Flash Posted August 26, 2021 Author Share Posted August 26, 2021 Okay Team, Some interesting results from further testing that I carried out this morning. So as a bench mark I used my multi meter to check a few voltage readings across the Moke's 325CCA battery : Moke battery at rest - 12.96 volts across the terminals (so still showing the benefits of the night before last's trickle charge) Moke battery under cranking - 10.13 volts across the terminals Moke battery under cranking - 9.57 volts at the coil's + wire I then removed the Moke battery and chucked in my 9 month old ute 650CCA battery: Ute battery at rest - 11.94 volts across the terminals Ute battery under cranking - 10.15 volts across the terminals Ute battery under cranking - 10.10 volts at the coil's + wire I then plugged the coil's + wire back into the coil and attempted to start the Moke using the ute battery. It fired up almost instantly, something the Moke has never done during my 4 year ownership. Its always needed around 20 seconds of cranking before it would fire. So it looks to me like the electronic unit inside the distributor is a lot happier when it receives a higher voltage. Does a 1.8 volt loss during cranking sound excessive ? Or should I just replace my existing 4 year old 325CCA Moke battery with a brand new higher rated battery and calling the job done ? Quote Link to comment Share on other sites More sharing options...
tortron Posted August 26, 2021 Share Posted August 26, 2021 still running a generator on it? probably the battery has had a hard poorly charged life and is passed it 9.5v under load is right at the time to look for a new battery stage 3 Quote Link to comment Share on other sites More sharing options...
Lord Gruntfuttock Posted August 26, 2021 Share Posted August 26, 2021 Think around 9.6v is minimum crank voltage. Here's one I did yesterday with new battery and new alternator... 1 Quote Link to comment Share on other sites More sharing options...
Lord Gruntfuttock Posted August 26, 2021 Share Posted August 26, 2021 I'd shout myself a new battery given it runs noticeably better. I did that even tho it was the regulator giving the problem (diagnosed after new batt) Nice knowing you have a good battery in any case... Did you say what voltage you get at battery with engine running? 1 Quote Link to comment Share on other sites More sharing options...
Flash Posted August 26, 2021 Author Share Posted August 26, 2021 7 minutes ago, tortron said: still running a generator on it? probably the battery has had a hard poorly charged life and is passed it 9.5v under load is right at the time to look for a new battery stage Thanks Tory, it's been upgraded to an alternator. Quote Link to comment Share on other sites More sharing options...
Flash Posted August 26, 2021 Author Share Posted August 26, 2021 2 minutes ago, Lord Gruntfuttock said: I'd shout myself a new battery given it runs noticeably better. I did that even tho it was the regulator giving the problem (diagnosed after new batt) Nice knowing you have a good battery in any case... Good advice. Much appreciated. 1 Quote Link to comment Share on other sites More sharing options...
Lord Gruntfuttock Posted August 26, 2021 Share Posted August 26, 2021 Yeah was only yesterday I hooked up my new alternator/regulator and car runs way better when cold. Must be giving a fatter spark. Wish I'd done it a while ago. Have you measured output when running at battery? If that's 13.8 - 14.2 odd volts then charging circuit is sweet... 1 Quote Link to comment Share on other sites More sharing options...
moparmuppet Posted August 26, 2021 Share Posted August 26, 2021 Minis were always bad at earth wires not earthing. They would cook the throttle cable and choke cable using them as earth returns. I know you said you had cleaned them but there will be probably 2 of them and the one from the engine subframe to the bellhousing gets forgotten. A good check is to use your jumper lead from the body of the starter motor to the battery earth or a known good subframe earth. High resistance will cause lower cranking speed, voltage drop and heat. I assume Moke battery is under rear seat? 2 Quote Link to comment Share on other sites More sharing options...
Flash Posted August 26, 2021 Author Share Posted August 26, 2021 2 hours ago, Lord Gruntfuttock said: Yeah was only yesterday I hooked up my new alternator/regulator and car runs way better when cold. Must be giving a fatter spark. Wish I'd done it a while ago. Have you measured output when running at battery? If that's 13.8 - 14.2 odd volts then charging circuit is sweet... Yeah, I was reading your build update this morning and noted the improved voltages you achieved with your upgrade. Bloody good outcome, so well done. I'm getting 14.28 volts across the battery when the engine is running. Its been upgraded to an alternator with internal regulator so I can't complain about those results. 2 Quote Link to comment Share on other sites More sharing options...
Flash Posted August 26, 2021 Author Share Posted August 26, 2021 1 hour ago, moparmuppet said: Minis were always bad at earth wires not earthing. They would cook the throttle cable and choke cable using them as earth returns. I know you said you had cleaned them but there will be probably 2 of them and the one from the engine subframe to the bellhousing gets forgotten. A good check is to use your jumper lead from the body of the starter motor to the battery earth or a known good subframe earth. High resistance will cause lower cranking speed, voltage drop and heat. I assume Moke battery is under rear seat? Yep, the bellhousing one on my Moke goes straight to the body. It's the flat braided coppery looking type. I cleaned up both ends and even took the fresh paint off the body under the fixing bolt. It broke my heart to do it, but in the past I've experienced earthing issues through fresh paintwork which took me forever to diagnose. Good tip about the jumper lead, so thanks for that. I'll give that a go and recheck voltages just to make doubly sure my earth strap is good. 1 Quote Link to comment Share on other sites More sharing options...
hohocc Posted August 26, 2021 Share Posted August 26, 2021 If you do go the new battery route bigger and better is normally not much more expensive than bare bones minimum. Cleaning the existing earth straps is always a good idea. Adding an extra one if it's easy can't do any harm either. Sounds like you are making progress! 1 Quote Link to comment Share on other sites More sharing options...
Flash Posted August 26, 2021 Author Share Posted August 26, 2021 2 hours ago, hohocc said: If you do go the new battery route bigger and better is normally not much more expensive than bare bones minimum. Cleaning the existing earth straps is always a good idea. Adding an extra one if it's easy can't do any harm either. Sounds like you are making progress! Thanks for the suggestion. I've got a few spare engine earth cables lying around. Should be easy enough to fit an extra for peace of mind. Quote Link to comment Share on other sites More sharing options...
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