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[MorbidBBQ]

I have a 2013S with a 2015 battery, and I was looking for specifications on the inputs ranges for the accessory charger.  I can find a used 7.5KW power supply for ~ $100.

https://www.cisco.com/c/en/us/products/collateral/switches/nexus-7000-series-switches/Data_Sheet_C78-437761.html

They are a bit too big to cart around with me, but I want to hook one up permanently at home to my NEMA 14-50 outlet.

Is this a feasible idea, or am I off my rocker?

Do people know the input specs for the accessory charging port?
The only thing I've found is the 100Amp fuse (DC or AC?).

It looks like the zero quickcharger is 96 volts.
http://www.zeromotorcycles.com/shop/index.php?main_page=product_info&cPath=15_5&products_id=194&zenid=42u6gbejhg8c7s0g4b5vgc4bu6

[MorbidBBQ]

Now that I know the zero quickcharger is 96 volts, I'm looking at other options.
A quick internet search doesn't return anything for 96volt power supplies.

What would happen if I tried to charge it at 48 volts?
Is it possible to combine 2 48 volt chargers for 1x96volt?

This is where I start to get dangerous with my limited knowledge from that elective i took a decade ago on AC/DC Circuit Design & Theory...

[Fred]

Take a look here:
http://www.electricmotorcycleforum.com/boards/index.php?topic=6405.0

[Doug S]

96 volts won't get you anywhere near a full charge...that's actually fairly depleted for the Zero batteries. Most of the chargers you'll find OTC have a way of adjusting their output voltage a bit, and they're adjusted somewhat higher for the Zero S/SR/DS/DSR. I'm not sure the exact voltages the quick-charge guys are using, but 110VDC would be a pretty safe value, with 116VDC being pretty aggressive. IIRC the onboard Zero charger terminates at 114VDC. Since fast-charging is a bit harder on the batteries, you might want to terminate somewhat earlier to be gentler on the battery.

But generally, if their output voltage can be adjusted to an appropriate value by some sort of programming or even an internal trimpot, server power supplies make excellent battery chargers. Since they're designed to be used in parallel in a large rack, they offer true Constant Current/Constant Voltage (CC/CV) operation. In other words, the power supply will try to regulate up to its voltage setpoint, but it won't put out more than its "constant current" value, even if the output voltage is significantly lower than the setpoint. This behavior allows them to be paralleled easily in a rack, and it works great to charge batteries too -- in fact, that's called "two-state" charging, and it's specified for the Zero batteries.

I'd have a hard time recommending it, though. Save your sheckels and invest in one of the aftermarket fast-chargers you can mount on the bike. Why would you want to leave it at home? I just (finally) got my Diginow installed and operating, and I'm very happily planning trips now. Can't do that with a charger you can't take with you.

[MorbidBBQ]

96 volts won't get you anywhere near a full charge...that's actually fairly depleted for the Zero batteries. Most of the chargers you'll find OTC have a way of adjusting their output voltage a bit, and they're adjusted somewhat higher for the Zero S/SR/DS/DSR. I'm not sure the exact voltages the quick-charge guys are using, but 110VDC would be a pretty safe value, with 116VDC being pretty aggressive. IIRC the onboard Zero charger terminates at 114VDC. Since fast-charging is a bit harder on the batteries, you might want to terminate somewhat earlier to be gentler on the battery.

96 volts is what zero is selling; I doubt they would sell a charging accessory that can't get it to a full charge.  Is it possible that the charger doesn't need to supply more voltage to a battery than its capacity?

But generally, if their output voltage can be adjusted to an appropriate value by some sort of programming or even an internal trimpot, server power supplies make excellent battery chargers. Since they're designed to be used in parallel in a large rack, they offer true Constant Current/Constant Voltage (CC/CV) operation. In other words, the power supply will try to regulate up to its voltage setpoint, but it won't put out more than its "constant current" value, even if the output voltage is significantly lower than the setpoint. This behavior allows them to be paralleled easily in a rack, and it works great to charge batteries too -- in fact, that's called "two-state" charging, and it's specified for the Zero batteries.

I'd have a hard time recommending it, though. Save your sheckels and invest in one of the aftermarket fast-chargers you can mount on the bike. Why would you want to leave it at home? I just (finally) got my Diginow installed and operating, and I'm very happily planning trips now. Can't do that with a charger you can't take with you.

I've already got the EVtricity charger, and its working great.  I'm just wondering why more people haven't tried the server power at what appears to be 1/10th the cost.  It would be ugly, clunky, & heavier; so that's why I'm thinking of using it as a superduper home charger (DubJ!).  FOR SCIENCE!

$69 https://www.newegg.com/Product/Product.aspx?Item=9SIA8WV56M6547



Fred, thanks for that other link.  I see the author (remmie) talks about connecting 2 57v supplies in a series; which fries my brain.  How do you connect 2 AC/DC converters in a series?

[BrianTRice@gmail.com]

What Zero sells (Quick Charger) is rated for 96V but customized at the factory to match the 116V full charge voltage.

The EVTricity charger IS a server power supply.

