short question about orion_xs I have one installation on by boat with 2 AGM batteries (one direct for engine and one as backup for engine or house) the third battery lifepo4 is house battery only, my solar panel charge the lifepo4 battery only and with one Orion XS I CHARGE ALSO THE LIFEPO4 battery from starter battery, the problem now is that the lifepo4 battery is always 100% with solar panel and my question is how I use the solar panel to charge also the second AGM battery if the lifepo4 battery is 100% full.
This depends on the voltage specifications.
If the voltage you charge the LiFe battery to is very close to and equal or less then the absorption voltage for the AGM battery, then you can use an ACR (Automatic charge relay like the Cirix) to charge the AGM. If the voltages are dis-similar then you need another dc/dc converter.
Is good idea to install one second Mppt charger for the AGM battery? My idea is to install one second Mppt charger for the AGM battery and to redirect the positive of the solar panel in to on-off-on selector if the lifepo4 battery is fully charged I have to turn the selector (disconnect the positive from lifepo4 battery) and to send the positive in to 2nd Mppt for the AGM battery, both Mppt with common solar panel negative cable.
With an ACR, this is not necessary, as soon as the battery charged by solar reaches the threshold voltage, then the ACR will close, and both batteries will be charged, once the sun goes down, the ACR opens, and the batteries are isolated again.
Hi Mike!! Thanks for your response, my concern is that because the one battery (that I charge with solar panel) is lifepo4 I am afraid to connect the lifepo4 with the 2nd engine AGM battery, what ACR you suggest?
Like I said, this depends on the voltage range. Typivally a 12V lithium can charge to 14.4V, which is also generally fine for an AGM. Hence there is no reason why an ACR that closes at 13.8V should not be used. Do check the opening voltage of the ACR though, as this may also stay closed until the Li battery is below 50%. However, with daily charging from Solar, this should not be an issue.
