Battery Charger Specification Questionnaire Instructions
Custom design and manufacture of state-of-the-art battery chargers, UPS, and power supplies for OEMs in a hurry!
Technical helps for the specification of custom battery chargers. We have put this questionnaire together to help you think through the various options and decisions you can make. This isn't an exam, just fill in what you can, we can help you supply the rest!
1. Brief Description: It helps to know what this charger is to be used for, what unique characteristics it might have, what the target market is, etc.
2. Dimensions: (Optional) What size would you like to see? This is important in order for us to decide whether to use surface mount or through-hole manufacturing, and whether to use a linear transformer or a high frequency switching power supply.
3. Open Frame: Do you want a board level product, a complete unit including case and silk screening, or something in between?
4. Enclosure material: Are you looking for a steel case, aluminum extrusion, or molded plastic case?
5. Color: (Optional.) We can paint any style case, anodize aluminum, or use colored plastic.
6. Input voltage: Do you want 120 VAC 60 Hz, 240 VAC 50 Hz, or universal input? Universal input comes in two varieties, automatic or switched. If you are going to supply the DC input for the charger, what voltages are available?
7. Input voltage notes: For low wattage chargers it often makes sense to use a wall mount power supply (up to 10 watts or so). These are usually already UL listed, very cheap in price, and customers are used to using them. For higher power there may also be off-the-shelf power supply options, but it may be cheaper to integrate a PowerStream designed power supply into the charger.
8. Power Supply Power: (Optional.) Usually what is important is the charging power, but if you have an application that requires a limited input power put that here.
9. Power Supply Efficiency: This is only occasionally an issue--for example if there is limited power such as charging from a solar panel, or where heat dissipation is a problem. Higher efficiency is more expensive and comes in a range of efficiencies versus cost. Talk to one of our engineers about your needs if this is an issue.
10. Input frequency: 50 Hz, 60, Hz, DC, etc.
11. Battery Type: If you have chosen a battery type please tell us the details. Every battery manufacturer has its own preferred charging method. We would like to use the best charging algorithm. However, if the battery company wants expensive features that you might not need (for example temperature compensation over a large temperature range) we will discuss the options with you.
12. Charge time: Charge time is dependent on the battery type and the charger power. Generally a faster charger is more expensive because it requires a larger power supply.
13. Output voltage: Optional. Usually we design the charger to optimize the charge cycle. However, if you intend to operate your device from the charger during charging, or without the battery pack, you might need to specify the ripple, noise, regulation, and protections.
14. Battery discharge options: This is an option for NiCd batteries only. It conditions the battery by discharging to a set voltage, before the charging starts.
15. Preferred charging methods: These are methods to determine the end of charge. Different battery chemistries and manufacturers require different methods. There is no need to fill this in, as PowerStream will determine the best way to charge your battery. If you know exactly what you want please indicate it, or describe it in the space provided.
16. Battery charger indicators: Tell us what you want to indicate the charging status. Options go all the way from none, the low end (a single LED which changes color or goes out when the charge is complete), or the high end, a mechanical meter (or LED analog meter) that indicates charge current. Other options are a multi-LED bar display, a three light display (power on, charging, and battery failure for example), or whatever your industrial designer comes up with!
17. Temperature/operating range: (Optional.) The larger the range, the higher the cost. No need to have an operating range greater than the safe charging range of the batteries.
18. Humidity: (Optional.) This is not a big concern except for high voltage chargers, and marine applications.
19. Altitude (Optional.) If you have airborne or mountain top requirements we will want to design the heat management to your needs.
20. Shock and Vibration: (Optional.) Our products are designed for long life under normal use. If there is a severe shock requirement (mounted on a generator?) let us know.
21. Safety Requirements: (Optional.) Most customers have some requirement for safety agency approval. All products shipped to Europe need CE marking. We have a safety engineer on staff who can help you decide which agencies are appropriate for your product. An option is to have us design to safety and EMI standards without actually registering with the agencies.
22. EMI Requirements: (Optional) Electromagnetic compatibility standards may be a requirement depending on market area and type of circuitry used. Any product containing a microprocessor or a switching power supply comes under FCC regulations in the USA. In Europe there is a susceptibility as well as emissions requirement. . In both areas there are two classifications: A for heavy industry, and B for residential, commercial and light industry. We can advise you on the requirements, and can meet any standards as required.
23. Target Price: We can make a charger for $1 or $10,000. I bought a flashlight that uses a charger circuit consisting of a diode and a resistor. It takes up to 2 weeks to charge it, but it is cheap! We want to match our technology to your customer's expectations. Cost is affected by charger power, size, sophistication of the charging algorithm, and cosmetics (case and display). For example lithium-ion batteries require a smart charger to prevent explosions and maintain a long battery life. Lead acid batteries are very robust and the charger can be cheap if you don't care about getting the ultimate in battery life. If you can't give us a target price, tell us what performance level (high, medium, low) you want to see.
24. Equipment safety. Class I--grounded, Class 2--double insulated, Class 3--Internal (battery or solar) powered.
25. Operating Environment. Indoor or Outdoor, mobile (moving land vehicle), marine, portable, stationary, permanently connected, etc.? Each of these and other environmental factors (altitude, humidity, etc.) have their own performance and cost tradeoffs. These are a vital consideration for reliable operation. PowerStream Products are designed for indoor use at altitudes up to 6000 ft (1828 m) unless specified otherwise.
24. Other Thoughts: Who will design the plastic molded case? Do you need a breadboard or brass board for early testing?