Renogy Battery Monitory - Shunt terminals are too big?!

[RunDSG]

Hi all,

I’ve read as much as I can find relevant to this problem and hoping for some expert advice.

I’ve purchased a 500A Renogy Battery Monitor (I think you are all familiar). The installation is simple enough, except the bolts on the shunt are 10mm and all my accessories (negative terminal connections) seem to be 8mm. What’s the simplest way to resolve this?

• Is it best to use a bus bar? I have a conventional camper - fridge, diesel heater, LED lights, 100W solar. 100A sufficient? Any recommendations? Do I need to ground a bus bar?
• Or is there some kind of clever adaptor I can use?

Any help, much appreciated.

 

[Dellmassive]

Most shunts use the 10mm bolts as they rated 500A.

Easiest way is add a busbar..

One conection from battery neg post to shunt.

Then shunt to ground. Either via the busbar or just add the busbar.

All negs need to be ground... And only the shunt connects to the battery.

 

[Dellmassive]

i was playing with my seat base install the other day . .


this is my battery NEG to shunt to seat bolt ground.

 

[Dellmassive]

the add any style of basbar to add all your negs too.

Amazon.co.uk : busbar

 

[Dellmassive]

or, just cut the ring ends off and use a screw down style connection.

https://amzn.to/3r2LCLn

 

[RunDSG]

Thanks @Dellmassive. This is extremely helpful.

I’m feeling rather thick, though, so let me see if I’ve got this right.

Neg battery post to shunt.

Then either:
- shunt directly to ground, or
- shunt to bus bar, which goes to ground.

If the shunt goes directly to ground. Then the busbar has all the accessory neg connections, and goes to ground and does not return to the neg terminal on the battery.

(And then of course the Renogy monitor needs power from the pos, etc.)

I had thought the shunt needed a direct connection to the neg wires from the accessories. I’m sure I don’t have a clear understanding yet of how this works. Why does the busbar need a ground if the shunt returns the connection to the negative terminal?

Thanks again.

 

[Dellmassive]

victron example:



power flows from the AUX battery,

out to your loads,

then back via a ground,

through the shunt,

back to the battery NEG post.

this way the shunt can meter out all power in/out.

.

 

[Dellmassive]

now imagine adding a bus-bar into the mix . .

like this example . .


the main point is that the sunt MUST be the only thing conected to the battery NEG post, so that all power flows through it.

 

[Dellmassive]

another example . .

 

[Dellmassive]

the thing they don't show clearly is that when you connect the other side of the shunt to a chassis ground - a seat bolt for example.


the shunt will meter out ALL aux loads that are connected to ANY ground point.

so you can use a secondary bus bar or any other chassis ground point.

because the flow of power will flow fromthe AUX battery . . . . through your loads . . . . then down to any ground . . . then throught the chassis. . . . back to the shunt . . . . then back to the AUX battery - where the circuit is complete.

 

[Dellmassive]

https://uk.renogy.com/content/files/Manuals/RBM500-G2.pdf

 

[Dellmassive]

Diagrams, Schematics & Wires -- How I Done It --

Nice one! A lot of people ask me for this so you now have a nice little side line ;)

www.t6forum.com

 

[Dellmassive]

Diagrams, Schematics & Wires -- How I Done It --

Cable size vs Amps - cheat sheet: I have Been supplied with a travel volts dcdc charger wiring kit xl. Cable size is 16mm and includes a 50amp fuse. Is this sufficient for a 120ah agm of which i will be running lighting, usb sockets, fridge and diesel heater Only by that chart i could...

www.t6forum.com

 

[Skyliner33]

Hi all,

I’ve read as much as I can find relevant to this problem and hoping for some expert advice.

I’ve purchased a 500A Renogy Battery Monitor (I think you are all familiar). The installation is simple enough, except the bolts on the shunt are 10mm and all my accessories (negative terminal connections) seem to be 8mm. What’s the simplest way to resolve this?

• Is it best to use a bus bar? I have a conventional camper - fridge, diesel heater, LED lights, 100W solar. 100A sufficient? Any recommendations? Do I need to ground a bus bar?
• Or is there some kind of clever adaptor I can use?

Any help, much appreciated.

