The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: georgesgiralt on June 15, 2016, 07:37:01 AM

Title: regulator voltage for AGM batteries
Post by: georgesgiralt on June 15, 2016, 07:37:01 AM

Hello,
I think jet lag had killed my brain.
I can't find the cutting regulator voltage one should aim for an AGM battery.
I have repaired the old Wherle electronic regulator which came with the bike 32 years ago (BD244 fried) and  want to install it to please the AGM battery fitted.
Many thanks for your help.
P.S. : the CHITECH electrical manual gives ON=13.8V OFF=14.7V and mean= 14.3V for a flooded battery. And my Wherle has a resistor adjust to set the voltages...

Title: Re: regulator voltage for AGM batteries
Post by: montmil on June 15, 2016, 08:26:57 AM

I believe the AGMs like 14.2v. Read that somewhere. AGMs and MotorradElektrik's electronic VRs in all three of my Airheads. Batteries last close to 60 months. Hope I haven't just jinxed myself. <knock wood>

Title: Re: regulator voltage for AGM batteries
Post by: Barry on June 15, 2016, 09:06:37 AM

I would set the regulator at whatever the battery manufacturer recommends as the charging voltage. There will be some variation with temperature so pick a value at the ambient temperature when the regulator is being set.  

If you don't have that information my battery has a recommended range of 14.5 - 14.8 volts at 20 Deg C with a -30mV/Deg C adjustment for increasing temperature. So I have mine set at 14.5 volts which would also safe up to 35 Deg C although the negative temperature coefficient of the regulator should take care of that anyway.   I judged 14.5 Volts to be quite a conservative setting and could probably have gone higher.

Title: Re: regulator voltage for AGM batteries
Post by: georgesgiralt on June 15, 2016, 02:53:32 PM

Thank you for the information.
A French guy told me not to increase the voltage too much for fear this could evaporate the "liquid" in the AGM battery killing it.
I'll ask the seller about the manufacturer value I should use and set the regulator at that.
if I can, !I'll play with the regulator and my hot air gun to see if it actually change the voltage with temperature ...

Title: Re: regulator voltage for AGM batteries
Post by: jonathanrowley on June 18, 2016, 04:04:02 AM

Quote

I can't find the cutting regulator voltage one should aim for an AGM battery.

14.3V Max from my reading on the topic

Title: Re: regulator voltage for AGM batteries
Post by: Barry on June 18, 2016, 07:19:58 AM

You mustn't overcharge an AGM as any gassing off through the safety valve results in lost electrolyte that can't be replaced which ultimately leads to a failed battery. The battery manufacturer knows best and the charge voltage is so important AGM and Gel batteries often have this information printed on the battery casing. Mine does so it might be worth a look.

Title: Re: regulator voltage for AGM batteries
Post by: Einar on June 18, 2016, 07:55:02 AM

Range between 13,7 and 14,3V would be my suggestion.
My own bikes all have regulator output in that range.