I took the batteries out and clipped them individually onto a SLA 12v charger. It seemed to be working, the 11.8v battery came up to 13v. The other battery came up to 9.1v after sitting a bit, but the SLA charger wouldn't initiate charging it. It seemed to lose voltage on the SLA charger
A lot of chargers have a low voltage / safety shut off so they can't accidentally spark when they are not hooked to anything & or shut of a low voltage.
Wire your bamboo's in parallel ( 2 batteries 12 volts) & charge them. This will allow the charger to kick on. After they are wired together check the voltage. Connect the charger & recheck them. Is it higher? Assuming it is let them charge for a few hours together, the goal is to get them to 12.8 or above. At that point you should be able to properly charge them with the Lipo charger
DON'T GIVE UP! I have a lot of these batteries. I too am unsure of how these things will last but my oldest ones are approaching a year & I have yet to have a failure.
dogman is the most pessimistic person I have met in this forum. He's NOT WRONG, just negative. He's been shorted out 1 to many times.
Worst case you're dealing with Clean Republic in the USA. Explain the problem & ask them to send you 2 fresh batteries FROM THE SAME LOT! Tell them that your friends from Endless Sphere don't think very highly of these batteries & you would like to prove them wrong.
Definition of "Motorcycle Battery" How dogman describes any small 12 volt battery that is to be used in a conventional 12 volt starting system.
Read "Staring System". It has very different characteristics from what we are attempting to use them for. Look at my pics on page 1 of this post. See how they are snugly sitting inside an expandable foam insulation. That & the lack of any extra electronics means they will take a pretty good physical beating. As a 12 volt starter battery & probably even in a UPS they will last a long time.
Knowing all of this I'm still willing to experiment with them for the sake of cheap & easy e-bike power. If you can get better than lead acid acid power at 1/4 th of the weight it boils down to overall value. If you can get LifeP04 performance & at least a 500 cycle life for 60% of a BMS supported battery it's probably worth it.
For what it's worth. When I get a new bamboo I hook up a 55 watt 12 volt halogen bulb & a meter & plug it WHILE I'M WORKING IN THE SHOP so it can be monitored. They all come through with a 12.4 through 13.1 volt charge on them. Run them down to 11 volts. WATCH CLOSELY !!! WHEN THEY HIT 12 VOLTS THEY START DROP LIKE A STONE. I then use one of their 14.8 LifeP04 charges & bring them up to max which is as per my muti-meter 14.9 or 14.77 with my Watts Meter. If you want to test them again & I always do, using 1) 55 watt 12 volt halogen it should take 1) 12 volt bamboo 1) hour to discharge from 14+ volts down to 12 volts & another 10 min. or so to get down to 11 volts. DON'T GO BELOW 11 VOLTS as you can damage the battery pack.
FINAL NOTE: THERE IS NO WAY TO CUT THIS PACK APART TO A POINT WHERE YOU CAN CHARGE THE INDIVIDUAL CELLS UNLESS YOU HAVE NO INTENTION OF PUTTING THEM BACK INTO IT'S ORIGINA. BOXL. ALSO... ONCE THE PLASTIC COATING IS SCRAPED THROUGH AS IN MY PICTURES THE METAL CASING IS NOT ISOLATED FROM THE GROUND ( - ) I.E. you can get a reading up to 3.3 volts between any 2 battery casing's & up-to the total pack voltage from the ground ( - ) terminal & one of the battery casing's.
Hope this helps. Email me direct or call me if you need more info.
Matt
ezgo-now.com