Chevy Volt Lithium Battery Project

So far I am very pleased with the Chevy Volt Lithium Project.  The batteries have been in the 2015 Montana 3611RL for a little over two weeks in the storage lot.  This is off grid location, and only changing is completed via Solar Panels.  We had cold cloudy day yesterday, so solar output was only 70.8 AH for the entire day.  Since I have AC Inverter on 7/24, and the Satellite receiver on all the time, the daily load is around 184 to 190 AH per day.  So we started today (full Sun day), already 120 AH in the hole from previous day plus the AH used over night.

Today's output was 241 AH, and Solar Controller was in Absorption for 276 minutes, but that just means the Lithium Batteries fully charge and didn't need any more power for 4.6 hours of the daylight hours today.   Once the batteries reach 12.06 vols, the batteries are disconnect from the RV and the power is provided by Bootscaps and Solar Panels while the Sun is shinning.

Now lets get to the fun stuff (pictures), btw the previous blog post had more information on my project.

Battery Box Top View 21" W x 24" L x 15" H

Battery Box Bottom View

Old Battery Installation - Six 6V Trojan 105

Old Batteries Removed

Chevy Volt Batteries have liquid cooling

When it get to hot I can open the compartment door

Another look at plumbing

I had a minor set back here.  The electric water pump is DOA, so now I need to drain the system and put another pump in there.  I have a few months before temperatures get above 90 degrees.  The heater is working fine, and we are going to be near freezing tonight.

All those wires on top are the Battery Management System (BMS) that I created.  See previous post for more info

 

Battery Box with lid on.  No venting required, no maintenance either.

Because to the Chevy Volt batteries are Lithium Ion, the cell voltages are different from most common Lithium batteries used in RV's today (LifePO4), there are three cells to make 12V, where LifePO4 use four cells.  It is very important that the Lithium batteries not be over charged or discard.

My target voltage per cell is 4.02 volts per cell.  So when my battery pack is 12.06 Volts, it is fully charge.  The 4.02 volts per cell is really the 80% level.  Charging to 90% is around 4.1 volts per cell, and 100% is around 4.2 volts per cell. 

The batteries will last a lot longer, at 80%.  The batteries are expected to last 15-20 years when charged to 80%.  If you charge to 90% 4.1 volts per cell, the life drops to 7-8 years, and at 100% 4.2 volts per cell, life drops to 4-5 years.

Had Residential Fridge and Satellite Receiver running for 24 hours.

Used 184 Amp Hours over night.

Battery Voltage Dropped from 12.06 Volts to 11.48 Volts

After running Fridge for 36 hours I turned it off.  Panels are facing East and West, not getting 100% of rated power, but was still able to harvest 340.9 Amp Hours on one day when the Fridge was running.

More picture can be found at Lithium Battery Project