Car Audio batteries for 5 years olds!!!
What battery should I buy, is it safe? can I run it with my Lead acid starter?
There was a time where I needed someone to explain lithium to me like I was a 5-year-old, if you are reading this there is a good chance that you are overwhelmed like I was back on day one.
I am going to answer a lot of questions that you probably have so hang tight!
Lets start with the Safety part first! Is Lithium safe to run in your vehicle?
the answer is very simple, YES!!! lithium batteries are no more dangerous than that wet/AGM lead acid battery that is under the hood!!!
Step 1:
Identifying your vehicles charging voltage. You need to know this before you make decisions on anything else going down this list, the golden rule here is this... The option and route you take from here will only ever be as good as the voltage your vehicle charges at, if you charge at 13.8v, this means your vehicle is only ever going to be able to put a 13.8v charge back into your battery, it does not matter what the charging range is of that battery.
Identifying your charging voltage can be done at times via your HUD, some vehicles have this built into what you can view, some vehicles have dedicated voltage displays in the dash, I prefer to check this the old fashion way, Digital Multimeter, if you do not have one, they can be picked up for as little as $7 at Harbor Freight!
set the meter to 12v, - to - and + to B+ (battery positive)
It is good to see what this reads from a cold start, and then what it settles to once your vehicle is warmed up! Go ahead and write this down so you don't forget!!!
Step 2:
Let's now take a look at some of the most popular battery chemistry types in order, please take not here that there are some chemistry types here that I will not include as I do not believe that the have a place in car audio.
Lifepo4 aka LFP - Safe charging ranges from 13.2v to 14.7v with the optimal charging voltage being from 13.8v to 14.6v with the exception of some cell types that are safe to charge all the way up to 14.8v (EVE for example) LFP is ideal for any vehicle charging inside of optiomal charging voltages. LFP is ranked at one of the safest chemistry's that you can choose, some of the most common LFP options today are the Glow Voltage series 1, 2 and 3, with cell types like, CALB, EVE and SAPT being some of the most popular options for D.I.Y builders! if you want to plug and play, Glow Voltage is going to be your go to every single time!
Lithium titanate oxide aka LTO - Safe charging ranges from 14.6v to 16.2v with the optimal charging voltage from 15.4v to 15.8v, LTO like LFP is regarded as some of the safest battery options available for car audio, some of the most common LTO options found in car audio will include, Prismatic LTO aka Scib There are different options with this cell type but we will cover this in another blog post! Yinlong and Plannnano, the choice you make here will generally be dictated by available footprint, your budget and what your goals are for your particular build!
CMAX - Safe charging ranges from 14.8v to 16.6v with the optimal charging range from 15.6v to 16.2v CMAX is the wild card of the bunch, almost literally, When CMAX is done right it is safe, I cannot stress this enough, if you are not confident DIY building a bank for CMAX then I highly recommend partnering with a reputable company who has the experience, I am going to shout out Vibration Audio as the go to in this space. You will notice that there are different options when it comes to CMAX and just like the LTO options in prismatic cell types we will cover the pros and cons or each cell type in another blog post!!!
(picture credit to Vibration Audio!)
Step 3:
Can I run these batteries with my factory lead acid/AGM starting battery? Lead acid and AGM generally like all battery types, have a 'safe' charging voltage, this is generally 12.8v-14.6v and very similar to the boundaries for LFP, so in this case YES you can run your factory lead acid in parallel with your LFP battery, is it safe? Yes! is it good, No! not really! if you are looking to get the absolute maximum performance out of your LFP battery, you should let it work alone as the lead acid/AGM battery effectively turns into an Achor for your LFP battery to drag around behind it, however if you are not quite confident just yet don't stress, run your LFP option in parallel with your factory under hood battery, and start your lithium journey and learning here before we dig into the ways to get more out of what you already have!!!!
So what about the LTO and the CMAX?! OKAY!!! so if you are charging inside of the optimal charging voltages for these cell types you should absolutely NOT be running or mixing these two cell types of periods, generally speaking do not do this either way! you are effectively over charging you lead acid and it has now become unstable and unsafe!!!
Step 4:
Understanding the gaps! Okay so let's break this down into super layman's explanations, Let's say that you are charging at a voltage of 14.6v! this puts you inside the Optimal charging voltage for LFP and the minimum charging voltage for LTO, so what should you choose? the charging voltage limits represent the battery's voltage at its lowest charge and its highest charge, so in this case your LTO is effectively boarder line flat at this point or as we will call it, in a very low state, this means that your alternator is likely going to work harder during a cold start and generally work as hard as it can continuously as it is not geared to recover the LTOs optimal state. If you have a '100ah' LTO bank at 14.6v your LTO is likely closer to '30ah' because the charge voltage is so low, while it might perform slightly better than LFP even in its low state, just understand that it's not going to work as good over a longer period of time, as you continue to go lower and stay lower you are more likely to experience lower voltage more frequently and in doing so unknowingly introduce distortion to your setup putting your equipment at risk.
Some will argue that that the guys charging 14.7 and 14.8v still get better results even with LTO at a low state, (even I have put this through testing, yes, they have some ground to stand on) however in the real world we have other obstacles that are going to case roadblocks while doing so. Think of it like this, if you have even a small parasitic draw in your vehicle would you prefer to have a battery in it that is always in a low state or always in a full charged state? for me, I am going to have to admit that while those few extra points of a volt are nice, I feel like the tradeoff of knowing my vehicle is going to start after a few days of not driving is worth it vs returning to a flat that can't be jump started by another vehicle safely or without damaging your alternator due to the sheer abuse it is going to go through to recover that dead LTO bank from scratch!
You should now be armed with the knowledge to make a wise decision on what battery and what chemistry type is right for you! I hope I have been able to bring value to your car audio learning curve;
I appreciate you checking us out!!!