Range drop

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Rocketman
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Range drop

First off, Happy New Year to all, this is a great board and have learned a lot from all the posts. Not enough to fix current problem, though. Had a rider bring an Emax Sport to me with complaint of range dropping from about 20 down to 5. This occured after he fixed a flat on rear. I pulled seat and measured the two 4 bat strings and they all metered above 13, and then disconnected 3 in each string and they measured between 13.07 to 13.2. Bike is about 3-4 yrs old, has about 700 miles on the odo, and has China sili bats 12v/20 ah. Owner appeared to be diligent about keeping bats charged as routine. I even checked to see if the relays are working which they appear to be. With key on, work the kickstand switch and you can hear them click on and off, although don't know if they are BOTH working. Did I miss anything? I'm at the bottom of my bag of tricks. Really would like to get him riding again. That is the goal. Any help would be appreciated. Thanks.

fisher727
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Re: Range drop

Have you read the other blog about a range problem in a Zapino.

http://visforvoltage.org/forum/5584-battery-end-life-question

It appears that the controller is limiting the voltage above the normal 10.5 volt cutoff in this Zapino. This would definitely be a possible item to check. The controller is next to the rear tire and maybe somehow the controller was effected by the tire change.

Eric Fisher
www.SiliconeBatteriesUSA.com

antiscab
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Re: Range drop

Hi Rocketman,

do you have an AH counter?
id suggest doing a capacity test on the batteries.

the charger for these batteries isnt temperature compensated, so will go into thermal runaway in some circumstances (its happened to me twice on my emax).
when it goes into thermal run away, the capacity of the battery pack is reduced substantially.
you may find its just a coincidence that the range dropped when the tire was replaced.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

chas_stevenson
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Re: Range drop

Rocketman,

When you tested the batteries did you have a load on them? Even a bad battery will have good voltage at rest, the only way to know for sure is to check the voltage under load. I use a car headlight. I connect the meter to the battery and then apply the load (headlight) if the battery is weak the voltage will drop to below 10.5 volts within about 5 minutes. This should not happen with a good battery which has just been charged. I also use a 12-volt charger to charge the battery before testing.

Grandpa Chas S.

Rocketman
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Re: Range drop

Thank you all for responses.

Fisher727 - Thought maybe connections got "disturbed" somehow myself, but they all seem tight.

Antiscab - No AH counter. Does therm. runaway show any physical damage? Seen some PB's that looked scary.

Chas - Tested without load, will try as you suggest. No headlight other than eGO 24 volt or 12v directionals at this time, would that be enough load? I'm assuming bats should be disconnected from string when testing.
These second level diagnostics are a little more of a challenge but I have to learn them. Wish there was some kinda continuing education class to take. I've got to look around for that.

Thanks, again to all, will try these possibilities

Vince

antiscab
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Re: Range drop

it depends on how long the batteries were overcharged in a single session as to whether it will show any physical damage.
i know all my batteries ballooned out and let off this horrible stench.

ive also observed some of my batteries bubbling away well after the charge should have finnished.

I highly recommend getting an AH counter such as a cycleanalyst or a v3 data logger by eagle tree systems.
that way you can measure how many AH you have pulled from the pack when the batteries are low.
that will let you know pretty quickly where the problem is.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
conversion

PJD
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Re: Range drop

Rocketman,

I assume that this e-max is in stock condition with the two series strings connected in parallel, via the two relays. There is also a multi-function electronic module traditionally called the "black box" (but it was white in earlier models). This black box's functions include a relay for isolating the kickstand safety switch circuit, a circuit for isolating the key switch from excess current, and a circuit to manage the single-charger/double charger feature of the e-max.

For charge management, the black box connects the two series strings together so a single charger charges both strings. But, if two chargers are connected (an alternative provided for for faster charging - that's why there is a charge receptacle in each side of the scooter), the black box senses two chargers (via the third signal wire on the charger), and opens the connection between the strings, so each charger charges each series string independently.

The problem that arises is that if one of the two relays sticks open even briefly while riding, half of the full current goes through the black box connection instead, burning it out. Then, when the pack is charged again with a single charger, only one of the strings get charged, and the range drops dramatically. This is what happened to me.

