This question doesn't relate to an e-bike, but an electric scooter (Dualtron Spider)
Hi, I was reading through the sticky in regards to parallel battery setups, and my plan is to run two 16S5P packs (one pack is LG MJ1 with 10 cycles and is internal to the scooter, and one pack is Sanyo GA cells with no cycles) in parallel, both with their own BMS. Everything makes perfect sense to me (don't let the two packs resting voltages deviate too much from each other, etc)
The reason I decided to run the packs in parallel instead of as a second battery to switch between is due to the fact voltage sag is pretty rough on a single battery (it could draw upwards of 54A peak and 30A sustained, at maximum settings you can see 10V of sag) where running them in parallel would also run them cooler and have a lot more headroom.
My questions:
What exactly would happen if I charged through the scooter with both batteries connected in parallel on the discharge? If I connect 2x 2A chargers directly to the scooter which is directly connected to the MJ1 pack, would the MJ1 pack in essence, de facto charge the external pack? Given the total input current is no more than 4A, I can't see that doing any damage at all considering the scooter will be off during the charging process.
If this is confirmed to not be harmful, how would this question play if I were to up the input current to 8A? (The scooter's spec sheet indicates that up to 8.4A charging is acceptable). I don't necessarily mind charging the batteries separately while disconnected, but when one of your use cases would be to cover extremely long distances, sometimes doing so may not be plausible. Would not fully charge the cells if using the 8A charger, I have a Charge Doctor to cut the charge when voltage hits 64-64.5V.
Second question is if both batteries have separate input lines, can't we parallel those lines together as well so that we can charge from a single source with the discharge connector off, or is that a waste of time?
Thank you so much in advance for any guidance you all may provide!
Hi, I was reading through the sticky in regards to parallel battery setups, and my plan is to run two 16S5P packs (one pack is LG MJ1 with 10 cycles and is internal to the scooter, and one pack is Sanyo GA cells with no cycles) in parallel, both with their own BMS. Everything makes perfect sense to me (don't let the two packs resting voltages deviate too much from each other, etc)
The reason I decided to run the packs in parallel instead of as a second battery to switch between is due to the fact voltage sag is pretty rough on a single battery (it could draw upwards of 54A peak and 30A sustained, at maximum settings you can see 10V of sag) where running them in parallel would also run them cooler and have a lot more headroom.
My questions:
What exactly would happen if I charged through the scooter with both batteries connected in parallel on the discharge? If I connect 2x 2A chargers directly to the scooter which is directly connected to the MJ1 pack, would the MJ1 pack in essence, de facto charge the external pack? Given the total input current is no more than 4A, I can't see that doing any damage at all considering the scooter will be off during the charging process.
If this is confirmed to not be harmful, how would this question play if I were to up the input current to 8A? (The scooter's spec sheet indicates that up to 8.4A charging is acceptable). I don't necessarily mind charging the batteries separately while disconnected, but when one of your use cases would be to cover extremely long distances, sometimes doing so may not be plausible. Would not fully charge the cells if using the 8A charger, I have a Charge Doctor to cut the charge when voltage hits 64-64.5V.
Second question is if both batteries have separate input lines, can't we parallel those lines together as well so that we can charge from a single source with the discharge connector off, or is that a waste of time?
Thank you so much in advance for any guidance you all may provide!