The battery and my heat problem

[overtonmath]

I have a 48V 15Ah sunthing battery. The motor and controller came from EM3EV. The problem I am having is the heat. The controller gets so hot that I can't touch it. I just burned through my second plug on the battery. What is causing this problem? I think the motor size fits the battery size (I think its a 500W engine) Could it be the result of not having wired my bike with the right gauge wire? The wire I used to wire the bike up is a different gauge than the wires coming off the battery...a smaller gauge. That might account for the plug melting, but would that also be the reason for the controller getting so hot?

Thanks for your help

 

[mark5]

What kind of plug is melting? An Anderson Powerpole-type (picture) plug?

How thin is the thin wire you used--lamp cord thin? Are you carrying your battery in a trailer (I think you've mentioned that before)?

 

[amberwolf]

The problem I am having is the heat. The controller gets so hot that I can't touch it.

That's really quite hot for a controller to be on an ebike. Way hotter than anything on my bike gets even in direct sun here in Phoenix, plus the heat generated by running it hard.

This means that either:

A ) you have an undersized controller vs your power needs so that it is pulling so much current thru the controller to run the motor that it gets hot and stays hot

B ) you have the controller in a place where it can't be cooled by airflow properly

C ) there's somethign wrong with the controller and/or hte motor that is causing either high resistnace in the controller or something else in the motor, causing the controller to heat up wya too much.

(or multiple of the above, possibly other things too).


Does the motor also get really hot?

I just burned through my second plug on the battery. What is causing this problem?

If only the plug itself is heating/melting then it is not making a good connection, is too high a resistance so a lot of power is being wasted at the conneciton point as heat.

To fix that, you'd need a differnet kind of connector. What kind does it use now?



Do you have a wattmeter? If so, what current does the system pull at maximum, and what current does it pull continuously?

 

[overtonmath]

I have a volt meter. Not sure if it has a watt option. Maybe these pics will help clarify.

 

[mark5]

If you're riding your ebike with the controller in the bag mount it outside instead. The controller needs air moving over it or it'll get hot.

 

[wesnewell]

And the wiring and connectors to the battery should be large enough to carry the max amps of the controller. Typically 12awg is ok for most controllers, but the bigger the better to avoid voltage drop.

 

[dogman dan]

Not terribly surprising that type of plug melted. it's not really up to 1000w of dc. If the controller got hot enough, it could have helped heat sink too much heat down that wire, helping it warm up. I think the plug just melted because its ok only for 250w bikes.

Hot controller would result if you smother it in a bag. Some climates can get away with this, but I never try it this far south.

 

[overtonmath]

Not terribly surprising that type of plug melted. it's not really up to 1000w of dc.

Can you recommend a 1000w dc plug?

 

[\/ampa]

Not terribly surprising that type of plug melted. it's not really up to 1000w of dc.

Can you recommend a 1000w dc plug?

EC5 plugs are good. I use them for a 1500w charger and they dont get warm.
[youtube]3zCGbGzYw04[/youtube]

 

[dogman dan]

The two most common favorites are 45 amps or larger Anderson power poles, or even more popular RC hobby bullets.

Anderson 45's can take 12g wire, but 5 mm bullets can handle up to 8g. 4mm bullets with 10g wires should work very well.

In case it wasn't clear, you need at least 12g wire for 1000w, or it will get at least warm in use, if not hot.

 

[dnmun]

it is best to just solder the connections from the battery to the controller. you can put the controller circuit current on a switch and even turn off the battery by turning off the circuit current in the BMS.

 

[amberwolf]

FWIW, on CrazyBike2, I just did solder all of the power-handling connections from contorller to motor, and contorller to battery switch; I do still have a circuit breaker (really it's jsut a power switch for me) and one anderson SB50 in the power path to the battery (so I can easily swap out packs or add others if necesary for range), but all the other connections formerly done with PP45s (and some various gauges of wire ) are now solid connections.

It has already fixed one problem that I'd had with phase connections warming up, and increased my takeoff torque enough for a butt-dyno to notice.

 

[overtonmath]

In case it wasn't clear, you need at least 12g wire for 1000w, or it will get at least warm in use, if not hot.

Thanks for all the help. I was using 16gauge wire. So now I will switch to 12. Could the wire size be causing the controller to heat up as well?

 

[dnmun]

your controller gets hot because it is inside the bag. someone already clued you.