121805eg c-charger 5000 out of commision

[cpoint]

I have 3 batteries, 2 are on a switch "1, ALL, 2 or OFF". 3rd battery is gen battery, which have never been used last several years, as I never got around getting it to work. but that has it's own on of switch

so the 2 batteries are #1 for engine #2 for house. But current charger is charging all 3.

All 3 batteries are multipurpose deep cycle marine AGM batteries, purchased at NAPA Auto Parts.

[Midnightsun]

Not sure how that Charles unit is hooked up as I see only 2 positive battery leads in the picture making me think it is a 2 bank charger unless there is another red lead not seen the way the picture was taken. You may have an isolator splitting to the third bank.

Here is post I made on the Charles unit although mine was a 60A. viewtopic.php?f=12&t=3966&hilit=charles

[cpoint]

there are 3 actually, 3rd one is under the left side wires in picture. It's definitely 3 bank unit there now. Thanks for the link, I did read through. Not sure I missed something, but as I said not an expert on electrical, basic knowledge only. So looking at 80amp ones, hard to find, and few I found are over $1k. I do see 60amp of the ProNautic brand, I assume that's closer to 80amp then the 50amp version. But still not sure if 50 amp would be damaging anything? or just slow charging? or is it sufficient for my usage? As I mentioned, House bank is only using the lights, etc... and 3rd battery for GEN is mostly full if not dead by now. So mainly I am normally charging the House battery. I assume the start battery is usually full and is not used at dock while on charger. and when on water it is charged by engine, assume the house also gets charged by the engine. So given this information, in reality I think only house battery is charging up when battery is used at dock or on water. So if I get the 50amp ProNautic, that would mostly be charging 1 bank most of the time when in use, when no one is onboard, nothing really is getting used as all is turned off. Only bilge pumps and carbon monoxide alarms are drawing minimal power. And thankfully the bilge is always dry and pumps never go off. If that's the situation, would the 50amp model be sufficient to charge the AGM battery (house battery) normal?

[cpoint]

OK, I just called west marine and they assured me 50amp version will just take longer to charge, but wont harm the battery or any system. And that it would fully charge. so I will order either 50amp or 60amp. But will still read responses here if any to change my mind I guess

[km1125]

50 or 60 would be fine. The other issue to consider is how much DC amps you're using when sitting at the dock, just enjoying the boat. Could be running all kind of lights, radios (marine and am/fm), 12VDC fans, etc. It's not as big an issue today with LED lights, but years ago when I had all incandescent lights were were sitting at the dock with some friends with nearly all the lights on and the radio playing and I was actually draining the battery down even with the charger running, because I only had a 30A charger and was drawing more than that with all the loads.

With a typical 356 I wouldn't go with 40 or less. 50 or 60 would be fine. If you had a huge house bank then I'd be pushing for a larger charger... at least 25% of the rated amp-hours on the house bank.

[bud37]

Just consider what we have said....I would consider increasing your house bank size at some point so keep that in mind. Both Hans and I have decent house banks being handled by a 1250p as do others so I don't think you will be far wrong starting there.....good luck with your instal.....

[cpoint]

Thanks km and bud. We don't really spend enough time on it. specially last 2 years with a granddaughter, our weekends are packed. so I think sounds like 50amp will do. I changed all lights to LED, and they are not used hours on at a time. Usually AC is running at dock, which is direct from dock. So I have minimal things on DC. I am sure it will be fine. at worst assuming I have everything running so that battery drains as not enough charge, can switch to alt battery. So based on our usage, I think I am convinced 50amp will suffice. Thanks all for the suggestions, and recommendation of the model. You guys are the best.

[Midnightsun]

cpoint,

I think you missed the part that the Charles units divide it's total output into 3 banks and does not output more even to any one even if other banks are full. Basically your house bank never sees an 80a charge on the Charles, 28a at best. A 50a Pronautic will charge 50a to the house bank assuming the 2 start batteries are full which they normally are. Bottom line is even a 30a Pronautic will equal an 80a Charles when it comes to supplying a house bank in need. A 50a Pronautic is a big upgrade from the 80a Charles you have.

[cpoint]

Midnightsun, thanks for that, now I feel better on the decision. I'll update here once the unit gets to me and I install. looks like a straight swap looking at the pictures

[km1125]

Source of the post cpoint,

I think you missed the part that the Charles units divide it's total output into 3 banks and does not output more even to any one even if other banks are full. Basically your house bank never sees an 80a charge on the Charles, 28a at best. A 50a Pronautic will charge 50a to the house bank assuming the 2 start batteries are full which they normally are. Bottom line is even a 30a Pronautic will equal an 80a Charles when it comes to supplying a house bank in need. A 50a Pronautic is a big upgrade from the 80a Charles you have.

That's not really true. The Charles charger uses diodes to isolate the outputs, just like the Pronautic. So they're both single chargers with diode-isolated outputs. The charge delivered to each output is based on the load, so any of the outputs can consume up to the rated load of the charger. This means any of the individual outputs, or a combination of all outputs, can supply the total rated current of the charger.

This is different than some chargers with isolated outputs where there is a dedicated amount of charge to each bank, say a 2x10A or 3x20A where each output is limited to 10A or 20A. These are essentially multiple smaller chargers built into one case.