Anyone have any idea how many amps it would take to power a car seat? - Edited

"E90M3" (e90m3)
05/28/2019 at 11:01 • Filed to: None

Back when I was in college, !!!error: Indecipherable SUB-paragraph formatting!!! and I got a seat out of a W123, then made a frame for it, and put it in our living room. I’ve found some decently priced E92 sport seats, but unlike the W123 seat, it’s electric. Now I know they’re 12 volt DC motors but I don’t know how many amps they’d need to work correctly.

I had a powered E36 seat as my desk chair (I have a picture, but it’s on my personal computer at home) in that same apartment. I was able to make the motors move with a 12V DC inverter that I think output 3A. It could barely make the seat move and I couldn’t sit in it and move it or it’d trip the inverter out. So anyone have any idea what amps a seat motor runs on?

Edit:

I took your advice and found a fuse diagram:

It looks like it’s on a 30A fuse, which is a lot.

DISCUSSION (19)

BlueMazda2 - Blesses the rains down in Africa, Purveyor of BMW Individual Arctic Metallic, Merci Twingo > E90M3
05/28/2019 at 11:09

More than 3.

BrianGriffin thinks “reliable” is just a state of mind > E90M3
05/28/2019 at 11:09

From some quick research (and some very minor electrical training), I believe you’d need 5 to 7amps, which is a lot. More if you want to heat it, of course. Some have had success with converting a laptop charger.

facw > E90M3
05/28/2019 at 11:12

Someone here built a racing simulator seat using a power seat from a car, but I don’t remember what they used. If you have a spare PC power supply around, you could start with that, even a fairly weak one should be able to put out way more than 3A on the 12V rail.

HammerheadFistpunch > BrianGriffin thinks “reliable” is just a state of mind
05/28/2019 at 11:12

most laptops take 19 volts though.

benjrblant > E90M3
05/28/2019 at 11:15

What’s the fuse on that circuit rated for? 15 a? If you can’t find a rating on the motor, I’d look there.

benjrblant > BlueMazda2 - Blesses the rains down in Africa, Purveyor of BMW Individual Arctic Metallic, Merci Twingo
05/28/2019 at 11:15

This is the kind of quality content that oppo needs.

E90M3 > BrianGriffin thinks “reliable” is just a state of mind
05/28/2019 at 11:16

I did google it before I asked and I guess I just didn’t ask the question correctly. I was thinking of going the laptop charger route, but I didn’t know how many amps to get. My charger for my Lenovo only puts out 2.25 amps. Looks like I can find some power supply in that range.

Akio Ohtori - RIP Oppo > E90M3
05/28/2019 at 11:16

Check the fuse size from the car? My guess is 10 - 15 amps. Might have to go with a brick-style supply, but a 15A 12-14V supply should be available. Since car batteries deliver 12.4 - 14.0 (ish) volts, I’d shoot for a 14V supply so the motors run a little quicker. That might be a terrible idea though.

E90M3 > benjrblant
05/28/2019 at 11:16

Ah, that’s a good idea, d idn’t even think of that.

diplodicus forgot his password > E90M3
05/28/2019 at 11:16

Does your e92 have powered seats? Do you have access to a clamp on meter? Could just look at the size of the fuse for the seat too

Future next gen S2000 owner > E90M3
05/28/2019 at 11:17

What do you think the fuse on that circuit would be, 10? Probably 2/3 rds to 3/4 of that.

Alternatively, you could mount a deep cell 12V under it and call it good.

BlueMazda2 - Blesses the rains down in Africa, Purveyor of BMW Individual Arctic Metallic, Merci Twingo > benjrblant
05/28/2019 at 11:18

This is the quality content I’ve blessed Oppo with since 2014.

Highlander-Datsuns are Forever > E90M3
05/28/2019 at 11:18

You could just put a car battery under the chair and connect it with jumper cables, then trickle charge the battery.

E90M3 > diplodicus forgot his password
05/28/2019 at 11:21

My E92 doesn’t, but my M3 does. I might be able to get access to on of those meters. Someone else suggested to pull the fuse diagram, and it’s on a 30A fuse, which is more than expected.

E90M3 > Future next gen S2000 owner
05/28/2019 at 11:21

30A, apparently .

Future next gen S2000 owner > E90M3
05/28/2019 at 11:26

So about 20A is my guess. The motor should also have a amp rating on it. 12V at x Amps as well.

E90M3 > Future next gen S2000 owner
05/28/2019 at 11:30

I googled image searched the motors and I didn’t see the amp rating on them.

someassemblyrequired > E90M3
05/28/2019 at 12:20

I have an A4 seat as a desk chair, I just use this to power the seat when I need to adjust i t (12V, 30A) :

https://www.amazon.com/gp/product/B009EIANT2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Works as good as in the car. The wiring terminals on that box are garbage, but it’s $20 plus a power cord.

TheTurbochargedSquirrel > E90M3
05/28/2019 at 12:35

If it’s a 30A fuse find a supply capable of a peak draw of 30A (20-25A continuous should do it) , and then fuse at 30A. You should be able to find an industrial DIN rail power supply that would work (the 12V rail of a PC power supply could also work but would require more research into current limits than I can research right now). You could also put an ATV battery in the seat and keep it constantly topped up with a trickle charger.