Attention! Alternatorless modders. Get your voltage up - Page 2 - Fuel Economy, Hypermiling, EcoModding News and Forum

blueflame · 03-23-2009, 05:34 AM

Quote:

Originally Posted by SVOboy

How much weight is added when going to 18 volts?

Depends on the size of the batteries, 6x20a 6v batts shouldn't be much heavier than a 1x60a 12v single batt.

More importantly is it weight that improves FE or not.

gascort · 06-01-2009, 11:06 PM

Orange4boy, did you ever find a better solution to get your voltage between 13 and 15? I'm in the same boat; I've managed to drive a couple of tanks with no serpentine belt; eliminating my a/c, p/s, and alt. I had no drivability issues, but no dramatically improved FE.
I'm considering adding some other batteries in series to get my voltage up to 14 or 15. I'm also considering using a separate battery altogether that is 14.4V, like my cordless drill.
My ideas:
The only things that need to run at 14V are the injectors and the ECU, right?
I was mainly thinking about doing some 2V batteries in series with the regular battery and the injectors/ECU.
Anyone have a good idea for getting 2V? I was thinking about several D cells wired in parallel, (2 D cells in series, with several parallel branches) but I've been told you can't charge some kinds in parallel. I can't pull them out of their wiring each time I need to charge them. Anyone know what types I should use?

MetroMPG · 06-01-2009, 11:36 PM

Quote:

Originally Posted by gascort

Anyone have a good idea for getting 2V?

I have a hillbilly way of getting 2v. Don't know if it's a good idea:

Get an old battery (that still works).

Drive a screw into the top of the case in such a way that you make contact with the cell interconnect and tap just one cell (6 2.x volt cells per 12v battery). Recharging may be an issue though.

A guy at a parts store told me about this approach. He said he occasionally provided old batteries to a farmer who needed 10v for an electric fence. He tapped the battery using this method.

You could theoretically use each of the 6 cells, then recharge the battery. Of course if the cells aren't drawn down to the same state of charge each time (unlikely), the cells will be unbalanced, and the battery will soon be toast.

orange4boy · 06-02-2009, 02:22 AM

I think the most efficient way to get 16v is two 8V golf cart batteries. A 14.5v power supply with enough amps to run everything would be pretty pricey. I found a 25A one for $100 new. (no budget for it at the moment) Although that would be cheaper than the two batteries, It would not be enough to run everything. I should really run the fuel pump (for better, or at least stock vaporization) and the coil (for hotter spark) off something with higher voltage.

My interim duct tape solution was to run a 50 amp battery charger off an inverter powered by my 2 12V deep cycles. It worked ok but I'm worried it may overcharge the starting battery. I guess since alternators run at 14.5 this would also eventually overcharge a starting battery but the opposite is often true with many batteries failing from undercharging and stratification.

I had a bad front caliper that was dragging which I just replaced so it will be interesting to see if my numbers change much. My coast down seems better now. Previous to the discovery, my FE seemed to drop through the course of a long trip which I first attributed to the slow voltage drop of the batteries but this may have been the rotor heating up slowly and thus increasing the drag on that bad caliper.

I have been a bad ecomodder and have not been keeping track of my mileage partly due to the frustration of my slowly worsening mileage. The discovery and repair of the dragging caliper has given me some optimism to get back at it.

I also want to address the back of the van where I have been told most of my aero drag resides.

By the way, I halved the opening delay and noticed no difference in the readings. The FE was still much improved over the 12 battery bank. The half reading was a guess but I thought if it made a difference it would be a good starting point to see if it made any difference

I still have not done much in the way of actual tank readings though due to not having a reliable, simple set up yet.

Good to hear from you and good luck.

gascort · 06-02-2009, 06:20 PM

Metro, I like the idea of getting a battery and just using one cell; I agree with the limitations you cited, but in theory you could supply 3V to it and charge it too; just difficult to get 3V automatic trickle chargers, and would be less reliable. You could even get a junk battery with a bad cell; just don't use that one!

