Alternator bypass & engine preheater mod

[paulgato]

...but it's funny: I've not had to use my alternator for local driving for the past couple of months or so, but now I have almost literally 'deleted' my alternator by shorting it out, driving around without one is making me quite nervous. I'm watching that volt meter like a hawk and I am paranoid about getting stranded with a flat battery. I've got a new (used) alternator on order and I'll be much happier once that's installed.

[California98Civic]

Originally Posted by paulgato

...but it's funny: I've not had to use my alternator for local driving for the past couple of months or so, but now I have almost literally 'deleted' my alternator by shorting it out, driving around without one is making me quite nervous. I'm watching that volt meter like a hawk and I am paranoid about getting stranded with a flat battery. I've got a new (used) alternator on order and I'll be much happier once that's installed.

I hear you.

[oldtamiyaphile]

Originally Posted by paulgato

Yes, I'm not that familiar with using rivets, and I don't have a riveter tool. It sounds like a good and satisfyingly quick process, although I'd be concerned about any protruding rivet heads, especially on the inside, as these plates will potentially be pressing hard against the battery wall. Maybe flush rivets are available?

Don't Optima batteries have round corners where the backside of the rivets can safely live? Flush riveting would usually mean countersinking the backsides in some way. I'd still use some adhesive (Sikaflex) on the parts, couldn't hurt. Even better would be to find someone with a sheet metal brake (with the size of the fabrication in question, a DIY brake like you'll find on instructables might suffice) and then you'd only have one join.

[paulgato]

Another conversation with Enersys UK tech support about Odyssey batteries. This time to find out why they require a minimum of 40% of the Ah rating as a charge current - in other words, a 100Ah battery will require at least a 40A charger. This I only found out AFTER buying the battery of course.

It turns out this is the case (so I will need to buy yet another charger!) and that charging at a lower than 40% rate will SIGNIFICANTLY reduce the number of cycles and the overall life of the battery. Conversely, there is no upper limit on the size of a charger provided the charge voltage is properly regulated. The battery itself will limit the amount of current going into it. Charging at a high current will have no adverse effect on the battery whatsoever. (The guy I spoke to had done some testing using an industrial charger capable of well over 1000A.) Another very useful conversation. It turns out the technology for these Odyssey batteries was developed in the UK by a company that was later acquired by the Enersys group.

So, I need to get another charger. Unfortunately powerful chargers will always have fan cooling, which means they cannot be waterproof, which means engine bay installation is not ideal. So I shall have to get another charger AND find another place in the vehicle to install it. (Maybe I should have a re-think. Maybe the Odyssey is not such a great choice after all and maybe I should return it. Maybe a supercapacitor array in the engine bay and two deep cycle 100Ah batteries in the rear is not such a crazy idea after all.)

...As to WHY the Odyssey batteries work so much better with a higher charge current, the guy I spoke to said there are different theories as to why that is but in truth no one really knows. They just know that IS the case in practice.

[paulgato]

Originally Posted by oldtamiyaphile

Don't Optima batteries have round corners where the backside of the rivets can safely live?

Optima batteries may well have spaces where rivet heads could sit, but Optima batteries don't need reinforcing as they have cylindrical cells with spiral-wound plates. It's an Odyssey battery I am trying to deal with, and those are rectangular with flat plates, and have flat sides all round.

[ctgottapee]

I saw the mention of HID headlights a while back and didn't see if you switched over.

I found that my HIDs were so bright, I went down to just using one HID headlight @ 35w. For the other lamp, I purchased a 3w LED bulb that illuminates the headlight socket so it looks like there is a headlight.
They do draw a heavy inrush current at start up; possibly more expensive ones compensate for this. They have their own power supplies so voltage drops are not an issue.

I'm surprised your radio uses so little power. My uses half an amp when it's off just to store it's settings.


lots of good info in this thread

[RedDevil]

Originally Posted by paulgato

Another conversation with Enersys UK tech support about Odyssey batteries. This time to find out why they require a minimum of 40% of the Ah rating as a charge current - in other words, a 100Ah battery will require at least a 40A charger. This I only found out AFTER buying the battery of course.

It turns out this is the case (so I will need to buy yet another charger!) and that charging at a lower than 40% rate will SIGNIFICANTLY reduce the number of cycles and the overall life of the battery. Conversely, there is no upper limit on the size of a charger provided the charge voltage is properly regulated. The battery itself will limit the amount of current going into it. Charging at a high current will have no adverse effect on the battery whatsoever. (The guy I spoke to had done some testing using an industrial charger capable of well over 1000A.) Another very useful conversation. It turns out the technology for these Odyssey batteries was developed in the UK by a company that was later acquired by the Enersys group.

