I may have murdered my a SLA :(

[OzzyU812]

Its says in the owners manual, "Never charge the batteries for more than 24 hrs." Which I wasn't it was closer to 9 hrs. But I got the bright idea of putting it on a outlet timer to reduce the time its on the charger after its charged. Now it has about 66% of its range. It has about 150-200 charges on it. The manual says it should be good for 300. It could just be a sign its coming to the end of its natural life.

What do you think, its showing its age or did I wound it with the timer?

 

[Link]

No, SLA batteries just suck. 200 cycles is about all you can reasonably expect out of them.

 

[dak664]

Well, FWIW here's a theory I have developed over the years. A lead-acid battery is not fully charged until the constant-voltage absorption phase is complete. This can take hours and requires a smart charger that uses the right voltage, 13.2 to 14.4 depending on temperature. When less than fully charged, sulfates form and increase the internal resistance of the battery. The higher resistance results in higher voltage when charging, which results in early termination of the constant-current bulk charge. When using a dumb charger, each cycle gives less charge, allowing more sulfates to form, and the capacity goes down some more.

The solution is to keep the battery in absorption phase for as long as it takes to reduce the built-up sulfates, which can take many days or weeks. This is a good use for a PV panel since it needs only a few milliamps of current. A panel can be conditioning several sulfated batteries and still be used for bulk charging. I use cheap homemade PWM chargers, ATTiny85 based. But the voltage must be kept within tight limits, if too high hydrogen will form and the SLA will dry out. It's less of an issue with flooded batteries since the water can be replaced.

 

[snowcrow]

I'm in total agreement with dak664! I've been using wind & solar at camp now for the past 5 years, and it sounds like he is into the very same thing.

Use only a smart charger on SLA's and let them stay on the float stage to try and bring them back. The longer you leave them in a sulfated state, the harder it will be to bring them back, if at all

Blessings, Snow Crow

 

[Lessss]

Open your packand use a 12V smart charter on each individual cell. While open test each cell in the pack to see if any runts or DOA.

 

[OzzyU812]

Well, FWIW here's a theory I have developed over the years. A lead-acid battery is not fully charged until the constant-voltage absorption phase is complete. This can take hours and requires a smart charger that uses the right voltage, 13.2 to 14.4 depending on temperature. When less than fully charged, sulfates form and increase the internal resistance of the battery. The higher resistance results in higher voltage when charging, which results in early termination of the constant-current bulk charge. When using a dumb charger, each cycle gives less charge, allowing more sulfates to form, and the capacity goes down some more.

The solution is to keep the battery in absorption phase for as long as it takes to reduce the built-up sulfates, which can take many days or weeks. This is a good use for a PV panel since it needs only a few milliamps of current. A panel can be conditioning several sulfated batteries and still be used for bulk charging. I use cheap homemade PWM chargers, ATTiny85 based. But the voltage must be kept within tight limits, if too high hydrogen will form and the SLA will dry out. It's less of an issue with flooded batteries since the water can be replaced.

Your post required research on my 1st cup of coffee LOL
FWIW - for what its worth
PV panel - Photovoltaic panel
PWM - Pulse-width modulation
ATTiny85 - Are you talking about these? http://www.mouser.com/Search/ProductDetail.aspx?qs=8jWQYweyg6NCiiaOb5GI9Q%3D%3D Are there instructions on building a charger with them? Is there something I can buy off the shelf of does it have to be built?

Your 2nd paragraph is about how to bring it back or to charge it like that all the time?
The charger I'm usings output is 24V 1800mA. Your saying I need to go even lower? If so how low should I go? I have lots of old ac to dc converters laying around. lIke the ones used on cell phones, cable modems & the Atari 2600. ( Don't know why that came to mind, maybe something funny in my coffee) I think most of them are 12v, if I find one with the Amps low enough maybe I can try one on each individual cell?

I don't know the intellegence level of my charger. I asked it simple math questions with no response. Since its a currie e-zip, the cheapest e-bike out there its most likely dumb. They do offer a quick charger, could that be a smart charger?

Yea!! I just looked at my bike on the wally world site. It is a smart charger!! Here's the link if you need it: http://www.walmart.com/catalog/product.do?product_id=8467094

BTW, Where is spellcheck and how do you add pic attachments here?

I'd like to thank everyone for you replies!! I'm very new to e-bikes. Only had this thing since June.



Thanks

 

[diver]

I use one of these to condition my battery's
http://www.vdcelectronics.com/batteryminder_12248.htm

 

[dogman dan]

Do you ride a lot? Like more that 300 battery cycles a year? Then Lifepo4 may be cheaper over the long term. Proper care of sla's makes a huge difference, but it can be tedious. If you will get two years out of a new set of sla's then it may be worth waiting for lifepo4 to improve some more.

 

[dak664]

http://www.boatelectric.com/sulfation.htm is a description of sulfation. I don't know if the pulsers described do any good, never tried them.

