If I Double the Battery Capacity on My Boat, Will the Existing Charger Work?

Question:

Hi Jeff. You installed (2) L-16 AGM batteries on my boat for a total of 380 Ah house bank. If I added 2 additional L16s, to double my house capacity, could the 3 phase smart charger/battery monitor you installed handle this? Also, could the 80A alternator handle this? The current 2- L16 bank re-charges at approximately 13% per hour when underway. Thanks again for your help! - Bob

Answer:

For battery charging, you should have at least 10% of battery capacity as a charge rate. If your battery bank went to 760 amp-hours, your 60 amp charger would chronically undercharge the batteries. Also, those batteries were installed in 2013 and you should always wire batteries in one bank and ensure they are the same age and type. A new pair of L16s shouldn't be wired in parallel with your older pair of L16s. Your 80 amp alternator would be OK to handle the charge. - Jeff