Bulk charging on Portable generator

[Kevin J]

Trailer: 2021 Bullet 250bhs
WFCO: WF-8900 series 3-stage converter
Bulk charge: 14.4V (Although the converter is outputting 14.4 VDC, you will not be able to read that on a voltmeter due to the voltage-current
relationship). Bulk Mode will be maintained until the current draw drops to approximately five Amps, or until the timer reaches four hours (whichever happens first).
Absorption: 13.6V
Float: 13.2V
Portable generator: A-iPower SC2300i inverter generator (with120V 30A outlet)
Batteries: 2 x 6V GC2 (210AH@20hr).

Question: When no shore power, I want to run my generator efficiently. ie. target bulk charging only.

What is the best way to do this? ie. How can I tell when my trailers converter changes from Bulk to absorption mode?

Thanks all for any advice.

[chuckster57]

Your converter will choose charge rate based on battery state of charge (voltage), I don’t believe you can “select” charge rate.

[Kevin J]

Thanks Chuckster.
Yes I just wish there was a way of telling when it switches modes. Running a gas generator to charge batteries when they are in the absorption or float stage is a waste.

I should have mentioned I also have a Victron Smartshunt which is set to full charge 13.0V and 4% tail current.
I have thought maybe I could change these settings to detect bulk mode; ie. when it drops below 14.1V and 5Amp current it is moving from bulk to absorption. That would mean the battery is at 80-85%.

I found with the SmartShunt last year that it seemed to fault to 100% charge at times when there was no way it was at 100% charge.

[ChuckS]

You could use a simple clamp on amp meter to monitor the amperage charge to the batteries

First two images are the amp draw my hydraulic pump motor placed on my two GC2 batteries during slide out retraction ( my three slides are all hydraulic), followed by a retraction of the six point hyd level up system and then an Auto level plus extending the slides back out..

Last image shows the charge rate after I finished all the above actions and then plugged the fifth wheel back into shore power

While it might take a bit longer charging in absorption mode it’s better on the two GC2 batteries I have.. They are now 7 years old..

[Kevin J]

Thank you for that suggestion