Juggernaut Ultra Battery Management System

[ClarkP]

Anyone know at what voltage the Ultra BMS balances the cell packs?

I'm moving to a 80% max charge (52V) for most trips in order to extend battery life (100%-54V only for long rides). Does the BMS balance the cell packs as it charges (e.g. even at 80%) or only after full charge? Apparently some BMS balance by draining the highest V cell pack once full charge is reached & then charge all again (allowing the lower V packs to "catch up") which means you don't rebalance unless you fully charge for a while.
Thanks

 

[JimE]

Grin Technologies suggest that balancing only occurs at 100% and they recommend leaving the battery on the charger overnight at 100% to make sure that the balancing is complete. You might ask also how often to balance the battery - Grin says every month or so but that is a lot of work.

Cycle Satiator Lithium Battery Charge Simulator

The Satiator Charge Simulator is a web application for creating custom charge profiles for your lithium battery pack. It allows you to view a simulated charging graph to see the charging time in difference scenarios, produce partial charge profiles to maximize battery cycle life, and download...

www.ebikes.ca

 

[ClarkP]

Thanks, and I’m using GTs Cycle Satiator to manage the charging.

Not an expert but I’m pretty sure the BMS design sets this and that, while most do it at 100% over a period of time as you suggest, other BMS may do the cell balancing during the charging process at other stages by monitoring the varying voltages along the way.

Wonder if Roshan could clarify how the Juggernaut Ultra BMS works specifically? And per Jim’s suggestion, how often to balance? Thanks.

 

[roshan]

Anyone know at what voltage the Ultra BMS balances the cell packs?

I'm moving to a 80% max charge (52V) for most trips in order to extend battery life (100%-54V only for long rides). Does the BMS balance the cell packs as it charges (e.g. even at 80%) or only after full charge? Apparently some BMS balance by draining the highest V cell pack once full charge is reached & then charge all again (allowing the lower V packs to "catch up") which means you don't rebalance unless you fully charge for a while.
Thanks

Our BMS only start balancing cells around full charge.

 

[Feliz]

Just for general interest, I recently purchased a battery from a supplier in England who manufacture their own quality batteries and they told me their BMS continually balances the pack throughout the charging process so not every BMS only balances at 100%, just sayin'

 

[roshan]

Just for general interest, I recently purchased a battery from a supplier in England who manufacture their own quality batteries and they told me their BMS continually balances the pack throughout the charging process so not every BMS only balances at 100%, just sayin'

Let me clarify:
When charging occurs via a bms, the series cells are all charged within acceptable tolerance. The tolerance depends on the bms. Say 0.2V for example. So when cells are being charged, the bms doesn't balance cells if they are all between the said tolerance. Once the pack reaches a pre-set hvc voltage, the bms then balances the cells within a second tolerance (usually within 0.05V). This is generally how most bms works.

Some bms have both the tolerances mentioned above set to the same value. These batteries take much longer to charge as the bms goes through a lot more balancing cycles. Our bms' only fully balance cells once the pack is near full capacity.

So this begs the question: if the charging balence tolerance is set to 0.2V, would you call your pack balanced in the middle of a charge cycle? I wouldn't but may be the UK manufacturers do.

Active Battery Cell Balancing | Analog Devices

With passive and active cell balancing, each cell in the battery stack is monitored to maintain a healthy battery state of charge (SoC). This extends battery cycle life and provides an added layer of protection by preventing damage to a battery cell due to deep discharging over overcharging...

www.analog.com

 

[Feliz]

Let me clarify:
When charging occurs via a bms, the series cells are all charged within acceptable tolerance. The tolerance depends on the bms. Say 0.2V for example. So when cells are being charged, the bms doesn't balance cells if they are all between the said tolerance. Once the pack reaches a pre-set hvc voltage, the bms then balances the cells within a second tolerance (usually within 0.05V). This is generally how most bms works.

Some bms have both the tolerances mentioned above set to the same value. These batteries take much longer to charge as the bms goes through a lot more balancing cycles. Our bms' only fully balance cells once the pack is near full capacity.

So this begs the question: if the charging balence tolerance is set to 0.2V, would you call your pack balanced in the middle of a charge cycle? I wouldn't but may be the UK manufacturers do.

Active Battery Cell Balancing | Analog Devices

With passive and active cell balancing, each cell in the battery stack is monitored to maintain a healthy battery state of charge (SoC). This extends battery cycle life and provides an added layer of protection by preventing damage to a battery cell due to deep discharging over overcharging...

www.analog.com

Good clarification, thanks Roshan. I wasn't saying which was better or worse or right or wrong, I'm still luvin' my Classic after a year.

