Wiring in second battery bank

[bricklin]

I have a new second battery bank for a thruster .
I plan to fit a voltage regulator which allows me to charge new battery bank only when main starter battery bank fully charged .
Question … what would stop my new thruster battery bank running down and the thruster pulling large current on my 16mm charging cables running from bank one to bank two

 

[PaulRainbow]

Several recent threads covering exactly this subject

 

[bricklin]

Thanks but don’t see anything on my concern

 

[pvb]

I have a new second battery bank for a thruster .
I plan to fit a voltage regulator which allows me to charge new battery bank only when main starter battery bank fully charged .
Question … what would stop my new thruster battery bank running down and the thruster pulling large current on my 16mm charging cables running from bank one to bank two

A decent DC-DC charger will have a maximum current limit. Maybe look at the Victron Orion models and read the user manuals.

 

[bricklin]

Thanks for reply , although confused .
Battery bank one is currently being charged by boat engine and 240 volt vitrion charger when boat at dock.
My question … how do l link fron battery bank one to new battery bank two.
Assuming l am right , l have bought vsr unit and intend to run 16 mm cables between banks .???
If this is correct , what stops new battery bank from running low some day and drawing full power from bank one ??

 

[halcyon]

Thanks for reply , although confused .
Battery bank one is currently being charged by boat engine and 240 volt vitrion charger when boat at dock.
My question … how do l link fron battery bank one to new battery bank two.
Assuming l am right , l have bought vsr unit and intend to run 16 mm cables between banks .???
If this is correct , what stops new battery bank from running low some day and drawing full power from bank one ??

Assuming bank 1 not on charge, no current can be drawn, if engine running or mains charger on then VSR is engaged, current can then flow. But this depends on VSR design, if bow batt is low, then a large current can be drawn, but this will drop charge voltage and VSR should drop out. The problem is how long it takes to drop out, this delay can be quite long, this could cause a problem then in the charging cable.

Brian

 

[William_H]

You might consider the simple option of connecting thruster bow battery directly in parallel with engine battery. Fit hefty fuses at each end. Assuming you always have engine running and charging when thruster is used. The relatively light cables you have will when no thrusting ensure bow battery remains at same state of charge as engine battery. When thrusting engine alternator and engine battery will provide some power to support the thruster battery. The current depending on exact total resistance of the circuit.
Concerns with this simple arrangement are that cables might get warm when thrusting. Need to check. Also bow battery will assist to some degree when engine cranking.
This may be a trap to mask a bad engine start battery. ol'will

 

[PaulRainbow]

Thanks but don’t see anything on my concern

See here: Bowthruster Battery Install

 

[pvb]

My question … how do l link fron battery bank one to new battery bank two.
Assuming l am right , l have bought vsr unit and intend to run 16 mm cables between banks .???
If this is correct , what stops new battery bank from running low some day and drawing full power from bank one ??

A VSR won't restrict the current flowing, and the cables must be fused to prevent excessive current flowing. On the other hand, a DC-DC charger will have a maximum current which it can provide, so there'd be no chance of excessive current in the cables.

 

[bricklin]

Assuming bank 1 not on charge, no current can be drawn, if engine running or mains charger on then VSR is engaged, current can then flow. But this depends on VSR design, if bow batt is low, then a large current can be drawn, but this will drop charge voltage and VSR should drop out. The problem is how long it takes to drop out, this delay can be quite long, this could cause a problem then in the charging cable.

Brian

We are getting close to my concern. If battery bank 2 ran down for some reason would the constantly charged bank 1 have the vsr open and bank two draws full power for the thruster .
Note . Bank one will always be getting charged from either 240 volt when in dock or from boat engine
Keep in mine the bank 2 new thruster uses 50mm cables .
Now l have been told to fit a diode on the positive charger cable ,that maybe stops battery bank 2 from Drawing power ?? PS am l correct in saying the vsr opens when it sees a charging voltage .

 

[PaulRainbow]

We are getting close to my concern. If battery bank 2 ran down for some reason would the constantly charged bank 1 have the vsr open and bank two draws full power for the thruster .
Note . Bank one will always be getting charged from either 240 volt when in dock or from boat engine
Keep in mine the bank 2 new thruster uses 50mm cables .
Now l have been told to fit a diode on the positive charger cable ,that maybe stops battery bank 2 from Drawing power ?? PS am l correct in saying the vsr opens when it sees a charging voltage .

No, the VSR closes when it sees the charging voltages.

Fitting a diode in the charging cable is a stupid idea. You need current to flow from battery 1 to battery 2, so the diode will need to allow that to happen, all it can do is to stop the current flowing back from battery 2 to battery 1. It cannot regulate or stop the current flowing to battery 2.

Everything you need to know is in the thread i linked to. If the operation of the VSR concerns you, fit the B2B charger suggested by PVB.

 

[bricklin]

Sorry l meant to say closes when it sees voltage .
No idea why auto engineer give me diode to stop current flowing back from battery 2 !!
I wonder what size of cable l would need from battery one to battery 2

 

[PaulRainbow]

Sorry l meant to say closes when it sees voltage .
No idea why auto engineer give me diode to stop current flowing back from battery 2 !!
I wonder what size of cable l would need from battery one to battery 2

See post #8

 

[Supertramp]

See post #8

At the risk of oversimplifying, add an isolation switch to your charge cables and control it yourself?

 

[bricklin]

You might consider the simple option of connecting thruster bow battery directly in parallel with engine battery. Fit hefty fuses at each end. Assuming you always have engine running and charging when thruster is used. The relatively light cables you have will when no thrusting ensure bow battery remains at same state of charge as engine battery. When thrusting engine alternator and engine battery will provide some power to support the thruster battery. The current depending on exact total resistance of the circuit.
Concerns with this simple arrangement are that cables might get warm when thrusting. Need to check. Also bow battery will assist to some degree when engine cranking.
This may be a trap to mask a bad engine start battery. ol'will

intresting idea.
With 16 mm cables from battery bank one to bank two that’s an idea . Just fit fuses to protect the 16mm cable.
Then if battery bank two ever ran totally down and tried to draw excessive current fuse would blow .
Could also fit the vsr , by the way it’s only rated at 140 amp.
Battery two good for 200/300 amps from thruster

 

[PaulRainbow]

intresting idea.
With 16 mm cables from battery bank one to bank two that’s an idea . Just fit fuses to protect the 16mm cable.
Then if battery bank two ever ran totally down and tried to draw excessive current fuse would blow .
Could also fit the vsr , by the way it’s only rated at 140 amp.
Battery two good for 200/300 amps from thruster

If you read what i linked you to, twice, you'd see your answers. You seem to ignorant to do that though, so i'll leave you to it.

 

[bricklin]

If you read what i linked you to, twice, you'd see your answers. You seem to ignorant to do that though, so i'll leave you to it.

Sorry cannot see link !!

 

[PaulRainbow]

Sorry cannot see link !!

See here: Bowthruster Battery Install