Brammo Owners Forum
Brammo Enertia Discussion => Brammo Enertia Plus => Topic started by: seanmcp on October 19, 2010, 01:22:48 PM
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Electrical Engineering Background here so I'll ask nerdy questions hopefully someone has real technical data for:
What are the peak & sustained current draws during a recharge of the Plus from as close to empty as the cells get when charging with the stock (onboard) charger? Please provide data for both 200-240V single phase 2-pole (a dryer-style plug which I see mentioned as supported) and 120V single phase single pole standard household lighting circuits (commonly 15A max, with 12A usable sustained max).
I ask as I'm trying to see if I can induce coworkers here into these units, and if so, I'd need to build my own charging rig(s). I manage several facilities with capacities in the MW range each, so a few kWh here and there isn't an issue, but I do need to plan accordingly for the charging station layout and being able to quantify the numbers for an accounting standpoint.
Currently (no pun intended), since I haven't seen any real data, I'm basing my scratched notes on an 800-900W charger which'd be the 'right' size for a unit to both handle peak draw for that size of pack and provide enough juice to 'finish it' in ~8 hours. The good thing (well, one of many) about LiIons are they accept charge better than old Lead Acid cells with less loss. A good 90+% load-side efficient 850 watt unit could push right at 6 kWh into a cell in 8 hours if it could do it in a perfectly flat supply, but sadly, the real world is messier than that. Luckily, 12A @ 115V nominal = 1.38 kW so there's plenty of 'slack' on a 15A lighting circuit to handle the initial part of the charge curve. I know, the engineers there did all this math before, but I wondered how 'close' they came to the line and how long they 'stay there'. UL listing means I don't have anything to worry about, obviously, from a safety perspective, but I do have to figure out what my load profiles for multiple guys charging up in the AM will look like, and that's the curve I am missing ATM.
That said, few things are more fun than being an electrical geek and finally feeling like it's the right time to buy a VERY practical electric motorcycle! Thanks, Brammo :)
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Unless somebody from Brammo speaks up you're not going to be able to get that info as there aren't any of these "in the wild".
From an Enertia standpoint only 120V is supported (stock at least) and the display indicates 8-9amp draw and an estimated charging time (on the display) of about 3 hours (from 10% remaining). My Kill-A-Watt typically shows around 3.2 kwh for that.
Hope some of that is useful to you.
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Supposedly the Empulse also supports Level 2 charging...I wonder if the Enertia Plus will have that as an option.
Right now there isn't much level two charging available, but that will change fairly fast. I plan to install level two charging in my garage this Janaury if I get my LEAF, or if I cancel the LEAF, at least before I get the Fiat 500 EV in 2012 (which is the car I really want).
Not at all a deal breaker...the Enertia doesn't NEED level 2 charging to be a wonderful commuter. But I imagine that future versions likely will support level 2 charging, and it would be a welcome add on if Brammo made it available to the current model coming in the Spring.
Gavin
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Is the 8-9A sustained w/o a drop for the duration of the charge, except the tail off? That's 960-1080W from the plug to the input side of the charger, so with decent efficiency that's 875-975W to the cell. 8 hours @ 875W would be 7kWh of total output juice from the charger, and the LiIons accept charge pretty readily VS lead acid. It's just hard to know w/o having my own meter on one or someone reporting what their killawatt says hour by hour if there's an initial hard charge at say 1000W from the charger which drops over time evenly, or if it's more varied. I'm enough of a nerd I'd happily walk by my killawatt every 15 minutes for 8 hours and record current draw (well, I'd use one of my logging meters and let it do the work, but you know what I mean *grin*).
One of the news articles today about the Plus mentioned 120 & 220V charging (they mentioned 4 hour charges using a dryer outlet, as their analogy, but media tends to have the least technical view on things), which made me hope for the 220 ability to be onboard. Added complexity, sure, but I was hopeful. The majority only mention the standard charging circuit, so I'll assume I'm stuck with low and slow. That's just fine if I build a charging location for multiple folks, as I'll just hang a small subpanel worth of feeds in a parking area for them and spend a few bucks painting 'Employee EV Parking' on the concrete pad :)
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The few times I've checked on it during the main charging cycle it has been the same draw. It would seem to need to be that much continuously in order to draw 3kwh in 3 hours. After the main charge it will go into "balancing mode" which according to Brammo draws about 50w.
