52v BBSHD and 48v Battery

Chuy

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What issues, if any, will I encounter if I connect a 48v battery to a 52v BBSHD motor?

I did not know there where two versions of the BBSHD motor. Greenergy’s order process did not provide/offer a choice. When I open the box it had a 52v sticker. And a 48v battery is on the way from a different vendor. Will the motor run under powered? Will I have incorrect readings on the display? I have e-mailed the vendor but I don't expect a response until Monday, if at all. I may get their attention if I try and return the motor. But, if I am likely not to encounter any issues, I will put it together that way. Has anyone mismatched the motor and battery as such?

IMG_1281.jpeg
 

fabbrisd

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This is your 1st mid-drive build - right ?

1. You are 100% fine - so you know the BBSHD you puchased (Aliexpress - right ?) "technically" is rated for 48V but that sticker shows you have the correct/updated version which can accept up to 52V . Did the QR code bring up the full specs ?

2. Have you rechecked that you have correct match to the bottom bracket of your build ? Your shot shows 68mm - that "normally" means you are not building a Fattie with wide bottom bracket ?
 

Chuy

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@fabbrisd Yes, I ran the QR code, it just does an automatic Google query for a BBSHD motor.

And I have a non-fatty bike. It is a normal MTB I put together from a Nashbar frame I bought in 2007’ish. it has sentimental value. This is why I am not ditching it to get an assembled ebike. And I don’t have room in the garage for another bike.

I really just need it to work for a year or two. At which point I will convert my wife’s 10 year old Costco MTB with a 48v BBS02, give her this 48v battery, and get me a new 52v battery.

Yep, Aliexpress. Greenergy is the vendor. They also sell on eBay and Amazon, but the price is less via Aliexpress by about $130 For the same components, BBSHD motor and DM03 display.
 

hsdrggr

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Yes, I had the exact same situation. It works 100% fine. I eventually flashed the BBSHD controller with the 48v firmware. The only real difference is that the max amperage setting on the 48v firmware is 30amps instead of 28amps on the 52v firmware.
The 2 amps difference wasn’t even noticeable. Plus on my Eggrider display I routinely ride in Road mode and have it set at 20 amps max. I have off-road mode set to 30 amps, but I rarely use it in that mode.
 

fabbrisd

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Chuy - the EggRider display mentioned above would be a very nice match - the EggRider offers some detailed features that "other" displays just don't have, You might want to check that out..
 

Chuy

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@fabbrisd I actually have one on order. From Golden Motor Bike in Canada. Their list price is on the high side but their shipping, $8 to me, is the lowest I found and leveled out the total price. Plus, I wanted to support them for all the free content they have on utube. I learned many things from them.
 

ElHegpah

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Low Voltage cutoffs on the controller and battery measurements on the display will be incorrect unless you can change these by setting the battery type.

The controller will shut you off early because the lower limit is much higher for a "52V" battery than a "48V" battery. 58.8v and 54.6v fully charged, respectively.

Motor itself will run slightly slower, but no harm or problem, other than the above.
 

Chuy

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@ElHegpah Is that Low Battery Protect in the Basic tab? I set it to 38 volts, the lowest allowed setting. My battery shuts off at 36.4 volts. Are you saying the cut-off will be higher than 38 volts? The Eggrider does have voltage calibrations to adjust to the battery’s actual voltage output, and has battery mAh input fields - for up to three different batteries. I’ve clocked 30 mph on the flats, about normal from what I have seen for a 42t chainwheel and 11-34 cassette. I’m still on my battery’s first charge And have only put 20 miles on the motor. Life and adverse weather has cut short my riding time but I hope to change that soon.
 

ElHegpah

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LVC. Low Voltage Cutoff.

Bit of a judgement call whether you use 3.2V per cell, (41.6V total for 13S battery) 3.0V per cell, (39V) or some other lower number. Your Battery BMS is using 2.8, generally you set the controller to a higher per-cell number, as it is easier to recover from. Controller LVC, turn off and back on, and/or disconnect from battery, you can still limp home a bit with low power. Battery LVC, you have to connect a charger, and wait a while.

The same numbers for a 14S battery are one cell value higher.
 

m@Robertson

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My 48v motor has no difference on the LVC vs my various 52v/30a motors. The sole difference was the amp limit and the fact it was a hard 28a ceiling that cannot be adjusted by your standard issue Bafang settings alteration. Its locked up deeper in firmware.

This all came from Bafang deciding a few years ago they wanted to break the use of 52v batteries out of warranty concerns - which, considering zillions of BBSHDs havd been running fine for years on 14S packs tells me there was an ulterior motive involved, and this happened shortly before they took further steps to take their products to proprietary protocols and batteries.

Since they made the initial limitations, it seems the position has softened somewhat as its pretty easy to find vendors who have gotten around the limits (plus the BBSHD lives on rather than being phased out of production as was the original plan).

Bafang also fiddled with their displays so they would no longer work on a fully charged 52v battery. But you can buy displays from dealers that have defeated this limitation. Other 3rd party displays don't have the problem. My DM03, DZ40 and another mid-sized one whose alphabet-soup name I forget at the moment work great with 52v.
 
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