Lithium Rechargeable Batteries on Homemade Electric Car

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Lithium Rechargeable Batteries on Homemade Electric Car

Lithium Rechargeable Batteries on DIY EV?

Should you be using lithium iron phosphate batteries (LiFePO4) on your homemade electric car? Lithium rechargeable batteries are the ideal battery choice for a Do It Yourself (DIY) electric car.

Lithium batteries are perfect to be used on EV because they are light weight, durable and can generate the power output almost twice compared to a conventional lead acid battery.

However, before you start stocking up on lithium batteries for your EV conversion project, here are 3 things you should know.

Lithium rechargeable batteries require a programmed charger.

Although the lithium battery has many advantages, it does have an Achilles’ heel. This type of battery can easily be damaged by overcharging. When the LiFePO4 is overcharged, it has a tendency to bulge thus breaking its outer casing. One good example is when we overcharge the battery of our mobile phone.

Over mobile phone uses the same rechargeable lithium battery as it power unit. If we constantly overcharge our phone, you will notice a shortening of your battery life.

If you were to remove the phone battery unit and place it on a table, you will notice a slight bulge at the center. The same scenario will happen with lithium batteries on electric vehicle.

To overcome the issue of overcharging lithium batteries, we have to use a special programmed charger known as a Battery Management System (BMS). It is best to use a BMS from the manufacturer of the lithium batteries because it would have been carefully tuned and adjusted.

Requires power equalization.

In order for the BMS to work properly on your electric car, the individual battery unit on your EV has to be equalized. To perform the equalization, you will need a device known as a balancing module for each battery.

The function of the balancing module is to constantly check and record the condition of the battery from its state of charge to its internal core temperature. All the information will then be sent to a master control unit.

Lithium battery pack master control unit.

The third key component of a lithium battery pack is the master control unit. Its key function is to control the charging and discharging of individual battery.

With its centralized data processing system, the central control unit will prevent overcharge and over-discharging of the lithium rechargeable batteries on your electric car.

If you have the budget, by all means use lithium batteries on your homemade electric car. But before you do so, make sure you understand the importance of the 3 components above. Doing so will ensure your lithium battery pack to last a long time.

Homemade Electric Car Conversion Guide

Do you want to know how to convert a conventional car into a pure plug-in electric vehicle? If you do, check out the Electric Conversion Made Easy guide by Gavin Shoebridge.

Gavin is from New Zealand is a well known as the EV Guy. He has personally converted a Mitsubishi Tredia into an EV in his garage on a shoestring budget. To learn how he did it, click on the link below.

==> Click here to visit Gavin Shoebridge’s web site now!

By | 2012-08-16T09:35:25+08:00 June 28th, 2010|EV Conversion|4 Comments

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  1. Bud Butler January 2, 2011 at 7:51 am

    I just acquired a 144V battery I think is a lithium. It has a lable with EV-PH6RH26C EV Energy , and another with A EV 68021 1E100-PZA-0032 NAIS Maitsushita. I wonder if I should keep the battery and controller all together, or can they be used seperatly? It came out of a 2oo? honda civic .(wrecked)

    Would appreciate any advice. Thanks, Bud

  2. Johannes du Preez February 16, 2011 at 6:48 pm

    If I install a wind power charger would the battery require the same device to charge, or would it be fine from an alternator, similar when you charge your cell phone from the motorcar.

  3. Emil June 14, 2011 at 8:16 am

    well I am glad you asked firstly lifePO4 batteries do not suffer from cell drift you can charge a lifePO4 battery leave it on the shelf for years and the loss of charge will be negligible this due to the strong ionic bonds of the outer valence electron in the P and S orbitals the this negates the need for shunt regulators (battery balancing modules) that is all the cells see and receive the same amount of current when charging and dicharging there is no reason for any of cells to discharge or charge at uneven rates so no need for power equalization either, best to keep it simple by using a Lee Hearts batt-bridge to compare one half of the pack with the orther and “if” there is a difference conduct a diagnostic on that half of the pack. usually there is a phatom load on the problem cell or a manufacturing fault and “NOT” due to a lack of a BMS, for the most part all of the shunt regulators that I have tested have failed due poor components or curcuit stress and failed to signal the charger to switch off resulting in over charging, best to program the charger to under charge the battery pack as a whole and balance at the baottom and charge up to set level that is slightly under charged in line with the IU curves.

  4. Emil June 16, 2011 at 8:48 am

    The Lithium 356 does not use a battery management system (BMS) to maintain and manage individual pack cell voltages. BMS, religiously promoted by early EV enthusiasts, appears to be an unnecessary accessory for LiFePO4 chemistry. This heretical view, first championed by Jack Rickards at EVTV, seems increasingly justified as electric fires have been associated with several BMS installations

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