Space Cell Pro 3 - 10 amp BMS?

ahhh. That makes much more sense now.

I found this on AliExpress.com. It isnā€™t the exact same ā€œBMSā€ i have but it is pretty close. It says it has ā€œOver-Current Discharging Protection:50A (Max.)ā€ . I guess this is a 50amp BMS after all. I think i am still going to bypass it as i donā€™t trust it to do anything but balance the cells and I could use those extra amps i would gain. Thanks everyone for the help, thoughts and conversation. Kudos.

Iā€™d like to reiterate that I think the Space cell Pros bypass the BMS by default. The BMS you linked will not handle 50A continuous and is meant for burst output.

Hereā€™s a response from @carl.1

I hear you and i wouldnā€™t trust the BMS for any kind of discharge protection as I stated above, but there is evidence (if you look at the wiring diagram in the link, it is exactly how my/your BMS is wired) that there is some kind of protection again over-current discharging and being that neither of us are BMS experts, i wouldnā€™t totally discount that evidence. Take a look at @evoheyax thread about bypassing the BMS if you are interested in bypassing it, he has detailed the process pretty well. Lastly, your battery and mine are different Space Cell 4 vs Space Cell 3, you have more batteries in parallel (probably different BMS too) so you can achieve a 80a continuous discharge ā€œsafelyā€ while i can only hope to achieve 60a best case ā€œsafelyā€. Donā€™t always trust the guy manning the support emails. Iā€™m not saying he is wrong but he could be and if he is, you would be the one out $ 400. Thanks for the insights, appreciate it.

yea i know how to bypass a bms. Iā€™ve helped a bunch of users on here with bms wiring including evoheyax. I said i was skeptical of enertion support and was merely showing you what they said to me. I could take a look at my bms again but Iā€™m pretty comfortable with my assumption that itā€™s bypassed.

No worries, i hope you didnā€™t take what i said personally. Iā€™m just basing my views on the facts that iā€™ve uncovered so we donā€™t need to assume. Historically the Spacecell has come with a 30 amp and 50 amp BMS. That is why my BMS was so surprising. I do see that there is some kind of 50 amp protection, but i donā€™t speak Ali Express english so i canā€™t verify that for sure, but wouldnā€™t discount that completely either. Your battery pack is more than likely not bypassing the BMS by default, Jason has historically not been fond of that idea according to this forum and according to the wiring diagram that shows that. Just donā€™t want you to hurt your battery as i know how expensive it is. Either way i sincerely appreciate your thoughts and input and are very kind.

Using a bms for always balancing the cells (to get balanced discharging) should help maintaining the life of the cells long and 40USD (for a 60A BMS) isnā€™t a big expense If you have the charge-only one. Maybe you can think of upgrading it later when the warranty expires if you didnā€™t put many cycles through the battery yet.

that sounds like a good plan. Are there any you recommend or suggest in particular ?

I use that specific one on 8S, I never tried other BMSes, on 8S I am not plugging in the last two balance leads, it seems to do the job up until now, it took 3 weeks to arrive and I paid 5$ shipment to the UK. I tested the short-circuit protection (by mistake) and it seems to work as well (tried to charge for a second with reverse polarity lol). I have set 50A as battery max on the VESC and I have an 8S5P configuration. The bms fits horizontally in the space cell enclosure.

The space cell battery donā€™t use a BMS to control discharge.

The two mechanism to prevent overy discharge are the fuse and the settings in the vesc which control current draw.

Inside the space cell is a charge / balance circuit and a mosfet switch for turning the circuit off.

Technically speaking the space cell pro 4 can output peaks of 80a and there wonā€™t be a problemā€¦

However i always suggest a fuse.

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This could be because that style of inline fuse holder fuses are quite common in 40 and below amperage for the use of Vehicle fuses. However when you start looking at 50+amp in a vehicle they tend to use the square fuses which are much more expensive and also bulkier.

can u send me a link to where u purchased or point me in the right direction. just want to read up on it.

got it. thatā€™s great news. is this something fairly new ? I was confused by the other posts on the forum especially the one where someone bypassed the BMS. Theoretically I could get a 60amp inline fuse and rock my batt max at 50 amps if I wanted to right?

yes, you can. you will need a new fuse holder though

We are always innovating and being reiterative with our products.

After months of testing with vesc we realise that it can control current better than most BMS. Plus with a fuse you can protect your cells easily.

Also due to the rise of popularity of hub motors we needed a solution that can allow people to draw more current from battery if needed.

Until there are specific custom made BMS for esk8 no BMS is better.

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Thereā€™s an ebay link in my post above and this is from their site (supower).

I feel the same way. I wish there was an easier way to balance cells than a bms, like something you plug into the balance connector (and leave permanently, like a bms) that it shifts volts around to cells until they are all the same.

Well there you have it. I was wondering WTF was going on inside these raptor cells as well, the last few i cracked open sure had a lot of space left over.

This is at least the third iteration iā€™ve seen of the regular raptor packs.