Where do you fit the shunt for the Victron BMV 712, I want it as near to the battery as possible, but the battery tub (in the hab floor) is plastic so won't support the weight or dissipate the heat without possibly melting the plastic ?
Where/how to fit Victron shunt.
- Thread starter The Artilleryman
- Start date
- Dec 31, 2010
- 2,989
- 7,096
- Funster No
- 14,797
- MH
- Frankia Platin i7900
- Exp
- Since 2010
It should be the first connection from the negative side of your battery then all other negatives from the shunt, the shunt shouldn't get hot enough to melt plastic and has feet to mount it.
OP
OP
If the battery was upright that wouldn't be a problem, but it looks like it will be on it's side due to battery being too tall for the box (under floor) and am not sure about it hanging down from the post - possibly OK if bolted direct via the mate bolt.
A shunt is basically a large low resistance lump of metal. It has less resistance than a standard fuse, and it should not get hot. The whole point of a shunt is that is is a very low but very accurate calibrated resistance, with a circuit that measures the very low voltage drop, typically about 50mV, very accurately. It shouldn't get any hotter than the cables it is connected to.
Also I see you are the latest victim of the 'mate' spellcheck. If you type M 8 without the space, it gets changed to 'mate'
Also I see you are the latest victim of the 'mate' spellcheck. If you type M 8 without the space, it gets changed to 'mate'
- May 8, 2011
- 4,144
- 52,583
- Funster No
- 16,317
- MH
- IH Tio 630 RL
- Exp
- Since April 1846 but have always camped.
Could someone explain the purpose of a shunt please?
Subscribers do not see these advertisements
It measures current. If you add up all your current used over time, you can see how much charge you've used. It's a much more accurate way of estimating how much is left in your battery than just using the voltage.
- Dec 31, 2010
- 2,989
- 7,096
- Funster No
- 14,797
- MH
- Frankia Platin i7900
- Exp
- Since 2010
Mount the shunt next to the battery just use a battery lead from the battery post to the shunt then connect the negatives to the opposite side of the shunt if you have to many cables use a busbar.
At the moment I've only got the negative to the Elektroblok. But in the future I'll be adding a B2B and a different AC charger in there.
(And doing something about that screw)
- Dec 31, 2010
- 2,989
- 7,096
- Funster No
- 14,797
- MH
- Frankia Platin i7900
- Exp
- Since 2010
This is my setup my lithium battery is just out of shot bottom right.
OP
OP
If you don't, you will run the risk of a trip to A & E.
Subscribers do not see these advertisements
OP
OP
Quite interested in your setup. What make is the fuse box and isolator.
Is the isolator used to isolate the leisure battery ?
- Dec 31, 2010
- 2,989
- 7,096
- Funster No
- 14,797
- MH
- Frankia Platin i7900
- Exp
- Since 2010
Yes isolator does the leisure battery the busbar and fuse holder is a victron power in.
How to Add Fuse Holders to a Victron Lynx Power In for a DIY Camper Electrical System
This video will teach you how to add fuse holders to a Victron Lynx Power In so that it can hold fuses in the same way that the Lynx Distributor can.Parts Ne...
www.google.com
haganap
LIFE MEMBER
- Dec 5, 2007
- 12,975
- 27,915
- Funster No
- 974
- MH
- Niesman+Bischoff 79e
- Exp
- I'm an oldbie MH number 10
Mine floats on stiff cables, it doesn't need screwing down because it's so tight and can't do any damage.
One thing of interest in my set up though.
I have a 3kw go live inverter. This basically powers the van through the 12v batteries. The only load I could find is back from inverter which I have used.
Works fine but instead of saying charge it says discharge when I've got engine running or plugged in. It says it at a rate I would expect to see having 20 years of experience of using these things. My BM1 has only been in since Friday so I expect its still learning. I've also not had a good play with the settings yet but anyone see an issue I'm not seeing?
One thing of interest in my set up though.
I have a 3kw go live inverter. This basically powers the van through the 12v batteries. The only load I could find is back from inverter which I have used.
Works fine but instead of saying charge it says discharge when I've got engine running or plugged in. It says it at a rate I would expect to see having 20 years of experience of using these things. My BM1 has only been in since Friday so I expect its still learning. I've also not had a good play with the settings yet but anyone see an issue I'm not seeing?
Have you got the yellow and white voltage sense wires from the shunt the opposite way round? You could try swapping them to reverse the charge/discharge direction.
haganap
LIFE MEMBER
- Dec 5, 2007
- 12,975
- 27,915
- Funster No
- 974
- MH
- Niesman+Bischoff 79e
- Exp
- I'm an oldbie MH number 10
I'll have a check. thanks.
Subscribers do not see these advertisements
haganap
LIFE MEMBER
- Dec 5, 2007
- 12,975
- 27,915
- Funster No
- 974
- MH
- Niesman+Bischoff 79e
- Exp
- I'm an oldbie MH number 10
thanks for that, I did indeed have the yellow and the black and white added on the shunt at the wrong place, should have been the other way round. However, lost a screw in the battery box when I changed it, 2 min job ended up with battery out all cables off kind of day but now all sorted.
