Replacing batteries on Giant LaFree Sport (first generation)

[cvcalhoun]

I recently got one a Giant LaFree Sport bike, which was probably one of the first ones ever made. It worked fine for about 50 miles, then wouldn't turn on. So I went to replace the battery. I got the appropriate new batteries. But bike shops won't install it, battery shop won't install it, lowest estimate I got from a bike repacking place was about $400. The prior owner says she always did it herself. But I've unscrewed every screw I can find, and I still can't get into the case to do this. Does anyone have any ideas?

The picture below is how far I got. As you can see, with the top off, there is a rim all around that holds the batteries in place. It's split in the middle, suggesting that it should be possible to lift up the two halves, but I can't find a way to do that. Any thoughts on how I open that up to get the old batteries out and put the new ones in?

 

[indianajo]

Ebike batteries are welded up from individual cells. On Lithium ion batteries the welding is a dangerous process which can lead to a huge chemical fire if the arc or flame penetrates the battery case. I suggest one leave the welding of LiIon cells to trained people in a foreign country. Definitely not something that should be done indoors in a residence or apartment. Stacks of cells pressed together, as D cells in a radio, do not make a reliable connection at the 4 amps per stack that e-bike grade cells should put out. Lead acid batteries are cast or wound, then inserted in a rubber molded case which is glued to a plastic molded top. Taking the insides out & replacing them is not done.
I bought my bike battery as a unit, then wrapped in a shell of aluminum angle so I could mount it to the bicycle. You apparently have a used battery where the battery is wrapped in a plastic molding. This molding can be sawed off, but can't be replaced by any process involving a machine costing less than $300000. Whereas you can buy aluminum angle at the home store, saw it up in to appropriate legs, drill holes, and screw them together with #10 or 5 mm screws. The battery itself is wrapped in a piece of heat shrink plastic, the 8" variety available from ali. I further wrapped my battery in sheet packing foam to insulate it from cold, and then heavy plastic bag to keep the rain off and disguise it. My bag is green.
Your battery shows a voltage of 12.6 to 14.something. This is an extremely obsolete battery. You can still buy scooter batteries of that kind, which are usually lead-acid technology that doesn't offer much energy density or range. It won't have the mounts matching your original battery. Enclosing the scooter battery in a cage that can be screwed to any part of the bike is up to you. I used aluminum angle. Steel would also work. I pointed the screw ends out so the screws wouldn't wear holes in the battery. The foam wrapping I put around my battery allowed me to get a long screwdriver in from the opposite side and hold the screws while I tightened the nuts on the outside. I used elastic stop nuts from mcmaster.com so the nuts wouldn't fall off. I used stainless steel screws & nuts so they wouldn't rust in the rain. My battery cage has been assembled now for 4 years, and hasn't come loose. Wannabe thieves have loosened one or two nuts while I was inside the store shopping, but never completely removed even one because elastic stop nuts fight you all the way off. My battery cage has 24 screws & nuts. Mcmaster.com sells screws & nuts in boxes of 50 or 100 each. Alternate sources are grainger.com and fastenal. Freight is usually higher on grainger because they ship each item from a different warehouse. Mcmaster only has two warehouses and 80% of orders come in one box, for as low as $9 freight for small items.
Happy designing and building.

 

[cvcalhoun]

Ebike batteries are welded up from individual cells. On Lithium ion batteries the welding is a dangerous process which can lead to a huge chemical fire if the arc or flame penetrates the battery case. I suggest one leave the welding of LiIon cells to trained people in a foreign country. Definitely not something that should be done indoors in a residence or apartment. Stacks of cells pressed together, as D cells in a radio, do not make a reliable connection at the 4 amps per stack that e-bike grade cells should put out. Lead acid batteries are cast or wound, then inserted in a rubber molded case which is glued to a plastic molded top. Taking the insides out & replacing them is not done.
I bought my bike battery as a unit, then wrapped in a shell of aluminum angle so I could mount it to the bicycle. You apparently have a used battery where the battery is wrapped in a plastic molding. This molding can be sawed off, but can't be replaced by any process involving a machine costing less than $300000. Whereas you can buy aluminum angle at the home store, saw it up in to appropriate legs, drill holes, and screw them together with #10 or 5 mm screws. The battery itself is wrapped in a piece of heat shrink plastic, the 8" variety available from ali. I further wrapped my battery in sheet packing foam to insulate it from cold, and then heavy plastic bag to keep the rain off and disguise it. My bag is green.
Your battery shows a voltage of 12.6 to 14.something. This is an extremely obsolete battery. You can still buy scooter batteries of that kind, which are usually lead-acid technology that doesn't offer much energy density or range. It won't have the mounts matching your original battery. Enclosing the scooter battery in a cage that can be screwed to any part of the bike is up to you. I used aluminum angle. Steel would also work. I pointed the screw ends out so the screws wouldn't wear holes in the battery. The foam wrapping I put around my battery allowed me to get a long screwdriver in from the opposite side and hold the screws while I tightened the nuts on the outside. I used elastic stop nuts from mcmaster.com so the nuts wouldn't fall off. I used stainless steel screws & nuts so they wouldn't rust in the rain. My battery cage has been assembled now for 4 years, and hasn't come loose. Wannabe thieves have loosened one or two nuts while I was inside the store shopping, but never completely removed even one because elastic stop nuts fight you all the way off. My battery cage has 24 screws & nuts. Mcmaster.com sells screws & nuts in boxes of 50 or 100 each. Alternate sources are grainger.com and fastenal. Freight is usually higher on grainger because they ship each item from a different warehouse. Mcmaster only has two warehouses and 80% of orders come in one box, for as low as $9 freight for small items.
Happy designing and building.

Thanks for your response. I already had the appropriate batteries, which amazingly enough are still readily available. (I got them from Walmart.) My problem was that I couldn't figure out how to get the case open. Fortunately, the prior owner came and showed me, so all is now well. I was quite relieved, inasmuch as two bike stores plus a battery store had basically told me that my only choice was to pay anything from $400 to $1,500 to get the batteries repacked--and that was well more than what I paid for the bike (or what it was worth).