Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Keith]

I'd like to be able to check the state of charge of my packs while they are off the bike. Doing that would require getting the contactor to close and using a voltmeter. I've been through the wiki and searched this forum but I can't find anything specific for the modular pack enable logic. Charging off bike is done with a simple connection to the QuiQ that is just three wires, V-, V+ and enable. The adaptor also has a jumper that must be present or the contactor will not close. Measuring the enable wire during charging shows about 1V above V- when connected and charging and about 3.5V if not connected to the pack. Ideally I'd like to convince the pack to close the contactor with a passive circuit. That would be a just a SB Smart connector with a connection for a voltmeter. But I'm guessing that the DeltaQ sources current on the enable wire that the pack pulls down to begin charging. Maybe a small battery and resistor could supply that current?

Here's a picture of the power pack adaptor wiring, I'm thinking of modifying that to allow a voltage check. I have four packs, so at times I may have three on the shelf and one in the bike. It is not convenient to shuffle the packs on and off the bike just to get charge levels, so a quick way to read voltages would be great. I could get a rough idea from the BMS LEDs but that requires removing the plug to press a reset button every time. And it only reads 25%, 50%, 75% and 100% levels, too coarse for my purpose. If the pack needs to see charging voltage then I don't think this idea is practical, but hopefully if can be done simply. Does anyone know how? I can do some trial and error but this seems like a simple question.

[Doctorbass]

If you only want to see voltage to give you a great idea of the SOC then i think one of the two main pins( i dont remember if neg or pos) and one of the small pins on the signal ping row near right will give you directly the pack voltage.
Doc

Zero work with "BMS enable" pins and "throttle enable" or "throttle engage" signal pins to activate or not the bike or battery or bms.

Doc

[Keith]

The most voltage I could find is 12V from P1 to V-. About 3V to V- on some other pins. It seems like the contactor needs to be closed first. Or maybe some other condition to enable high voltage?

[Doctorbass]

The most voltage I could find is 12V from P1 to V-. About 3V to V- on some other pins. It seems like the contactor needs to be closed first. Or maybe some other condition to enable high voltage?

No, contactor dont need to be closed to see voltage of the pack. the pack voltage is present on one of teh NEG or POS and one of the little pins i'm 100% sure as i tested that

Doc

[Keith]

I found it! That pin is very corroded on my packs, black in color, so dark that I thought it was not installed, invisible against the black plastic housing. It is S1, the top left female contact, opposite the V- contact. Maybe that corrosion is part of my isolation issues. So, now that I know, checking voltage is very simple, nothing to build just probe the right pins. Thanks Doc!

But I would like to be able to close the contactor. That would make it possible to use the packs to drive an inverter, much handier than using a generator during a power outage. I don't know if anyone has done that with these packs, but I've seen comments that suggest it is possible by feeding an inverter with the high voltage DC at the point before AC conversion is done. I've looked but have not found an inverter that is designed for ~100V DC input.

[Doctorbass]

Add dielectric grease to all pins that you see corrosion! this will save you alot of problem.

Doc

[Keith]

OK, I've done it, got the contactor to close. As I suspected a battery and resistor on the enable wire does the trick. Here's a diagram for those who are interested.

I've been using dielectric grease on these connectors. Interesting that the high voltage affects corrosion, the other pins look fine.

[BrianTRice@gmail.com]

Nice. I've added this to http://zeromanual.com/index.php/Advanced_Modifications#Charging_Off_Bike

[Keith]

I happened to see that in the manual just as I was telling a friend about it, thanks Brian. I have to say it is a thrill to light up a 100W bulb from a pack and know it will stay lit for a long time. I also like the work you did on the charging options table, very nice.

[Keith]

Here's how to measure the voltage and get a rough conversion to state of charge. The graphs are approximate, derived from MBB log file data.

[Cama]

Here's how to measure the voltage and get a rough conversion to state of charge. The graphs are approximate, derived from MBB log file data.

Thanks for sharing your knowledge, Doc and Keith.

Is the link between voltage and state of charge different from 2 brick to 4?

My 4 brick (Zero SR 2016) is @ 88,8 V by 0 % stafe of charge.

[togo]

Here's how to measure the voltage and get a rough conversion to state of charge. The graphs are approximate, derived from MBB log file data.

Awesome!

But isn't there a difference between voltage under load and voltage when charging? I think the chart should have two lines.

[Keith]

Maybe two lines isn't enough! The red line is this morning's very careful attempt to get super accurate data. No load, no charge current, identical conditions. I started with a single full pack and stopped every time the dash indicator dropped by 5%. Left the bike on, verified the dash display, read the voltage at the external charge connector twice, wrote down the reading and rode the next 5%. Took it down to 0% and rode some more. 22 data points with 4 digit accuracy. Except it isn't that simple. I'll get the log files of this ride and subsequent charging and scratch my head some more later.

[togo]

Maybe two lines isn't enough! The red line is this morning's very careful attempt to get super accurate data. No load, no charge current, identical conditions. I started with a single full pack and stopped every time the dash indicator dropped by 5%. Left the bike on, verified the dash display, read the voltage at the external charge connector twice, wrote down the reading and rode the next 5%. Took it down to 0% and rode some more. 22 data points with 4 digit accuracy. Except it isn't that simple. I'll get the log files of this ride and subsequent charging and scratch my head some more later.

Awesome!  Thank you!

A cluster of lines in a chart representing different discharge and charge conditions would be most informative.  I've had the biggest SoC drifts when I've had a variety of riding conditions and partial charges, definitely constant highway driving draws with a very differnt level of accuracy vs stop and go or mountainous twisties, but I haven't been able to coorelate.  Thank you so much for your systematic approach, and for sharing the results.

[Keith]

Here is all of the glorious voltage data from my MBB and BMS logs during my test ride and charging. Conditions are a single pack, 2016 FX, riding between 5% SOC dash increments from 100% to 0%, and charging at 18 amps. Note that the dash SOC display does not match the log SOC numbers as can be seen in the stopped points. MBB, BMS and DVM voltages agree closely. This was done in sport mode. I am surprised by the amount of regen shown in the battery amps but the test was done on mountain twisties. I now think that the slight rise in voltage seen at lower SOCs is probably due to the raised pack temperature. So a more accurate voltage to SOC conversion table for off bike stored packs would require controlling the pack temperature for each measurement.