I recently installed a (20-40 amp)stby alternator and wired the b-lead to my existing ampmeter shunt used for the D-180/Plane Power 60A alternator. The shunt is located so it reads the current in/out of the battery. When I turn the main alternaotr off the ampmeter shows about -8 amps (as I would excpect) but when the standy by alternator kicks on the amp meter doesn’t change. Still shows negative amps even though the load is well within the capacity of the stby alt. Should I have installed a 2nd (40amp)shunt for the stby alternator? If so, will the D-180 accept two different current imputs? Thanks, Steve
Stby alternator and new shunt?
- Thread starter Steve_G
- Start date
jakej
Well-Known Member
Steve,
If you have the system set up so that you can only switch between Alt #1 & Alt #2 (not both together) then you can use 1 shunt. Separate ANL fuses, or circuit breakers will be used on each alternators.
I’m suspecting you have an issue with Alt 2 - did you check the field wiring etc & the voltage/amp output with a multimeter ?
If you have the system set up so that you can only switch between Alt #1 & Alt #2 (not both together) then you can use 1 shunt. Separate ANL fuses, or circuit breakers will be used on each alternators.
I’m suspecting you have an issue with Alt 2 - did you check the field wiring etc & the voltage/amp output with a multimeter ?
The D180 only has one shunt input.
jakej
Well-Known Member
In addition to my comment here is an idea (one of several possible) I’ve used before -
FWIW-
Put a double pole ON-Biased (mom) switch in the Dynon ammeter wires. It should be in the ON position for the main #1 Alt & pushed (it will spring back when you let it go) to the #2 Alt position to check it’s output when you have # 2 Alt field turned on. As your # 2 is more likely a backup then, providing the system volts are more than say 13+ volts then # 2 is working & you can use the switch to occasionally check the amps output if you want.
FWIW-
Put a double pole ON-Biased (mom) switch in the Dynon ammeter wires. It should be in the ON position for the main #1 Alt & pushed (it will spring back when you let it go) to the #2 Alt position to check it’s output when you have # 2 Alt field turned on. As your # 2 is more likely a backup then, providing the system volts are more than say 13+ volts then # 2 is working & you can use the switch to occasionally check the amps output if you want.
Jake,
Good idea with mom switch. especially since the D-180 can only accept one shunt input. Also as you have suggested I still need to verify the stby alt output. This is a B&C stby alt and regulator. The regulator is set up to energize the field circuit when the voltage drops to about 13v (there is an annunicator light that illuminates) Also it has a current sensor that will cause the light to flash if the load exceeds 20amps. This appears to work as it will flash when I load up the system so presumably there is current? However I have a cheap hall effect current sensor I plan to install to verify the stby current.
Thanks! Steve
Good idea with mom switch. especially since the D-180 can only accept one shunt input. Also as you have suggested I still need to verify the stby alt output. This is a B&C stby alt and regulator. The regulator is set up to energize the field circuit when the voltage drops to about 13v (there is an annunicator light that illuminates) Also it has a current sensor that will cause the light to flash if the load exceeds 20amps. This appears to work as it will flash when I load up the system so presumably there is current? However I have a cheap hall effect current sensor I plan to install to verify the stby current.
Thanks! Steve
jakej
Well-Known Member
Steve, you have a great setup there in the B & C units, they are all I use & recommend nowadays as another brand & automove types caused too much grief & frustration for my customers.
Also IMO I’d still just stay with the Dynon shunt & ditch the cheap Hall effect sensor. The annunciator light will come on if #1 Alt is unable to do its job for whatever reason, then do a quick switch check of # 2
Also IMO I’d still just stay with the Dynon shunt & ditch the cheap Hall effect sensor. The annunciator light will come on if #1 Alt is unable to do its job for whatever reason, then do a quick switch check of # 2
Jake,
Agree. Don’t plan to keep the hall effect sensor - just use it for an initial check. However if there is current from the 2nd alt why doesn’t it show on the display via the dynon 60amp shunt? From what I read shunts are designed with specific amp ratings and the sensor connections are some small percentage of this. If I try to push a smaller current through the larger rated shunt it won’t register on the sensor? Sound right? If so, I’ll get a smaller rated shunt and connect the sensor to the dynon via the mom switch.
Thanks Steve
Agree. Don’t plan to keep the hall effect sensor - just use it for an initial check. However if there is current from the 2nd alt why doesn’t it show on the display via the dynon 60amp shunt? From what I read shunts are designed with specific amp ratings and the sensor connections are some small percentage of this. If I try to push a smaller current through the larger rated shunt it won’t register on the sensor? Sound right? If so, I’ll get a smaller rated shunt and connect the sensor to the dynon via the mom switch.
Thanks Steve
jakej
Well-Known Member
The Single Dynon shunt will show amps from either of the alternators.
What switching method do you use when switching the alternators ( ‘field’ wire) between #1 & #2 ?
Do you have 2 B&C Alternators & regulators ?
[i]If I try to push a smaller current through the larger rated shunt it won’t register on the sensor? Sound right? [/i] - not correct ! I have done many installations running dual alternators with both “B” leads going to the same shunt.
Is #2 Alt working ? ie, is it showing 13+ volts when engine is running at higher than idle eg 1500-1700 rpm ?
Have you thought of installing the shunt/s so that they read the amps output from the alternators ? With that method two results happen-
1. You can see if the alternator IS actually outputting amps &
2. When you turn on devices like landing lights, fuel pumps & other higher current drawing devices, you will immediately see the extra current draw - if no extra current draw then those devices are not working. Just saying
Pm me if you wish.
What switching method do you use when switching the alternators ( ‘field’ wire) between #1 & #2 ?
Do you have 2 B&C Alternators & regulators ?
[i]If I try to push a smaller current through the larger rated shunt it won’t register on the sensor? Sound right? [/i] - not correct ! I have done many installations running dual alternators with both “B” leads going to the same shunt.
Is #2 Alt working ? ie, is it showing 13+ volts when engine is running at higher than idle eg 1500-1700 rpm ?
Have you thought of installing the shunt/s so that they read the amps output from the alternators ? With that method two results happen-
1. You can see if the alternator IS actually outputting amps &
2. When you turn on devices like landing lights, fuel pumps & other higher current drawing devices, you will immediately see the extra current draw - if no extra current draw then those devices are not working. Just saying
Pm me if you wish.