Hello folks,
Before you ask “WHY?” or comment negatively understand that this bike and I have done many-many miles, so I do feel rather attached to her. “HER” because of the Cranberry Red color; and my wife allowed me to purchase her back in 1999 to commute to work from the ACE train station in San Jose to Silver Creek Valley Road (>12 miles). I have all of the original tools, bags, pump and Service Manual with schematics. I even found my logbook showing over 8.3K miles ridden on her using x4 different SLA sets. Rain or shine, she never let me down; except those darn SLA batteries would barely last a year. Yes, the 24V EGV is too slow, thus why I have a WW Hydra XL on order. But until the molds for my new frame get done and bike in my hands, I really wanted to see if I could get my Cranberry Girl on the road and running again….
So today I took her out of the barn and removed probably 16 years of cobwebs and dust. She is still filthy and will get a sponge bath soon, but I needed to see if she still “WORKS” before I would consider purchasing another pile of batteries. Attached a 24V bench supply I have, limited current to 3A (supply max!); she fired right up with some WELCOME BEEPS and turned the rear wheel just fine. Horn and lights all work too!!! Time for next step;
DA BATTERIES….
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Having read every post on this EVG Forum, I know this post is going to be DARK, unread and unloved. But just in case there is some other fool out there like me that wants to get a simple & safe ebike working again, hopefully you will have an answer/solution below. I really appreciate the inspiration from the writings of
@kauaikit,
@Court and others to motivate me to start this project. I do hope it turns out sucessful…
First step was to open the old EVG 24V battery box and remove the old 12V 12Ah SLA (sealed lead acid) cells. These buggers weigh approx. 7.7lbs (3.5kg) or 15.5lbs (7kg) together. I remembered I would almost run out of battery as I would ride home from the ACE station. So, GOAL#1 – REDUCE BATTERY PACK WEIGHT (half?) & GOAL #2 – IMPROVE AMP-HOUR.
Today was really fun, as I was rummaging in the barn for all the EVG things, I found a receipt for my first purchased EVG battery replacement pack. Sadly, I was told from the dealer in Santa Cruz it was to be a new one. Some $300 w/ shipping and several weeks later, my first replacement battery pack arrived. It was pretty obvious it was a rebuild unit with all the scratches and pry marks. That lesson educated me to buy batteries from the local brick and mortar. I stopped in to the local Batteries Plus Bulbs today and they offered me a $60 unit, where I need x2 and hit with tax, core charges, etc. That would have been approx. $150 and give me the same performance I had over 20 years ago. Giving GOAL#3 – Cost less than $300. I found a 15Ah SLA on Amazon x2 for <$60 and free shipping. Brick & Mortar is truly dead….
The EVG 24V battery box has two 150x100x100mm compartments for the SLA. I looked at the
LiPo RC batteries as per a post in this forum, but they are VERY EXPENSIVE and really need a super special charger to not IGNITE! I saw another
forum post where a 36V EVG guy was going to try an array of 18650 cells (15x7), so that gave me an idea to look for maybe a 7s7p or 6s6p pack. I’m taking the sage advice from
@kauaikit to do a 6S pack as 7s might be too much voltage (29.4v). To further, I used the bench supply to test the battery warning lights, they seem to match Lithium Ion curves, but I do plan to add a battery measurement display. So today I placed a purchase for x2 6s5p 18650 packs. They measure approx. 110x100x70mm, weigh less than 1.5kg, have integral BPS and come with a small computer brick like AC powered battery charger. Here is my plan, and I would love some advice from battery people like
@greeno to make sure I will not be starting fires in the barn as a result of this ½-baked plan! I plan to hard wire parallel both 6s5p packs together with 15A auto blade fuses from the two packs positive terminals. I believe there is enough room in the EVG box to include the two AC powered battery chargers as the EVG pack has a C13 AC port. My question to the forum is, can I just plug in a charger to each battery knowing that the two chargers will be in parallel too. Any issues doing this?? Or do I need to think of paralleling the two packs with x2 current diodes to isolate the chargers??? Also placed on order are new brake pads, tires, and tubes.
So if this works, I will have a new 56Ah, 24V (1.3kWh) battery pack for the Cranberry Girl. That is more than 4 times the range and way less than 1/2 the weight (4kg or 8.8lbs savings!). Including the brake pads, tires & tubes, I am right at $300....
More to come….
-BB
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