View Full Version : Breaking in a Battery Pack

17 September 2010, 1112
I've read a lot about how to care for a Lifepo pack in an EV application, but now that I've run my EBR a couple of times, I realized I don't know all I should about breaking in and optimizing an AGM pack.

At present, I have six 22 AH AGM scooter batteries. I'm charging them with Battery Tenders. On my first run, I took the bike out for about 4.5 miles before I started to feel like the pack was losing its punch. I had been running the motor on the rack and had a couple of unsanctioned runs up and down the cul-de-sac prior to putting on these miles, so the pack was not 100%. And, on my first run, I was admittedly working the wrist a little harder than I should have. The dang thing is just fun to ride!

On my second run this afternoon, I went 8.3 miles on a fresh charge. At the end of the run, the pack voltage was showing at 70.8V. I had to stop the run because I found my drive sprocket had moved a bit on the shaft. Time for some threadlocker on that. Other than that, the conversion is rock solid.

Anyway, my questions are

1) How far does one typically draw down an AGM pack and stay in the safe range?

2) Is pack voltage a reasonably accurate indicator of what's left in the tank? I realize voltage equates to fuel pressure as opposed to fuel quantity, but it is still related.

3) Last -- after a run, is it recommended to let the batteries rest before beginning the recharge? They are not hot. They're a little warm, but no more than a hound dog's belly. (I say this because I'm petting the hound as we speak. Belly temp and batteries feel about the same.)

Thanks for the insights. I am totally thrilled with this conversion, even in its current state!

17 September 2010, 1217
When one of your batteries starts to hiss loudly, you will want to stop. :(


17 September 2010, 1427
I'll bet that one was warmer than a hound dog's belly.

17 September 2010, 1430
A hound dog's belly? Hmm, I guess Herndon is a little further south than I realized :rolleyes:

17 September 2010, 1815
Yes, it is good to cycle at low speed (at least slow acceleration) any lead battery pack for at least 15 to 20 times.
Lifepo4 I have seen require even more.