It wouldn't hurt to always charge a battery at absorption voltage, except that the initial current would be too high if the battery has been discharged much. High currents don't give the lead sulfate time to diffuse into the plates, so it reacts at the surface which reduces the effective plate area and also possibly falls off in little chunks which eventually short the cell. So the initial "bulk" charging phase involves a current limit which depends on the capacity and plate porousity (and I would guess should derate over the life of the battery). When the current drops below the limit the rest of the charging is done in absorption phase. When the battery is fully charged the voltage can be reduced to a float value which is just high enough to prevent any more electrochemical reactions (and hence won't get rid of sulfation).

Battery manufacturers usually supply charging info e.g. http://www.pacificpowerbatteries.com/aboutbatts/Deep%20Cycle%20Battery%20FAQ/dcfaq6.html but charger manufacturers rarely do. I am sure there are good chargers available but most are a black box and to the battery pack provider "smart" might also mean increased revenue from early battery replacements. It is not difficult or expensive to put together your own once you get together all the materials, and you will know exactly how they are working. Also you can log charging data into a computer via USB or MMC card e.g. http://www.dakx.com/BC100/Solarcharge.gif is from my USB charger. Here http://www.dakx.com/BC100/tiny85buckchargers.jpg are two of them on a proto board (no soldering needed), you could probably squeeze 4 of them together for about $50 in parts.

Source code for all kinds of chargers and microprocessors is available on the web. Powering with a 50 watt or so PV panel is good for a beginner since shorts or misconnections won't cause fires or damage anything valuable, at most a $2 processor. Try not to short batteries though

 

[OzzyU812]

I use one of these to condition my battery's
http://www.vdcelectronics.com/batteryminder_12248.htm

It does look cool. Maybe sometime in the future.

Do you ride a lot? Like more that 300 battery cycles a year? Then Lifepo4 may be cheaper over the long term. Proper care of sla's makes a huge difference, but it can be tedious. If you will get two years out of a new set of sla's then it may be worth waiting for lifepo4 to improve some more.

O yea, I ride it alot. Its my primary tranport to work. I'm definitely upgrading to 10Ah24V LiFePo4 batteries from Cyclone . Its just such a better value 2400 cycles for $400 vs. 200-300 for $100. That's about 2-3x more cycles for the money. Not to mention extended range which would reduce the number of cycles needed. I think I actually got about 150 cycles out of it, but it still has some life in it. I don't think the wife can object too much since she spends $400 a month on gas, payments and insurance on the SUV! Don't get me wrong she is usually very supportive in my endeavors.

Plus I can use the remaining SLA to power a killer light!

I not entirely sure how this will play into my ultimate goal of a 1500W Cyclone motor. The Cyclone site says its to be mated with 10Ah48V LiFePo4 batteries. I know that if I run 2 10Ah24V LiFePo4 batteries in series the voltage will double to 48V. But what about the Amps? Do they double also? I wouldn't want to fry it due to double the amps. It been a long long time since I studied OHM's law. LOL

Here's a real noob question for ya. What's a BMS? Is that the controller? googled BMS and it wasn't helpful.

http://www.boatelectric.com/sulfation.htm is a description of sulfation. I don't know if the pulsers described do any good, never tried them.

It wouldn't hurt to always charge a battery at absorption voltage, except that the initial current would be too high if the battery has been discharged much. High currents don't give the lead sulfate time to diffuse into the plates, so it reacts at the surface which reduces the effective plate area and also possibly falls off in little chunks which eventually short the cell. So the initial "bulk" charging phase involves a current limit which depends on the capacity and plate porousity (and I would guess should derate over the life of the battery). When the current drops below the limit the rest of the charging is done in absorption phase. When the battery is fully charged the voltage can be reduced to a float value which is just high enough to prevent any more electrochemical reactions (and hence won't get rid of sulfation).

Battery manufacturers usually supply charging info e.g. http://www.pacificpowerbatteries.com/aboutbatts/Deep%20Cycle%20Battery%20FAQ/dcfaq6.html but charger manufacturers rarely do. I am sure there are good chargers available but most are a black box and to the battery pack provider "smart" might also mean increased revenue from early battery replacements. It is not difficult or expensive to put together your own once you get together all the materials, and you will know exactly how they are working. Also you can log charging data into a computer via USB or MMC card e.g. http://www.dakx.com/BC100/Solarcharge.gif is from my USB charger. Here http://www.dakx.com/BC100/tiny85buckchargers.jpg are two of them on a proto board (no soldering needed), you could probably squeeze 4 of them together for about $50 in parts.


Source code for all kinds of chargers and microprocessors is available on the web. Powering with a 50 watt or so PV panel is good for a beginner since shorts or misconnections won't cause fires or damage anything valuable, at most a $2 processor. Try not to short batteries though

Thanks for for mountian of infomation you provided! I did look at it breifly last night and its very informative. I'll make some time this weekend to study it.

 

[dogman dan]

Bms is the battery management system. There are several other acronyms for essentially the same thing. Lifepo4 is touchy in a way, and sturdy in others. To deal with the touchy items you need to make sure the thing never gets below 2.1volts, ever. So the bms will shut down at some predetermined voltage, usually somewhere between 2.5 and 3 volts. You also need to not draw too many amps of current, so there is a shutdown for that above a set limit too. And the last thing is when charging, it's best for cycle life to balance the cells to the same voltage every charge, so the bms will help the charger do that.

