Backup Battery Control Circuit

For control in the backup battery controller circuit, L4949, 4093B integrateds are used, the status of the main battery is checked and when necessary, the backup battery is activated via the 80 amp relay – Control Circuit for L4949 4093B and Backup Battery

12/24V Auxiliary Battery Controller

It is common practice to add a second battery to caravans and the like; Thus, any electrical or electronic device used while the vehicle is stationary does not discharge the main battery.

Our circuit automatically connects two batteries when the main battery is charged to a high enough voltage. If you connect a charged main battery to a relatively flat auxiliary battery, a fairly large current can flow from one to the other for a short time, causing a short voltage drop in the main battery.

Backup Battery Circuit

Source: http://www.siliconchip.com.au/cms/A_108048/article.html

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