The black box has been the source of lots of other problems as well, so the many people have eliminated the black box, and arranged the battery pack into a parallel-pair-in series arrangement. I'll write up provide updated instructions if there is interest (I only recently discovered some thins that need to be done to prevent premature key switch failure if the box is eliminated)

I'm not sure how fixing a rear tire caused the problem - probably a coincidence.

Of course, the "silicone" batteries have a quite a reputation of premature failure.

By the way, as Chas pointed out the open-circuit voltage of the batteries does not give any kind of indication of the battery's health. A bad battery will have a perfectly fine open-circuit voltage. You have to actually do a discharge test of the battery with a voltmeter and ammeter connected and measure the actual watt-hours produced. My preference is four #1157 auto bulbs soldered together in parallel, with the bottom nubs soldered so both filaments are burning). Such an arrangements draws almost exactly 10 amps.

Mik
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Re: Range drop

These second level diagnostics are a little more of a challenge but I have to learn them. Wish there was some kinda continuing education class to take. I've got to look around for that.

Vince

You are right in the middle of it! No need to look any further ;-)

Regarding range drop after tyre change: Are the breaks binding or the tyre rubs against something? Or is the wheel not spinning freely for any other reason?

You might be barking up the wrong tree, eeeeh, battery.....

This information may be used entirely at your own risk.

There is always a way if there is no other way!

MOSFETmeltdown
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Re: Range drop

Mik/Rocketman, just what I was thinking - I take it that the rear wheel isn't binding?

On another electric bike - a Lectra - one owner found that after adjusting the chain tension, his range dropped markedly. Turns out that the rear (drum) brake was affected by the wheel position 'rearward movement' made in order to tighten the chain....

Just a thought.

Dave.

PJD
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Re: Range drop

It seems hard to believe that a large drop in range would be the way rider discovers a dragging brake or tire - the drag of the brake itself should be very noticeable.

Then again, there was an e-max user early on who kept riding his e-max with loose rim/hub motor bolts until three of the four bolts came completely off and the fourth was about to come off.

He then practicality threatened to sue poor old Larry Malz the soon to be out-of-business e-max importer/distributor down in Austin over it.

Rocketman
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Re: Range drop

Thanks again. sometimes I feel like a bucket of rocks is smarter than me.
Checked for brake drag early on, appears to be loose and OK.
Wheel does appear to be off centerline, but no way to adjust.
Will try 4x1157's for load. As I understand it, if it drops to 10.5 volts quickly (5-10 mins) then bats are bad.
Can get at 3 of each string easily, so will try that first.
Any way to tell if black box is good or bad? I would imagine, that one string should be in worse shape than the other if it's bad.
Thanks again for all the thoughts and help...and patience...my head hurts... but just a little... I will stay with it until it gets to be fun!
Till next time.

PJD
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Re: Range drop

The black box problem can be easily checked by first just checking the voltage at one of the charging receptacles then the other. If the voltages are different (more than 0.1 volt) than the black box is probably allowing the charging of charging only one sub-string. But to eliminate the case of it the sub-strings coincidentally being the same voltage, also plug the charger into the receptacle on one side of the scooter and check the voltage at the receptacle on the other side. The voltage should jump upward when the charger is turned on. If it does the black box is working correctly, if not the black box is not.

Of course, also check that one of the relays is not sticking open. The only purpose of the double relay setup was to keep the sub-strings isolated for the the two-charger fast-charge feature on the e-max. (Actually, using two chargers works fine even if the sub strings connected). So you can run the scooter on one relay just fine.

Rocketman
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Re: Range drop

Ok, all that's done. Made the string of 1157's. Added one bulb at a time and then took amp reading, trying to understand, and then predict the relationships between amps volts and watts. Metered out at 9.58 amps.
Checked the voltage at both charging ports and both read 53.8, so sounds like black box is good.
Also read one outlet previously, and it read 53.3 and after plugging in charger and turning the charger on, the other outlet jumped to 59.4
Batts all checked out. for example, open circuit was 13.31. After 1 min read 12.64, after five read 12.59, thats only a .05 drop leaving it well within the "good" zone. Several even showed less than that drop, but none exceeded it. So, in summation, bats., relays and black box are good. That leaves motor, controller and throttle? I think I'll take for a ride and see how it does.
Any further thoughts?. Spoke with owner and he said he did not disconnect wires when he took wheel off.
Thanks again for the help.

