Both lane lights flashing on startup?

Tecnam P2008 912iS with an AGM Lead Acid battery... using the GPU as a charger, I began getting Lane errors on first start when cold. Installed a new battery but no improvement. Switched to a Battery Minder for AGM lead acids with temperature compensation and have not had a problem since. The battery voltage is about 0.5V higher with the new charger.

d.

Daniele Carlo Brotto wrote:

Tecnam P2008 912iS with an AGM Lead Acid battery... using the GPU as a charger, I began getting Lane errors on first start when cold. Installed a new battery but no improvement. Switched to a Battery Minder for AGM lead acids with temperature compensation and have not had a problem since. The battery voltage is about 0.5V higher with the new charger.

d.

Can you share which model battery charger you bought? Is it this one? https://a.co/d/5ufLDSQ

My airplane specifies an AGM Lead Acid battery. I'm using an Odyssey PC545. My charger is the AGM version of the charger in your link. I began monitoring the Lane voltages (output on the 912iS CAN bus and displayed on my Dynon screen.) When cold and prior to the Battery Minder, the voltages would collapse upon engine start, the Lane lights would come on and while the voltages would recover after engine start, the Lane lights would stay on. The engine started pretty quickly though, a couple of blades. Performing a Lane check would clear the lights, so I was pretty sure it was due to the deep voltage drop upon starting. Now I just engage the power to the Lanes and fuel pump, set the throttle to the bottom of the "green" range on the Dynon, wait for the Lane lights to go off (about 3 seconds) and start the engine, one or 2 blades. The Lane voltage does not collapse, and the Lane lights stay off.

What battery are you using?

d.

Daniele Carlo Brotto wrote:

My airplane specifies an AGM Lead Acid battery. I'm using an Odyssey PC545. My charger is the AGM version of the charger in your link. I began monitoring the Lane voltages (output on the 912iS CAN bus and displayed on my Dynon screen.) When cold and prior to the Battery Minder, the voltages would collapse upon engine start, the Lane lights would come on and while the voltages would recover after engine start, the Lane lights would stay on. The engine started pretty quickly though, a couple of blades. Performing a Lane check would clear the lights, so I was pretty sure it was due to the deep voltage drop upon starting. Now I just engage the power to the Lanes and fuel pump, set the throttle to the bottom of the "green" range on the Dynon, wait for the Lane lights to go off (about 3 seconds) and start the engine, one or 2 blades. The Lane voltage does not collapse, and the Lane lights stay off.

What battery are you using?

d.

I have an Odyssey PC680. I thought the voltage collapses upon the starter engaging on every plane and plane battery? It's not supposed to do that? Did that in my last plane, which had a Continental engine, at every start. 

Do you have the 2A BatteryMinder charger or the 8A version? 

Yah, there will be a drop in voltage when the starter load is engaged. This is due to the high current coursing through wiring, connections, battery impedance, and original battery source voltage and condition. My described voltage "collapse" was seeing the Lane voltage tape that I display on the Dynon well into the Yellow range. With my latest setup, the voltage drop is minimal.

There is a lot of information on Odyssey AGM batteries here:

AMER-EN-TM-ODY.pdf (odysseybattery.com)

You must use a charger designed for AGM and not just flooded Lead Acid batteries. The referenced manual states that you need to supply 40% of the rated current to charge a fully discharged battery. So in the case of your battery that would mean 40% of 16 AHr or 6.4 Amps. So the 8 A, AGM setting on this charger should work:

Amazon.com: BatteryMINDer 128CEC2: 12 Volt-2/4/8 AMP Lead Acid Battery Charger, Lithium (LiFePO4) Battery Maintainer, and Battery Desulfator : Automotive

Note that there are other references that say 10% to 25% of the battery AHr rating is sufficient.

In actual use, the battery is never really being charged from a highly discharged state. The manual states that a "maintenance" regime to keep the battery topped off is suitable (0.5 to 1.5 amp range). I've been using the 2 Amp version of the Battery Minder AGM charger with good results.

What charger are you presently using?

d.