sla 3x12v12ah losing speed question

[jeohearn]

I am not a technological person and know very little about batteries. (Although I do know that a lifepo4 would cost me between $500-$600 per month and last longer)
After 3-4 months of use, 5 days per week, charging twice daily for a 7 mile one way commute, I am just now experiencing a decrease in speed (of 5 mph) during the final mile of this commute. The commute is relatively flat but there are some minor hills, and the one way to work is a not very noticeable slight uphill grade most of the way. Does this seem reasonable at this point in the batteries life? Is this normal?
Next question: how much longer will this battery last -will it gradually lose speed earlier and earlier in my commute...or will it suddenly just die?
Thanks for your help.
Jeff

 

[dumbass]

I am not a technological person and know very little about batteries. (Although I do know that a lifepo4 would cost me between $500-$600 per month and last longer)
After 3-4 months of use, 5 days per week, charging twice daily for a 7 mile one way commute, I am just now experiencing a decrease in speed (of 5 mph) during the final mile of this commute. The commute is relatively flat but there are some minor hills, and the one way to work is a not very noticeable slight uphill grade most of the way. Does this seem reasonable at this point in the batteries life? Is this normal?
Next question: how much longer will this battery last -will it gradually lose speed earlier and earlier in my commute...or will it suddenly just die?
Thanks for your help.
Jeff

Remember there are several things that kill SLA batteries. You don't say what size/kind of motor and setup you have. So assuming the worse case you were running full throttle for the full 7 miles and recharging at work. I'm guessing those batteries were sucking wind by the time they saw that charger. Then headed home again at full throttle and driving them into the ground again. Based on 4 months at 5 days per week that's about 160 days * 2 - 320 full charges. I would say your lucky they lasted that long. Yes SLA batteries can last much longer but not if they are run into the ground twice a day. I would guess that they will continue to degrade and total death is just around the corner. However, there is always a charce you may have only one battery that is weekening. You maybe able to do a full charge and a timed load test on eack battery and found the week battery. But likely at the rate you have been using those packs they are all dieing. Hard to say how much longer they have but if I were you I would buy a bus token just in case.

Yes lifepo4 packs are much more expensive but you can shell out 100 bucks every 4 to 5 months or $500 once every few years.

 

[deardancer3]

could I ask if your batteries are any colder now than when you started?

once below 50F, SLa's lose some 'umph', a technical term.

d

 

[torker]

Actually that should only be 160 cycles not 320 and I would think 7 mi. on 12 ah would be acceptable. But even 160 cycles is getting up there for lead. I would also suspect one bad battery or the cold may be getting to them.

 

[dumbass]

Actually that should only be 160 cycles not 320 and I would think 7 mi. on 12 ah would be acceptable. But even 160 cycles is getting up there for lead. I would also suspect one bad battery or the cold may be getting to them.

OPPs!! Your right.

 

[deardancer3]

jeohearn, didnt you post a bit back about really cold hands? If you are riding in the cold, that is what is decreasing your battery speed and range.

Bring your batteries indoors to keep them warm, charge at room temp, wrap in insulation for the ride.

if you cant bring in, then research a small heating pad with some controls or a timer.

others have written about the topic this winter.

If you have cared for your SLA's, it a little early for them to be going weak, unless they were problematic to start.

d

 

[amberwolf]

I'd agree on this. Plus, perhaps a moderator could combine all of the duplicates of this thread that were started in different parts of ES into just one of them?