I think I found what I need:
https://www.ebay.co.uk/itm/Solar-Pwm-Charge-Regulator-Controller-F2-3a-Auto-Working-Mini-12v-Battery-Kit/123030383603?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D50428%26meid%3D5139ad1f87f94effbb76237e2762b06c%26pid%3D100675%26rk%3D4%26rkt%3D15%26sd%3D202136719442%26itm%3D123030383603&_trksid=p2481888.c100675.m4236&_trkparms=pageci%3A2f0d4721-3582-11e8-8ff4-74dbd1808523|parentrq%3A803522091620ab6ab66403fbfffa2836|iid%3A1