View attachment 143179

@Dellmassive has added all the info you asked for, but I’m a bit concerned about those 3 black wires going through that hole with no grommet for protection.

 

[Dellmassive]

Neg battery post to shunt.

Then either:
- shunt directly to ground, or
- shunt to bus bar, which goes to ground.

- correct.

+++

I had thought the shunt needed a direct connection to the neg wires from the accessories. - Not necessarily, as long as the shunt has a good ground it will see any other grounded load.

+++


Why does the busbar need a ground if the shunt returns the connection to the negative terminal? - the common practice is to connect the battery NEG to the shunt, and then the SHUNT to GROUND - thats it.

Then you can use a busbar or ground stud or any other ground you like - as a separate connection. (nothing to do with the shunt)




+++

 

[Dellmassive]

here is a good example from @Jollyvan

Seat Base Electric + EHU + Solar Install + Charger + DC-DC -- How We Done it --

Valence U27-12XP LifePo4 under passenger seat Victron Battery Protect 12/65 Victron BMV712 Smart Battery Monitor Ablemail AMS 12-12-30 Ablemail Battery Manager Bluetooth Battery Monitor BM2 (x2) Victron Blue Smart Charger on Fly leads for both batteries USB connection to Valence BMS Connection...

www.t6forum.com

+++

battery NEG to shunt
shunt NEG to NEG busbar
NEG busbar to seat bolt chassis ground.

++




.

 

[RunDSG]

@Dellmassive has added all the info you asked for, but I’m a bit concerned about those 3 black wires going through that hole with no grommet for protection.

Glad you spotted this. I’ll pop some protection in there. (Not my work here, but also not claiming I wouldn’t have known better.)

Thanks!

 

[RunDSG]

here is a good example from @Jollyvan

Seat Base Electric + EHU + Solar Install + Charger + DC-DC -- How We Done it --

Valence U27-12XP LifePo4 under passenger seat Victron Battery Protect 12/65 Victron BMV712 Smart Battery Monitor Ablemail AMS 12-12-30 Ablemail Battery Manager Bluetooth Battery Monitor BM2 (x2) Victron Blue Smart Charger on Fly leads for both batteries USB connection to Valence BMS Connection...

www.t6forum.com

+++

battery NEG to shunt
shunt NEG to NEG busbar
NEG busbar to seat bolt chassis ground.

++


View attachment 143214

.


View attachment 143215

All of this is incredibly helpful. I think I’ve got it now. Appreciate the education!

I’ll purchase myself a busbar and some connecting wires. I’ll connect my shunt to the busbar and back to the negative terminal and also attach to a ground. Would I be ok with a 100A shunt and 25mm2 wires?

I’ll need to look for a ground near my battery, which is underneath my RIB seat. Would a screw in the RIB frame suffice, I wonder? Otherwise, the battery is surrounded by cabinets and flooring. Hmmm…


Thanks again!

 

[Dellmassive]

Why don't you use the existing chassis NEG cable that was on the battery NEG post.

Move that over to the shunt.

Then just install a new peice of cable the same thickness from the shunt to the battery NEG.

It needs to be chunky and suitable to carry the whole system power, that's why it's normally a fat cable and bolted to a ground stud or seat bolt.

I would not screw a cable to the seat frame.


Post some pics around the battery area for us to see,,,,, so we can offer some ideas.

 

[RunDSG]

Why don't you use the existing chassis NEG cable that was on the battery NEG post.

Move that over to the shunt.

Then just install a new peice of cable the same thickness from the shunt to the battery NEG.

It needs to be chunky and suitable to carry the whole system power, that's why it's normally a fat cable and bolted to a ground stud or seat bolt.

I would not screw a cable to the seat frame.


Post some pics around the battery area for us to see,,,,, so we can offer some ideas.

So, are you saying one of these existing neg cable is already a ground to the chassis? How do you know?

Does this photo help at all? Boxed in on the left and right. Cavity to the left is empty as far as I know, but impossible to get into. There’s a white panel which mounts on top with a couple centimetres of space underneath. Not sure where to mount busbar and shunt yet. (In front is consumer unit and battery charger, behind is some space with seat belt retractor thing on the right. Back panel is removable with magnets, not fixed.)