Low battery problems

[Jez]

I wonder if anyone can help.

I've fitted and mapped a couple of Solaris ECUs on Interales and both have a similar problem: if the battery is not 100% charged the solaris goes off line during startup - I think its due to the voltage drop as the starter motor kicks in. Is there a recommended way of sorting this out?

[David_Wallis]

Check that the 12v feed to the Ecu isnt disappearing when your engising the starter, If that fails I'd check to see what voltage you have at the battery terminals whilst cranking and then compare this to the voltage at the ecu pins when cranking.

If your voltage is ok at the battery then you need to address the voltage drop on the cable supplying the ecu feed, and potentially add a new one.

If the voltage at the battery terminals (both) is dropping then you battery isnt big enough or good enough..

Might also be worth checking the voltage between the + terminal on the battery and the chassis when cranking just to eliminate bad grounds.

David

[Jez]

Thanks - I'll give it a go. Thing is, the standard ECUs in both cars never had a problem - the Solaris is fitted using a loom adpater so the wiring is all the same.

[David_Wallis]

We've seen cars and wondered how they have run with the wiring they had.. its only when you go to a more capable ecu you realise how bad some signals are.

If the ecu is loosing power whilst cranking the OEM may have had 'something' to deal with this.. doubt it but...