I want to charge my two lead-acid batteries connected in series to a stair-case lift. I do not have a proper charger (don't have ebay/amazon here) but I do have a 19V, 3A laptop charger (SMPS). I also have to use something else than a typical charger because there is a 2-3V voltage drop from the supply to the batteries (was bigger).
I plan to buy a boost converter (a 600W one because that's what I found in my neighbourhood: youtube link) and charge the batteries with the help of that step-up converter (and the protective diode).
Is the following math right? (without the diode voltage drop)
The batteries are 12V, 7Ah lead-acid and I will limit the current to 10% of the capacity. What do you think?
- the boost converter has constant voltage regulation and current limiting capabilites
- the batteries will be continuously standby charged (with float voltage) and will be lightly used