Replacing my charger. Config questions

[Justin_NSA]

I plan to replace my Xantrex Freedom 20 charger/inverter with a Sterling Power Pro. I don't need the inverter feature. I think I can get by with the 30AMP charger even though mine is 100AMP. I have 2 105AH batteries in parallel for the 'House' side and 1 114AH for the 'Start' side. Both banks controlled by an A/B/ALL switch.
I have configuration questions. The Power Pro is a 3 bank charger. Is it better to wire in the new charger just like the current one? I. e. DC Neg goes to the Neg side of the 3 batteries. A single DC Pos (fused) cable goes to the switch and charging is distributed from there. My DC output cables from the charger are 0/2 AWG welding cable to handle the current. I'll have to replace them with something smaller to fit the 30AMP charger
Or...do I reconfig the setup somehow (directly?) to make use of the charger's 3 banks? Then I would have to reconfig the A/B/All switch for system power. This gets confusing but maybe preferred given the capability of the 3 bank Sterling

 

[Maine Sail]

Do you have an ACR or Echo type charger? If so then just run one + output to the house bank and call it a day. If not, run one output to the house and one to start. Each bank would need a fuse within 7" of + battery post. Running a charger to the "C" post if a battery switch is not the best choice...

Remember the outputs of most "multi-bank" chargers are not isolated or charging at different profiles. They all share the same exact charge profile....

Installing a Marine Battery Charger (LINK)

 

[Justin_NSA]

I'm not sure which it is. It only has 1 POS and 1 NEG DC output cable(s). The bottom of page 23 in the manual says it can be wired to a selector switch like it is currently
http://www.xantrex.com/documents/Discontinued-Products/Freedom series 1.pdf
I'm guessing that the new charger will be able to be wired the same way but I don't know if it preferred since we're comparing new technology with tech that probably came out with the boat in '91

 

[Maine Sail]

I wan not referring to your old charger. I was asking if you have any sort of ACR/Combiner or Echo type charger on-board?

Did you read the link I provided?

 

[Justin_NSA]

I think what I'm gleaning from your article is that I could jumper the 3 outputs and use a single pos + to the selector

 

[Justin_NSA]

I wan not referring to your old charger. I was asking if you have any sort of ACR/Combiner or Echo type charger on-board?

Have you read the link I provided?

No charger but the Freedom 20. I always try to read and comprehend your writings! I'm not sure I've gotten to a point of knowing the best way to config it

 

[Maine Sail]

No charger but the Freedom 20. I always try to read and comprehend your writings! I'm not sure I've gotten to a point of knowing the best way to config it

The Freedom 20 is an inverter & charger.. We don't care about that if you're removing it....

One more time...... Do you have an ACR/Combiner or Echo type charger installed on your boat???

 

[Justin_NSA]

One more time...... Do you have an ACR/Combiner or Echo type charger installed on your boat???

I thought I answered that when I said "No charger but the Freedom 20". The Freedom 20 is wired directly to the batteries and selector switch. Maybe I don't understand what you are asking.

 

[Maine Sail]

I thought I answered that when I said "No charger but the Freedom 20". The Freedom 20 is wired directly to the batteries and selector switch. Maybe I don't understand what you are asking.

An ACR or Echo Chargers are devices that sit between two banks to charge one bank from the other regardless of the charging source; alt, shore, solar, wind etc..... An ACR is just an electronic relay that is activated and de-activated based on charge voltage being present or not.

If you don't have one, and it sounds like you don't, then run one output to the house bank and one output to the second bank. The third output just sits there looking pretty...

Set the absorption & float charge voltage based on the more expensive and larger house bank. Do not go through the battery switch. All banks on-board will have a common negative bus so run the charger neg there.

 

[Justin_NSA]

That makes sense. Thanks for your patience
I don't have a diagram of the selector switch but I could probably disconnect the charger + feed to it and run it and one other to the 2 battery banks. Then I'm assuming the selector only directs DC bank power to the main panel

 

[Maine Sail]

That makes sense. Thanks for your patience
I don't have a diagram of the selector switch but I could probably disconnect the charger + feed to it and run it and one other to the 2 battery banks. Then I'm assuming the selector only directs DC bank power to the main panel

A charger connected to the "C" post is not a good idea in regards to potentially damaging voltage transients.

Picture this, your batteries are charging in bulk at 30A when someone flips the battery switch through OFF. Your instruments are on drawing a measly 0.3A and all of a sudden the 30A battery load is gone. This is what we call a voltage transient.

What do you suppose will happen to the voltage at the "C" post of the battery switch when the battery load instantly vanishes? Sure the regulator will eventually get it under control but in the interim, until it can, your 12V electronics could have seen 50V or more and already be toast. Chargers, alternators, solar, wind etc. should all feed directly to the bank with the only thing in the path to the battery being a properly sized fuse.

 

[Justin_NSA]

Got it. Cable comes off of the 'C' post to eliminate transients. Need to replace my single huge fuse with one for each bank.
I haven't traced out the alternator circuit yet. I'll make sure regulated voltage goes to the batteries. We don't run engines long enough for any significant charging to happen. Just enough o get in and out of the sail cove.