installed the lithium

Short post as I am worn out.

The actual installation was a matter of minutes. All the finagling in a tight space, moving stuff, looking up stuff in manuals, etc, too up the time.

order of operations

I started pulling the FLA GC2 late this morning and had everything buttoned back up by 3p.

1. remove everything from the van that’s in the way
2. shut down panels
3. pull GC2
4. reconfigure solar charge controllers to new settings
5. run voltage sensing wire to 50A controller
6. reconfigure HVD setup on voltage-sensing relay (VSR for alternator charging)
7. install power switch on the VSR for absolute control if something goes wrong. Also allows disconnection from house bank since higher Li resting voltages can hold the VSR closed.
8. reconfigure battery monitor (shunt)
9. install foam board insulation where battery will go
10. install battery warming pad and thermostat
11. tape temp sensors to battery
12. install the Rebel Batteries 100Ah “retro” batt; it was resting at 13.19v.
13. enable VSR with switch, test alternator charging. This was the scary part; what was going to be the acceptance rate? ~29A, which is Excellent. 20A is optimal with 50A being the max for longevity (BMS will allow 100A). I let it run for a while and voltage stabilized around 13.4v. This must mean there is sufficient resistance through the chassis ground to control the charge rate. Acceptance will be somewhat higher when bank voltage is lower (12.5v or whatever).
14. shut down engine and switch off VSR.
    Excellent. 20A is optimal with 50A being the max for longevity (BMS will allow 100A). I let it run for a while and voltage stabilized around 13.4v. This must mean there is sufficient resistance through the chassis ground to control the charge rate.
15. shut down engine and switch off VSR.
16. switch on panels - ~27A under partial clouds. Since solar charging power tends to increase slowly as the sun rises it will be interesting to see what the charge rate is under normal conditions.
17. button back up the battery box
18. move everything in the van to be in the way again

first thoughts

The voltage stability of Li is impressive. Internal resistance is so low and the voltage curve so flat that the battery could be accepting hundreds of watts and barely budge the voltage. FLA’s resistance was so high that at the same charging current voltage would soar to Absorption (14.7v) very quickly.

I don’t think the voltage sensing wire is working on the controller. I can measure the voltage at the connector but the controller doesn’t seem to notice. I may have to read the manual. /gasp

The GC2 were removed on their 1,115th day. They did a good job for $200. I’ll try to find a recycling place to get a couple bucks out of them, and maybe all this ammo brass I’ve been dragging around.

comments

twitter comment thread for this post