can you recondition SLA Gel batteries?

[morph999]

I got one of these black and decker chargers that has a recondition function. And I got some CSB 1234WF2 batteries and I wondered if I could try to recondition them (desulfate them).

Also, when I come back from a ride, the batteries only take about 1 to 1.5 hrs to recharge but they are supposed to be 12v8ah batteries so if I'm charging them at 2 amps then shouldn't it take about 4 hrs to recharge? They've never taken over 1.5 hrs to recharge.

 

[Russell]

Morph,

How long is it taking to recharge your batteries after each of your rides?

-R

 

[morph999]

since I've had the batteries, they've never taken over 1.5 hrs to recharge.

I've got a black and decker that uses 2 amps and I've got a 48v charger that uses 3amps to charge and neither one has over charged longer than 1.5 hrs.

 

[morph999]

I just finished charging them today. I probably rode it about 1.5 miles and the 48v charger, charged all 4 batteries in one hour. I don't have a cycle analyst yet so I can't tell you much more than that.

So far the range I've had with these batteries has been only about 1.5 to 2 miles. Today I didn't even go very far, just testing the speed so it didn't give out on me today.

 

[Russell]

since I've had the batteries, they've never taken over 1.5 hrs to recharge.

I've got a black and decker that uses 2 amps and I've got a 48v charger that uses 3amps to charge and neither one has over charged longer than 1.5 hrs.

One time I drained my 3-12V/9AH battery pack to cutoff (31.5V) using 5.7AH and it took 4 1/4 hours for my 1.8A charger to fully recharge the pack. The last time I rode I used just 3.3AH and it took 2 1/3 hours to recharge.

I would suggest you check the voltage on each of your batteries with a voltmeter and jot that down then go for a short ride, a mile will do. When you come back measure each battery again with no load and once again with the motor spinning at full speed off the ground. If the voltages for each battery are close each time then your pack is well balanced, if not charge each SLA separately with your 2 amp charger before you put them back together in series.

-R

 

[nomad85]

I just finished charging them today. I probably rode it about 1.5 miles and the 48v charger, charged all 4 batteries in one hour. I don't have a cycle analyst yet so I can't tell you much more than that.

So far the range I've had with these batteries has been only about 1.5 to 2 miles. Today I didn't even go very far, just testing the speed so it didn't give out on me today.

If it only takes an hour to recharge they have barely been used and still have lots of juice left. I did a 2 mile ride on 60v of SLA today(same batts as yours, but they have been used a bit) and it took about 2 hours to charge them. The batts are fine, however desulfating is always a good thing to do(the soniel charger I recommended does it on every charge) with SLA's so go for it
Seriously though, you need to stop thinking the batteries are the problem(I am beginning to feel a bit insulted), If they were truly dead it would take at least 4 hours to charge them, it is either the controller LVC or the motor drawing to much current causing a big voltage sag(in that case you would need to parallel more batts together or use a lithium battery. to see if they are dead use a multimeter and check the voltage, if it is around 11-11.5v, they are indeed dead. I may be a bit off, does anyone know the SOC to voltage relationship with SLA?
Anyway I bet they are at 12.5v or higher resting voltage when your bike starts acting up. You can get a cheap multimeter for under 10$ or you can use mine when you come by next week and we can put the battery question to bed for good :wink:

 

[nomad85]

I would suggest you check the voltage on each of your batteries with a voltmeter and jot that down then go for a short ride, a mile will do. When you come back measure each battery again with no load and once again with the motor spinning at full speed off the ground. If the voltages for each battery are close each time then your pack is well balanced, if not charge each SLA separately with your 2 amp charger before you put them back together in series.
-R

That's a good idea, since you have that nice 12v charger, you might as well use it to keep them balanced. I don't do that with mine, and they are still performing like new, but doing so would likely make them last longer, I don't really care as I have a ton of them.

 

[Russell]

Nomad,

It still sounds like he's hitting the controller's LVC and all it would take is ONE weak battery to do that. The resting voltage isn't gonna tell you as much as running the bike until it exhibits the problem and then checking the individual battery voltages under a load. For comparison sake I snapped some pic's of my WU meter after my first ride and these are the numbers;

AH used: 4.810
WH used: 168.0
Vmin: 31.62

Resting voltage after ride: 35.49 to 35.65 or 11.83 to 11.88 per battery

This is for 3 12V/9AH batteries very much like the ones you guys are using.

-R

 

[nomad85]

Nomad,

It still sounds like he's hitting the controller's LVC and all it would take is ONE weak battery to do that.

I think its just the motor drawing to much current, or a controller issue rather than a bad battery, I have used/sold a lot of these and never had a bad one( I have ruined a few, but that was me being foolish). Like I said though, if they are bad I will exchange them. Considering the condition and appearance of the kit morph received from cycle9, I would assume the problem lies there and not in the batteries. I had to rewire the hall wires to make it work due to previous damage before morph even got the kit, if he had hooked it up himself the whole thing would have shorted out, 5 wires had exposed metal around the area they enter the hub including 2 phase wires, and the controller does not work properly with the throttle, the battery indicator and power button have no effect even though it is wired up correctly. I guess I just resent the accusation that something I supplied is at fault when the other variables are so suspect.

11.8v resting voltage sounds about right for 50-75% discharge if I recall correctly. Thanks for the data

 

[Russell]

Nomad,

It still sounds like he's hitting the controller's LVC and all it would take is ONE weak battery to do that.