The reason not to use a server power supply is that they are not rated for weather or vibration, and could fail with no manufacturer support and might cause damage.

If any of this scares you, then it should. These efforts are inherently risky and should be avoided if at all possible. Breaking a $15000 EV by saving $1000 on charging equipment is foolish.

[DonTom]

96 volts won't get you anywhere near a full charge...that's actually fairly depleted for the Zero batteries. Most of the chargers you'll find OTC have a way of adjusting their output voltage a bit, and they're adjusted somewhat higher for the Zero S/SR/DS/DSR. I'm not sure the exact voltages the quick-charge guys are using, but 110VDC would be a pretty safe value, with 116VDC being pretty aggressive.

116 volts cannot be too aggressive as I just measured my DC battery voltage at the Anderson Connector. Ignition key must be on to read this voltage. I get 117.00 VDC with my bike (2017 Zero DS ZF 6.5) at 100% charge, nothing but voltmeter connected to the bike. That makes me believe the DC charge voltage would be above 120 VDC to get any usable current to charge the batteries up to 100%.

-Don-  Cold Springs Valley, NV

[Doug S]

That makes me believe the DC charge voltage would be above 120 VDC to get any usable current to charge the batteries up to 100%.

Regardless of how the numbers may make it seem, battery SoC (State of Charge) isn't absolute. Is 116VDC 100% charge? If not, is it 112VDC or 120VDC? On the other end, is 92VDC 0% (completely depleted)? Or is 88 or 96?

In reality, it's a sliding scale. If you somehow bypassed the safeties and charged your Zero battery up to 140VDC even once, you've killed it. If you discharge it down to 60VDC, ditto. Conversely, if you never let it get below 102VDC, and never charge it above 110VDC, it will last an extremely long time.

When the Prius first came out (some of us are old enough to remember that!), people were extremely skeptical of the life of the NiMH battery. Everybody was saying you'd have to spend $15,000 every 50,000 miles to replace the battery pack. But there are Priuses on the road with in excess of 500,000 miles, still running fine with their original batteries. The secret? The Toyota engineers narrowed the operating range of the battery pack very significantly -- they only discharge down to the conventional 40% SoC, and only charge up to 60%. By limiting the operating range that much, they've achieved ten or maybe 100 times the number of cycles anybody thought they could. Batteries thrive under that kind of service.

So go ahead, charge your battery up to 120VDC if you want to. Discharge it to 85VDC. You WILL get higher capacity and more range that way....just don't complain when your battery fails after 25 cycles.

Or you can rig up a charger that stops at 112VDC, and make sure your SoC indicator never reads below 40% or so. You'll have much longer battery life at the expense of range and convenience.

Or you can just stick with Zero's design, which guarantees you 2500 cycles, and gives the advertised range. It's your call.

[DonTom]

Regardless of how the numbers may make it seem, battery SoC (State of Charge) isn't absolute. Is 116VDC 100% charge? If not, is it 112VDC or 120VDC? On the other end, is 92VDC 0% (completely depleted)? Or is 88 or 96?

I think you missed my point. I will always stick to using the Zero recommended stuff, that wasn't my point.

But how is it possible to charge a battery to 117 VDC with less voltage than 117VDC? I used the onboard charger ONLY (not even a quick charger used) to get to 100% charge which was exactly 117.0 VDC measured on my bike's Anderson connector after it being fully charged more than ten hours ago. 117.0 was my battery voltage. If that is too high, then it's Zero's mistake, not mine.

And to fully charge such a battery, to get any usable charge current, the charger voltage will have to be above the fully charged  battery voltage. Just like a so called 12 volt (~12.7 volt) lead acid battery needs about 13.3 volts for it to even start to charge (13.8 volts to charge is more typical).

-Don-  Cold Springs Valley, NV

[Shadow]

...But how is it possible to charge a battery to 117 VDC with less voltage than 117VDC? I used the onboard charger ONLY (not even a quick charger used) to get to 100% charge which was exactly 117.0 VDC measured on my bike's Anderson connector after it being fully charged more than ten hours ago. 117.0 was my battery voltage. If that is too high, then it's Zero's mistake, not mine.

Stock on-board charger may charge up to 117Vdc at a reduced rate. We're all just guessing based on observations unless having read the secret firmware code.

The Sevcon motor controller will refuse to turn on if the battery is above a certain voltage (118Vdc?)

[DonTom]

Stock on-board charger may charge up to 117Vdc at a reduced rate. We're all just guessing based on observations unless having read the secret firmware code.

The Sevcon motor controller will refuse to turn on if the battery is above a certain voltage (118Vdc?)

Sounds  right.  The way they get more charging current is to increase the charging voltage. But as the battery gets more charged, the current will automatically decrease. And the BMS I assume further adjusts the charging current by adjusting  the voltage to make the charging current best for the battery's SOC.

There's no way to adjust charging current without changing the charging voltage, but sometimes a very slight amount of voltage  can  cause  a relatively large change in current.