A shunt works by measuring the tiny voltage drop across a very small but very accurate resistor.The voltage drop is a few millivolts, up to 50mV maximum. In the BM1 the precision voltage meter is in the display unit, so the tiny voltage drop is transmitted by two dedicated 'sensor wires', the yellow and white ones I think. So they have to be the correct way round.
Other shunts like the Victron have the voltage meter on a chip right next to the shunt, and transmit the result to the display over a data connection, so that problem is less likely to arise.
Other shunts like the Victron have the voltage meter on a chip right next to the shunt, and transmit the result to the display over a data connection, so that problem is less likely to arise.
- Sep 30, 2022
- 204
- 152
- Funster No
- 91,610
- MH
- Rapido V68
Can I ask if anyone can confirm the sequence for installing on a Victron shunt in my van? (Rapido V68, with two 100amp AGM batteries and a Victron MPPT controller, a factory ECU that came with the van.
1: Isolate parallel batteries by disconnecting live
2: Disconnect negative from parallel
3: Install new negative lead from batteries to Shunt and take the old negative (previously connected to batteries) to output on shunt
4: Take positive lead from shunt to batteries
5: re connect positive lead
Questions please:
1: Is the sequence correct
2: What is the new lead that goes from negative to shunt (amp)
3: How do you attach to positive terminal on battery from shunt, is this a spade connection. I am assuming this is the last terminal in parallel config.
Your help is much appreciated.
Mike
1: Isolate parallel batteries by disconnecting live
2: Disconnect negative from parallel
3: Install new negative lead from batteries to Shunt and take the old negative (previously connected to batteries) to output on shunt
4: Take positive lead from shunt to batteries
5: re connect positive lead
Questions please:
1: Is the sequence correct
2: What is the new lead that goes from negative to shunt (amp)
3: How do you attach to positive terminal on battery from shunt, is this a spade connection. I am assuming this is the last terminal in parallel config.
Your help is much appreciated.
Mike
Attachments
Last edited:
First priority: if your two 100Ah batteries are in parallel, as I expect they are, then the diagram is definitely wrong. If you connect them like the diagram - in series - you will cause a lot of expensive damage to all the habitation electrics.
- Sep 30, 2022
- 204
- 152
- Funster No
- 91,610
- MH
- Rapido V68
Apologies, you are correct, was thinking parallel but drew series on original post
Subscribers do not see these advertisements
Attachments
OP
OP
Victron goes in the Negative cable and is marked :- "Battery Only" which connects to the negative terminal - new lead - and "Load and Charger" to which you connect the old negative lead.
No connection to battery Positive.
No connection to battery Positive.
On the negative side, you can either link both negatives together, then connect one of the negatives to the shunt. Or connect both battery negatives to the shunt with separate links. Both methods will work fine, but the second way, with separate links, is slightly preferable in terms of voltage drop. The thicker the wire, the less it matters.
On the positive side, it's similar. You can link both positives together, then connect one of the positives to a nearby fuse. Or connect both battery negatives to the fuse with separate links. Again, both methods work fine, but the separate links method is slightly preferable in therms of voltage drop. There's no fuse in your diagram, but I presume that's just an oversight. All wires from a battery positive should have a fuse very near the battery.
The shunt requires a thin positive wire from one of the batteries, doesn't matter which one. This supplies the tiny amount of power the shunt circuit requires, and allows the shunt to measure the battery voltage too. A small fuse is required on this thin wire, maybe 2A.
Any new negative wires should be the same as the old wires, or thicker, because they are carrying the full current to the battery.
On the positive side, it's similar. You can link both positives together, then connect one of the positives to a nearby fuse. Or connect both battery negatives to the fuse with separate links. Again, both methods work fine, but the separate links method is slightly preferable in therms of voltage drop. There's no fuse in your diagram, but I presume that's just an oversight. All wires from a battery positive should have a fuse very near the battery.
The shunt requires a thin positive wire from one of the batteries, doesn't matter which one. This supplies the tiny amount of power the shunt circuit requires, and allows the shunt to measure the battery voltage too. A small fuse is required on this thin wire, maybe 2A.
Any new negative wires should be the same as the old wires, or thicker, because they are carrying the full current to the battery.
- Sep 30, 2022
- 204
- 152
- Funster No
- 91,610
- MH
- Rapido V68
Yes that will work. Equal links between the batteries, and connecting the load cables to different batteries, equalises the voltage drop between the batteries. It only works for two batteries, but the method of equal links to the fuse and shunt works for any number of batteries. And as I said, the thicker the wire, the less it matters anyway.
Stealaway
Free Member
- Jan 8, 2013
- 8,496
- 11,548
- Funster No
- 24,202
- MH
- Burstner Lyseo 690G
- Exp
- Happy FLT since 2011
Its take the high load current through it and take a small reading from it for the ammeter
Subscribers do not see these advertisements
Join us or log in to post a reply.
To join in you must be a member of MotorhomeFun
Join MotorhomeFun
Join us, it quick and easy!
Log in
Already a member? Log in here.