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Do I Need a Battery Charger to Remap a Car?

Unbelievably I see this question asked so many times, in my opinion remapping a vehicle without a good battery stabilisation unit is the Number 1 cause of bricking an ECU

Why Should I Stabilise The Battery During Remapping?

Stabilising a battery during the read and write process of OBD remapping an ECU is absolutely critical, it’s also good practice and recommended whilst communicating with a diagnostic tool, especially during coding.

A good BSU (battery support unit), is as essential as the programming tool itself for OBD remapping, Alientech with their Kess recommend not letting the voltage drop below 12.5v and Autotuner will possibly fail to write with inadequate voltage, both tools without battery support can end up with a situation where communication with the ECU via OBD is no longer an option, and the vehicle no longer starting, and worst-case scenario, a new ECU being required.
xHP who are the leaders in BMW gearbox tuning are very specific with their requirements, the voltage going to the ECU must be set at 13.8v, BMW amongst other manufacturers require the slightest drop in voltage and it can break the line of commutation with a potentially disastrous outcome.

So as this is common knowledge, how do so many tuners end up bricking their customers ECUs? Simply, people cut corners and either don’t buy the right equipment, or make no effort to stabilise the battery at all, and 99/100 times they will be lucky.
Think of it as Russian Roulette with your car..

 

What Can I Do To Prevent Bricking An ECU Through Inadequate Battery Support?

There are many suitable battery support units on the market, there are also some that are not suitable at all, battery support units and battery chargers are very different tools, although many good battery support units have the capabilities of charging a battery.

A battery support unit in diagnostic / supply mode can maintain a constant voltage to the battery, and can react in milliseconds to fluctuations in voltage such as a door being opened, a battery charger does not have this capability, and smart chargers only kick in when the battery falls below a certain level, this causes the voltage to spike up and down.

Modern vehicles can draw a lot of power by just turning the ignition on, and during the writing process when remapping, many manufacturers such as VAG and particularly Mercedes have a habit of the radiator cooling fans kicking in, I believe they are known in the trade as the fans of death!

Amongst the many battery support units on the market, the favoured one amonst the tuning community seems to be the GYSflash 100-12, this provides 100AMP supply with adjustable voltage, I would say 100AMP is the minimum you should be looking for when looking for a battery support unit, as it’s not unusual to see 75AMP usage being called for during flashing, and I’ve seen the tool on it’s limit with a large Mercedes 4×4 and a Bentley.

GYSFLASH 100.12 HF

ALLWAYS BE SAFE AND STABILSE, £600 SPENT ON A GOOD BATTERY SUPPORT UNIT / CHARGER IS MUCH CHEAPER THAN A NEW ECU OR DAMAGE TO YOUR REPUTATION

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