It would make sense to reduce the charge voltage as temp rises. This is standard practice on most good battery charging systems (not that I am saying that this is a good charging system!)
Split-Chargers & Bluemotion
- Thread starter superflyguy
- Start date
Well Mike, that was a better effort than my basic readings, i just sat in the back with a multimeter while my wife drove around on the weekend.
Mine stayed the around the same voltage 14.55-14.57 the whole time, having said that the stop/start was switched off.
But mine is a AU delivered T6 132kw stop/start Euro 5 engine model, with same starter and leisure battery.
Out of interest, i couldn't see the amp ratings for the second battery from your test.
Mine stayed the around the same voltage 14.55-14.57 the whole time, having said that the stop/start was switched off.
But mine is a AU delivered T6 132kw stop/start Euro 5 engine model, with same starter and leisure battery.
Out of interest, i couldn't see the amp ratings for the second battery from your test.
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Quick question regarding the T6 Euro 6 engines, do you have the option to turn off the Stop/Start?
Im trying to work out why i'm not getting the variable voltage that mike is getting.
I've only tried it with the Stop/Start switched off,
Now that the Swivel Seat mounting are bolted on, the access is not great
to check with the Stop/Start on.
should have checked earlier when it was easy.
Im trying to work out why i'm not getting the variable voltage that mike is getting.
I've only tried it with the Stop/Start switched off,
Now that the Swivel Seat mounting are bolted on, the access is not great
to check with the Stop/Start on.should have checked earlier when it was easy.
irishwales
Member
yes there in a button to disable it on the dash
mike
Member
I didn't measure the 2nd battery current: after the initial verification with scope and multimeter I relied on VCDS measurements.
Also I don't have anything that can handle the initial inrush current
Thanks Mike,
The VCDS would be more accurate than the use of multimeter and the way i got the results.
I look forwards to if your results change when it gets warmer.
I have my Votronic battery monitor, that should tell me the amperage input once i install it.
The VCDS would be more accurate than the use of multimeter and the way i got the results.
I look forwards to if your results change when it gets warmer.
I have my Votronic battery monitor, that should tell me the amperage input once i install it.
If the battery was full when you did your tests that could explain the constant voltage.
Yes a BCM controlled 150A relay but it amounts to the same thing as the only thing it does additionally is switch off with Start Stop.
Edit: Thinking about it, I would be interested to see if there is an adaptation value in the BCU that would allow me to increase the voltage a bit closer to 13v so it would open and avoid the parasitic drain when the alternator is not charging...
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I'm dragging this thread up again as I am now using the Ring RSCDC30 in a 'real world' situation and having problems with charging the leisure batteries.
I'll describe the wiring for a start...
+ve feed from engine battery taken from fuse 3 (100A) in the 'E' box via a 15 sqmm cable to a 4 way fuse box under left front seat then via a 40A blade fuse and double 4 sqmm cables to the RCSDC30 located under the right front seat.
-ve to the RCSD30 is by double 4 sqmm cables to the chassis lug under the right front seat.
+ve output from RCSD30 goes back to a separate fuse box under left front seat, 40A blade fuse and common bus-bar which connects twin leisure batteries each separately fused one under the right front seat and the other in the kitchen furniture. Both leisure batteries have their -ve leads commoned at an ammeter shunt then to chassis ground under the right front seat. All other leisure services are also fed from this 10 way fuse-box.
The fuse boxes are like these but without the LEDs.
The ammeter shunt was fitted to enable a digital ammeter to be fitted later, it is rated at 75mV / 100A but the meter is not yet fitted.
The reason for the double cable runs was simply to attain greater cross sectional area with cable that was to hand and is more flexible than a single thicker run.
The RCSD30 also has a 100W PV panel attached which seems to charge well.
Now to the problem...
When the leisure batteries reasonably discharged but not low enough to trip my CRX65 fridge out on low volts the RCSD30 fails to charge the leisure batteries once the vehicle smart alternator drops its output i.e. starter battery up to 80% charge and float voltage drops to about 13.4V.
The RCSD30 then cycles bringing the charge up to teens of amps then drops out. This continues ad infinitum.
Voltage measurements when this is happening are as follows...
Vehicle battery voltage floats at 13.4V then drops to 13.0V measured at its terminals when RCDS30 cuts in.
RCDS30 input voltage floats at 13.4V then drops to 12.6V measured at its terminals when RCDS30 cuts in.
