Help with battery size fitting for a merida big seven

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kenl   1 mW

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Help with battery size fitting for a merida big seven

Post by kenl » Jun 11 2021 7:01pm

Hi all

I'm having a dilemma of finding the right battery pack to fit my frame that will be suitable for the bbshd that I already have from lunacycle
But the jumbo shark from the measurement I did does not appear to fit

I've looked at em3ev super shark which will fit just fine but it's only 25A and I will need it a 30A for it.
My plan is not to go crazy fast and only look to stay around 40kph

Need some idea how to get around the battery issue

Thanks
Ken

TNC   100 W

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Re: Help with battery size fitting for a merida big seven

Post by TNC » Jun 11 2021 10:15pm

Just to clarify, when you're saying 25A and 30A in a Super Shark, which one are you referring to? I was looking at the Super Shark category and didn't see anything at that level. I'm thinking you're talking about the amperage of the motor, right?

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Chalo   100 GW

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Re: Help with battery size fitting for a merida big seven

Post by Chalo » Jun 11 2021 11:58pm

If you get a triangle battery or a rack battery, you may not have the same problem meeting your controller's current demand.

There's nothing especially wrong with Hailong battery cases, but they're not the only game in town.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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E-HP   100 MW

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Re: Help with battery size fitting for a merida big seven

Post by E-HP » Jun 12 2021 1:56am

Ya, the small frame definitely is pretty tight on space. I'd look for a triangle pack like Chalo suggested.

Image

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Re: Help with battery size fitting for a merida big seven

Post by TNC » Jun 12 2021 9:21am

Did a quick scan of the internet but didn't see it. What does a 30ah bicycle battery weigh as a general average?

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E-HP   100 MW

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Re: Help with battery size fitting for a merida big seven

Post by E-HP » Jun 12 2021 10:17am

TNC wrote:
Jun 12 2021 9:21am
Did a quick scan of the internet but didn't see it. What does a 30ah bicycle battery weigh as a general average?
Assuming 13S9P of 35E cells, 117 cells at 50g each, about 13lbs of cells, plus case and bms. That would be 31.5Ah.

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Re: Help with battery size fitting for a merida big seven

Post by TNC » Jun 12 2021 7:10pm

E-HP wrote:
Jun 12 2021 10:17am
TNC wrote:
Jun 12 2021 9:21am
Did a quick scan of the internet but didn't see it. What does a 30ah bicycle battery weigh as a general average?
Assuming 13S9P of 35E cells, 117 cells at 50g each, about 13lbs of cells, plus case and bms. That would be 31.5Ah.
Wow!...that's a load of battery...LOL! I'm still not clear on the OP's description of the battery he was looking at. He mentions EM3ev Super Shark at "25A". I didn't find any Super Sharks or Jumbo Sharks higher than 17AH. I had looked at EM3ev for batteries earlier this year and didn't remember any 25AH batteries in their Shark series so I was just curious. I'm just wanting to make sure what measurement the OP is referring to so he gets the best advice. I'm still wondering if the 25A and 30A he is referring to is his actual motor max amperage for the BBSHD. Even EM3ev's biggest triangle battery appears to be 20.4AH. I'm new to the battery game for these ebikes, so I may be off here...LOL!

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E-HP   100 MW

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Re: Help with battery size fitting for a merida big seven

Post by E-HP » Jun 12 2021 10:19pm

TNC wrote:
Jun 12 2021 7:10pm
I'm still not clear on the OP's description of the battery he was looking at. He mentions EM3ev Super Shark at "25A". I didn't find any Super Sharks or Jumbo Sharks higher than 17AH. I had looked at EM3ev for batteries earlier this year and didn't remember any 25AH batteries in their Shark series so I was just curious. I'm just wanting to make sure what measurement the OP is referring to so he gets the best advice.
The quality of the advice that the OP gets is dependent on the information provided. Maybe at some point the OP will return and provide more info, but not worth guessing at until then, IMHO.

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Re: Help with battery size fitting for a merida big seven

Post by kenl » Jun 13 2021 5:25am

Thank for the the feed back all.

Sorry the 25A and 30A was referring to the controller of the bbshd. While putting my order in for the super shark em3ev told me the super shark rated continuous 25A is too low for the HD requirements. Eg pulling too much amps off the smaller pack, creating unnecessary heat and stress to the pack and such. Correct me if I understood that.

I just did some more measurement on the frame after taking the water bottle holder off, It appears it's might just fit the jumbo shark. Just. With about 10cm to play with on both directions. I'll need to go back and check the location of the bolt and reconfirm

Alternatively will have to go triangle but do like the ability to have the battery locked in place with a lock for some low level security when I need it.
Last edited by kenl on Jun 13 2021 5:25am, edited 1 time in total.