PJD
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Re: Range drop

Actually, you have NOT excluded the batteries as the problem.

You have to test each battery by discharging it until the voltage goes down to about 10 volts. Typically it will hold a steady, slowly declining voltage over time, then the voltage will drop rapidly. Record volts and time elapsed at 5 to 15 minute intervals. If you can do it, record volts and amps and time elapsed.

A good 20 AH battery will take about 1:20 to 1:30 to discharge with your 4-bulb setup (i.e. about 12-15 AH at C/2), a bad battery, less.

Repeat for each battery.

Sorry to say, but unless you set up an automated system with a datalogger, there is no less labor intensive way to do it.

Alternatively, (as Matt suggested) you can buy and install a cycle analyst or similar product on the scooter (google it) and it will effectively do this test on each battery as you ride the scooter.

Of course you can also just replace all eight batteries - replacing the bad with the good - and be done with it.

I recommend BB EB-20-12 batteries, but frankly, sealed lead acid batteries are just not a good power source in deep cycle use when they have to be connected in series. There have been endless discussions about how to address this - using powercheq or smartspark equalizers, or parallel-charging each battery instead of bulk string charging. But this still doesn't fix the problem because the individual cells in a SLA can never be properly equalized like flooded batteries can. The SLA's nearly always fail due to just one cell in the battery going bad due to imbalance in the individual battery. SLA's were developed mostly for standyby-applications, and simply don't work too well in continuous deep-cycle use.

Rocketman
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Re: Range drop

Thanks PJD, for hanging in there with me. Almost relieved to know that I had more testing to do with the bats. Good lesson. Weren't kidding about time consuming, but still gets the job done, and the repetition helps re-enforce the lesson. Have re-tested 4, and two went below 10 volts after 20 mins., so I'd say they are meeting the criteria for being bad. Will have rest done today. Checked out B&B's @ House of Bat, thanks for lead. TBC
Vince

PJD
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Re: Range drop

It is tedious.

BTW, you did top-off each battery with a 12V charger before stating the test?

Also, the batteries that check out good should be promptly re-charged so they stay good.

I should have mentioned that I had no luck mixing silicones along with conventional SLA's. When charging, the voltage on the new SLA's went too high due to differences in charging resistance. So, you may need to get all new batteries anyway.

The new pack should be wired into parallel pairs rather than the two series strings arrangement. The use of balancer (powercheq or smartspark) is also pretty much mandatory to help protect the investment.

Here's the old rewire diagram:

//i109.photobucket.com/albums/n77/PJD123/BatteryRewire.jpg)

I have since converted my e-max to Thundersky lithium. Scroll on down this forum for my account of doing this.

Rocketman
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Re: Range drop

Tedious, yet effective.
Owner decided to go with all 8 new, so no compatibility issues...dodged that bullet at least...the stock charger should do the trick at least.
You mention to change wiring, but not the why. I would imagine that, and powercheq are ways to maximize performance/lengevity, but would think stock config. would be adequate. Stock is rarely optimal, but usually adequate, and me, in my neophyte state (and the owner) would be happy with just getting back to square one. Would then be able to "upgrade" as need and pocket allow, as those equalizers didn't appear to be inexpensive. Unless you're telling me that new bats will only last a month, that would not be cool. Hope all else is well.
Will check out the Thundersky convert, thanks for making it available.
Thanks once again for all the info. I'm might just learn enough to stay out of "trouble".

fisher727
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Re: Range drop

Rocketman
Can you give us your email address and or phone to your Electric Scooter shop there is Southern California. It is hard to use the mail service in this site. I am not sure we are getting messages to each other in a timely manner. Thanks

Eric Fisher
www.SiliconeBatteriesUSA.com

PJD
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Re: Range drop

The purpose of the rewire to "buddy-pairs" is that it reduces by half the chances of a battery getting badly out of balance - because parallel-connected batteries automatically stay balanced relative to each other. The result is longer pack life. It then allows the use of just three instead of six "powercheq" balancers if you kept the stock battery wiring.

It also eliminates the possible black box-related problems I discussed earlier.

