Hitec HTS-SS connections question

[Burt37]

Hello everyone

I've just spent the last three days reading all the threads related to the Hitec telemetry system and I'm still no sure of how to get around this problem.

I have an electric converted CH-47. The servos, ESC, HTS-SS and receiver run on a separate battery while the motor takes the power from two 4S Lipo. Now the Aurora 9 already shows me the actual voltage of the NiCad battery. No worries there. So I bought the HTS-SS blue, so that amongs other data I would have been able to also see the Voltage in the two Lipos that are btw connected in parallel. Obviously because I'm connecting only to the positive of the lipos, I have nothing showing on the Aurora regarding the voltage. Can someone please help me understand if:

1: it is actually possible to have two battery reading on the telemetry (one from the NiCad and the other from the Lipos).

2 if yes then where do I take the negative from, without burning anything and where does it go.

Thanks

[A.T.]

Originally Posted by Burt37

I've just spent the last three days reading all the threads related to the Hitec telemetry system and I'm still no sure of how to get around this problem.I have an electric converted CH-47. The servos, ESC, HTS-SS and receiver run on a separate battery while the motor takes the power from two 4S Lipo. Now the Aurora 9 already shows me the actual voltage of the NiCad battery. No worries there. So I bought the HTS-SS blue, so that amongs other data I would have been able to also see the Voltage in the two Lipos that are btw connected in parallel. Obviously because I'm connecting only to the positive of the lipos, I have nothing showing on the Aurora regarding the voltage. Can someone please help me understand if:
1: it is actually possible to have two battery reading on the telemetry (one from the NiCad and the other from the Lipos).
2 if yes then where do I take the negative from, without burning anything and where does it go.Thanks

Question would have been better placed under the Hitec Radio thread or an email/phone direct to Hitec Warranty & Service
Note: Hitec USA only services North/South America and Canada. (- Closed Weekends)

At this time, there is provision for one display, best info under
Telemetry - Battery Voltage via SPC and/or HTS-SS Blue for EP Models
refer also the extract
"27Nov11:
Hitec HTS-SS BLUE Sensor Station & HTS-Volt
- Manual and pictorial "How To" Connect to Battery Lead."
- see attached .pdf of previous Q&A Posts "HTS-Volt_Earth for GP & Opto BEC"

ex Hitec USA Support Forum Sticky:
Aurora 9, AFHSS Spectra Modules, Optima Transceivers, Minima Receivers
& Telemetry - FAQ & Undocumented Features
- Mixes, Setups, Tips. {Individual Links often updated}

Alan T.
Alan's Hobby, Model & RC FAQ Web Links

[Burt37]

Originally Posted by A.T.

Question would have been better placed under the Hitec Radio thread or an email/phone direct to Hitec Warranty & Service
Note: Hitec USA only services North/South America and Canada. (- Closed Weekends)

At this time, there is provision for one display, best info under
Telemetry - Battery Voltage via SPC and/or HTS-SS Blue for EP Models
refer also the extract
"27Nov11:
Hitec HTS-SS BLUE Sensor Station & HTS-Volt
- Manual and pictorial "How To" Connect to Battery Lead."
- see attached .pdf of previous Q&A Posts "HTS-Volt_Earth for GP & Opto BEC"

ex Hitec USA Support Forum Sticky:
Aurora 9, AFHSS Spectra Modules, Optima Transceivers, Minima Receivers
& Telemetry - FAQ & Undocumented Features
- Mixes, Setups, Tips. {Individual Links often updated}

Alan T.
Alan's Hobby, Model & RC FAQ Web Links

Thank you Alan

Yes I did post it in the wrong section. Can the moderator move this thread to the appropriate section please...

Thanks for the reply, unfortunately I already have going trough the links you posted...

So the bottom line is that, or I monitor the Servos battery or the motor battery but NOT both. Bummer. There must be a way around.....

Burt

[Adventurer]

Originally Posted by Burt37

Thank you Alan

Yes I did post it in the wrong section. Can the moderator move this thread to the appropriate section please...

Thanks for the reply, unfortunately I already have going trough the links you posted...

So the bottom line is that, or I monitor the Servos battery or the motor battery but NOT both. Bummer. There must be a way around.....

Burt

The only way to monitor both packs is to connect the negatives of both packs together creating a common ground. If you do this, then both voltages will be visible on the A9. But beware that any electrical noise on the Lipo circuit can now find it's way into your electronics. I suspect that this is not a problem for the receiver as I've never heard of noise issues from anybody using the SPC on their main packs. Just be careful.

This has been a issue that many (including myself) have complained about to Hitec. We wait on baited breath.

[Burt37]

Originally Posted by Adventurer

The only way to monitor both packs is to connect the negatives of both packs together creating a common ground. If you do this, then both voltages will be visible on the A9. But beware that any electrical noise on the Lipo circuit can now find it's way into your electronics. I suspect that this is not a problem for the receiver as I've never heard of noise issues from anybody using the SPC on their main packs. Just be careful.

This has been a issue that many (including myself) have complained about to Hitec. We wait on baited breath.

Hello there..

I was hoping that the ESC (that has both batteries going trough) already did that for me.

So you are sure that nothing will fry if I connected the two earth together?

I'm willing to try but I'm afraid to burn something.

If I connect the lipo battery trough the SPC, would the voltage show in the radio?

If yes, then I really don't get why Hitec gives you the voltage pick up in the telemetry box design for electric RC like the HTS-SS, when you already have that option built in in to the receiver.... Then you get two separate screen in the radio, one called receiver, the other called Volt sensor. If you can only have one, why two different screen?

The idea to me was to be able to monitor both (servos,receiver voltage) and (lipos, motor voltage). It does make sense....

[Adventurer]

Originally Posted by Burt37

Hello there..

I was hoping that the ESC (that has both batteries going trough) already did that for me.

So you are sure that nothing will fry if I connected the two earth together?

I'm willing to try but I'm afraid to burn something.

If I connect the lipo battery trough the SPC, would the voltage show in the radio?

If yes, then I really don't get why Hitec gives you the voltage pick up in the telemetry box design for electric RC like the HTS-SS, when you already have that option built in in to the receiver.... Then you get two separate screen in the radio, one called receiver, the other called Volt sensor. If you can only have one, why two different screen?

The idea to me was to be able to monitor both (servos, receiver voltage) and (lipos, motor voltage). It does make sense....

I don't know what ESC you're running, but most ESCs deliberately isolate the motive (flight) pack(s) from the receiver packs. This is to keep the electrical noise generated by the ESC out of your reciever and electronics. On the bigger ESCs it's done with opto-coupling.

Connecting the two negatives together will defeat this objective, so beware. However, it's the only way to make the SS report the voltage of the flight-pack.

If you're concerned about connecting the two directly together, there was a suggestion to put a resistor between the two in an attempt to keep the noise transfer down. See the A9 thread on RCG for details, there was quite a lot of SS discussion in there. You can also put a volt-meter between the two negatives with everything hooked-up to make sure that there's no significant voltage difference between them. It should be in the millivolt range.

Connecting the motive packs to the SPC will then give you that voltage on the A9, but then you will lose the receiver pack voltage feed.

The reason for this design is historic I suspect. I think that the SS was targeted at liquid-fuelled helis in the days before the receivers had on-board telemetry. While the Optic receivers are targeted at single-pack BEC powered helis. There is no Hitec telemetry targeted at multi pack electrics, the SS-Blue is a kludge at best.