6 Volt Batteries of Choice

[Kenyon]

Does anyone have a recommendation for a brand of 6 Volt battery they are happy with? I did a search on here and 356registry and the Optima comes up well though its a bit odd looking.

I had a decent battery for years on the car. Since that failed I haven't had a great deal of luck. Even when fully charged the battery (which is about a year old and tested as working fine - I can't recall the make) will run out of charge cranking from cold before the car fires up and then need another half an hour or so after which it will be fine. I have also tried to solve the cranking issue.

I saw that the original supplied spec Porsche battery is 84 Ah but Porsche (Moll manufactured) 6 Volt battery is 77 Ah so assume anything in the area re Ah should be sufficient.

I think I'm after something hefty that will keep churning from cold until the car goes.

Any thoughts appreciated.

Phil

[neilbardsley]

This is the choose for most. Best am Hours and cold cranking.

https://www.tayna.co.uk/Optima-Red-Top- ... P9085.html

However, I've found that my 6v batteries need to be on constant tickle charge to work well.

PS sorry I've just seen you think it's odd looking but you can hardly see it under the spare on the odd time you have the bonnet open!

[Mike Smith]

PRS can supply the correct (Standard Looking) Battery

However, often we are flogging the life out of the battery with other problems
The age of our cars ensures that we have a number of Electrical problems - most revolve around poor connections

One that doesn`t is, of course, the Bush in the bellhousing - ALWAYS check that there is no wear in this bush - It supports the Armature in the Starter
1) - Starter Motor Brushes and or the Springs
2) - The breakdown of the insulation on both Armature and Field Coils

Contacts

1) - Contacts INSIDE the Solenoid - (this is the one that few people mention or ever check - it means opening the solenoid)
2) - All the Contacts to the Starter
3) - The contacts on the link between the Solenoid and the Starter
4) - The Earth Strap to the Transmission and to the vehicle body
5) - The Earth Strap Battery to the Vehicle Body
6) - The Positive connection to the Battery
7) - All the connections onto the Ignition Switch
- The Contacts inside the Ignition Switch

A Relay fitted either to the starter of the ignition switch is also a great mod
An Electric Fuel Pump will fill the carbs instead of all that cranking
Make sure that the Enrichment Pumps are working on your Carbs. (Remember you have no choke mechanism)

I am sure there are other things but these will keep you amused for a while

[roy mawbey]

Ah Mike,


Wise words and instructions indeed. So true the problems I guess for Phil of quite slow cranking. The standard type battery with the correct rating will work fine if you follow Mike's advice. I don't use a trickle charger but an ' accumate ' battery conditioner. You can leave these on for weeks and it causes no problems. It comes with easy to fit accessories so you can lift the lid after a run and connect up in 10 seconds. The accumate will show an orange light that turns green when charged. It then does not over charge!!. I used to to turn it off when green, now just turn it off when taking the car out.

The bushing in the transmission bell housing as Mike says will allow the starter shaft to drop if worn badly so affecting the starter condition. But.. you will have to remove the starter to see the blighter and ideally remove it. Various methods are possible in the end I bought the Stoddard extractor. If you had a plug gauge ( a long one ) with a correct diameter on one end and on the other end a step of larger diameter's that might help prove the wear. I tried with telescopic internal measuring equipment but could not reach properly that little bugger.

But.. as Mike again says every single earth point must be checked and made perfect. And meter checks made. This really can help. Also as I proved so well, directly the end cap riveted on the starter solinoid was removed by a specialist and the internal copper contacts cleaned the effect of both hot and cold starting was transformed. The starter bushing I changed helped, the earthing points proved helpful but the solinoid repair was magical !!

Again Mike is correct the car if left for a few weeks it will have float chambers low on fuel by evaporation. ( I guess ethanol in the modern stuff ) The churning will happen then and only an electric fuel pump will correct that. But.. the cranking speed on my starter now is so much faster it deals with the problem. My battery is now about 4 years old and working fine with the accumate.

I would say Broadway electrical services in Essex 01375 372 782 have my full recommendation for starter repair. Rob is the guy to ask for, he drilled out my riveted on solinoid cap and did the contacts then used nuts and bolts to refix it. He also checked the starter brushes, the armature and field windings. The windings were fine though.

Its not the easiest of jobs to get that starter out and replace it. Mike at PRS has done that many times!

He knows the system so well!! In you are a long way from Essex I can give you a few tips that will help you remove and place it.

Roy

[Mike Smith]

I don't use a trickle charger but an ' accumate ' battery conditioner. You can leave these on for weeks and it causes no problems. It comes with easy to fit accessories so you can lift the lid after a run and connect up in 10 seconds. The accumate will show an orange light that turns green when charged. It then does not over charge!!. I used to to turn it off when green, now just turn it off when taking the car out.

VERY Good Advice

[Kenyon]

Thanks - I appreciate the advice. I think then its a case of getting these underlying points checked / fixed rather than just continuing to blame the battery!

Phil

[Mike Smith]

Tick off a couple or so a night and you will soon get through them - Easy ones first is how I like to do it

With 6v - NO Crimped Connections

[Hugo 356]

I'm on my second Optima red-top and would recommend them. While they won't solve any underlying issues they are 6v, maintenance free and cope well with the stress of infrequent use, dry float bowls and mechanical fuel pumps. You'd be surprised how far you can get from home on a fully charged Optima and a faulty regulator...

[mycar]

I decided to go the traditional route and bought an old fashioned lead acid battery for my new engine. What can I tell you.... it fits nicely, it's got a reasonable number of cold crank amps and it wasn't too expensive.

https://www.tayna.co.uk/Type-501-Classi ... P3242.html

[neilbardsley]

Tick off a couple or so a night and you will soon get through them - Easy ones first is how I like to do it

With 6v - NO Crimped Connections

Why do you say that Mike? What do you use instead? I think I've got some crimped connections on my dyno.

[Mike Smith]

Properly Soldered Joints - No chance of any Voltage Drop

Crimped Connections - Possibility of a Voltage drop

1.5v Drop with 6v and you have lost 1/4th of your available power

1.5V Drop with 12v is (of course) only 1/8th - so far less critical

[Kenyon]

I was wondering what an acceptable drop should be on a 6 volt battery when starter motor is engaged? I'm assuming you can't take the 12 volt equivalent and half it.

Phil

[Mike Smith]

Sorry Phil,

Not something that I have ever thought about or measured, so have no answer

We work on the principal of attempting to get everything correct and that will alleviate problems

Poor connections are, of course, the enemy of the 6v system

[Kenyon]

Cheers Mike - I'll be having a go at the checks in your list on the Bank Holiday.

In the meantime I went for a Optima Red Top and will see how we go. Appreciate the underlying issues might be more technical.

Thanks very much for all the input.

[roy mawbey]

http://www.autotechnician.org/starter-v ... n-english/

If you read this text to the bottom you will see the voltage drop when cranking the engine is small around 0.5 v max. There is a diagram at the bottom showing connections to check this. Remember of course your new 6v battery has a charged value of slightly more than 6v. I think around 6.6v .

The battery of course has a high amperage applied when cranking so its only a voltage test you make with a multi meter. ( it needs a special ampmeter with a much higher reading scale to do tests on cranking power )

Another point to consider is the cranking of the engine if it were to start during this test. The voltage then would be different if the dynamo kicks in or by an alternator also if the test is made on a modern.

Presume this is the check you wanted to make? A resistance somewhere else in starting circuit can also be found using the meter.

Roy