question

francesco avatar image

Best float voltage and absorption time ("Energy Unlimited book)

  1. good morning, I have read (not all given my difficulties with English ....) the book "energy Unlimited", and I have a couple of questions.
    I live in a camper with a 300 watt PV system, 30 A mppt regulator and 2 service batteries (1 + 1 or in parallel, Agm 100 ah and cheap start battery 100 ah) and an engine battery.
    The AGM is almost 3 years old and 900 cycles and still works almost at 100%, the start battery for the services was replaced after 2 years and 700 cycles with another similar one.
    I think I use them in the best way:
    Absorption at 14.4v and floating at 13.7v, with temperature compensation with sensor on the battery.
    The average working temperature is 25 degrees Celsius in the Canary Islands.
    My Tracer 3210 regulator is great but has an adjustable but fixed absorption time. Default to 120 minutes.
    However, I copy the algorithm of the victronenergy regulators.
    If I discharge the batteries in the evening, for example Vb> 12.6, I set 1 hour of absorption.
    If 12.2 <Vb <12.6, I imposed 2 h of absorption, etc ...
    The average discharge each night is at 12.55 v.
    
    However, while reading the book, I had some doubts about the float voltage.
    The book says that a 13.8v float for a long time damages the batteries due to excessive gasification ... especially the VRLA batteries.
    My batteries on average float from 12.00 / 13.00 to 17.00 / 18.00 (more time in summer, less time in winter).
    The alternator supplies 14.2 v and I connect it to the service batteries with victronenergy cyrix, almost only at night while traveling or traveling in the rain, for the fridge etc. So it's not a problem.
    In your opinion, what is the best absorption voltage compared to the usage data I have provided?
    For now I have lowered from 13.8 default to 13.65.
    If I took it to 13.2 / 13.4 v would I get some advantages in battery life or some disadvantages?
    Thanks and I apologize for the length.
charging batteryvoltagebattery system voltageabsorptionfloat
2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

0 Answers