i have not calulated the chargeing requirements of the battery or the total load of the computer, the 2 ohm resistor was more of a safety precaution then anything else.
no one wants a lead acid electron containment device sealed or not to be overcharging spuing hot acidic steam while your driving down the road.
while a new battery may not do this right away I am thinking a few years down the road when battery is not much good anymore and is forgotten in the dash.
I need some kind of regulation circuit that will charge the AUX battery, power down when its fully charged and also supply the amperage for the computer when its running. the battery is basically to fill in the starting load and to keep the computer in sleep mode when im not using the car.
i guess this amounts to some kind of a slight "boost" circuit to keep the charge voltage slightly above the at rest car battery voltage of 12 volts and a current limiting stage that will throttle back the amperage when the load is nominal but prevent it from frying the battery should it be completely discharged for some unforseen reason, while STILL providing the computers inverter with happy power.
the computer inverter is not isolated from the AUX battery.
I have already considered augmenting the capacitors in the inverter as a last resort.
the Aux battery is isolated from back feeding the car battery voltage coming from the automotive fused circuits.
any thoughts or ideas how i can simply do this, would be very appriciated.
I have a large wealth of surplus power parts to choose from so i am open to any circuit design as long as it is resonably simply, robust and SAFE.
I dont want my car to leave a black sticky spot on the side of I95
I really want to KNOW why any system i may choose works because current regulation has always been a dynamic In which i sorely lack experiance, and i have a bunch of laser diodes i want to play with when i finally understand it enough to be dangerious with them.
Thank you again for your attention.
Jeff