Okay, I've got the puzzle for you! I"m an experienced e-trike builder, been doing it since 2006. I keep a detailed log so buckle up.
Current set-up: one power main goes to 2 Phaserunner motor controllers to 2 hub motors.
I generally run off of a pair of LiFEPO4 bricks at one time. They run in parallel and so are connected to each other. They are exact twins in every way possible. Each pack has 25A fuse on the positive line. I have experienced a sudden failure twice over the last 2 years with my main pair and with no warning. The second time is the bigger mystery.
New pair of 36V 30Ah batteries with 50A BMS' from known Amazon seller incorporated
into my personal trike power system on 10/6/18. Also, due to ahem a little accident involving saltwater, also new motors and motorcontrollers. New system running at max 50A, vs old system was closer to 42.
All is well for one year. On 10/9\19, driving on the flats at full speed at dusk, about 2.5 miles into the journey, sudden system failure. V flashes on the CycleAnalyst (CA) display and the the whole system turns off as I coast to the shoulder of the road.
As it turns out, my automotive key switch (rated to like 35or 40A) has fried, after 4.5 yrs of faithful service. To be clear, I was running ALL power through that switch.
I bypass the switch, but the CA prevents me from turning the system back on, because one of the batteries has been suddenly drained to below 29V.
Upon closer examination, I find that one of my two batteries has one of its two Anderson connector pins pushed back, preventing full contact on both pos and neg terminals. I am able to limp home on the remainimg battery. I failed to record which of the two batteries drained, whether it was the one with the bad connection or the one with the good.
After recharging them, the Left Battery was showing 39.7V at rest and 36.2V under load, and the Right battery was showing 40V at rest and 37V under load. This is before extended cell balancing. Four months later, using only the CA as a measuring device, the L batt showed 0.77 ohm resistance and likewise the R batt the exact same when connected separately. I did not document if this was at rest or under load. As you can see, my concern at the time of the incident was that that connector problem on one could have caused the twins to have an imbalance.
This first time, I am theorizing that the switch frying caused the sudden battery drain of the only battery that was solidly connected. But it is a chicken and egg problem as I dont know what happened or what caused what, only that there was no overheating issue or excessive system loading at the moment of failure (at full speed on the flats I am drawing about a third to half of max Amps)..
What happened? Your theories and explanations are very welcome here.
Fast forward now to the bigger mystery.
I installed a new Glide Cruisers switch which has a proper 50A relay and off I went, fast forward ANOTHER year of frequent journeying ( my Frankentrike is my principal mode of transport) with no issues.
On 11/3/20, I am on an unplanned (yes) bike camping trip. So i have borrowed a sleeping bag and I dont have chargers with me, just barely enough power for the total trip between my main set and my backup set.
I sleep overnight in the bag, no tent. It is California after 9mos of no rain so everything is bone dry even the sleeping bag has hardly any dew on it at dawn. I am 35mi away from home. I bid friends adieu (need to get home in time to vote!) and start along a road with gentle rolling hills. I am running at 25A at 15mph (vs 50A and 24mph) to conserve power. About 3miles into the return journey on a mild uphill running at half throttle with barely warm batteries, V starts flashing again oh no! total power failure. CA turns off.
I check connectors, seem okay no signs of sparking and pin alignment is solid. I try each battery separately and neither one can power the CA. Thats bad! The pair was at 37.9Ah when they failed and they showed a normal voltage before the sudden fail. Recall that they are 2x30 so thats 60Ah of range and I regularly get a comfortable 56 Ah out of them in the rare moments that I take them all the way.
Everything including the switch still works so I plug in my backup pair of batteries and pedal hard to get home with half of the banked power available.
Upon returning home, I get out the multimeter but its Radio Shack ass has finally kicked the bucket. I order a Fluke off ebay and charge all the batteries, keeping a close eye for overheating or swelling.
Fluke arrives a week later, by then cells are fairly balanced.
When I plug in my back up pair, the Phaserunner LEDs remain solid, as they should;, but when I plug in either my L or R battery that failed on the trip, the Phaserunners flash a 1—6 pattern, which is supposedly a Motor Hall Sensor Fault. Huh?
However, they are now able to power the CA, lights and horn so I decide to take them on a test run around the block. Both batteries work as tested separately, and after each is run for a minute, the flashing error code stops and is replaced by a solid ' on' LED.
The R battery measures 42.6A via Main or BMS wires after top up and the L battery measures 42.5A via Main or BMS wires after top up. The R later showed 39.9V at rest and 36.2 V under 25A load with .127 ohm resistance showing on CA; the L similarly showed 39.9V at rest and 36.1 V under 25A load with .126 ohm resistance. At 41 cycles, this is still a fairly new set of batteries.
Okay experts, what happened, especially the second time? I had ZERO equipment failures and no fuses blew. Why did my remaining 18ah of range suddenly evaporate in a flash? I think this could be any ebikers worst nightmare. It would be like filling up your gas tank and getting out to the middle of Death Valley and then discovering that your tank had a hole in it and your tank is empty!
