Juggernaut Ultra Battery Management System

[tomjasz]

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.

Exactly. But is the BMS on a typical pack able to charge at the rate the cells are capable of?

 

[JimE]

We don't have a good way of riding our Biktrix bikes in winter so we don't have a good way to charge the batteries to 100% to balance them and then ride to 85% for storage. I have ordered a load resistor from Grin Technologies so that I can balance at 100% and then discharge the battery to 85%. The resistor is 7 amp at 48 volts. To use the resistor I need to plug into the discharge port of the battery or into the wiring downstream from the battery. Has anyone seen a plug that will fit the battery discharge port? Any ideas? Thanks.

 

[tomjasz]

Has anyone seen a plug that will fit the battery discharge port? Any ideas? Thanks.

What do they use for battery leads? Pictures? I use e Grinspector with their resistors.

 

[JimE]

Here is a photo. The port on the battery in the photo doesn't look like our discharge port. And of course they run the resistor through the inspector box.

Grinspector - Grin Products - Product Info

We built the Battery Grinspector as a relatively inexpensive tool for ebike shops and advanced users that need to discharge test and characterize ebike battery packs. It is controlled with a Cycle Analyst running a modified firmware and allows you to charge and discharge the battery pack into...

www.ebikes.ca

Are you using the inspector with a Biktrix battery? If you do how do you connect the inspector to the battery?

 

[tomjasz]

Here is a photo. The port on the battery in the photo doesn't look like our discharge port. And of course they run the resistor through the inspector box.

Grinspector - Grin Products - Product Info

We built the Battery Grinspector as a relatively inexpensive tool for ebike shops and advanced users that need to discharge test and characterize ebike battery packs. It is controlled with a Cycle Analyst running a modified firmware and allows you to charge and discharge the battery pack into...

www.ebikes.ca

Are you using the inspector with a Biktrix battery? If you do how do you connect the inspector to the battery?

I'M A BIT CONFUSED BY YOUR QUESTION. Ooops cap lock...

I have or can make adapters for any battery. I have the complete Grinspector. Is that what you are using?

 

[JimE]

This is listed as an EEL Mini male discharge port 2-pin on the Reention battery web site. This is what I need - the 2-pin port. Where to find it?

 

[tomjasz]

Simple, google 2 pin ebike battery connector.

Inline Battery Charger Connectors - ElectricScooterParts.com

Inline battery charger plugs, ports, and connectors for electric scooters and electric bicycles.

electricscooterparts.com

 

[JimE]

Isn't the Internet great?
(Link Removed - No Longer Exists)
Hope it's the right part - ordered it.
They sell it to hook up camping gear to your bike battery

 

[Explorer-1]

Isn't the Internet great?
(Link Removed - No Longer Exists)
Hope it's the right part - ordered it.
They sell it to hook up camping gear to your bike battery

Nice! i need the opposite connector for the battery-side and they have that as well.

 

[JimE]

Charging our Biktrix batteries to a storage voltage of 85% is no problem with our Cycle Satiator from Grin Technologies. But we also need to charge to 100% to balance the cells once every couple months and then discharge back to 85% for storage over the winter.


I ordered a 7 amp resistor suitable for 48V from Grin Technologies to do the discharging. The resistor gets very hot so I mounted it on some aluminum plate and blocked the plate off the table with pieces of 1x2 wood. So first I charge the battery to full charge (54.5V) then leave it connected to the charger for 30 hours more to allow balancing. Then I connect the battery to the 7 amp resistor to get the voltage back down to 85% (52.5V). Done.


https://www.ebikes.ca/shop/electric-bicycle-parts/test-equipment/load-resistor-6-8.html
https://www.ebikes.ca/product-info/cycle-satiator.html
(Link Removed - No Longer Exists)


After some problems in the past with battery voltage going too low, my battery storage routine is now charge each month to 85% and charge to 100% and back to 85% about once every two to three months. You can see that I added an inline multimeter from Amazon to the resistor but the displayed voltage is very inaccurate since the battery is under load while discharging. It took 15 minutes for the battery voltage to stabilize after disconnecting the resistor. I then measured the battery voltage using a calibrated multimeter. So you don’t really need a voltage display unit.


