Help on focbox unity

Hi, i just wanted to make sure, are there any things i need to change in the focbox to use hub motors with it? And i assume max brake current can be the same amps as max motor current? Im not sure what to put for max braking regen current.

These are pretty basic questions. You should probably read a LOT more before hooking up, there’s some basic knowledge that’s hard to impart by answering a few questions. This basic knowledge may prevent blowing your stuff up.

But, basically, battery max amps and regen should be matched to the capabilities of your battery pack, and motor max and -max should be matched to the capabilities of your motors. If it’s too strong, all can be lowered to meet your skill level.

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No, i know what my motors and battery can handle, but for regen, im not sure if u put it same as battery current or if u supposed to put it at a lower current/certain percent of the battery current. And for everything else im just making sure so i actually dont blow stuff up lol.

Actually im kinda confused on my max amps for my metroboard battery cuz on the website it say 30 amps Continuous and so i email metroboard to see what the max amps r and he said 30 amps. I asked on the forums but seems like no one knows. (or no one responds to me lol)

he already answered this for you

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What i meant was im not 100% sure what my rated max amps r for my battery so i will just set it at 30 amps just to be safe.

didn’t they give you the answer?

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Yea, they said 30 amps max before the bms shuts down, but on the metroboard website it say 30 amps Continuous. So that was a little confusing for me because its 30 amps Continuous and max. Unless they meant it can output 30 amps Continuous but is also max which wouldnt make sense y they would do that.

go with 30a :slight_smile:

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Yea lol. Thx

Hey. :slight_smile: Generally you’ll get more help if you post specifics, like a link to the battery pack. Otherwise you get vague stuff like my first post. Looks like this one?

  • 10 mile Battery THIN (10S2P, 36V 4.4AH) rated for 30 Amps Continuous Discharge, 14AWG Silicone Wires and XT60 Female Connector, Electronic Switch to enable/disable discharge of Battery, 216 mm long x 160 mm wide x 21 mm high, 2.2 lbs. CHARGER

Unity battery amps is total for both sides, so 30A is a reasonable choice here. BUT! if metroboards told you bms is max 30A, maybe give it a bit of headroom, as you do not want the bms to trip. 25-28A perhaps.

For regen, you need to suss out what cells the pack has, and check the spec sheet on the cell. You can use 2x the max/fast charge rate safely. 2x because 2p. For example if the cell were Samsung 25R, the spec sheet says 1.25A standard, 4A max. So you can safely set regen to -8A. Note this is just an example – don’t use -8A.

The cell is NOT 25R though. The webpage for the packs proudly states LG MH1 for the bigger packs but conspicuously doesn’t state for the smaller packs, which probably means generic chinese cells. I couldn’t google it up. You’ll have to ask metro what cells are in there, and what the max charge rate for that pack is.

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The battery i have is the 55 mile one that uses LG MH1 like u stated in a 10s8p system. This is actually very helpful, thanks.

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Nice! spec sheet:

standard charge 1.55A, max charge 3.1A, so your battery regen should be -(3.1A x p_size). You can tweak it a bit higher if it’s not enough (within bms limits).

Did you say you have the 8p pack? MH1 max discharge is 10A on the spec sheet, so you’re really hamstrung by that 30A bms.

If you’re 8p, the cells can take -24.8, and chances are the bms can do -30, but check with metro, as that’s unusually high regen current. Maybe start at -8 to -12 and see how it feels.

Ok thanks.

I was just wondering, do motors have limits on how much current can go through for battery regen?

Theroetically, yes. In practice you can if you wish to set it very high.

So should my motors affect what i put in max regen current?

I’m thinking about getting that same battery in the interim. how do you like it so far, i wondered about that 30a BMS.

I haven’t tested it yet cuz the remote is taking a while to ship. If u wait a little ill definitely tell u how it goes. If u are going to use belt motors, then i cant give an accurate say on how it is for belt motors cuz i am using hubs from a chinese company. But i do plan on switching to belt motors soon, i dont think u would want to wait that long just to get my opinion of the 55 mile battery tho.

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If u worry the 30 amp limit of the bms is a bit low (i personally think so), u can get two 27 mile and connect them in parallel, u can get a total of 60 amps max. Theoretically, u will get the same range as the 55 mile battery cuz the 27 mile is a 10s4p with 12.8 AH and 55 mile is 10s8p with 25.6 AH(the 55 mile battery enclosure will fit two 27 mile cuz the 27 mile is exactly half the Height of the 55mile.) If u do that, it might cost a little more and u will have to do a bit of tweaking and soldering, mainly the charge cables and power on/off switch for the battery cuz u have 2 batteries (2 charge cable and 2 power on/off cable) and u only have 1 enclosure (1 charge port and 1 on/off switch.) Last time i checked they ran out of the 27 mile battery pack, so u could wait for more of those packs or just get the 55 mile to save u all that work, but with the cost of lower amps.

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