I think its just the motor drawing to much current, rather than a bad battery, I have used/sold a lot of these and never had a bad one. Like I said though, if they are bad I will exchange them.

11.8v resting voltage sounds about right for 50-75% discharge if I recall correctly. Thanks for the data

Nomad,

He needs a Watt's Up meter ! Everybody needs a Watt's Up meter (or CA)!! It would be so much easier for folks if they had some instrumentation

BTW, the data I posted was for pretty much a drained battery pack. The most I ever got out of the pack on the road was 5.4AH and the most under ideal conditions, an indoor constant current test, was 5.7AH.

-R

EDIT: and that's why you really need to test them loaded because the resting voltage for a depleted pack looks fairly good but if I continued to ride pretty much any load would have taken that 35.5V resting right down to cutoff.

 

[nomad85]

Nomad,

He needs a Watt's Up meter ! Everybody needs a Watt's Up meter (or CA)!! It would be so much easier for folks if they had some instrumentation

I have offered to test his bike with mine, so we should be able to figure it out pretty easily.

EDIT: and that's why you really need to test them loaded because the resting voltage for a depleted pack looks fairly good but if I continued to ride pretty much any load would have taken that 35.5V resting right down to cutoff.

I am probably wrong and 11.8v resting is close to 100% discharged, I saw someone post a general guideline and I am probably remembering it incorrectly. Your right that a the voltage under load is more telling, but if the load is too high, then the voltage will sag low even when it has juice left.

 

[dogman dan]

Duuhh, It is the batteries. They are too dang small! That motor is supposed to be fast, so it's most likely yanking a lot of amps on every startup. Pedaling more to get going would help, no doubt, but that motor simply needs more battery than 8 ah. 12 ah slas are skimpy enough for a fast motor. A slower wound motor might be fine, or a gearmotor, but if this forsen only has 4 windings or so, it will lug when trying to start. I bet it's making a lot of heat too while it trys to get going. So he's hitting the lvc earlier than usual, and the controller may have a highish lvc. The charger may be giving a light charge too, or a combination of all these factors. Look for a loose connector on the charger output side, posssibly where the wire solders on inside. A bad connection on the output gives the same signal as a full battery. I had that one happen to me , twice, till I stopped carrying around chargers.

I agree, we know nothing without a voltmeter. A watts up or cycleananlyst, even better. But a voltmeter can tell us if the voltage goes off a cliff when he hits the throttle. A test ride of the batts on nomads bike will tell all too. For all we know, that controller could have a shunt mod, or something too. Everything would make sense if that controller allows 70 amps!

 

[dogman dan]

Btw, those batteries may be higher discharge, but they aren't the EV type, so while they may work fine on motors that draw lower amps, they may not be suitable for this particular bike. They say high discharge efficiency, not high discharge rate. Higher up on the web page for the CB batteries, you see the wheelchair batteries.

 

[nomad85]

That would mean the motor is the problem(amp draw and the batteries are fine, but not right for that motor.)

 

[Mathurin]

Lead isn't charged when the charger greenlights, try letting the batteries on the charger at least overnite.

 

[Russell]

Lead isn't charged when the charger greenlights, try letting the batteries on the charger at least overnite.

It depends on the crossover point the SLA charger uses to determine when it switches to standby. If the charger switches to standby when the current is still relatively high then there's still a bit more juice to put in the battery. If the charger is well matched to the battery however when it goes to standby the battery is probably 99% full.

I don't leave my 36V SLA charger on the pack any longer than necessary because the standby voltage is at the high end of spec at 41.4V or 13.8V per battery. At this voltage it is pushing a bit too much current through the pack for standby use and doing nothing but generating heat in the battery.

You may have a point however if the individual cells in the lead acid battery are out of balance, then a prolonged trickle charge may help restore the balance.

-R

 

[morph999]

The motor is 22 lbs so yeah these batteries might be too small.

 

[Mathurin]

Right, good point about balancing, but wait: standby use would be something like emergency lights, on an ebike the batteries are in cycle use. Here is a datasheet for OP's batteries, you can see where the charger goes green, it's when the battery voltage reaches a plateau, but over the next few hours the batts slowly gain the rest of ~10% capacity. http://www.csb-battery.com/upfiles/dow01228270534.pdf Overnite is probably more then needed to reach it, but beyond a certain point there's almost nothing flowing per the drainbrain anyways. So, my batts sit on the charger all the time I'm not using them, and they seem to be quite happy for it, also it seems to give them more breath for sprints at 3C.


But I'm wondering about OP's setup, do you keep your batteries somewhere cold like an unheated garage around freezing temperature perhaps? Also, I wonder what wire size is used, and I know you have deans for connectors but maybe there's an oversight on connections somewhere between the batteries and controller, does anything there get even slightly warm? Also, what's been said earlier about running the bike until it exhibits the problem and then checking the individual battery voltages under a load seems like a good plan.

 

[Eric G]

Here's a state of charge chart...

If there's a shorted cell in a battery it will appear fine when checking with a voltmeter but if you put a load on it and check with a voltmeter it will drop real quick.

Eric

 

[nomad85]

Eric, Thanks for posting that, sounds right to me

 

[starrychloe]

Yes see www.reconditionbatteries.com/BatteryReconditioning.pdf