question

bossrox avatar image
bossrox asked

Are bulk & rebulk voltages different?

I couldn't find the answer to this in recent posts but since there's no setting for bulk voltage or a claim, just what is it on an smart solar 150/100? Is it the same as the absorption & is rebulk a different voltage than bulk? As I fiddled with the rebulk offset, I noticed that the highest voltage you can dial in is on 0 @ about 27.6 so I'm guessing & hoping bulk would be higher to at least the same as absorb but not higher.

I'm more concerned if it's higher than absorb as my AGM's shouldn't be fed anymore than 29 volts.

Anyone have an answer for this?

MPPT SmartSolar
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1 Answer
klim8skeptic avatar image
klim8skeptic answered ·

The re-bulk voltage setting is used to instruct the mppt when to switch between Float and Bulk charge states.

The re-bulk voltage setting is for when the mppt is in float state, and a large load uses more power than the mppt can sustain the battery voltage steady at the float setting. Once the battery voltage drops more than the re-bulk voltage setting, below the set float voltage, the charger will then switch over to Bulk charge state.

Once the charger is in the bulk charge state, the battery voltage will get up to the Absorption voltage setting, and then the mppt will switch back to the Float state. (no absorption period after a re-bulk)

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bossrox avatar image bossrox commented ·

I get what you're saying which kinda answers another question I posted about why I was seeing absorb getting skipped over after a rebulk but I've only seen that happen using user settings.

When I was using the presets, it always switched to absorb til it reached the set tail current, then switched to float.

With user settings I was seeing it switch from bulk directly to float with a 30-50 amp tail current & that won't charge a battery near as fast with that kinda reaction.

Thx for the feedback.


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