Cherry67
Member
- Joined
- May 13, 2018
- Messages
- 518
I am in the process of building up a preliminary version of the "Battery enhancer" i described in
https://secondlifestorage.com/t-Project-capacity-enhancer-for-mobile-home
Thanks to all who havel helped with questions and input.
Extracted from the mentioned thread is the functionality i need, means replacing a second home battery (the first is AGM 90 Ah) for "something better" (at moment called"unit")
[concept]
The "Unit" supervises the (first) home battery and does one of the following three things (as long as its own capacity lasts):
- on 12.8 Volt of the home batt it does nothing
- below 12.7 V of the home batt the unit starts to supply increasing current to the home batt with a linear correlation to lower voltages. In effect t takes the load which "obviously" drops the batts voltage, limited to 10 (just a figure at moment) Amps.
- over 12.9 unit starts to surge energy from the home batt (as well limited to 10 Amps), as well with a somehow linear correlation, because the original home battery is "obviously" fed.
- If the unit is "empty", it does nothing anymore on discharge, the AGM has to supply the load alone, and will be discharged then - as the last in the row (good for a lead battery to stay full at all times)
- If the unit is "full", it doesnt surge energy anymore, and the charger can fully load or "occasional balance" the AGM as usual.
So, in "Normal Use", the AGM stays mostly full (which it likes), the capacity is taken to and from the unit, cycling it. That increases lifetime of the AGM.
Shorttime high loads (inverter) need help from the AGM over 10 Amps, discharging it, but it will not be much SOC spent of the AGM.
In summary, i need just the Enhancer batt/the unit and a bidirectinal inverter, controlled to above rules. I have no complex connection to the mobiles circuitry, the circuitry or its parameters must not even be changed, but just a connection to the AGM, in parallel. There are some losses of energy, because it goes through the units inverters twice.
(But, i do not have limited resources of energy, i have limited resources of STORED energy, so no problem there).
In thinking about the system i found the name "Virtual Battery" for the concept, because it behaves like a battery, seen from the inside.
It supplies 12.8 Volt, with CV and CC on 10 Amps.
If i externally rise the voltage by a supply ( a "Charger"), the unit starts to surge energy to load the internal battery, which can be whatever type. The surge current is limited as well. The charged voltage does NOT have to match the battery full voltage, as every usual charger has to do (for decreasing the current).
I have not come across this concept ever, so it would be interesting for me if i have invented something already known (as it i the usual case... rotfl)
It looks like i can get 2-3 kWh (4-5 Pedelec Blocks per 36 v 18 Ah) plus two standard Alipress inverters with an Arduino in a PC case, and have 3-5 times the energy of an AGM for half the weight.
Currently i am building up a preliminary version with smaller convertesr i have in stock, that will be an about 3 Amp version.
Battery will be 36 Volt 18 Ah blocks coming from Pedelec ( bicycle) Batteries. These are used as they come out of the box, means not torn apart and repacked, because they are next to flawless as they are, plus very good mounted mechanically.
Each Block will get an own new BMS, the bluetooth version. At first i wanted to use a common BMS for all planned 5 blocks together, but that gives a hassle of BMS wires and connections which is a security risk by being damaged, so i made my mind up.
The converters will get their place in the old PC Mains adapter, gives it wonderful as a modular concept.
More informations and pictures will follow.
Update (re Redpackets notes below) The voltages might not be perfect correct, he is right, that has to be slightly adjusted for stable operation.
https://secondlifestorage.com/t-Project-capacity-enhancer-for-mobile-home
Thanks to all who havel helped with questions and input.
Extracted from the mentioned thread is the functionality i need, means replacing a second home battery (the first is AGM 90 Ah) for "something better" (at moment called"unit")
[concept]
The "Unit" supervises the (first) home battery and does one of the following three things (as long as its own capacity lasts):
- on 12.8 Volt of the home batt it does nothing
- below 12.7 V of the home batt the unit starts to supply increasing current to the home batt with a linear correlation to lower voltages. In effect t takes the load which "obviously" drops the batts voltage, limited to 10 (just a figure at moment) Amps.
- over 12.9 unit starts to surge energy from the home batt (as well limited to 10 Amps), as well with a somehow linear correlation, because the original home battery is "obviously" fed.
- If the unit is "empty", it does nothing anymore on discharge, the AGM has to supply the load alone, and will be discharged then - as the last in the row (good for a lead battery to stay full at all times)
- If the unit is "full", it doesnt surge energy anymore, and the charger can fully load or "occasional balance" the AGM as usual.
So, in "Normal Use", the AGM stays mostly full (which it likes), the capacity is taken to and from the unit, cycling it. That increases lifetime of the AGM.
Shorttime high loads (inverter) need help from the AGM over 10 Amps, discharging it, but it will not be much SOC spent of the AGM.
In summary, i need just the Enhancer batt/the unit and a bidirectinal inverter, controlled to above rules. I have no complex connection to the mobiles circuitry, the circuitry or its parameters must not even be changed, but just a connection to the AGM, in parallel. There are some losses of energy, because it goes through the units inverters twice.
(But, i do not have limited resources of energy, i have limited resources of STORED energy, so no problem there).
In thinking about the system i found the name "Virtual Battery" for the concept, because it behaves like a battery, seen from the inside.
It supplies 12.8 Volt, with CV and CC on 10 Amps.
If i externally rise the voltage by a supply ( a "Charger"), the unit starts to surge energy to load the internal battery, which can be whatever type. The surge current is limited as well. The charged voltage does NOT have to match the battery full voltage, as every usual charger has to do (for decreasing the current).
I have not come across this concept ever, so it would be interesting for me if i have invented something already known (as it i the usual case... rotfl)
It looks like i can get 2-3 kWh (4-5 Pedelec Blocks per 36 v 18 Ah) plus two standard Alipress inverters with an Arduino in a PC case, and have 3-5 times the energy of an AGM for half the weight.
Currently i am building up a preliminary version with smaller convertesr i have in stock, that will be an about 3 Amp version.
Battery will be 36 Volt 18 Ah blocks coming from Pedelec ( bicycle) Batteries. These are used as they come out of the box, means not torn apart and repacked, because they are next to flawless as they are, plus very good mounted mechanically.
Each Block will get an own new BMS, the bluetooth version. At first i wanted to use a common BMS for all planned 5 blocks together, but that gives a hassle of BMS wires and connections which is a security risk by being damaged, so i made my mind up.
The converters will get their place in the old PC Mains adapter, gives it wonderful as a modular concept.
More informations and pictures will follow.
Update (re Redpackets notes below) The voltages might not be perfect correct, he is right, that has to be slightly adjusted for stable operation.