Having done the above measurements and looked for the location of the volt drop it seems that the major loss is in the 40A blade fuse and its holder in about equal voltages.
It looks as if this volt drop is indicating to the RCDS30 that the source has dropped below its threshold and should stop charging the leisure battery(s). Then once the load has gone the voltage rises it switches in again.
Being on holiday in France it looks as if I have the simple option of temporarily short circuiting the fuse and its holder for this circuit then when I get home replacing it with a sturdier screw down Midi fuse like this.
Removing/disabling a fuse is not a thing I like doing but needs must in this case.
If I find that this is either the cure or not the cause I will post again but either way it's food for thought for anyone else wiring one of these units up.
Maybe my own fault for being a stickler for fusing every circuit at all risk points. I've seen too many fire damaged write-offs!!
Rod
I'll describe the wiring for a start...
+ve feed from engine battery taken from fuse 3 (100A) in the 'E' box via a 15 sqmm cable to a 4 way fuse box under left front seat then via a 40A blade fuse and double 4 sqmm cables to the RCSDC30 located under the right front seat.
-ve to the RCSD30 is by double 4 sqmm cables to the chassis lug under the right front seat.
+ve output from RCSD30 goes back to a separate fuse box under left front seat, 40A blade fuse and common bus-bar which connects twin leisure batteries each separately fused one under the right front seat and the other in the kitchen furniture. Both leisure batteries have their -ve leads commoned at an ammeter shunt then to chassis ground under the right front seat. All other leisure services are also fed from this 10 way fuse-box.
The fuse boxes are like these but without the LEDs.
The ammeter shunt was fitted to enable a digital ammeter to be fitted later, it is rated at 75mV / 100A but the meter is not yet fitted.
The reason for the double cable runs was simply to attain greater cross sectional area with cable that was to hand and is more flexible than a single thicker run.
The RCSD30 also has a 100W PV panel attached which seems to charge well.
Now to the problem...
When the leisure batteries reasonably discharged but not low enough to trip my CRX65 fridge out on low volts the RCSD30 fails to charge the leisure batteries once the vehicle smart alternator drops its output i.e. starter battery up to 80% charge and float voltage drops to about 13.4V.
The RCSD30 then cycles bringing the charge up to teens of amps then drops out. This continues ad infinitum.
Voltage measurements when this is happening are as follows...
Vehicle battery voltage floats at 13.4V then drops to 13.0V measured at its terminals when RCDS30 cuts in.
RCDS30 input voltage floats at 13.4V then drops to 12.6V measured at its terminals when RCDS30 cuts in.
Having done the above measurements and looked for the location of the volt drop it seems that the major loss is in the 40A blade fuse and its holder in about equal voltages.
It looks as if this volt drop is indicating to the RCDS30 that the source has dropped below its threshold and should stop charging the leisure battery(s). Then once the load has gone the voltage rises it switches in again.
Being on holiday in France it looks as if I have the simple option of temporarily short circuiting the fuse and its holder for this circuit then when I get home replacing it with a sturdier screw down Midi fuse like this.
Removing/disabling a fuse is not a thing I like doing but needs must in this case.
If I find that this is either the cure or not the cause I will post again but either way it's food for thought for anyone else wiring one of these units up.
Maybe my own fault for being a stickler for fusing every circuit at all risk points. I've seen too many fire damaged write-offs!!
Rod
Interesting and I would agree with your supposition. I try and solder as much as I can to remove the risk of high resistance joints, I also like midi fuses mounted in a link fuse holder as they are the same size.
Is the ring programmable? Can you set the cut off voltage?
Is the ring programmable? Can you set the cut off voltage?
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Thanks for the input Loz,
I agree with the soldering etc., which I do. It's the actual blade fuse and its holder that seem to be the culprits about which of course there is little I can do. I guess by the nature of this type of fuse of which 40A seems to be the largest the actual push in fitment must have an inherent resistance without making the parts of precious metals which is obviously a no-go.
As far as I can see there is no way of adjusting the threshold voltages on the Ring device unfortunately.
Serves me right for trying to get all the parts into one enclosure under the seat! Having swivels which restrict under seat access I like to have such things on an extended wiring harness so that it can be brought out behind the seat when access is required. This occasion proves me right sitting here on a French Aire. never mind a glass of 'Red' will help as will the EHU.
