[RE-wrenches] Load testing Lithium battery bank

[Larry]

Hey Ray,

I remember seeing huge banks of light bulbs as loads back in the early 
70's.

I need to test the entire bank as one unit as the first cell of 32 to 
reach 2.8 volts determines the capacity for the bank. I just saw Home 
Depot has a 2kW 120 volt water heater for $10. Guess I need to do some 
welding.

Thank you,

Larry Crutcher
Starlight Solar Power Systems

On 3/17/15 11:59 AM, Ray Walters wrote:
> Hi Larry,
>
> I think you hit on the best load already: water heater elements rated 
> for 120 v.  We have also used dump loads for wind turbines like the 
> air heating elements from Bergey, but they are only about 1 kW each.  
> Another possible source are the resistor banks for old golf carts 
> (before they had controllers, they used resistor banks to operate at 
> slow speeds)
> A very long time ago, an inverter company had a demonstration that 
> used a large bank of incandescent light bulbs.  They used to make a 
> 300 watt bulb for mining, so 33 of those would work.  (maybe a few 
> more bulbs, since your voltage is bit lower than 120 v)  Cheap 
> electric space heaters would work too.  You also might look around at 
> an electronics surplus store.
> Whatever you do, it sounds like a lot of time and work to set up. Any 
> chance of doing a smaller load test for subsets of the total bank?  
> You might be able to use a standard 12 v battery load tester then.
>
> Good Luck.
>
> R.Ray Walters
> CTO, Solarray, Inc
> Nabcep Certified PV Installer,
> Licensed Master Electrician
> Solar Design Engineer
> 303 505-8760
>
> On 3/17/2015 12:41 PM, Larry wrote:
>> I am repairing and restoring a pair of poorly designed lithium-ion 
>> battery bank that suffered over discharge, damaging many cells. After 
>> cell replacement I need to perform a discharge test with a 10kW load 
>> to verify the remaining capacity. The battery voltage is 105 volts @ 
>> 100% SoC and 89.6 volts @ 0%
>>
>> I would like advice on how I can create an economical 10kW load. 
>> Water heating element? Wire wound resistors? Are there any GT 
>> inverters that will operate at these voltages?
>>
>> Thanks.
>>
>
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