I am not an electrical expert, but I'm not dumb and I've been dinking with this tech for 14 years. I am at a loss.
Segue
Current set-up: one power main goes to 2 Phaserunner motor controllers to 2 hub motors.
I generally run off of a pair of LiFEPO4 bricks at one time. They run in parallel and so are connected to each other. They are exact twins in every way possible. Each pack has 25A fuse on the positive line. I have experienced a sudden failure twice over the last 2 years with my main pair and with no warning. The second time is the bigger mystery.
New pair of 36V 30Ah batteries with 50A BMS' from known Amazon seller incorporated
into my personal trike power system on 10/6/18. Also, due to ahem a little accident involving saltwater, also new motors and motorcontrollers. New system running at max 50A, vs old system was closer to 42.
All is well for one year. On 10/9\19, driving on the flats at full speed at dusk, about 2.5 miles into the journey, sudden system failure. V flashes on the CycleAnalyst (CA) display and the the whole system turns off as I coast to the shoulder of the road.
As it turns out, my automotive key switch (rated to like 35or 40A) has fried, after 4.5 yrs of faithful service. To be clear, I was running ALL power through that switch.
I bypass the switch, but the CA prevents me from turning the system back on, because one of the batteries has been suddenly drained to below 29V.
Upon closer examination, I find that one of my two batteries has one of its two Anderson connector pins pushed back, preventing full contact on both pos and neg terminals. I am able to limp home on the remainimg battery. I failed to record which of the two batteries drained, whether it was the one with the bad connection or the one with the good.
After recharging them, the Left Battery was showing 39.7V at rest and 36.2V under load, and the Right battery was showing 40V at rest and 37V under load. This is before extended cell balancing. Four months later, using only the CA as a measuring device, the L batt showed 0.77 ohm resistance and likewise the R batt the exact same when connected separately. I did not document if this was at rest or under load. As you can see, my concern at the time of the incident was that that connector problem on one could have caused the twins to have an imbalance.
This first time, I am theorizing that the switch frying caused the sudden battery drain of the only battery that was solidly connected. But it is a chicken and egg problem as I dont know what happened or what caused what, only that there was no overheating issue or excessive system loading at the moment of failure (at full speed on the flats I am drawing about a third to half of max Amps)..
What happened? Your theories and explanations are very welcome here.
Fast forward now to the bigger mystery.
I installed a new Glide Cruisers switch which has a proper 50A relay and off I went, fast forward ANOTHER year of frequent journeying ( my Frankentrike is my principal mode of transport) with no issues.
On 11/3/20, I am on an unplanned (yes) bike camping trip. So i have borrowed a sleeping bag and I dont have chargers with me, just barely enough power for the total trip between my main set and my backup set.
I sleep overnight in the bag, no tent. It is California after 9mos of no rain so everything is bone dry even the sleeping bag has hardly any dew on it at dawn. I am 35mi away from home. I bid friends adieu (need to get home in time to vote!) and start along a road with gentle rolling hills. I am running at 25A at 15mph (vs 50A and 24mph) to conserve power. About 3miles into the return journey on a mild uphill running at half throttle with barely warm batteries, V starts flashing again oh no! total power failure. CA turns off.
I check connectors, seem okay no signs of sparking and pin alignment is solid. I try each battery separately and neither one can power the CA. Thats bad! The pair was at 37.9Ah when they failed and they showed a normal voltage before the sudden fail. Recall that they are 2x30 so thats 60Ah of range and I regularly get a comfortable 56 Ah out of them in the rare moments that I take them all the way.
Everything including the switch still works so I plug in my backup pair of batteries and pedal hard to get home with half of the banked power available.
Upon returning home, I get out the multimeter but its Radio Shack ass has finally kicked the bucket. I order a Fluke off ebay and charge all the batteries, keeping a close eye for overheating or swelling.
Fluke arrives a week later, by then cells are fairly balanced.
When I plug in my back up pair, the Phaserunner LEDs remain solid, as they should;, but when I plug in either my L or R battery that failed on the trip, the Phaserunners flash a 1—6 pattern, which is supposedly a Motor Hall Sensor Fault. Huh?
However, they are now able to power the CA, lights and horn so I decide to take them on a test run around the block. Both batteries work as tested separately, and after each is run for a minute, the flashing error code stops and is replaced by a solid ' on' LED.
The R battery measures 42.6A via Main or BMS wires after top up and the L battery measures 42.5A via Main or BMS wires after top up. The R later showed 39.9V at rest and 36.2 V under 25A load with .127 ohm resistance showing on CA; the L similarly showed 39.9V at rest and 36.1 V under 25A load with .126 ohm resistance. At 41 cycles, this is still a fairly new set of batteries.
Okay experts, what happened, especially the second time? I had ZERO equipment failures and no fuses blew. Why did my remaining 18ah of range suddenly evaporate in a flash? I think this could be any ebikers worst nightmare. It would be like filling up your gas tank and getting out to the middle of Death Valley and then discovering that your tank had a hole in it and your tank is empty!
I am not an electrical expert, but I'm not dumb and I've been dinking with this tech for 14 years. I am at a loss.
Segue