charging 100ah deep cycle lead acid battery from car alternator

[almac]

any damage caused charging a 100ah deep cycle lead acid battery by running jumper cables from the car battery teminals to the deep cycle battery ?. the alternator is an 85ah. not sure what is being delivered to the battery, the thermo fans are running to cool the engine not much else running

[Sunking]

Your car battery is larger than that. No real issues to worry about. As long as no electrolyte bubbles out over the top. Just don't make a habit of it.

[almac]

thanks appreciated