On the amps. The real way to increase amps is to increase the amps the controller will provide. In other words, a 20 amp controller will provide 20 amps, regardless of voltage. Since volts times amps equals watts, a larger voltage at the same amps will be more watts than before. Often to increase voltage much, you have to replace the controller anywyay. They say to increase speed increase voltage, to increase torque, increase amperage.

 

[OzzyU812]

Wife says no Lipo, for now anyhow. It has to wait til income tax time. So I'm have to settle for another SLA Its goin to be a waste of money in the meantime.

I've been thinking about running the batteries in parallel. If the controller controls the Amps. If I fry the stock one. Oh well, then I'll just run a switch. As I've been meaning to do. It just isn't powerful enough to warrant a controller.To Hades (kids study your Greek mythology) with all the junk wiring in the rack. The smart thing to do would be to test the switch set-up 1st. If I burn up a motor I have a spare!

The plan was/is to get the 10Ah 24VLiFePo4 batteries, then get a 2nd set of the 10Ah 24VLiFePo4 batteries & finally the Cyclone 1500w motor. Running the 10Ah 24VLiFePo4 batteries in series to equal the 10Ah 48VLiFePo4 battery pack. With the added bonus of having 2 BMS's and 2 chargers. All the while working on putting that 2nd Currie motor on the front sprocket. I may even wind up putting BOTH Currie motors up front. I'm designing the mount with that in mind. This http://www.endless-sphere.com/forums...?t=4936#p73522 insired me to put them both in the front, eventually. I wonder if he had the same problem I had and got free motor due to miscommunication.

I found some interesting parts for E-Zip's see my new thread here: http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=6923

 

[swbluto]

Jesus. What's with these guys under the financial yoke of their wife? :|

I'm the sole arbiter of my finances, thank-you-very-much.(Which is probably an indication I'm not getting married anytime soon. :lol

 

[OzzyU812]

Jesus. What's with these guys under the financial yoke of their wife? :|

I'm the sole arbiter of my finances, thank-you-very-much.(Which is probably an indication I'm not getting married anytime soon. :lol

We did just buy house. move in on Hollween. I waited til I was 35 to get married.

 

[swbluto]

Oh, so I take it wasn't a "serious" question. That's understandable.

And good time to buy a house! As sarcastic as that may seem, it's not sarcastic at all. The best time to buy a house tends to be the time when it's at its lowest and while I can't say this particular time frame is the "lowest" for your particular area, or even in general, I suspect we're close to the "housing" bottom comparing to the projected long-term.

 

[Lock]

Its says in the owners manual, "Never charge the batteries for more than 24 hrs."

...because the EV came with a cheap charger. IMHO cheapest (long-term) and best "upgrade" for most EVs is to get a high quality smart charger appropriate for your battery chemistry (assuming bms/controller are good quality to begin with...)
tks
Lock

 

[swampjeep]

OK, for all us newbs and non-electrical engineers, could you explain what a smart charger is and how to properly maintain a battery?

most of your explaination above went right over my head, I mean what is the "absorbtion stage" of the battery? I'm totally lost with all this, but I know I'm no dummy, just never delt with electrical things on this level.

 

[Lock]

Hi swampjeep
I'm not qualified to advise here either... squandered my life as an accountant <sigh>
I'm only suggesting any charger that has a reputation for quality and smarts... Plenty of ES folks can make knowledgable recommendations here. Even just dealing w/a reputable dealer will do the trick. Soneil chargers have a pretty good rep.
ebikes.ca has a good rep on ES as a good dealer.
There are others... Hope others on ES will chime in on this subject. If you search ES for "charger" you will find messages like this:
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=5416&p=104230&hilit=+charger#p104230
tks
Lock

 

[dak664]

Well, it seems pretty simple to me. Always connect the batteries to a smart charger when they are not being used. If the instructions say to disconnect after a certain period of time then it doesn't sound like a smart charger. This link is easy reading:

http://xoweycarforum.com.invisionzone.com/lofiversion/index.php/t393.html

My bicycle batteries are either being used or connected to PV panels through homebuilt chargers, their third recommendation. But the article is somewhat dated, PV is a good choice even when AC power is available.

 

[OzzyU812]

Is it possible with products like these:
http://www.absak.com/catalog/product_info.php/products_id/850
http://www.batterylifesaver.com/

Are these store bought versions of what dax was talking about? Sorry dax I haven't done my homework yet.
I'd hate to throw away $300 worth of batteries. Even if it means spending $100 - $150.

Its says in the owners manual, "Never charge the batteries for more than 24 hrs."

...because the EV came with a cheap charger. IMHO cheapest (long-term) and best "upgrade" for most EVs is to get a high quality smart charger appropriate for your battery chemistry (assuming bms/controller are good quality to begin with...)
tks
Lock

I doubt anything is good quality. Remember I'm dealing with the cheapest turnkey E-bike.