I wouldn't be surprised if the Enertia Plus (or the Empulse) can charge off either 220v or 110v. Going from 8 to 4 hours would have a lot more benefit to sales/marketing than going from 3 to 1.5 hours, plus for the Empulse the 10.0 pretty much demands 220v charging.
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Sean,
Since the Enertia will now have a 6 kwh pack just like the Empulse 6.0. It's very possible that the Enertia Plus may also have 220 V charger as an option. The Empulse 220V charger is APPROXIMATELY 2666 watts. It is not built into the bike. It is a stand alone charging unit as Brammo does not have room on the bike for it.
GSB
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One of the articles written about the Plus went out of the way to point out that there will be NO Level Two charging only 110 volt Level One. If this is true it is a little sad because virtually all of the chargers that are being put out on the market and installed at malls and other public places for the coming Leaf and other EV's will only be Level Two. So this means that IF the Plus charges only at Level One, we will be hunting for Coke machines to unplug at public places.
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:)...I can see warm cokes all over America in the coming years
as a solution I have one word:
adaptors
All SAE J1772 level 2 chargers plug into a standard plug at the car/bike end...all LEAFs and whatnot can charge at 110 or 220 in the same plug...adaptor will just dumb down the 220 to 110.
That said, level 2 would be nice.
Gavin
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Wow! Cool (and scary) to see our customers getting so smart about all of this EV technology! I like to think that Brammo has the smartest, most informed EV customers in the world. Great questions, Sean... I'm excited to learn more about what you're up to.
I'm actually not an EE, but I'll do my best to pretend... ;)
The Enertia Plus will be fit with an 850W on-board charger that will charge from a typical 120V/15A household outlet. As you've mentioned, 12A is the maximum current draw to leave appropriate headroom on the line. During the beginning of the charge cycle with the bike near full discharge, the charger will draw 12A for perhaps the first 5-10 minutes, then it tapers off to a fairly consistent 10A for the bulk of the charge. From about 95% onwards, it enters constant voltage mode and the current will begin to drop off to less than 1A at 99% SOC.
Highlander's bike doesn't quite match this as he and I have 720W chargers on our bike. These typically do not pull the 12A and hover around 9A for the bulk of the charge.
At this point, it looks like the Enertia Plus and the Empulse will have a custom connector accessible that will allow them to be "fast charged" from a Brammo off-board charger. The first fast charge stage will allow you to charge at 17A with the charger plugged in to an 120V outlet upgraded to a 20A breaker. The second stage will allow charging at 34A with the charger plugged into a 240V single phase household dryer outlet. This project is still in the works, so I may be revealing too much too soon, but I figure you guys (and gals) are here to get the inside scoop, so now you've got it...
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Sweet...have a separate dedicated 240v line sitting in my garage just waiting for the EVs to arrive :)
Gavin
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Brian,
Responses like this are why I've been lurking on the forums for so long and have devoured everything I could find on the Brammo bikes for a couple of years; I think Brammo has the level of "We *like* our customers" that many companies lack these days, and I like to support that (with kudos *and* actual money)! I'm biased, of course, since I'm also one of those 'start your own business and/or work for one because of the customers and because you like what you do for them' geeks which Brammo seems to be well-populated with. So, first and most importantly, thanks for being involved with customers/potential customers (I haven't bought the original Enertia due to, you guessed it, range anxiety, and the Plus just dealt with that handily!).
On to the topic at hand! If the 20A/120V single-phase/single-pole 'faster' charge option and even better 50A/240V single-phase/double-pole 'fastest' charge option are available, I'll happily become an advocate for and push for us to install setups for these for employees (and possibly customers, depending on legal liability type issues) at my company's various facilities on the East Coast. Electricity is something we use quite a bit of (ie, each of my 20 current sites are multi-MW locations), and have plenty of expertise in deploying it, and we're almost all huge proponents of efficiency gains. The higher-current/higher-voltage chargers are what really make the Electric Motorcycles the most tenable, and I'll happily buy (at an additional charge, as expected) an extra off-board charger to enable me to take advantage of quicker recharges at my one or 2 most common charge spots and have the maintained flexibility of charging at 'normal' outlets as needed.
