I’ve just taken delivery of a new AC180 and will be collecting a 435w panel on Tuesday. I’ve also got a Vtoman Jump 600x and have been using this with a 100w panel, in the Summer it can get to 100% early in the day and I then use it on pass through to power laptop/TV/whatever. The Vtoman doesn’t seem to have been harmed by this in any way.
My question is, would I be harming the AC180 by using it in the same way? I read contradictory things about how Bluetti batteries operate once they get to 100%, e.g. that at 100% the PV input turns off entirely until the battery goes down to 99%, which sounds like it would stress the battery (for all I know the Vtoman works the same way but displays differently).
I’d be grateful for some advice. Alternatives would be to use pass through while the battery is still charging, which would be fine, or just to charge the battery (possibly to 80%) and then use it without pass through, which is potentially a waste of energy (I could by another one and rotate, I suppose!). Since it’s October in the UK, this is unlikely to be a live issue for a while.
You are correct. When the AC180 is fully charged, the PV will stop charging, and the battery will supply power to the load until the SOCdrops to 99% before recharging.
When the battery is fully charged, if the power generated by the PV is directly fed to the load side, the battery will not be able to act as a buffer. The PV power input to the load side is uncontrollable, which can easily lead to damage to the load.
Thanks for getting back to me. Obviously, I’d like to maximise the amount of energy I can use on days where the panel produces more than the AC180’s capacity.
Am I right in thinking that frequently allowing the unit to cycle from 99-100% would shorten the battery’s life? If so, would it be better to connect a load at a lower SOC and let the batteries charge more slowly while powering devices? Or are both scenarios still pretty bad and I should think of another way of using the excess energy, if I’m lucky enough to have any?
I don’t know how clever the BMS is and to what extent pass through charging is bad for the AC180 - some web pages and manuals indicate it shouldn’t be done often if at all, others just say it’s a feature of the battery without any caveats. Thanks again.
Great, thanks. I’ll take the lack of a warning with either method of pass through (that is, while the unit is 100%, or at a lower SOC) as an indication that the AC180 can handle it - as I say, it’s not going to be an issue until next Summer.
I will continue to do a regular deep-ish discharge from time to time and will report back with any findings, good or bad!