Oddly enough, the batteries charged totally normal today, and the charger did cut off when appropriate. I didn't ride around too much since then yet, but at the moment everything seems OK.

I'm still concerned about how hot the batteries got the other night, so I will be monitoring this as time goes on.

Did you possibly have multiple power outages in a row that night. If the power goes off then back on then off again then on again in a short period of time the charger may get confused and think the battery needs a complete full charge even if it is almost fully charged. This will cause the charger to vastly over charge the battery pack and cook it. But this only will happen if you have multiple power losses or brown outs (low voltage or sags) in a row in a short time period in between them.

Ken Finch

I'm not aware of anything like that happening, as we had no power outages at work that day.

Interesting point though, I'll definitely watch out for that kind of situation in the future.

So how's the full-time at Mobility going for you so far?

Well it is very demanding work, physically and mentally. But the pay is good and I enjoy a challenge and the people working there are great to work with and good personalities. I am enjoying myself working there, I can see this being a long term position if I play my cards right and try not to fowl up. I feel I can trust them and feel comfortable around them.

Ken Finch

That's good to hear, glad it's working out for you. Chances are I'll run into you there someday soon, been meaning to attempt another ride down to the area-- but better make sure my battery is OK first! :P

Thanks again.

Ken Finch

You should open the battery box and have a visual and you
will know whats going on inside .There are only a few appliances
that are very susceptable to voltage drop and your charger is
one of them. Avoid long extention cords due to the voltage
drop.If you need to, use a larger gauge wire extention cord.
Another thing is, is there anything else that draws a lots of
power on that circut.
If you have somthing that could cause a voltage drop this
will cause your charger to act-up.
What you put in at one end (120vac) will give you a set
voltage at the other end .
If the voltage is to low the charger will never see the
high cutout limit causing the batteries to over charge.
Denis

For Lithium packs, a Battery Management System that monitors things at a cell level is pretty much a "given"...
With lead packs, if the separate batteries get "out of balance" - each not charged to the exact same voltage level - this is not so critical as with Lithium. Nothing will go "boom"... Worst case after a deep discharge ya can have a "cell reversal" and one badly out of balance battery will be ruined...

Perhaps for a small pack (2x or 4x 12V) this is not such a big deal... But the thing is, a series of lead batts are like a chain... the controller/motor only "sees" the weakest link. Hard for me to explain, but here is another explanation:

"Modern AGM type batteries fail to equalize their charging voltages when charged in a series string. A Rudman Regulator on each 12 volts battery or block of batteries will protect them from over voltage damage during the last phase of a charge cycle."
"The easiest way to maintain a equal charge on any single battery during a charging cycle is to regulate it's voltage. If all the batteries in your series string are at the same voltage during the Float stage of charging, then they will be equalized as much as possible. AGM type batteries capacity vary during manufacture, and they tend to get out of equalization during use during heavy EV cycling. The first battery to "fill Up" has a higher resistance and then robs the other batteries of the charging current that they need to be totally charged. Then during discharge the same happens to the first battery to be completely empty. So some batteries get damaged from over voltage and thermal, and some get damaged from cell reversal and never fully charged. An AGM string has very little "give" to it while finish charging. A battery bypass regulator gives the string the "give" it needs to protect the first to get full, and to pass the unneeded power along to the batteries that still are charging."

This explanation comes as a note used to "sell" the Rudman Regulator... $40 each, one per battery... Looks like this:


Rich Rudman of Manzanita Micro has been a leading light on the EVDL for many years. Manzanita product are considered the Gold Standard... Manzanita here:
link here

Anywhooo... just thought I would add this info/links here. This would only be of interest to folks looking to really maximize the useful life of their SLA batteries...

Cheers
loCK

Here is a link to a video the explains this situation again, showing the DIY approach to a cheaper but less energy efficient way of handling this, the "Zener Regulator":



tks
LoC

Found these:


here:
link to evequipmentsupply.com

good investment at only $11 each (per battery)
tks
lloK