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Lifep04 charge settings confusion

JoeyJibJab

New Member
Joined
Nov 13, 2020
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19
Location
Tasmania, Australia
Hi guys, I have a 24v lifepo4 pack (8s 400ah). I'm charging with a MPP solar 3024gk and am confused about the charge settings.

I've set the Bulk charge (C.V) to 28.8v and the float to 27.0v. I have no loads on the batteries as I'm just trying to get them to 100% so I can do a capacity test. I've got 1.5kw of solar charging the pack.

The issues is, the voltage never gets to the bulk stage. As soon as it hits 27v (float) it keeps the battery there. I always thought it was meant to hit the bulk voltage first before it goes back down to float? Is this correct?

Thanks
 
Hi guys, I have a 24v lifepo4 pack (8s 400ah). I'm charging with a MPP solar 3024gk and am confused about the charge settings.

I've set the Bulk charge (C.V) to 28.8v and the float to 27.0v. I have no loads on the batteries as I'm just trying to get them to 100% so I can do a capacity test. I've got 1.5kw of solar charging the pack.

The issues is, the voltage never gets to the bulk stage. As soon as it hits 27v (float) it keeps the battery there. I always thought it was meant to hit the bulk voltage first before it goes back down to float? Is this correct?

Thanks
I have Midnite Classic 150s and MPP Solar 3048LV - and set bulk/float the same (or as close as the input will allow) and the CC/CV works smoothly for me.

Maybe the CC/CV algorithm is different for lead-acid mode on some older charge controllers? sort of like equalize is lead-acid only algorithm to over-charge for a bit - but I've not heard of this as being desirable for lithium-ion mode.
 
Hi guys, I have a 24v lifepo4 pack (8s 400ah). I'm charging with a MPP solar 3024gk and am confused about the charge settings.

I've set the Bulk charge (C.V) to 28.8v and the float to 27.0v. I have no loads on the batteries as I'm just trying to get them to 100% so I can do a capacity test. I've got 1.5kw of solar charging the pack.

The issues is, the voltage never gets to the bulk stage. As soon as it hits 27v (float) it keeps the battery there. I always thought it was meant to hit the bulk voltage first before it goes back down to float? Is this correct?

Thanks
I wonder if your MPP needs to hit the re-bulk trigger to re-enter the bulk phase but it can't because the float voltage is higher than the re-bulk trigger voltage.
Different vendors have different names for things but the concept is usually the same.
 
Maybe I should just put both the Bulk and float at the same voltage then?
Your batteries, your call.
If you set bulk and float to the same voltage I expect that your charge will not terminate.
The charger will just keep your batteries at 28.2 volts as long as shore power is available.
Floating batteries above full resting voltage exposes them to unnecessary stress.
I might put both on 28.2v and see how we go
 
Last edited:
Your batteries, your call.
If you set bulk and float to the same voltage I expect that your charge will not terminate.
The charger will just keep your batteries at 28.2 volts as long as shore power is available.
Floating batteries above full resting voltage exposes them to unnecessary stress.
Yeah that's fair. I might contact support and ask them if they know what the issue is. I just manually switched the float to 27.2v once it reached 28.2v. All the cells are reading 3.4v now, so they are basically fully charged. I don't want to be manually switching voltages for obvious reasons.

Could be a firmware issue or something
 
Yeah that's fair. I might contact support and ask them if they know what the issue is. I just manually switched the float to 27.2v once it reached 28.2v. All the cells are reading 3.4v now, so they are basically fully charged. I don't want to be manually switching voltages for obvious reasons.

Could be a firmware issue or something
Did you look for a re-bulk parameter?
 
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