RoyPow Lithium upgrade questions

[Sergio]

A lot of shops seem to struggle with technology in general and lack a good understanding of the basic principles involved.

Until the recent "P" versions of RoyPow, the existing models did not handle Regen (charging) current very well.

If the Controller was set for too much Regen brake current and the Controller was improperly configured and allowed more battery regen current than the RoyPow internal BMS could handle, You could burn the Controller.

The issue is typical of drop-in lithium boxes with internal BMS that have no way to disable the cart in order to stop the excessive regen current and instead just disconnect the battery from the circuit.

Disconnecting the load (battery) when the Controller is on Regen brake operation can raise the voltage instantaneously to a very high level and damage the controller internal components.

The newer "P" models, the performance pack they mentioned, has a new replacement load (a very big external resistor), the RoyPow internal BMS can use to dissipate the excessive Regen current instead of removing itself from the circuit.

You can also disable Regen entirely or configure the Controller to stay within the limits of the lithium pack and it does work as well.

[RNajarian]

Thanks Sergio that makes perfect sense. So I assume, these issues do not affect series carts, and either RoyPow setup would work for them.

[derekfertig]

Originally Posted by Sergio

A lot of shops seem to struggle with technology in general and lack a good understanding of the basic principles involved.

Until the recent "P" versions of RoyPow, the existing models did not handle Regen (charging) current very well.

If the Controller was set for too much Regen brake current and the Controller was improperly configured and allowed more battery regen current than the RoyPow internal BMS could handle, You could burn the Controller.

The issue is typical of drop-in lithium boxes with internal BMS that have no way to disable the cart in order to stop the excessive regen current and instead just disconnect the battery from the circuit.

Disconnecting the load (battery) when the Controller is on Regen brake operation can raise the voltage instantaneously to a very high level and damage the controller internal components.

The newer "P" models, the performance pack they mentioned, has a new replacement load (a very big external resistor), the RoyPow internal BMS can use to dissipate the excessive Regen current instead of removing itself from the circuit.

You can also disable Regen entirely or configure the Controller to stay within the limits of the lithium pack and it does work as well.

Thank you for all of this! Has anyone in S. Fla had any luck getting these things installed at a local shop here?

[Sergio]

On a Series cart You still need to limit the "battery amps" to be less than the RoyPow maximum discharge, which is also considerably higher on the "P" models.

The motor "Armature Current" can be higher than the "battery amps" but less than the maximum amps the particular motor can handle.

The Navitas controller appears to have more granular parameters to deal with how to limit the battery current, like max amps per number of seconds, but those limits on the battery specifications have more to do with accumulated heat mitigation than hard set specifications so if you are trying to push the limits you also need to take in consideration external parameters that will influence how often you are reaching those limits.

Most of the drop-in lithium packs on the market seem to have been designed to replace the batteries for a "golf" cart usage and not off road with large tires or extra seating/cargo.

While I built my own Leaf cell pack instead of purchasing a drop-in pack, if the price was right, the S51160P looks like a good option for a golf cart application that involves a higher baseline current demand.

[Wakko47]

Originally Posted by derekfertig

Thank you for all of this! Has anyone in S. Fla had any luck getting these things installed at a local shop here?

The only shop I've found around here that seems honest and reliable is Jupiter carts. There are two dealers in Delray, but I've only been to the one on Military, and they didn't seem to do custom...just dealer stuff.

Are you all thumbs, or do you think you can do it yourself? PingEye is a member here in Orlando, and he's another whiz with lithium...not sure if he can/does work on other people's carts.

[simicrintz]

Originally Posted by Sergio

if anything is "frying" is due to lack of knowledge on the part of the installer.