Rod
I agree with the soldering etc., which I do. It's the actual blade fuse and its holder that seem to be the culprits about which of course there is little I can do. I guess by the nature of this type of fuse of which 40A seems to be the largest the actual push in fitment must have an inherent resistance without making the parts of precious metals which is obviously a no-go.
As far as I can see there is no way of adjusting the threshold voltages on the Ring device unfortunately.
Serves me right for trying to get all the parts into one enclosure under the seat! Having swivels which restrict under seat access I like to have such things on an extended wiring harness so that it can be brought out behind the seat when access is required. This occasion proves me right sitting here on a French Aire. never mind a glass of 'Red' will help as will the EHU.
Rod
Dave Hallford-Nye
Member
Hi Rod
Ditch the blade fuses and use midi link fuses. The ring unit is quite inefficient and a poor design it will prefer thicker single core hi flex cable.
What is the low voltage input cut off on the ring unit?
The heat is also high today and will have massive effects on the performance of the ring unit it derates and performs poorly in high ambient temperatures.
You need a redarc unit which compensates for long cable runs operates down to input of 11.9v, 97%+ efficiency and can work in extremely high temperatures
Dave
Yes the blade fuse on the input will go as soon as I am back in the UK in favour of a midi fuse in its own holder. Mean time I will bypass it when I can get to a supplier of the right bits to make a safe secure job if it.
Forget the temperature, I'm in eastern France where we have been lucky to see 15 degrees today! The existing cables are 15 sqmm from 'E' box to my fuse box and twin 4 sqmm from fuse box to Ring unit ( -ve to Ring is the same and very short).
Previously I have had no problems with the Ring unit especially the MPPT PV input part of it.
Rod
Forget the temperature, I'm in eastern France where we have been lucky to see 15 degrees today! The existing cables are 15 sqmm from 'E' box to my fuse box and twin 4 sqmm from fuse box to Ring unit ( -ve to Ring is the same and very short).
Previously I have had no problems with the Ring unit especially the MPPT PV input part of it.
Rod
Ring drop out voltage is 12.6volts to save vehicle battery, and it's restart is 13.1
Looks like the resistance is dropping it by enough for it to drop out thinking the source battery is low, then it recovers to its restart voltage and goes round and round..
I can't say that I've noticed any issues with mine so far using a blade fuse, but I'll have to keep an eye on it a bit more, it's run a cfx95dz2 fine with all day driving with fridge set to 2 deg, and freezer at -19 deg. And freezer was fine on the ferry as well.. Only issues I had were due to wrong spec wire on the leisure to socket that the '95 plugged into.
Looks like the resistance is dropping it by enough for it to drop out thinking the source battery is low, then it recovers to its restart voltage and goes round and round..
I can't say that I've noticed any issues with mine so far using a blade fuse, but I'll have to keep an eye on it a bit more, it's run a cfx95dz2 fine with all day driving with fridge set to 2 deg, and freezer at -19 deg. And freezer was fine on the ferry as well.. Only issues I had were due to wrong spec wire on the leisure to socket that the '95 plugged into.
Did you set the unit up for battery type before you started using it? I have noticed this strange behaviour on a few occasions before entering the set up procedure. The other thing is, are the 2 aux batteries identical in every way?
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Martyn, battery type was set-up to 'Flooded' as per the instruction booklet BULK 14.4V FLOAT 13.7V The batteries are Banner but without digging under the seat I can't remember which version.
Yes the batteries are identical except for the cable lengths from the commoning point and an additional strip fuse on the more remote one at the battery end.
Dave, Yes exactly, even when 'on the road' once the smart alternator drops the float voltage to 13.3V.
I'm going to short out the blade fuse & holder temporarily and see how it goes. I've been on EHU all night so shan't know the result until we have a while off grid and low PV input to drain the batteries sufficiently to test. I'll report back as and when.
Rod
Yes the batteries are identical except for the cable lengths from the commoning point and an additional strip fuse on the more remote one at the battery end.
Dave, Yes exactly, even when 'on the road' once the smart alternator drops the float voltage to 13.3V.
I'm going to short out the blade fuse & holder temporarily and see how it goes. I've been on EHU all night so shan't know the result until we have a while off grid and low PV input to drain the batteries sufficiently to test. I'll report back as and when.
Rod
I think you should alter the wiring to direct battery connection via 40 amp fuse to eliminate your fuse box and the VW fuses.
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