 

[ClarkP]

Thanks Roshan, that all makes sense and yes, the faster charge with balancing only at the end seems like the better trade off.

I am choosing to usually charge only to about 80% in order to extend battery life. (For longer rides I’ll charge to 100%). A couple questions If you don’t mind...

- How often do you suggest charging to a full 100% to allow the BMS to balance for maintenance?
- And for how long after 100% should we leave it on the charger to ensure it finishes the balancing?
- Finally, if I use the Cycle Satatiator, what V should I set the 100% charge to to ensure the BMS fully charges and triggers the balancing?

Very much appreciate the insights and info.

 

[ClarkP]

Roshan,

Any chance you can sanity check this logic for those of us who are using a Cycle Satiator charger?

I'm using Cycle Satiator to charge to 54.6V ~ once a month and leaving it on for about 3 hours after the first "charge complete" notification. I'm assuming that is the right voltage and charging time and frequent enough to balance the cell packs.

The rest of the time I will charge to 80% (52V) for shorter rides and in order to lengthen the life of the battery pack. (My understanding is that this can lengthen the useable life of the battery by 2-3X.)

Any insights appreciated.

Thanks,
Clark

 

[roshan]

Hi Clark,
That is reasonable to do. 54.6V is the fully charged voltage when the balancing happens.

 

[ClarkP]

Great, thanks Roshan! Absolutely love the bike.

Hi Clark,
That is reasonable to do. 54.6V is the fully charged voltage when the balancing happens.

thanks

 

[JimE]

Grin states that our small charging connectors on Biktrix batteries are only suitable for charging at 4 amps. The Satiator is capable of up to 8 amps depending on the model. The default amperage on our Satiator was set at 5 amps so I only use a charging routine I designed with a maximum of 4 amps. Too high amperage may cause all kinds of problems in addition to frying the connector.

 

[ClarkP]

Thanks Jim. Very helpful info. My regular charge setting is 3 amps and will use 4 amps as a max speed charge as you suggest.

 

[mbouck]

Grin states that our small charging connectors on Biktrix batteries are only suitable for charging at 4 amps. The Satiator is capable of up to 8 amps depending on the model. The default amperage on our Satiator was set at 5 amps so I only use a charging routine I designed with a maximum of 4 amps. Too high amperage may cause all kinds of problems in addition to frying the connector.

I will say this is my main complaint with the Reention Dorado-style packs - the 2.5mm barrel adapter is pretty weak/cheap. If you can talk to your suppliers, Roshan, I'd recommend they use a better (standards-based) charging plug that can handle greater amperage.

 

[roshan]

I will say this is my main complaint with the Reention Dorado-style packs - the 2.5mm barrel adapter is pretty weak/cheap. If you can talk to your suppliers, Roshan, I'd recommend they use a better (standards-based) charging plug that can handle greater amperage.

The barrel plugs support up to 5A. We only warranty our batteries with our chargers that go up to 4A.

 

[tomjasz]

I will say this is my main complaint with the Reention Dorado-style packs - the 2.5mm barrel adapter is pretty weak/cheap. If you can talk to your suppliers, Roshan, I'd recommend they use a better (standards-based) charging plug that can handle greater amperage.

Why would a seller spec a charge rate beyond most cell specifications, or a rate that stresses cells? The market demands are hysterical. We want bus get batteries with premium performance.

 

[tomjasz]

Grin states that our small charging connectors on Biktrix batteries are only suitable for charging at 4 amps. The Satiator is capable of up to 8 amps depending on the model. The default amperage on our Satiator was set at 5 amps so I only use a charging routine I designed with a maximum of 4 amps. Too high amperage may cause all kinds of problems in addition to frying the connector.

There are 5.5x2.2 plugs capable of higher amps but why? We want budget bike batteries with premium performance. Goofy!

 

[Deafcat]

I charge my 52V reention pack with 5A thru the typical barrel jack, no issues.... also going to 88% charge typical on Satiator.

 

[tomjasz]

I charge my 52V reention pack with 5A thru the typical barrel jack, no issues.... also going to 88% charge typical on Satiator.

I was shocked to find many makers using “typical barrel jacks” also using under 2A rated versions. EM3ev uses Reention cases bit with Cusmade 10A rated ports. http://www.cusmade.biz/Product/Detail/22

 

[Explorer-1]

Why would a seller spec a charge rate beyond most cell specifications, or a rate that stresses cells? The market demands are hysterical. We want bus get batteries with premium performance.

Simple, they don't! There is more than one cell in parallel in the pack, the effective charge rate for each cell is below cell specifications.