Using backup receiver battery with JETI DSM ESC? Voltage question

[SpeKopuZ]

Hi all,

I have a XQ-70 ESC/BEC (https://shop.pichler.de/Brushless-Regler-XQ-70) from Pichler and I am planning to add a backup receiver battery to the system. I found that JETI DSM ESC should work to connect the ESC as input 1 and a backup battery as input 2, but there's one sentence on the JETI website (https://www.jetimodel.com/katalog/dsm-esc-dual-switch-mixer.htm) that makes me doubt the setup will work:

"The DSM ESC then automatically switches between the inputs so that your receiver is always powered by the power supply with the higher voltage."

The XQ-70 has an output of BEC = 5V / 5A and let's say I use a LiFe backup battery with 6,6V. The question is: will the JETI DSM ESC then be using the backup battery always instead of the power from the XQ-70 ESC because the battery has higher voltage?

Thanks

 

[Oxymoron]

The question is: will the JETI DSM ESC then be using the backup battery always instead of the power from the XQ-70 ESC because the battery has higher voltage?

Yes, considering the function diagram provided:

(Source: Jeti)

 

[SpeKopuZ]

Thanks, so in that case I'd have to use a ESC/BEC with higher voltage for the backup battery to be really a backup, correct? With the current setup there wouldn't be much gain I think.

 

[Oxymoron]

Probably not the best solution, but you can use a DC/DC Step-Down Converter with sufficient power to reduce the back-up battery voltage to ~5.0V. Something like this:

 

[onki]

Hi,

Using a 5V BEC as main supply and a backup battery with higher voltage is always a very bad idea.
In this case 4 NiCd are even better suited but still too high.

Why don't you try to use a state of the art HV system rather than the ancient 5V stuff?

When you invest in a DSM 10 why don't you also invest in an ESC with adjustbale BEC so you can set it to 6V.

Onki

 

[SpeKopuZ]

Hi,

Using a 5V BEC as main supply and a backup battery with higher voltage is always a very bad idea.
In this case 4 NiCd are even better suited but still too high.

Why don't you try to use a state of the art HV system rather than the ancient 5V stuff?

When you invest in a DSM 10 why don't you also invest in an ESC with adjustbale BEC so you can set it to 6V.

Onki

Thanks Onki, it looks like that's gonna have to be the way to go. Any particular brand/model you recommend?

 

[onki]

I would recommend this ESC:

EMC-Vega - SWORD 80 A SBEC ESC - V2-609011

EMC-Vega - SWORD 80 A SBEC ESC - V2 Ausverkauft bis ca. 20. Juli In der neuen Version 2 mit optimierter Leistungselektronik.NICHT KOMPATIBEL MIT PROGRAMMIERKARTEN V1

www.emc-vega.de

A program card is required to setup all features.
Regarding the Jeti DSM there is also an alternative with telemetry support:

HEPF Voltario T60 mit JR Steckersystem - HEPF Modellbau

mit JR Steckersystem geeignet für: JETI, Multiplex, Graupner & Futaba inklusive Berührungsschalter-Funktion merkt sich den letzten Betriebszustand optionale

hepf.com

I am using both in HV RC setups with a 2s LiFePo as backup. The benefit of the Voltario is that it has a wide telemetry support and you can configure the second inlet as backup inlet with charge support of the backup battery.

Todays ESC BEC are very powerful and reliable. A backup battery is usually not required. I am using the backup battery mainly as standby power supply to operate my Jeti RC-Switch. The backup is a nice safety addon.

Best regards
Onki