I agree that ARBL has corrected significantly over last year. However, the performance of the company too has lagged its competitor Exide at least for the last year. My sense is that ARBL benefited immensely from the inaction/complacency of Exide in last few years and its growth was aided significantly by this factor. From whatever I can see, Exide is getting its act together hence, it won't be as easy as before for ARBL to walk away with market share going forward. Hence, I feel it is time that both Exide and ARBL gets valued equally as the former (Exide) is still market leader by a margin and much larger in scale.
Another part, which I feel market is not yet paying attention to is Exide's life insurance business which is growing, has reached critical size and is profitable too. If you assign a reasonable value to that business (2-2.5 times Embedded value), battery business will start looking attractive. Alternatively, if we think ARBL and Exide should command similar valuation, one is getting Exide's insurance business for free.
Having said that, ARBL remains an excellent business in its own right. However, from here on, it may not grow at 30% (as it used to) due to much larger base, agile competition,structural challenges on industrial battery side and limited room for margin expansion. I feel 15-20% growth rate is reasonable assumption for ARBL going forward. I personally, assign exit multiple of 22-25 times trailing and 20 times forward for such businesses (Where there is no optionality; non existence of non-linearity in growth). Thus, if one's return expectation of 18-20% CAGR, it makes sense to get into such businesses.
Disclaimer: This is not an investment advise. The views reflected here are just thoughts around the business. Investor should do their own due diligence or consult an investment adviser before making an investment decision.