But even with these change, if the scooter is being used almost daily, a year to a year and a half is the most you will get before a couple batteries start going bad - SLA' are not an optimal solution for scooters. If you could be sure of never dumping the scooter (big if) you could use flooded batteries and get much longer life because they can be periodically equalization charged.

Rocketman
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Re: Range drop

Thanks for great explanation, once again, PJD. At least I'm not feeling as "in the dark" as I used to. I'm learning what it feels like to be a "NG" again. New industry, new knowledge.
Don't know what I'd have done without this site.
"Bravo" to all involved.
Good luck on Sunday, to all Steelers fans.

leio
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Re: Range drop

The black box has been the source of lots of other problems as well, so the many people have eliminated the black box, and arranged the battery pack into a parallel-pair-in series arrangement. I'll write up provide updated instructions if there is interest (I only recently discovered some thins that need to be done to prevent premature key switch failure if the box is eliminated)

Yes please ! I would like to rearranged my pack and only this (no 60V or more upgrading). If you can explain it as simply as possible (I'm french and not an electronician)

I have this picture but the value of the resistor X is missingdiagrammod.jpg

Thanks for your help.

=D-----------born to be wired-------------C8

PJD
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Re: Range drop

There are several approaches, so I can't give exact directions the following is the general procedure:

With the black box removed, identify the +48 volt, always-on lead. Wire this to one of the wires running to the key switch. The wire from the key switch is connected to the red controller-logic power wire and to the positive wire to the relay solenoids. The negative wire from the relay solenoid will go directly to the negative terminal of the pack. Resistor "X" isn't necessary if you are keeping the 48 volt setup. It was primarily to allow these 48 volt relays to be used at higher voltage. But, even at 48 volts, a 30-40 ohm resistor reduces the current that the relay solenoid draws, and reduce it's drain on the pack a little bit.

The positive and negative leads from the charging receptacles are connected directly to the positive and negative terminals of the battery pack. The third wire from each charging receptacle is no longer used and can be removed.

I discovered an additional measure needed to avoid premature failure of the key switch. After the switch failed on one of my scooters, I discovered that there is considerable arcing at the switch, apparently due to inrush current to capacitors in the DC-DC converter and the controller. This can be prevented by adding one NTC Thermistor inrush suppressor to the controller logic power circuit and one to the +48 volt lead to the DC-DC converter. The specific inrush suppressor I used was a Thermometrics CL-40, but any such NTC Suppressor with a max steady state current of at least 4 amps should be fine. Actually, this measure doesn't have anything to do with removing the black box, it is just one more design flaw on many Chinese scooters.

taheibbor
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Re: Range drop

It seems hard to believe that a large drop in range would be the way rider discovers a dragging brake or tire - the drag of the brake itself should be very noticeable.

Then again, there was an e-max user early on who kept riding his e-max with loose rim/hub motor bolts until three of the four bolts came completely off and the fourth was about to come off.

He then practicality threatened to sue poor old Larry Malz the soon to be out-of-business e-max importer/distributor down in Austin over it.

So who gets sued now when nobody can get replacement chinese silicon batteries?

PJD
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Re: Range drop

Why would anyone want to get replacement Chinese silicone batteries? Deep-cycle-type, sealed lead acid batteries work at least as well and are cheaper.

fisher727
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Re: Range drop

PJD

I don't think you know what you are talking about. Silicone Batteries are very good batteries. I have them in my highway capable electric car which now has 9,000 mile on it and they still work like new. My off grid house is running off 48 Silicone Batteries and they are 2 year old and not one has gone bad. My cars uses them as starter batteries with out failure. Many of the manufactures of electric scooters are now moving to Silicone batteries to get the improved performance they offer. Early silicone batteries were produced by a company that did not have the rights to produce silicone batteries and they have left the market but they did produced a lot of bad silicone batteries. Greensaver battery corporation is the only legal manufacture of Silicone Batteries.

Eric Fisher
www.SiliconeBatteriesUSA.com

fisher727
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Re: Range drop

So who gets sued now when nobody can get replacement chinese silicon batteries?

There are replacement chinese silicone batteries available. They are made by Greensaver battery corp. They are available to be sued. What would you like to sue them for. Remember a lot of the early Silicone Batteries were not made by Greensaver.

Eric Fisher
www.SiliconeBatteriesUSA.com

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