Battery for 48v 500w rear motor geared ebike conversion kit?

As a hobby project I’m planning to do an ebike conversion of a hardtail mountain bike using a 48v 500w geared rear motor conversion kit. I’m trying to make sure that the battery in terms of Amp hours is in the correct range for the volts and wattage. Is there an industry standard range or is it wholly dependent on the specific conversion kit chosen? Any help in this regard would be greatly appreciated. Thanks!!!
PS I’ve seen the numerous posts about conversions being a waste of time/money but I’m doing it as a project and plan to patiently minimize time/expense because I already have an ebike...
 

JES2020

Active Member
Amp hours determines range, voltage speed.
Any 48 v battery should be fine, I'm not sure but I think if you put a battery with higher voltage AND use the correct controller, the controller will modify the volts to the motor. So if I'm right that would mean the controller is the important item to match.
As far as DIY being a waste of time/money... don't believe it, I just finished a 1500w 52v geared hub /w 48v 20 ah battery for $800! Not including the bike of course.
 
Thanks for that excellent basic explanation. So if I want to go farther on a charge cycle I should go for greater Amp Hours, making spending a few bucks more for higher Ah worth it in the long run. You’re ride sounds like a good one and I hope you get a lot of enjoyment from it!!!
 

AHicks

Well-Known Member
Increased amp-hours = increased weight. Consider lugging that extra weight around when you are buying/picking out Ah.

The lesson I learned from an early build of mine was a bike with a 75 mile range, and a butt with a 20 mile range, got NO extra benefit from the extra Ah. Just extra weight.

The bikes after that bike all featured smaller Ah batteries. I've since settled on something with about 14ah, and they will most often go several days on a charge (about 35 miles).

I realize full well there are those with butts that have much longer range than my butt. Just wanted to toss that out for you to mull over in your decision.....
 

harryS

Well-Known Member
Everyone knows this, but it's true. Name brand cells (Samsung, Sanyo, LG, Panasonic, Sony) deliver better range than generic unknowns, The better batteries will tell you what's inside, or give you the option to have higher grade cells.

If I had to buy a 48V pack today, I would go to these guys. It's $80 shipping for $460 total, WHile I've never personally dealt with them, they seem to have a good rep with DIY guys. And you get a smart BMS.
.

I've bought a few packs from U.P.P. on aliexpress. I always upgraded to better cells, but I don't think their BMS boards are very good (no balance circuits). Starts at $280, and costs $100 more for name brand cells, So it's $380 shipped,


If you;re looking at $250 batteries,you're looking at lower quality.
 

JES2020

Active Member
Increased amp-hours = increased weight. Consider lugging that extra weight around when you are buying/picking out Ah.

The lesson I learned from an early build of mine was a bike with a 75 mile range, and a butt with a 20 mile range, got NO extra benefit from the extra Ah. Just extra weight.

The bikes after that bike all featured smaller Ah batteries. I've since settled on something with about 14ah, and they will most often go several days on a charge (about 35 miles).

I realize full well there are those with butts that have much longer range than my butt. Just wanted to toss that out for you to mull over in your decision.....
This is a good point! I am learning that my rear end needs more cushioning..... seat wise not butt wise.
Even though I have a gel seat, it's not one of those wide spring loaded gel seats. If I ever plan longer trips, one of those is on my shopping list.
 
Thanks all for the comments and suggestions.
I was initially considering whether I could get away with a lower Amp hour (EX. 8Ah, 10Ah) for less $$$ but I've since learned from your helpful insights-so I'm probably going to shoot for a range of approximately 13-14 Ah. I'm looking for something in the mid-range and don't want to break the bank so I think that should be a reasonable compromise. I'll keep you posted as I go along with the project.
 

indianajo

Well-Known Member
If I had to buy a 48V pack today, I would go to these guys. It's $80 shipping for $460 total, WHile I've never personally dealt with them, they seem to have a good rep with DIY guys. And you get a smart BMS.
I've bought a few packs from U.P.P. on aliexpress. I always upgraded to better cells, but I don't think their BMS boards are very good (no balance circuits). Starts at $280, and costs $100 more for name brand cells, So it's $380 shipped,
If you;re looking at $250 batteries,you're looking at lower quality.
If you are going to export your debit card number to a country where you are not protected by the FBI wire fraud investigations, use a throw away debit card. Then throw it away, quickly, after use.
I bought 2 piles of trash labeled samsung cells from amazon and ebay. Neither would put out even 5 amps. Then I bought a good battery from lunabikes near LA. ebikeling around chicagoland also has a good reputation. About twice the price of the above.
I get ~30 hilly miles out of 17.5 AH 48v @8 mph. I do carry 60 lb groceries uphill 200', but I only weigh 170.
 
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JES2020

Active Member
Thanks all for the comments and suggestions.
I was initially considering whether I could get away with a lower Amp hour (EX. 8Ah, 10Ah) for less $$$ but I've since learned from your helpful insights-so I'm probably going to shoot for a range of approximately 13-14 Ah. I'm looking for something in the mid-range and don't want to break the bank so I think that should be a reasonable compromise. I'll keep you posted as I go along with the project.
Thought you should know, if cost is a concern, high amp hour batteries are going to last you longer, because a batteries life is determined by recharge cycles, and more ah means fewer recharges per mile.
It's a ballancing act but that makes it customizable.
 

harryS

Well-Known Member
If you are going to export your debit card number to a country where you are not protected by the FBI wire fraud investigations, use a throw away debit card. Then throw it away, quickly, after use.

You can buy the exact same Em3eV pack from California ebikes, but they charge you extra,
 

Clyde

Active Member
As Aliexpress sellers go you could certainly do worse than EM3EV or Unit Pack Power, but I'd use a preloaded debut card, too.
 

JES2020

Active Member
Debit cards are more risky, as the money comes out of your checking account and getting a refund can be a a bit*h
I have had someone buy airplane tickets in Indonesia on my credit card.
Didn't cost me a cent, credit cards have fraud guard. The most you can lose on the worst credit card policies is $50.
 

JES2020

Active Member
That's why you use a preloaded card, not one that links to your bank account.
Never tried them.
What happens if you get ripped off?
BTW with all the free time, I fixed the possible knife attack against my battery shield. I just wrapped the velcro straps in tin.
No way they are getting a tin snips in there : )
 
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Does anyone have any experiences buying from these “usual suspects” through Amazon Fulfillment or eBay? I know in particular eBay has a pretty good Guarantee and I’ve utilized it when a Seller (domestic or otherwise) is difficult or unresponsive...
 

AHicks

Well-Known Member
That's why you use a preloaded card, not one that links to your bank account.


Why don't you just send them a check, or a Western Union Moneygram, or easier yet, cash? You have about the same level of protection with those as you do a "pre loaded" card.....

BEST plan is to use a PayPal account funded by a credit card. This gives you 2 layers of protection (2 more than a debit card). If the deal gets sideways (it happens on occasion), you have PayPal to intercede on your behalf. If PayPal can't (won't) help, your second line of defense is the credit card company......
 

JES2020

Active Member
Why don't you just send them a check, or a Western Union Moneygram, or easier yet, cash? You have about the same level of protection with those as you do a "pre loaded" card.....

BEST plan is to use a PayPal account funded by a credit card. This gives you 2 layers of protection (2 more than a debit card). If the deal gets sideways (it happens on occasion), you have PayPal to intercede on your behalf. If PayPal can't (won't) help, your second line of defense is the credit card company......
Been there, done that ! Pay Pal has refused to help a couple of time, so I just go to the CC company.
Sit on it Pay Pal !