Battery/Controller Combo

BigBZ

1 µW
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May 19, 2014
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I'm new to this board so hello all.

A proper newbie question as a first post is fitting I think.

I have a MAC500/1000w motor and infineon 12FET 40A controller. I have just about finished fitting this (as well as repairing the bike as it was a state!) I am just about to order a 48v 40ah battery from ping.

I made the decision to go with this combo ages ago and was happy with it then so I don't know if I've already decided it is suitable or whether I had just overlooked the glaringly obvious back then.

48v x 40a = 1920w

I know the MACs are good for 2kw peak but would this continuously not be too much for my motor? Or am I missing something?

I have a CA V3 which can monitor the temperature of the motor but I don't want to rely on it.

Thanks
 
Welcome to ESland, where many marvels can be found. I don't see anything in the selection you've made which would be a problem. I'd proceed with that set of components with confidence. Ping is a very well respected supplier here, so don't overlook the obvious, of telling them exactly what you have and the battery you believe to be a good match to your setup and needs, and giving them opportunity to respond.

Your calculation is off. A 48 volt Ping battery should provide sufficient power for a 1000 watt motor. The question I'd ask Ping is whether their battery can draw 40 amps. I believe yes, but confidence building is often made with questions and seeing what the experts have to say. There are also a lot of folks here on the forum that have Mac's and variously fetted controllers. You may want to peruse the forum with the search capability and PM members who have what you have and prompt their response.
 
48v x 40a = 1920w

I know the MACs are good for 2kw peak but would this continuously not be too much for my motor? Or am I missing something?

40Ah is a lot of mass. Where are you going to put it? Only place I would consider is a trailer.

Pings stuff is great as well his support.

Do you need the 40Ah for range or what? I have heard that the new Pings are 3c but can't say for sure. You don't need 40Ah to make it run but if they are only 2c cells the I would consider a 25Ah since the 40 is heavy.

I'm running 12s 20Ah LiPo on a MAC 8t 12fet butrunning 35a out the controller.

Read that you are getting a CA V3 so you can cut down the amp draw thru it.

I read it again. You think that the 1920wats are what is going directly to the motor, NO, that is the capacity the battery has and is what will give you your range, mainly.

Dan
 
DAND214 said:
40Ah is a lot of mass. Where are you going to put it? Only place I would consider is a trailer.

Pings stuff is great as well his support.

Do you need the 40Ah for range or what? I have heard that the new Pings are 3c but can't say for sure. You don't need 40Ah to make it run but if they are only 2c cells the I would consider a 25Ah since the 40 is heavy......Dan
Well, yes and no. I just doubled the capacity of my A123 AMP20 12S 36V battery with a A123 26650 12S8P 36V battery so that I'd have the range for one particular long-range trip I make periodically. When you need the range, then its the better option, of having more capacity. Mind you, for my normal day-to-day riding I'm using less than 50% of just the 20ah of my new battery pack. But your point is a good one for anyone considering the battery they put on their eBike. No sense in spending money or carrying the weight if you don't need it. So first consideration is what those needs are. Yea, simple, but its amazing how many folk buy more that they need without really thinking about it.
 
Thanks for the replies

Dand214, the 40a in the calculation is the 40 amp output of the controller. I am aware that 48v x 40ah ~ 2kwh which is battery capacity, what I thought is the controller would be giving out a constant 40a, which with the 48v would be a constant 2kw and too much for my 1kw motor. I guess from the replies though that the controller will give up to 40a, depending on what the motor is pulling due to load etc? In which case a 2kw peak up hills for example should not be a problem. In hind sight this makes a lot more sense.
You wouldn't believe I work with motors for a living would you?

I didn't decide on a 40ah battery lightly. Despite the bulk and weight its the best part of £1000 which I'm not likely to buy on a whim. I need a good 50miles range. The battery pack will be split in two and placed as low as possible either side of the rear wheel on a pannier I have specially reinforced. It is heavy but should be tolerable so long as I keep the center of gravity low.
 
Awesome that you know how to calculate the Capacity! :)
Do you understand "C" rate?

If your pack can do 2C continuous then the 40ah Pack x 2C will be capable of 80amps at the rated voltage 48v = just under 4,000 watts or 4kw.

If you are into RC Lithium Cobalt (LiCo), some of those packs will do 65C Continuous with a 135C Burst! So just 10ah of LiCo could give you
650amps continuous to 1350amp burst! At 48v that's huges watts of more than 35,000 watts continuous! But extra caution charging and discharging these cells is a must!

These LiCo packs from Hobby King are less expensive at lower "C" rates of 20C continuous which is still huge at 48v.
At 10ah 20C would give you 200amp continuous at 48v, nearly 10,000 watts or 10kw. LiCo is lighter (power density) But has less cycle life than LiFePO4.

Properly sized LiFePO4 will not Voltage sag and usually will maintain it's voltage during it's capacity.
LiCo will have a voltage drop over it's capacity use of usually 4.1v to start per cell down to 3.65v per cell. Approx. 8v on a 48v (16s pack).

Welcome to the ES Forum!

Tommy L sends.... \m/ . . \m/
 
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