Battery end of life question

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alandf
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Battery end of life question

My Zapino has dropped from a 20+ mile range to a 9 mile range. I have 1250 miles on the scooter. I also use the standard 60 v smart string charger that came with the 2008 scooters. After taking all the body panels off and flipped the circuit breaker to the controller off I checked each battery in the series separately with a battery tester with a load. Every battery started with a 13.2 V reading then went to a 11.4 v reading under load. After turning the load off, it went to a 12.8 v reading. While this all fell within what I think would be good and balanced batteries I was surprised that all the batteries checked out the exact same (and all good). With the exception of turning off the circuit breaker, I left the batteries all connected. When testing I hooked the leads directly to the battery terminals of each battery.

Was this the correct way to test the batteries? Did I interpret the results correctly? Any additional advice on battery testing and/or troubleshooting?

Thanks in advance for any advice.

fisher727
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Re: Battery end of life question

During the winter the range will drop fairly significantly. Your batteries should not be worn out with that mileage. What type of driving do you do with your scooter. Is it all with the throttle wide open or at slower speeds. Do you have the speed restriction disabled. When you get to 9 miles what is the voltage. Your bikes controller should limit the minimum voltage to 10.5 volt per battery or 52.5 total volts to prevent over discharging of the batteries. This will cause your maximum speed to decrease at this point of you ride.

Eric Fisher
www.SiliconeBatteriesUSA.com

LinkOfHyrule
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Re: Battery end of life question

Just a note: Load testers aren't that great for determining the health of an SLA battery. Putting them on a load and draining them while monitoring how many Ah you get out of them with a wattmeter is a lot more telling.

Or at least that's what I hear.

The author of this post isn't responsible for any injury, disability or dismemberment, death, financial loss, illness, addiction, hereditary disease, or any other undesirable consequence or general misfortune resulting from use of the "information" contai

alandf
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Last seen: 11 years 2 months ago
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Re: Battery end of life question

Thanks for the responses. I live in Austin, Tx where the temperatures have been in the 60's. I have the speed limiter disengaged and I travel between 35-40 mph on flat land. I'll have to put the scooter back together before I will be able to answer the voltage at cut off question. Before I do that I want to run some wires in parallel to an external connector so that testing will be easier in the future. I'll also need to check into a wattmeter.

sgmdudley
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Re: Battery end of life question

I have a Zapino also, 2nd generation w/SLA. The 1st generation had Green Saver Silicone. I am the electric bike/scooter tech for the dealer I bought my scooter from here in Longmont, Colorado.

I use a Multi-Meter, a Load Tester and an Impedence Tester for testing batteries. I get a fair idea of how the batteries are in relation to each other, but it still does not test well enough to know how they will last during operation. Sears has a tester in the service bay for testing automotive batteries that would do this (similiar to what Fisher indicated) it is not cheap so I don't have one yet.

On my Scooter, I have the PakTrakr installed. I am able to measure Pack Voltage, Individual Voltage, Amps and State of Charge. Most useful during commuting is state of charge. I can tell at a glance what percentage of charge I have and drive to arrive back home with 50%.

That is the key for SLA
1) do not let Lead/Acid batteries sit in a partially discharged state. Always put them on a charger when you stop.
2) do not drop below 50% of charge.

For my scooter, I was planning to convert to LifeP04 but they are 1)still expensive, 2)some question about quality, 3)they need a BMS and I can't find a good one except in Australia.

My next best bet may be the green Saver Silicone.

The Impedence Tester I use measures Internal Resistance. This is important to battery health. A good battery will read around 10 milliohms. I tested a toasted battery @ 3 ohms, and a poor battery @ 24 milliohms. However, this is another of those "It isn't cheap" tools. Mine was used for $500.

Your test results sounded like all your batteries are at least equal in charge. This is great since you only have the string charger. Sometimes w/string charging you will get a low battery that will afffect the total charge, reducing range. I use 5 chargers and charge all 5 batteries at the same time using the Simplified Charging method described in this Forum under Batteries and Chargers.

Robert Dudley
E-Scoot Tech

alandf
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Last seen: 11 years 2 months ago
Joined: Tuesday, January 29, 2008 - 11:40
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Re: Battery end of life question

Thanks Robert for the detailed explanation. The PakTrakr sounds like a good investment. I guess the assumption is that whenever one has a drop in performance that it is a relative issue between batteries with one being weaker. At this point and with my limited testing I can't rule this out until I do a system load test (ride the scooter until it cuts out.)I will be setting up the simplified charging as described in the batteries and charger forum. I do have one question. When you say do not drop below 50% of the charge, how exactly do you measure that?

Thanks,

sgmdudley
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Re: Battery end of life question

the PakTrakr has many functions. One is State of Charge in percent.
http://www.paktrakr.com/

Robert Dudley
E-Scoot Tech

fisher727
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Re: Battery end of life question

The batteries in your scooter are rated at about 40 amp hours for 100 hours, 35 amp hours for a 20 hour discharge, and about 20 amp hours for a 1 hour discharge. If you discharged you batteries in one hour using 20 amps continuously, your bike would only be going about 28 miles per hour. At the end of your ride at 28 miles your batteries voltage under load would be at 10.5 volts or the cutoff voltage. After you let the bike sit for awhile you will see the voltage recover to about 12 volts and will increase to maybe 12.2 volts in an hour or two. When looking at a voltage chart you can determine that your batteries are at 40% charge or 60% discharged. Considering that your batteries probably contain 40 amps total energy you could use an amp hour meter to determine when you have used 20 amps total. The reason that your batteries would be under 50% after only using 20 amp hour of energy in a battery with 40 amp total is that some of the energy was lost as heat. The amount lost as heat is increased under higher loads because of the internal resistance of the battery. The higher this internal resistance is the more the loss to heat. That is why it is important to buy batteries that have very low internal resistance when the batteries will be discharged at a very high rate, like in a scooter. I understand it is OK to discharge some types of gel cell batteries below 50% without causing harm but I would put it on a charger immediately if you have discharged them below 50%.

Eric Fisher
www.SiliconeBatteriesUSA.com

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