Temperature sensitive power converter
The present invention provides a power converter for recreational vehicle (RV) batteries that uses time and ambient temperature to control output voltage. By employing a remote temperature sensor attached to the battery post, temperature information is sent to an output voltage control circuit in the power converter. When the power converter is powered up an internal timing circuit increases the output voltage by a preset amount for a timed period for rapid charging but is also adjusted to predetermined temperature curve controlled by the remote temperature sensor to prevent overcharge. The output voltage is held at the increased value until the internal timing circuit times out and the output voltage is reduced (setback) to the float voltage determined by the remote temperature sensor.
1. A charging system for recreational vehicle lead-acid batteries, comprising:
(a) a power converter connected to at least one battery;
(b) a voltage control circuit coupled to said power converter;
(c) a temperature sensor that connects said battery to said voltage control circuit and supplies battery temperature data to the voltage control circuit, wherein the voltage control circuit adjusts voltage output from the power converter to the battery according to a predetermined temperature curve to prevent overcharging of the battery;
(d) a timing circuit coupled to said voltage control circuit, wherein when the power converter is turned on the timing circuit increases voltage output from the power converter by a predetermined amount above float voltage for a preset time interval and then reduces voltage output to float voltage after said preset time interval elapses; and
(e) a manual switch that resets the timing circuit, causing another increase in voltage output above float voltage for the preset time interval.
2. The charging system according to claim 1 , wherein the predetermined increase in voltage output above float voltage is adjusted according to battery temperature data.
3. The charging system according to claim 1 , wherein if there is a failure in the temperature sensor power converter voltage output drops to a predetermined level to protect loads connected to the battery.
4. The charging system according to claim 3 , wherein the predetermined output level is approximately 12.6 volts.
5. The charging system according to claim 1 , wherein the power converter is connected to multiple batteries.
6. The charging system according to claim 1 , wherein voltage output is limited to approximately 14.45 volts to prevent damage to loads connected to the battery.
7. The charging system according to claim 1 , wherein the temperature sensor in part (c) is a thermistor.
8. A method for charging recreational vehicle lead-acid batteries, the method comprising the steps of:
(a) monitoring the temperature of at least one battery coupled to a power converter, wherein the power converter has a reference voltage against which it compares the output voltage of the battery, and wherein the power converter immediately compensates for any deviation from said reference voltage; and
(b) altering the output voltage value that the power converter detects coming from the battery according to a predetermined temperature curve, thereby adjusting voltage output from the power converter to the battery to prevent overcharging of the battery under varying temperature conditions without having to change the reference voltage of the power converter;
(c) increasing voltage output of the power converter when the power converter is turned on by a predetermined amount above float voltage for a preset time interval and then reducing the voltage output to float voltage after said preset time interval elapses; and
(d) using a manual switch to reset a timing circuit, causing another increase in voltage output above float voltage for the preset time interval.
9. The method according to claim 8 , further comprising adjusting the predetermined increase in voltage output above float voltage according to battery temperature data.
10. The method according to claim 8 , further comprising, in the event of a failure in the monitoring of battery temperature in step (a), dropping power converter voltage output to a predetermined level to protect loads connected to the battery.
11. The method according to claim 10 , wherein the predetermined output level is approximately 12.6 volts.
12. The method according to claim 8 , wherein the power converter is connected to multiple batteries.
13. The method according to claim 8 , wherein voltage output is limited to approximately 14.45 volts to prevent damage to loads connected to the battery.