Sizing a converter/charger

snoobler said:

I'm assuming you're talking about the AC to DC converter that takes your 120VAC input and provides 12V power as well as charges your coach batteries. If it's something else, please clarify.

Your 200Ah of batteries should be charged at 10-40A for typical AGM specs. Worth looking up your specific battery if they publish that.

A common converter size is around 50A. Since these supply power to the 12V bus you really don't need a larger one unless you plan to increase your 12V power usage. 50A @ 14V (charging) is 700W only about 1/5th the power available from 30A/120V RV shore power.

Personally, because I'm a nut job, I have a 100A PowerMaxx that replaced my 55A unit that failed. It's complete and total over-kill. It was only a little more expensive, and I already have another one for a different application. Ours failed because the genny VR failed and went unregulated. The 160V unloaded voltage killed the converter. It put out about 10A at that voltage, but on shore power 120VAC, we could only get about 2A out of it. I bought the type that actually functions as a 3 stage charger, NOT just a constant voltage supply.

Discovered this when the furnace blower drained the batteries by 11pm when we were plugged into shore power.

Adding two more batteries or solar don't factor in at all. IMHO, replace it when it fails, or when it doesn't meet your needs.

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snoobler said:

If the time comes, the Powermax has their Boondocker line that I'm really happy with. One can select operation as a 3 stage charger or as a constant voltage supply. You can also set your own absorption voltage, which makes them a good candidate for FLA/AGM and LFP batteries.

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snoobler said:

Boondocker Converters

12, 24 and 48 models.

They also have an older PM3 and PM4 product line. Can't find out for sure if these are discontinued, but I have PM4s.

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