Rode my Lectra motorcycle for the first time in awhile yesterday, and the range was very bad. I'd put it on the charger just before leaving but almost immediately the pack read as being very undercharged. It's a 60v SLA pack but the Cycle Analyst showed 48 volts or so while riding, and in the past I'd only see that voltage at the end of a ride. And yes 48v is less than 10v per battery, so any time it got that low was a dangerously deep discharge.
Last year (when I was employed and had a job to go to) my 10 mile commute caused a very deep discharge and pack voltage routinely going below 50v while riding by the end of the ride. I knew it was damaging the pack and have been keeping an eye on it the whole time. However this year I've not been riding it so much and the bike has been sitting idle.
I have a paktrakr installed on the bike as well as the cycle analyst. The cycle analyst shows pack voltage and other measurements. The paktrakr shows per-battery voltage and other measurements, but I keep it on the per-battery display. It showed that the #1 battery had much less voltage than the other four batteries.
After the ride I put it on the charger overnight and this morning it was still charging. Hurm. Turned off the charger and the paktrakr reported 14v per battery except for #1 which was 13.2v and but that voltage was dropping rapidly.
This means #1 battery is not holding a charge, while the others seem to be holding a charge. The other batteries might be suffering from a bit of overcharge cooking.
I have a bit of testing to do to verify ..
a) put #1 battery on a 12v charger for awhile and see what it does
b) use the 12v battery load tester to see what the cells are doing
If it still remains that #1 battery is dead, I have a temporary stopgap idea to install another 12v battery I have lying around into the pack. That battery might not be in too good a shape either but should keep the bike ride-able for awhile. As it is the bike is not ride-able. It can also be used to test the 48v20ah headway pack I have.
Longer term I want a LiFePO4 pack and have worked out the geometry for an 80+ volt pack at 60ah, but there's a little issue of employment and money..
the paktrakr draws the power needed to run off the fist battery for the lead acid variant.
only use the paktrakr whenthe vehcile is actually running or it will pull your pack out of balance.
its likely the paktrakr over discharged the first battery while sitting idle, and then the string charger overcharged the remaining batteries when you went to recharge.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Oooooohhh... good point. I hadn't installed a switch on the paktrakr until recently, and yes it was left on.
I've been using not a pack charger (a.k.a. string charger) but a pseudo bank charging setup. This involved three chargers, 2x 24v and 1x 12v. But I'm not sure that these chargers are working any more, and it's possible they got rained on. At the moment I'm using a pack charger.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Maybe not as bad as I thought. After sitting for a few hours the pack read #1: 12.8 volts, #2-5: 13.1 volts. #1 is on a 12v charger and will be checked after awhile.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Took quite awhile but eventually #1 battery became 14 volts, and removing the charger it slowly dropped to 13.2 volts. Took it over to a meeting, about a 3 mile ride, and the pack behaved as usual. #1 battery did not dip dangerously low.
Probably the case is that #1 battery was just undercharged for some reason. But I thought I'd already balanced the pack. It will take some more watching.
Also for the ride home - the meeting was on Google's campus, and I made sure to park in one of their electric vehicle parking spots. What they have is solar panels on carport installations spread all around their campus, and in most of them there is an interesting model for electric vehicle parking. They have power cords hanging from the carport on spring retractable thingies. You pull into a parking space, pull on the cord, extend it to where you need it to be, and plug it in. Very simple. I really don't know why anybody thinks electric vehicle recharging needs to be any more complex than that. Anyway, parked the motorcycle there, plugged in and let it recharge while in the meeting. Very cool, thanks Google, I'll go click on a couple ads. Curious thing - on the way out I noticed a Tesla Roadster in the same carport but it wasn't plugged into the power cord. Mebbe the on-board charger can't take a 120volts power cable?
For the ride home the pack appeared properly balanced, no problem with it, I was even pretty strong on the throttle enjoying full acceleration and not a problem.
It appears the core is that the paktrakr sucks juice out of battery #1 and you really need an easy way to turn off the paktrakr when the vehicle is parked. Unfortunately the paktrakr manuals didn't manage to get this across to me -- maybe it says this, but I don't remember it saying so.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Good to hear the battery still has some life, it will likely still be the first to fail though.
in the manual, it does state the first battery loses around 5ma (10ma for the module the display is run off, more if you have a data logger) more than the rest of the batteries.
Thats 0.24Ah/day of imbalance.
i use a relay (driven from the dc-dc through the "ignition") that switches the first wire on each paktrakr module on/off with the bike.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Isn't it 0.12Ah / day instead of 0.24Ah?
When I was planning to include a Paktrakr8 into the M-BMS I thought I'd give it a dedicated NiMH cell to drain on channel 1.
Like this: M-BMS with Paktrakr8 Switch Array
That allows to use the Paktrakr without causing imbalance.
This information may be used entirely at your own risk.
There is always a way if there is no other way!
Left it on the charger overnight again. This morning the charger was on float, the voltages were #1: 13.4v, #2-5: 13.8v. Clearly the #1 battery has some weakness. After a couple hours off the charger the voltages are all 13.2v.
I'm thinking powercheq's are in order.. but that I want to switch over to LiFePO4 when conditions warrant.
In my case everything is turned on and off manually. Not the best idea especially as sometimes I forget to turn on the lighting system. On the new bike I'm building up the ignition switch is going to drive the whole system.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki