Any body heard of Boost stage or mode of charging?

Ampster

A friend sent me a link to a charge profile that included a Boost setting with a voltage to be entered, That profile also has a voltage setting for Absorb and Float at the same section on the input page. 

I Googled it and one definition looks to be a special kind of low current charging to bring back Lithium cells or Lead Acid batteries, 

mcgivor

The boost voltage is a term used to describe a second charging should the float voltage drop below a certain value,  Epever controllers use this but refer to absorption as constant charging, see page 6 of attached pdf 
This would appear to be a rebulk then a lower voltage mini equalization of sorts, from my understanding, the Epever/ Tracer, which may be rebranded uses this, what is the charge controller in question?  

Vic

Some Schneider MPPT Charge Controllers use a different Boost Charge approach,   as noted below"

"Boost charging allows for better utilization of flooded lead acid batteries under moderate cycling in off grid applications. Boost charging encourages a short duration charging voltage—above the gassing voltage—at the beginning of the absorption charge state. Testing has shown that boost charging improves battery performance by providing a regular mixing of the liquid electrolyte. Boost charging specifically discourages capacity-robbing acid stratification and plate sulfation. Boost mode charging can be enabled by selecting 'custom' battery type and by setting the bulk voltage higher than the absorption voltage. The multi-stage charge algorithm then attempts to use the higher bulk voltage for the first hour of the absorption stage—unless interrupted by the max absorption timer or exit current threshold. 1. Boost charging encourages gassing of flooded lead acid batteries. 2. Boost charging is NOT recommended for AGM, GEL or any other electrolytelimited and/or valve regulated sealed battery application. 3. Boost charging may result in higher-than-normal water consumption. However, the benefits of boost charging are likely to be greater than the extra watering effort. Check battery water levels at least once per month. 4. Boost charging has maximum benefit when used on batteries that experience moderate cycling. An unoccupied cottage, for example, where batteries are full the majority of the time, may not benefit from boost charging - especially if battery watering is difficult."

Above taken from the Schneider Conext   SCC MPPT 60 150.   Copyright 2015,  Schneider Electric.

This type of Boost charge is not very common in Solar Charge Controllers (in my NA-oriented opinion).

FWIW,   Vic

Dave Angelini

Boost actually originates from Schneider Solar on their mppt-60-150 circa 2005 when it was developed. Forms of it have been around quite some time, but Schneider named it in the general press. Their intended use of boost was for the 3 step charge process to improve charge for some batteries.

Ampster

Thanks, that is not consistent with what i found Googling it but consistent with other descriptions. My Skybox does not reference it but lines up with what @mcgivor mentioned. I do have a setting for rebulk which does appear to have to be set at a lower setting than Float.

Dave Angelini

Welcome !

https://www.se.com/us/en/faqs/FA229722/

Ampster

That description is also different than others have reported earlier as a Rebuik. It is consistent with what @Vic said earlier and I can see it would only apply to Lead Acid. It is not something I would do with Lithium because the normal setting for Constant Voltage or Absorb is essentially as high as I would take my pack. As far as the acquaintance that asked the initial question I will just leave it at that. I am not clear if he was talking about a Lithium pack or Lead Acid and I have lost communication with him.  It does look to be a constant voltage stage of charging, just at a higher voltage for a brief time. Although it would look to be disabled if the Absorb voltage and the Boost voltage settings were the same. Is that a correct assumption?

Dave Angelini

Yes if the same voltage, bulk and absorb is entered in during config. on Schneider electronics. Schneider has a few other ways  (not boost) to charge lithium based on BMS, Soc, and custom lithium.

The best way to charge Lithium (my opinion) over time is the BMS and the charger are networked and charge based on Soc. Just too easy, safe, and repeatable. No need for external shunts and a bat mon. It does need to be designed in for residential use to do lithium safely in a home, or to have it insurable.

mike95490

It seems that lead acid chargers all differ over what BOOST is and new meanings are coming along weekly, making any standardization pointless for L.A.  Choose the brand you like.  "Re-Bulk" makes sense, Boost is just noise because each brand uses it in a different manner.

However -

Standard wise, BOOST seems (IMHO) be best used as Li battery recovery:
https://batteryuniversity.com/learn/article/low_voltage_cut_off
 batteryuniversity makes no major reference to boost other than that specific LI recovery mode.

Dave Angelini

I was told by Schneider back in 2005 or so that a very large Gigante FLA, that was genset charged up in some Canadian snowland Telcom wanted Boost. They said it prolonged the time before EQ was required and staff did not have to be there for the EQ until the snow melted.

Boost to them was a mini EQ that worked. Not much Lithium when they coined the term in 2005.

Ampster

Thanks, It does sound like a mini equalizing setting the way Schneider is using it. Either way it is another Constant Voltage mode of charging. My guess is it would be disabled setting the voltage to the same value as Absorb?

Ampster

mike95490 said:

It seems that lead acid chargers all differ over what BOOST is and new meanings are coming along weekly, making any standardization pointless for L.A.  Choose the brand you like.  "Re-Bulk" makes sense, Boost is just noise because each brand uses it in a different manner.

I saw a great sticky on another forum where a guy basically said there are only two types of outputs from a charging source. Constant Current and Constant Voltage. It made sense to me from an electrical framework since current and voltage are the only two things really come out of a charger. Since I haven't used a Pb battery in 10 years but have to interface with an inverter that was developed with a Pb market in mind that has been a helpful way to understand the various phrases used by manufactures. I agree standardization is pointless and the only thing that makes sense is terms like CC and CV which describe what the charger is actually doing. 
In the world of Lithium batteries it is more common for people to use CC and CV since those are the two variable in any charging algorithm. Most lithium charge profiles use a profile that ends during CV stage when the current tapers to less than 10% of the charge current. Often the BMS is set to do any balancing during that stage via an individual cell voltage setting that would shunt any cell that went about a predermined setting. Years ago I had a charger that was designed for EVs and it had user profiles one of which could lower the current in CV mode to allow the BMS time to balance any cells that needed adjustment. 

Marc Kurth

And now some "converter" manufacturers are touting their multi-stage chargers as having:

Boost Mode at 14.4v to 14.6v for 2-3 hours

Regular Mode at 13.8v to "finish the charge"

Storage Mode at 13.1v to 13.3v

Dave Angelini

Put some AC / DC on, you will be fine

Ampster

It's all marketing hype. CV probably sounds like a disease to them and Constant Voltage sounds bland.