Orange4boy, I'm interested in how well your inverter - charger works - basically like a homemade DC-DC up converter, since you need AC to increase voltage (I think).
I'm going to look for said DC-DC converter and price it before I opt for the 8V golf cart batteries, since I've already invested in a really nice (optima yellow top) deep cycle battery. Wish I would've thought this ahead and realized the 12V problem.
Thanks!
Thanks for the info

orange4boy · 06-03-2009, 03:27 AM

If you have the extra juice the inverter-charger works well. It's a bit of a pain though because most chargers are not designed to be power supplies. but you have to turn on the ignition, turn on the inverter, turn on the charger then hope the charger does not decide that the batteries are full and stop charging.

I think you may need to have an extra battery. I'm not sure how it would work to try to charge a battery with itself. Will it become a black hole, sucking up the universe? we do not know... Will it work as a power supply with no battery attached? I have not tried that yet... There is also the problem of efficiency losses because with each conversion you lose some power to heat. So if you have the extra capacity, fill your boots. I suppose if you are just powering the coil and the fuel pump you could get away with a small, cheap dc-dc converter. I'm considering this myself. It saves the pain of turning those suckers on and off every time you use the car.

There are chargers out there that are both a dc-dc and a charger. Can't remember the name right now...brain. not. working... error... error...does not compute.

gascort · 06-05-2009, 06:49 PM

I scoured the internet last night to no avail; can't seem to find a 12VDC to ~15VDC converter that will put out more than 1 amp. I figure the fuses are for 10A, so even with a capacitor, I'd need something that can put out 5-10A to run the computer and injectors. I'm a bit bummed, but I think I can MacGyver a solution like you did; I already have some 95W 120VAC inverters (yes, I know, less than 1 amp) and a 14.4V battery charger; maybe getting a more powerful inverter??
I tried harder to find 2V batteries or 4V batteries; RadioShack does have some... maybe that way will work.
Anyone else have insight?

gascort · 06-05-2009, 07:10 PM

Here's a 4V battery; the biggest I could find.
Ebay Link
10 amp hours... not too bad

gascort · 06-07-2009, 10:41 AM

Just bought this battery from Ebay. It's a 4V sealed lead acid battery with 9AH of capacity. $21.50 shipped,versus $25 shipped for the 10AH one.
If my logic is correct, my Optima Yellow Top D34/78 has 55AH of capacity. It has been fine to get me to and from work. Since this new battery I'm adding in series is 4V out of the total 16, it will only be providing 1/4 of the amps to the circuit, so its 9AH * 4 = 36 effective amp hours relative to what the optima was providing. Add that to the fact that I'm only powering injectors, coil, and ecu, and it should be just fine.
Next step: determine how I want my solar charging to work for this setup!

orange4boy · 06-07-2009, 06:02 PM

Here's what I found, but all need an inverter

I swear, I found a 12 - 14.5v buck converter somewhere. I'll keep looking.

There are more 24-14.5 volt units around but that would mean another battery.

16 volt batteries and accessories:993 - Powermaster 16V Battery Accessories

Someone makes a Li 16V battery for racing. Only $1999 special for you. (There are cheaper ones)
https://p10.secure.hostingprod.com/@...1536435320330c

Iota 110 to 13.5V charger/power supply IOTA Engineering DLS Series AC/DC Power Converters and Battery Chargers for 12VDC Systems
Iota Regulated Battery Chargers
EVDL - Ruggedizing an Iota power supply for DC

C use

This link is to a DIY16v battery chargerAutomatic 12V Lead Acid Battery Charger

I also thought of using an 18V cordless drill battery just for the coil.

I don't know if all that info will help or hinder. Seems like the cheapest way is probably the inverter/charger combo like I have. All readily available and cheap. I found a 750Watt inverter at a dewalt repair/clearance centre for $25. I got the 50A charger for $60 at the same place. I was using 35A to run everything last night.

Good luck.