Again, thanks for the response, and also thanks for the info on the *possible* options coming for charging; I can assure you that if an off-board higher-speed charger is available at any reasonable cost, I'd buy at a minimum one and possibly 2 just for myself, and I'd expect many would do the same if they had locations where they could be deployed!
Sean McPherson
Wow! Cool (and scary) to see our customers getting so smart about all of this EV technology! I like to think that Brammo has the smartest, most informed EV customers in the world. Great questions, Sean... I'm excited to learn more about what you're up to.
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At this point, it looks like the Enertia Plus and the Empulse will have a custom connector accessible that will allow them to be "fast charged" from a Brammo off-board charger. The first fast charge stage will allow you to charge at 17A with the charger plugged in to an 120V outlet upgraded to a 20A breaker. The second stage will allow charging at 34A with the charger plugged into a 240V single phase household dryer outlet. This project is still in the works, so I may be revealing too much too soon, but I figure you guys (and gals) are here to get the inside scoop, so now you've got it...
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Wow! Cool (and scary) to see our customers getting so smart about all of this EV technology! I like to think that Brammo has the smartest, most informed EV customers in the world.
OK here's a piggyback question (that may very well crush Brian's assumption of smart customers): what happens when a customer takes the bike to Europe? (a very real scenario for me as I might be moving there mid-late next year.) Do you need another type of off-board charger for this, or the one mentioned by Brian should do at the 220V 50Hz current? so I guess the full question is: is it possible to charge a "stock" Enertia or Enertia Plus in Europe, if not, what mod or additional equipment is required?
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Another good question...
The on-board charger will work with standard mains voltage and frequency in Europe, but you won't be able to charge any faster. The output is still limited to 850 Watts although you would technically have more power available on European mains supply.
You would just need a charge cord with the appropriate end to plug in to an EU outlet. The input to the charger under the seat, where the other end of the charge cord plugs in on the Enertia (and Enertia Plus) is universal.
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During the beginning of the charge cycle with the bike near full discharge, the charger will draw 12A for perhaps the first 5-10 minutes, then it tapers off to a fairly consistent 10A for the bulk of the charge. From about 95% onwards, it enters constant voltage mode and the current will begin to drop off to less than 1A at 99% SOC.
I made a slight mistake on my response here... the current reported by the bike on the dash is actually DC output current registered by the batteries. Thus, you'd need to know that we charge at roughly 86 volts in order to determine the wattage being pulled from the wall outlet. The rms current will, of course, be lower than what the bike reports on the DC side.
I should have said "the charger will OUTPUT 12A for perhaps the first 5-10 minutes..."
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Okay, my experiment this morning is relevant to this discussion. I have a Kill-a-watt meter and was watching the amps. Yes, it was measuring 12-10A when I first initiated the charge. Then, it was in 99%SOC and well into the charge-balancing mode. It was about 1A to 1.7A. Then, I turned the key to the "off" position, ending the charge. I looked at the Kill-a-watt meter: 1A. Something is still drawing power from the wall. Was it just the meter itself? Easy to find out - I unplugged the bike. 0A.
So, why is there still a trickle coming into the bike when charging mode is off? Vast conspiracy of collusion between the power companies and Brammo, or a simpler explanation?
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a simpler explanation?
I give it a try.
If you turn the key to the "off" position, you disconnect the charger from the battery managment system but the charger stays connected to your power outlet. As long as the charger is connected, it will pull a small zero-last electric stream.
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The second stage will allow charging at 34A with the charger plugged into a 240V single phase household dryer outlet. This project is still in the works, so I may be revealing too much too soon, but I figure you guys (and gals) are here to get the inside scoop, so now you've got it...
Thx for the input Brian.