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Re: Help with battery size fitting for a merida big seven

Post by TNC » Jun 13 2021 1:14pm

kenl, any of those super or jumbo sharks at 52V that I saw will have enough power to run a BBSHD...as long as frame fitment is good. That jumbo shark at 17AH seems like a relative bargain.

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Re: Help with battery size fitting for a merida big seven

Post by 99t4 » Jun 14 2021 1:55am

kenl wrote:
Jun 13 2021 5:25am
I just did some more measurement on the frame after taking the water bottle holder off, It appears it's might just fit the jumbo shark. Just. With about 10cm to play with on both directions. I'll need to go back and check the location of the bolt and reconfirm
You can add rivnuts to the downtube in the necessary locations at low risk. Remember you may need additional clearance to slide the battery on/off the base.

Will this triangle pack fit?
https://calibike.com/product/48v20t-ele ... -warranty/
Specs list 38A Continuous Discharge Current
Triangle 10.5″ x 15.0″ x 18.0″ x 3.75″ wide

kenl   1 mW

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Re: Help with battery size fitting for a merida big seven

Post by kenl » Jun 14 2021 6:55am

so i finally got sometime, went away and got some home work done on this.

this is for the em3ev jumbo shark dimension of
Maximum dimensions of: 88mm thick. 113mm tall, 368mm long (See the outline drawing in additional images, for details). Please allow about 18mm forwards and 8mm upwards for the battery to clear the slider that attaches to the water bottle mounts.

i doubled checked these and hopefully it is right

sharing this in case its i've got it all wrong or if it does become useful to someone else that might have the same bike frame.

wasnt exactly sure what way to do this but this is what i had.
merida - jumbo shark.PNG
merida - jumbo shark.PNG (262.5 KiB) Viewed 145 times

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Re: Help with battery size fitting for a merida big seven

Post by 99t4 » Jun 14 2021 6:43pm

Just make a lifesize cardboard cutout of the battery profile (to include the mount and attach/detach clearances) and hold it in position on the frame, see if it physically fits.

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E-HP   100 MW

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Re: Help with battery size fitting for a merida big seven

Post by E-HP » Jun 14 2021 8:06pm

99t4 wrote:
Jun 14 2021 6:43pm
Just make a lifesize cardboard cutout of the battery profile (to include the mount and attach/detach clearances) and hold it in position on the frame, see if it physically fits.
I made one for the same battery. I had to do some scaling in Photoshop to get the dimensions correct so that it would print to scale, and had to print it on two sheets; spray mounted the prints onto cardboard and cut it out.

kenl   1 mW

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Re: Help with battery size fitting for a merida big seven

Post by kenl » Jun 15 2021 5:15am

E-HP wrote:
Jun 14 2021 8:06pm
99t4 wrote:
Jun 14 2021 6:43pm
Just make a lifesize cardboard cutout of the battery profile (to include the mount and attach/detach clearances) and hold it in position on the frame, see if it physically fits.
I made one for the same battery. I had to do some scaling in Photoshop to get the dimensions correct so that it would print to scale, and had to print it on two sheets; spray mounted the prints onto cardboard and cut it out.
Thanks guys, I should have just done that in the first place. :bigthumb:

Looks like a easy fit after all.
Jumbo shark on order now
20210615_200609.jpg
20210615_200609.jpg (3.1 MiB) Viewed 113 times

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Re: Help with battery size fitting for a merida big seven

Post by TNC » Jun 15 2021 9:53am

kenl, just out of curiosity, which amp hour version did you go with?

kenl   1 mW

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Re: Help with battery size fitting for a merida big seven

Post by kenl » Jun 15 2021 8:15pm

TNC wrote:
Jun 15 2021 9:53am
kenl, just out of curiosity, which amp hour version did you go with?
17.0ah on the 35e cells. 14s5p
So going back to the 30A question, they were referring to the continuous discharge value the pack could handle and they recommended to stay away from the 14s4p as it could only handle 20a continuous. That's my understanding anyway

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E-HP   100 MW

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Re: Help with battery size fitting for a merida big seven

Post by E-HP » Jun 15 2021 9:00pm

kenl wrote:
Jun 15 2021 8:15pm
TNC wrote:
Jun 15 2021 9:53am
kenl, just out of curiosity, which amp hour version did you go with?
17.0ah on the 35e cells. 14s5p
So going back to the 30A question, they were referring to the continuous discharge value the pack could handle and they recommended to stay away from the 14s4p as it could only handle 20a continuous. That's my understanding anyway
5P x 8A = 40A continuous under ideal conditions and when new. 30A probably provides a decent margin if you aren't running 30A continuously. Others may have differing opinions depending on how conservative they are.

4P x 8A = 32A so they are basically using 5A to be conservative (20A for the pack). If you used 5A, then that would be 25A for the 5P pack.

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