# How do I figure out max continuous discharging current of a battery?

Looking into ordering a battery for a prototype I'm working on. The power rating for my product requires 4610.6mah to power it for 1 hour and I'm looking for a battery that can support its run-time for up to 10 hours. so 46000mah-50000mah would be ideal.

Upon messaging 1 of the manufacturers they asked me "What is the max continuous discharging current of the battery you need?" This was based on LI-ION batteries and not LiPo.

With me being a newbie to battery ordering can anyone provide me with an explanation as how I can find out the max continuous discharging current for a battery that is say 50000mah?

• You look at whatever current the device you want to attach to it draws. Apr 24, 2018 at 9:34
• This is the information they supply with the battery in question. So what am I looking for? Apr 24, 2018 at 9:46
• You want to connect a battery to another battery? Apr 24, 2018 at 9:48
• If that's all the data they give you, what you are looking for is a better battery, or at least one with a better datasheet. Apr 24, 2018 at 10:12
• @PlasmaHH what I'm looking to do is connect this battery to my circuit. Apr 24, 2018 at 10:58

If your product requires 4.6 Ah for 1 hour then all you can say is that the average current your product requires is 4.6 amps. This is the average and not the peak. The peaks may be very large (circa 10 amps) but may only last for sub milliseconds in time. If you have reasonable capacitance on your circuit the battery may not see these peaks.

However, if in the period of 1 hour you have sustained currents greater than 4.6 amps, this is the number you should be telling the potential battery supplier. So, to make it clear, you offer them informattion about the current (amperage) profile of your product so that they can recommend the best battery for the job.

can anyone provide me with an explanation as how I can find out the max continuous discharging current for a battery that is say 50000mah?

You are probably looking at this the wrong way round but, if you need to know this, then the data sheet for the battery should tell you. There is no generic answer to this.

You read the battery datasheet. Either it will tell you the max discharge current, or it will tell you the capacity at a particular discharge rate, probably in the form C/20 where C means the capacity.

You know the current you need : 4.61A.

If the battery data lists a continuous discharge current of 5A or more, you are good.

If it lists the capacity as 50Ah at C/10, that means 50Ah over 10 hours, or 5A, you're good.

If it lists the capacity as 50Ah at C/20 (common for lead-acid), that's 2.5A so you might want a better battery.

EDT as Andy says, if your device draws bursts of higher current, you also need to know the max (not continuous, maybe called peak) discharge current of your battery matches whatever your load needs.

(i know that this is old but i'm answering anyway for anyone who looks for this) since you need it to run for 10 hours you will need more than one batteries in parallel so the discharge rate of the batteries adds up for each battery, for example if you have 20*18650 cells at 2500mAh with a discharge rate of 5A each you will get a battery with 50Ah capacity and 100A discharge rate so you'll be fine