Considering how many quick chargers are allowed, I would think it would be rather difficult to get enough POWER (watts) to over charge such a battery.  Say you put on 300 DC volts on a battery that needs a charge. That voltage will DROP instantly to a much lower voltage under the load of the battery or else that will have to be one heck of a charger that will take almost all the power possible from your house.

Didn't I hear that each charger draws 13 amps at 120 VAC? Five chargers allowed. 13 times five is=65 amps. 65 amps @ 120 volts=7,800 watts AC input. Somewhat less DC output. I would think not many power supplies will handle enough power to blow out one of these batteries.  If the voltage under battery load is much above the 117 volts I measured, that will be one heck of a power supply.

Before you could get enough voltage to get enough current to overcharge the bike's battery from a single outlet,  the circuit breaker in your house will blow.

-Don-  Reno, NV

[Skidz]

I beg to disagree. A charger can be set to for example charge to 192v at max 10 amps, and will never use more than 1920W of DC so around 2100W of AC power but will destroy your battery for sure...

[Doug S]

But how is it possible to charge a battery to 117 VDC with less voltage than 117VDC?

Of course it's not. But what's the accuracy of your voltmeter? And how accurate is the charger? I don't want to quibble about +-1VDC. That's only 0.8% of the measurement, which isn't bad in the real world.

And to fully charge such a battery, to get any usable charge current, the charger voltage will have to be above the fully charged  battery voltage. Just like a so called 12 volt (~12.7 volt) lead acid battery needs about 13.3 volts for it to even start to charge (13.8 volts to charge is more typical).

That may be true, in which case the charger is just set a couple of volts higher. But I'm not entirely sure it's true, anyhow. You're comparing two very different batteries. For all I know, if you apply 117VDC to a Li-ion battery overnight, it will trickle charge up to that exact voltage.

My main point is just that we're always talking about SoC numbers as if they're absolute, and they're not. There is no hard-and-fast voltage where the battery is at "0%" capacity, nor "100%", nor any value in between. These are engineering decisions made by Zero.

[MrDude_1]

What Zero sells (Quick Charger) is rated for 96V but customized at the factory to match the 116V full charge voltage.

The EVTricity charger IS a server power supply.

The reason not to use a server power supply is that they are not rated for weather or vibration, and could fail with no manufacturer support and might cause damage.

If any of this scares you, then it should. These efforts are inherently risky and should be avoided if at all possible. Breaking a $15000 EV by saving $1000 on charging equipment is foolish.

The diginow is a telecom power supply... Sure its awesome, but its also not designed for vehicle use.

96 volts won't get you anywhere near a full charge...that's actually fairly depleted for the Zero batteries. Most of the chargers you'll find OTC have a way of adjusting their output voltage a bit, and they're adjusted somewhat higher for the Zero S/SR/DS/DSR. I'm not sure the exact voltages the quick-charge guys are using, but 110VDC would be a pretty safe value, with 116VDC being pretty aggressive.

116 volts cannot be too aggressive as I just measured my DC battery voltage at the Anderson Connector. Ignition key must be on to read this voltage. I get 117.00 VDC with my bike (2017 Zero DS ZF 6.5) at 100% charge, nothing but voltmeter connected to the bike. That makes me believe the DC charge voltage would be above 120 VDC to get any usable current to charge the batteries up to 100%.

-Don-  Cold Springs Valley, NV

That is NOT how a CC/CV power supply works.
The bike is never supplied with voltage above the final charge amount. What happens is its supplied at the constant current limit, until the charger hits the max voltage.
then the current slowly drops as the voltages come closer. At no point is the output voltage of the charger raised above that battery max to increase the current.

[DonTom]

I beg to disagree. A charger can be set to for example charge to 192v at max 10 amps, and will never use more than 1920W of DC so around 2100W of AC power but will destroy your battery for sure...

Sure you can set it at ten amps at 192 volts. But if the battery draws more than ten amps, that voltage will drop. And at 192 volts, it probably will draw more than that ten amps. But if not, then you're safe anyway. The real question is how much current can these batteries handle? Seems like quite a bit, considering how many quick chargers can be used.

10 amps at my measured 117 DC volts is  1,170 watts. With several chargers, which we are allowed to use, we have to be way over that! That means when your ten amp  charger at 192 volts exceeds  ten amps of current, you're not going to get 192 volts from that single charger. The voltage will drop as the current increases above ten amps.

IOW, I would think your charger would overheat well before the battery. 192 volts at 10 amps is capable of 1,920 watts. The AC input will be even higher than that 1,920 watts, AC current draw would be quite high, perhaps enough to blow your house 20 amp circuit breaker. 120 VAC at 20 amps is 2,400 watts. Getting quite close.

I own more voltmeters than I can keep track off. I doubt if any of them are more than a volt off at 117 VDC.  But I will check with several different high quality meters next time. I will do some more checking later and post some more info here. One of the things I want to see is the charging voltage under the load of the battery when the battery is somewhat discharged.  If I can find a DC current meter that can read high enough, I will check the DC charging current also from a recommended quick charger.  Right now, my bike is at 100% charged, so I have to check it after a ride today.

-Don-  Reno, NV