2 batteries, a dual shore power charger, and one BMS shunt...

JCDriller

Adventurer
Hello to all the electrical gurus out there. I am a simpleton who needs some advice.

I'm currently working on the 12v/110v wiring for my trailer (HERE and I can't figure out how to wire up the following items.)

Victron BMV-712 w/ Shunt
Powermania M230 Dual shore power battery charger
Dual Odyssey Group 31 Batteries

PZGCwK6.jpg


All (-) has to pass through the 712's shunt in order to register it with the BMV so it can accuracy provide a % charged state of the batteries. I'll be running the Odyssey's in parallel so the negative cable connects to the shunt before the Inverter or the fuse panel, but what about the Powermania? It has 2 (+) and 2 (-) leads, one for each battery. If I connect these to each battery the BMV won't register the charge from the Powermania shore charger.

I know I have to combine both (-) powermania leads and feed them through the shunt, then on to the batteries in parallel. But what do I do with the (+) powermania leads. Should I combine them and run them into the first battery which is parallel connected to the second or should I put one powermania (+) lead on each battery?

Thanks guys!
 
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Joe917

Explorer
Your battery charger can charge two battery banks. your batteries in parallel are one bank, effectively one battery.
 

JCDriller

Adventurer
So just double up the powermanias leads to maximize the amperage of the charger and stick them on the parallel circuit. Thats what I figured, I always like to over complicate things.
 

JCDriller

Adventurer
Read the charger instructions. you may have to only use one set of leads.

I have, it doesn't really go into this scenario. They don't demonstrate how to run the power through a shunt. Their parallel wiring scheme for 2 batteries is just one lead per terminal. I called and talked to them today and the very nice gentlemen on the other end stated that I could treat it as one big bank, but the smart charger wouldn't have much control and I'd likely have unbalanced batteries with one always undercharged. He stated I'd be best with 2 of the BMV monitors which isn't going to happen. Crap.

Anyone else have any thoughts?

Version 1

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Version 2

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Version 3

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Joe917

Explorer
Did the rep instruct you to double up the leads. Looks to me that you should only use one of the outputs. The shunt is OK. There is no reason the batteries would be unbalanced as long as they are the same age and type.
 

JCDriller

Adventurer
Sounds like your Powermania Tournament Grade Turbo Charger has more features what are useful to your proposed application.
You might have to forget its two bank ability & just run with it anyway.
Btw,
As I read its cutsheet, it states ”total output” 30A. What may suggest less than 30A is available if only using one pair of charging leads.
Further,
Makes me wonder how this chargers named ”turbo” operates. Might speculate has something to do with utilising energy escaping via hydrogen bubbles...

This does seem like a nice charger, but it actually came uninstalled with the trailer, so I'm working with what I have. Also, the batteries are identical and both brand new with the same resting voltage.

The Powermania guy said yes I should double the leads if I'm hooking it up to one battery, each lead is only capable for 15a, 30a only when combined. He didn't really have much to offer about how to place the leads with my particular situation. I think I'm most likely to go with Version 3, why? Don't know, just seems to be the most balanced. I'm open if anyone wants to talk me out of it.
 

JCDriller

Adventurer
Your versions are all the same.

As I said, I'm a simpleton. So I'm assuming because they are wired in parallel the batteries don't care where the connection is coming from. Roger, I'll go KISS and keep it simple stupid.

Thanks for setting me straight.
 
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