Custom BATTERIES

Before you buy a battery you need to look at two important parts of your car audio system: First, what do you have for an alternator and second, how much power do you need.

Alternator - Your alternator has a voltage and amp out put. Do you have an over sized alternator? Do you out put 13.4v, 14.4v, 15+v? How many amps does your alternator put out? Your alternator should match your battery system or you need a DC-to-DC charger to make the systems match. You need to be able to charge the battery, don't buy a battery you can't charge it.

Amplifiers - How much power do you need? Most groups selling battery often claim 15K watts, do you need 15K watts? If you have a 5k watt amplifier you don't need 15K watts. IMPORTANT: Volts * Amp = Watts. If you need 15K watts and you have a 14.4v system you need 1042amp. This is a rough calculation, but it gives you an idea of how much power you need. So if your alternator puts out only 200amps, where are you going to get the other 800amps? This is where your batteries come in.

Think about it like a car. You don't just care how fast it goes, you also care about how much gas it holds, how far you can travel and can you get the type of gas needed for the car.  You should be suspicious if a company claims 3000 watts depending on your alternator. Lets look at a 6Ah battery that claims 3000 watts. Let's do the math, 3000w divided by voltage (I'm going to use 14 volts because an LTO battery with 5 cells). To do 3000w you need 214amps. Remember Volts * Amps = Watts. They state the battery C rate is 20 (C rate is the rate of discharge), so it can output 6 *20 or 120Amps. You need 214? So yeah it depends on your alternator, because its supplying 94Amps of the 214amps needed. Now is where it gets really sad, this battery discharges really fast, but its tiny 6Ah. That means it can put out 6amps for 1 hour. if you put out 120 your battery will last 3 minutes, or one song (best case). You might think the alternator is charging your battery, but all its power is already taken by the 3000 watts needed by your system. Your battery will not recharge until you stop playing music.

Important - Most car audio batteries do not have a BMS (battery management system) so you can damage your battery if you draw the volts too low, too high or charge when the temperature is too low. Most car audio battery companies like to talk watts, large numbers. You should care about what voltage your battery supports, what's is the maximum voltage, and what is the minimum voltage so that you don't damage your battery. You really need to know what temperature you can charge and discharge. Because there is no BMS, you can ruin your battery if you try to charge in too cold of a temperature.

Make sure your battery can support your load. How many watts do you need? Divide your amplifier watts by the voltage of your system. That tells you how many amps you need. Now buy or build a battery that meets your needs.

Example I saw an ad for 15,000 watt battery! 29Ah SCIB! "Big Power". Lets do the math, 15,000 watts divided by 16.8 (I'm being generous) tells us you need 893 Amp. That is a lot of power. For this battery to put out 893Amps it C rate would be 31. It can put out 15K watts for a very short time. The battery cell is listed as 10C continuous and pulse above 30C. If discharges 893Amp it can do it for 1 min and 57 sec. No even one song. $900 battery and you can't play one song.

Other Options

• Yinlong LTO have 45Ah battery cells that are 10C and you can buy 90Ah battery which gives you 900Amps without depending on pulse discharge numbers.
• Eve LifePO4 have 116Ah battery cell that is 3C and you can buy 3 batteries which gives you 1044Amps again without depending on pulse discharge numbers.
• SCiB makes a 20Ah battery cell that are 10C and you can buy 100Ah battery which gives you 1000Amps.