I tested our Biktrix 11 Ah battery. I learned that it takes 15 minutes for the resistor to drop the battery voltage to 85% at a rate of 370 watts and 7 amp load. Of course the discharge time will vary according to the battery size. Test by discharging for 5 minutes at a time. Wait 15 minutes for the voltage to stabilize then measure with a multi-meter. Repeat until you get the voltage you want. I should add that I felt all wires and there were no hot or even warm wires during this whole process.

 

[Deafcat]

For what it's worth, I charge my Reention Dorado 52V pack at 5.7A with cycle satiator, that's 300 watts, no issues. To be on the safe side, I never unplug the barrel jack charging cable while under full charging, only once it's done or after interrupting the charge by the satiator interface.

 

[Deafcat]

Charging our Biktrix batteries to a storage voltage of 85% is no problem with our Cycle Satiator from Grin Technologies. But we also need to charge to 100% to balance the cells once every couple months and then discharge back to 85% for storage over the winter.


I ordered a 7 amp resistor suitable for 48V from Grin Technologies to do the discharging. The resistor gets very hot so I mounted it on some aluminum plate and blocked the plate off the table with pieces of 1x2 wood. So first I charge the battery to full charge (54.5V) then leave it connected to the charger for 30 hours more to allow balancing. Then I connect the battery to the 7 amp resistor to get the voltage back down to 85% (52.5V). Done.


https://www.ebikes.ca/shop/electric-bicycle-parts/test-equipment/load-resistor-6-8.html
https://www.ebikes.ca/product-info/cycle-satiator.html
(Link Removed - No Longer Exists)


After some problems in the past with battery voltage going too low, my battery storage routine is now charge each month to 85% and charge to 100% and back to 85% about once every two to three months. You can see that I added an inline multimeter from Amazon to the resistor but the displayed voltage is very inaccurate since the battery is under load while discharging. It took 15 minutes for the battery voltage to stabilize after disconnecting the resistor. I then measured the battery voltage using a calibrated multimeter. So you don’t really need a voltage display unit.


I tested our Biktrix 11 Ah battery. I learned that it takes 15 minutes for the resistor to drop the battery voltage to 85% at a rate of 370 watts and 7 amp load. Of course the discharge time will vary according to the battery size. Test by discharging for 5 minutes at a time. Wait 15 minutes for the voltage to stabilize then measure with a multi-meter. Repeat until you get the voltage you want. I should add that I felt all wires and there were no hot or even warm wires during this whole process.

Also need to point out:

Charging to 85% has nothing to do with storage voltage, re battery wear. Simply charging that extra 15% is where the battery wear is incurred... Thus, charging to 100% and discharging back to 85% has not reduced wear whatsoever.

Charging for storage should aim for 50% charge or so, maintenance of temperature is more important than charge level. Losses in storage are pretty minimal, compared to wear from everyday full charging, so I tend not to worry about storage charge... Packs I'm not using often I just store below room temperature.

If you're aiming to just maximize capacity on a pack you use lots, cut off charge at 85-90%, balance with a 100% charge every 50-100 charge cycles, or every three months, whichever comes first... Something like that. No hard guidelines, we're all still pretty new at this.

 

[JimE]

I'm not trying to reduce wear but only trying to keep to the recommended storage charge of 85% during the winter season recommended by the Grin Tech staff. Even with 85% the self-discharge is high enough to require charging every 30 days to keep the BMS low voltage cutoff from shutting the battery down - been there done that.

 

[tomjasz]

I'm not trying to reduce wear but only trying to keep to the recommended storage charge of 85% during the winter season recommended by the Grin Tech staff. Even with 85% the self-discharge is high enough to require charging every 30 days to keep the BMS low voltage cutoff from shutting the battery down - been there done that.

OK, what voltage are you calling 85%? I’ve never had a Grin use 85% as a storage voltage. 50% is a typical suggestion. I’ve never seen any of my batteries over 6 years to self discharge to BMS shutoff.