Who this is for:
Battery nerds that have top-balancing gear and maybe some spare similar cells. I'm one of them that has done this.
What this is NOT:
Not an anti-bms campaign. You are going to be using an external fuse and an LVD like a Victron or similar.
Not promoting unsafe operating conditions.
Not promoting a "cheap" alternative to a bms. These days, it actually costs more if you don't have stuff.
Not promoting the use of wiring up trash random cells with speaker wire.
Not a production-quality battery that you give to your unskilled neighbor.
Not designed to cause a furious forum uproar with any hidden campaign.
Objective:
After an initial top-balance, one does not dance around with a bleeder all over the cells to try and make them all perfectly equal in voltage. A 4S 12v configuration keeps it manageable. Your application could be as simple as an inexpensive msw inverter and a grocery-store led bulb in a house fixture as your bench light.
Operational goal with a practical twist:
Because each cell has slightly different amounts of capacity and internal resistance, after an initial top balance, in operation a wider delta-variance up to 100mv or so is allowed because they are going to dance around a bit. If your top balance is good, and your cells aren't totally different, then a CV is set to get them no wider than between say 3.45 and 3.55. Or say 3.5 and 3.6v.
A low CV is recommended, like 14.0 to maybe 14.2v
Unlike other top-balance demonstrations which show ops dancing around with a manual bleeder resistor, you are going to simply let this 100mv delta variance be. The battery nerd in you will be watching this perhaps every cycle with your multimeter collecting dust. Later, after many cycles, you may be confident enough to not do this each and every time.
If you can't obtain a near 100mv variance or less, that means your top-balance was not good in the first place, or you have too much of a variance of capacity or internal resistance in your cells, or your wiring structure has high-resistance elements. (you cleaned your terminals and bus-bars right? Ring terminals instead of clip leads!)
HERESY!
Not really. This is just an interesting experiment for us battery nerds. Will your battery operated in this manner degrade so fast that you won't get past a week's use? Or will it last 8 years? You tell me!
What it will do is make use of some of the gear you bought to do a top balance on your 48v bank only once, and maybe make use of some spare cells getting lonely in the corner. And you aren't dancing around with a manual bleeder, which from a propeller-head standpoint, sometimes making cells exactly equal in voltage is actually UNbalancing a bank. It's a fine detail, but don't tell anyone.
Battery nerds that have top-balancing gear and maybe some spare similar cells. I'm one of them that has done this.
What this is NOT:
Not an anti-bms campaign. You are going to be using an external fuse and an LVD like a Victron or similar.
Not promoting unsafe operating conditions.
Not promoting a "cheap" alternative to a bms. These days, it actually costs more if you don't have stuff.
Not promoting the use of wiring up trash random cells with speaker wire.
Not a production-quality battery that you give to your unskilled neighbor.
Not designed to cause a furious forum uproar with any hidden campaign.
Objective:
After an initial top-balance, one does not dance around with a bleeder all over the cells to try and make them all perfectly equal in voltage. A 4S 12v configuration keeps it manageable. Your application could be as simple as an inexpensive msw inverter and a grocery-store led bulb in a house fixture as your bench light.
Operational goal with a practical twist:
Because each cell has slightly different amounts of capacity and internal resistance, after an initial top balance, in operation a wider delta-variance up to 100mv or so is allowed because they are going to dance around a bit. If your top balance is good, and your cells aren't totally different, then a CV is set to get them no wider than between say 3.45 and 3.55. Or say 3.5 and 3.6v.
A low CV is recommended, like 14.0 to maybe 14.2v
Unlike other top-balance demonstrations which show ops dancing around with a manual bleeder resistor, you are going to simply let this 100mv delta variance be. The battery nerd in you will be watching this perhaps every cycle with your multimeter collecting dust. Later, after many cycles, you may be confident enough to not do this each and every time.
If you can't obtain a near 100mv variance or less, that means your top-balance was not good in the first place, or you have too much of a variance of capacity or internal resistance in your cells, or your wiring structure has high-resistance elements. (you cleaned your terminals and bus-bars right? Ring terminals instead of clip leads!)
HERESY!
Not really. This is just an interesting experiment for us battery nerds. Will your battery operated in this manner degrade so fast that you won't get past a week's use? Or will it last 8 years? You tell me!
What it will do is make use of some of the gear you bought to do a top balance on your 48v bank only once, and maybe make use of some spare cells getting lonely in the corner. And you aren't dancing around with a manual bleeder, which from a propeller-head standpoint, sometimes making cells exactly equal in voltage is actually UNbalancing a bank. It's a fine detail, but don't tell anyone.