GT500 sees battery as DC Supply - RC Groups
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Aug 10, 2017, 12:42 AM
Registered User

GT500 sees battery as DC Supply

I have a 24V SLA battery bank that I occasionally use with my GT500. I use the regenerative discharge feature to put my LiPos into storage charge, and put that energy into the SLA batteries. It typically works as expected. But occasionally, if I discharge a second batch of batteries, the GT500 will run for a minute then display an error message saying it detects a DC supply present and will not allow regen discharge. To get past this error message, I need to select a different supply without regen discharge, and discharge my lipos into the resistive load. Why would the GT500 see the battery as a DC supply?
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Aug 10, 2017, 07:56 PM
Registered User
The GT500 senses a DC supply if the input voltage rises above a certain threshold during the time when the regenerative amps is low.

Could you pls post your charger settings as well as specs of your SLA battery bank? If we are able to replicate the symptoms, perhaps we can fine tune the code to get the correct behaviour.
Aug 10, 2017, 08:43 PM
Registered User
Thanks for the reply. I'm including a photo of my current battery settings. I've tried adjusting these settings to overcome the DC supply error message, with no success. The batteries I'm using are Enersys Cyclon "E" cells, VRLA batteries. The are 2.0v 8.0Ah cells in series. The application sheet for these cells can be found here.
Aug 11, 2017, 06:44 AM
Registered User
Thanks for the link.

May I know the total discharge amps as well and if you are discharging from 1s packs?
Aug 11, 2017, 04:00 PM
Registered User
I am typically discharging various 3S packs into the SLA battery. My discharge rate would depend on the battery, typically a 1C discharge, and would be between 1A and 2.2A. I haven't used this feature a lot, I don't recall if I have parallel discharged any batteries. If so, the peak discharge current would have been 8.8A.
Aug 12, 2017, 01:56 AM
Registered User
Thanks, we'll look into it.

Meanwhile, if you haven't already done so, I suggest checking the connections to make sure they are tight and both input and output cables are in good condition. If you have another SLA supply battery, it would also help to see if the spare SLA pack produces the same symptoms.
Aug 17, 2017, 07:31 AM
Registered User
Hi trimmkm,
I have not been able to reproduce the symptoms of the error message. I'll probably need more info from you to proceed. Could you email me at to discuss?

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