So, I need to get another charger. Unfortunately powerful chargers will always have fan cooling, which means they cannot be waterproof, which means engine bay installation is not ideal. So I shall have to get another charger AND find another place in the vehicle to install it. (Maybe I should have a re-think. Maybe the Odyssey is not such a great choice after all and maybe I should return it. Maybe a supercapacitor array in the engine bay and two deep cycle 100Ah batteries in the rear is not such a crazy idea after all.)

...As to WHY the Odyssey batteries work so much better with a higher charge current, the guy I spoke to said there are different theories as to why that is but in truth no one really knows. They just know that IS the case in practice.

That is strange. I cannot see how charging on a low current could be bad for a battery, unless it is has a shorting cell.
What is known to limit the life of a battery is how deep you discharge it; dicharging beyond 40% SOC does indeed reduce the life of a battery; you can discharge a lead acid battery to 75% many thousands of times, but discgarging to say 10% will kill it within a few 100 cycles.
40% may well be the most economical point; beyond that the damage you do to the battery outweighs the benefit of prolonged running without alternator.
IMHO instead of charging it hard you might well focus on avoiding deep discharge.

To play devils advocate: if they get you to buy an expensive charger for your battery they make sure you will buy another like battery if it goes bad, or you would have wased all that money on the charger...
I would like to see proof that you do need a big charger for a big battery.
At least it does have the benefit of fully charging your battery within a few hours, but that's it.

I have restored some dead batteries to more or less full capacity by trickle charging and short bursts of discharge. I do have an OptiMate4 desulphating charger that does that automatically for motorcycle batteries (it could not cure my car 35Ah battery btw; it had a shorting cell). The thing to avoid there is high voltage; if the battery does not take the current it is essential not to push it by raising the voltage.
My charger could output no more than 1 Amp.

[oldtamiyaphile]

Originally Posted by ctgottapee

I'm surprised your radio uses so little power. My uses half an amp when it's off just to store it's settings.

There is something seriously wrong with it. Typical standby is 10-25ma.

500ma is typical 'ON' power consumption (with a modern TFT screen), muted.

If yours really draws 500ma, that's 6amps after being parked overnight or the equivalent of running with your headlights on for nearly an hour. A new unit would be a good eco mod.

[ctgottapee]

Originally Posted by oldtamiyaphile

There is something seriously wrong with it. Typical standby is 10-25ma.

500ma is typical 'ON' power consumption (with a modern TFT screen), muted.

If yours really draws 500ma, that's 6amps after being parked overnight or the equivalent of running with your headlights on for nearly an hour. A new unit would be a good eco mod.

Yeah, it's a 1993 factory AC Delco model.
It's not even the worst offender in the car.
The premium systems in the car use a lot of juice too. I guess the reliability of cold start electronics was low then. My power seat controls/system is always powered so it can auto adjust based on the keyfob used (set per driver) before they sit down when they unlock the car.
The exterior key lock is always lighted, run by a 15w bulb and a long length of fiberglass filament; kinda creative before LEDs existed.
And there is an air compressor that inflates the rear shocks as a ride control mechanism. It's not air tight so it is also always on, and occasionally runs to push the bladder back up while sitting.



I have climate control, but it still uses the resistance elements for fan power.

[ctgottapee]

paulgato: I know you thought the coolant preheat wouldn't be as good as the oil pan preheat, but I think your oil preheated will run into the same problems.
As soon as it makes one pass through the engine, it will cool to ambient as the engine will be cold. I would be willing to wager you would see no change in the oil temp gauge by the time it cycles around.

The coolant preheater has the benefit of warming the entire engine; it will even warm that oil from the pan on its first pass after startup. And it also warms the oil that remains inside the engine/filter/distribution system.

Of course calculating the electricity heat used in comparison to mileage saved is still difficult.
The toyota prius uses a coolant preheat (actually a storage system) so it appears the engineers think it's relevant - they might be calculating emissions savings into the equation too. Other threads on ecomodder describe the system and attempts to mimic it. Toyota could do the same with the oil pan but they don't.

Even when the preheated coolant is dissipating it's heat, it is still a benefit in warming the engine whereas the oil pan will dissipate heat readily to the exterior of the car which doesn't do much. I would only be willing to try it if I used one of the interior direct contact elements that routes through a whole in the side of the oil pan as it's really efficient. Drilling and reliably sealing aluminum is not an easy at home task though.

You shouldn't have dry start issues on a properly developed car. Even my oil filter comes standard with a drain back valve.