Fast charging is where it's at w/ all EV's. Look at the Leaf w/ 50 kw of charging (2C). With the charging rates you guys have posted on your website (empulse) you are only charging at 1/3 C and we all know even the slowest recharge rate for a Li bat is one hour (1C).
Since you guys have an OFF BOARD charger this actually gives you a little flexibility:
If you are going to charge at 34 amps and around 90 Volts for the 6.0 I would suggest for the Empulse 10.0 you hold the current the same and just increase the Voltage from the 88 V for the 6,8 to 111V for the 10. This would basically allow you to keep the same wire sizes but at the same time increase the power output of the charger to 3740 watts from about 2900 watts. It's a win win from both the customers and mfg/cost point of view. You guys can keep your mfg cost down and the customer gets a faster charge!!!
GSB
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I will ask the following understanding that "the project is still in the works" and there may not yet be an answer or Brammo may not want to answer:
1. What I'm inferring from the discussion is that there will possibly be an optional charger available from Brammo that will allow a faster charge for the Enertia + by plugging this device into a 240V outlet that one may have at their house or workplace and then plugging in the Enertia + into that device which will reduce the time that it would take using the standard 120V plug straight into a 120V outlet. Is this the correct conclusion?
If this is correct, will this device have an adapter that can fit on a SAE J1772 plug which is the new standard for all chargers in the U.S.? For instance, will you be able to take this device along with you and pull into the mall or workplace where there is a new J1772 charger with Level Two charging and use the optional Brammo device to connect to the J1772 charger or will you need access to a standard AC 240V 3-prong plug receiving wall outlet like one has for a household dryer, etc?
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George,
The Enertia Plus and Empulse use an 88.8 Volt nominal battery. This means that they charge at just over 100V. I'm not familiar with the Leaf's fast charginig, but we typically like to see charging rates no greater than .5C to prolong the cycle life of the batteries. Nissan may have a cell that is more tolerant to "fast charging", but there is no doubt that the cycle life will be less than if they were charging at a lower rate.
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If this is correct, will this device have an adapter that can fit on a SAE J1772 plug which is the new standard for all chargers in the U.S.? For instance, will you be able to take this device along with you and pull into the mall or workplace where there is a new J1772 charger with Level Two charging and use the optional Brammo device to connect to the J1772 charger or will you need access to a standard AC 240V 3-prong plug receiving wall outlet like one has for a household dryer, etc?
The 220v charger for the Enertia plus and the Empulse, according to Brian, Is an OFF BOARD charger. If you are going to charge at work, you will need to keep a charger at work or carry it with you. You would then plug this charger into a standard 220V, 40 amp (or 50 amp) outlet. Since the J1772 plugs put out 220VA/C I suppose Brammo could put a receptacle on their off board charger that would accept the J1772 handle but you still have to have your own Brammo offboard charger. The J1772 charging system is for EV's with an ON BOARD charger.
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George,
The Enertia Plus and Empulse use an 88.8 Volt nominal battery. This means that they charge at just over 100V. I'm not familiar with the Leaf's fast charginig, but we typically like to see charging rates no greater than .5C to prolong the cycle life of the batteries. Nissan may have a cell that is more tolerant to "fast charging", but there is no doubt that the cycle life will be less than if they were charging at a lower rate.
Brian,
The Empulse 10. is 111 V while the 6 and 8 are 88. So if you have a charger that puts out 34 amps to the battery at 100 volts for the 6 and 8, You will need to have a charger that puts out a around 120V for the 10. If the 10. charger is 34 amps to the battery (like the 6.0 and 8.0) and the required 120V DC (for the 10.) this gives you a charger that is around 4080 watts and you will be charging at less than .5C. --GSB
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Since the J1772 plugs put out 220VA/C I suppose Brammo could put a receptacle on their off board charger that would accept the J1772 handle but you still have to have your own Brammo offboard charger. The J1772 charging system is for EV's with an ON BOARD charger.
The issue here is all the UL listing crapola once you start plugging A into B into C :) Sadly, lots of things make perfect sense from an electrical PoV but legalese gets in the way!