Paul's how NOT to convert a Metro

[TheSGC]

Originally Posted by bennelson

When I take the Metro out to events, I flat tow it behind the S-10 pickup. I have no way of knowing exactly how many miles are "towed" instead of "electric-propelled". However, since I was driving on electric for a while before reseting the odometer, I think it is more or less a wash right now.

Is there really a difference on how the EV moved as long as it did with batteries in the trunk and an electric motor in the hood? It's the EV magic!

[MetroMPG]

Ha! TheSGC: the ForkenSwift has been flat towed about 600 km/400 mi total distance to various EV shows. I disconnected the speedo cable so as not to skew my numbers :P

[rmay635703]

Originally Posted by TheSGC

How did the commute go?

I wonder how the Alum batteries handle under load compared to the lead acid ones.

I have been itching to drive my EV more, but it has been snowing for the past three days and I haven't finished my water heater yet.

My limited experience with alum batteries is that they are best as stationary batteries running light loads.

They droop in voltage much more almost down to 6v (but come back) and also bubble like an edison battery with probably the same charge efficiency, they also have a fast self discharge rate. They operate at much lower voltages because of the insolubility of the electrolite in solution, however you can run them flat without much issue it seems.

I have tested 3 batteries as alum, the first was junk to begin with and failed with a broken interconnect. The next ended up with a shorted cell (was before too) The 3rd a trojan T-1275 that only had about 30ahr left came back after some cycling 160ahr at 3 amp load, however the under load capacity was much lower and at much lower voltage (hard to guage going from 11.5v to 10.5v). Also I found you needed to use the battery straight after charge to have the best range.

Perhaps I am doing something different, looking at the "old" information it appears alum is to be added to water then mixed in the acid in most old recepies. Sometimes mixed in with cobalt and epsom salts. Perhaps the really good alum batteries have had the owners leave some acid in there, and sludge feeds the alum reaction but it also causes internal shorts which is how most of my batteries have ended up, shorted.

If anyone wants to test alum, go right ahead just make sure you do it on sulphated batteries, not ones with broken cells or broken interconnects. Alum doesn't really work on new batteries or ones that more or less are good.

Alum can potentially increase capacity beyond the original rating but it has the devistating side effect of offering that capacity at a linear discharge down to about half your original voltage. And in my experience only at lighter loads but perhaps my set of batteries were all failures. Some have claimed their alum batteries function at voltages higher than original, not sure how that would happen, would be nice if someone who was good at making sucessfull conversions would show how to do it correctly.

Also I would think EDTA or epsom salts work more reliably as Alum apparently needs a pretty specific situation to work ideally. Good though if the battery is a boat ancor, could at least use them to run lights and actually originally alum batteries were used to run lights, telegraphs and other long use light load applications prior to 1905. (one guy linked a book from 1899 describing an alum powered telegraph) So no we aren't crazy, there were alum batteries very early on but obviously had some problems or we would be using them now.

Cheers
Ryan

[vpoppv]

Originally Posted by rmay635703

My limited experience with alum batteries is that they are best as stationary batteries running light loads.

They droop in voltage much more almost down to 6v (but come back) and also bubble like an edison battery with probably the same charge efficiency, they also have a fast self discharge rate. They operate at much lower voltages because of the insolubility of the electrolite in solution, however you can run them flat without much issue it seems.

I have tested 3 batteries as alum, the first was junk to begin with and failed with a broken interconnect. The next ended up with a shorted cell (was before too) The 3rd a trojan T-1275 that only had about 30ahr left came back after some cycling 160ahr at 3 amp load, however the under load capacity was much lower and at much lower voltage (hard to guage going from 11.5v to 10.5v). Also I found you needed to use the battery straight after charge to have the best range.

Perhaps I am doing something different, looking at the "old" information it appears alum is to be added to water then mixed in the acid in most old recepies. Sometimes mixed in with cobalt and epsom salts. Perhaps the really good alum batteries have had the owners leave some acid in there, and sludge feeds the alum reaction but it also causes internal shorts which is how most of my batteries have ended up, shorted.

If anyone wants to test alum, go right ahead just make sure you do it on sulphated batteries, not ones with broken cells or broken interconnects. Alum doesn't really work on new batteries or ones that more or less are good.

Alum can potentially increase capacity beyond the original rating but it has the devistating side effect of offering that capacity at a linear discharge down to about half your original voltage. And in my experience only at lighter loads but perhaps my set of batteries were all failures. Some have claimed their alum batteries function at voltages higher than original, not sure how that would happen, would be nice if someone who was good at making sucessfull conversions would show how to do it correctly.

Also I would think EDTA or epsom salts work more reliably as Alum apparently needs a pretty specific situation to work ideally. Good though if the battery is a boat ancor, could at least use them to run lights and actually originally alum batteries were used to run lights, telegraphs and other long use light load applications prior to 1905. (one guy linked a book from 1899 describing an alum powered telegraph) So no we aren't crazy, there were alum batteries very early on but obviously had some problems or we would be using them now.

Cheers
Ryan

I am still using one alum battery in my pack, and it seems to follow exactly what you are describing. Honestly, once I find a suitable replacement battery, I will be removing it from the pack. However, given that it was not working so well anymore as a lead/acid, it is no real loss. Also, as you say, it has the advantage of being able to discharge very low without fear of damage. As a lead/acid, it was degrading progressively every day. Since the conversion, its performance has been increasing (it gains 1/100 of a volt per day).

Edit: I just scored 2 more group 31 batteries. That makes 5 for the Toyota, plus 3 group 27s. I was planning on 72v, but if it ends up at 96v, so be it. Who am I to argue with the battery Gods?

[TheSGC]

How's the EV been driving?

[vpoppv]

Originally Posted by TheSGC

How's the EV been driving?

Really well actually. I still would like to replace the alum battery because it shows 10.81v after commute. The battery I have on the desulfator is doing WAY better and is up to 12.39v after commute. That's up from 12.05v, so quite an improvement. I've really been looking forward to Spring Break to get some serious work done on the Toyota. I have a solid set of 6 group 31 batteries for it, and a good supply source. Has it warmed up yet where you are? It was about 70 here yesterday....

[TheSGC]

Originally Posted by vpoppv

Really well actually. I still would like to replace the alum battery because it shows 10.81v after commute. The battery I have on the desulfator is doing WAY better and is up to 12.39v after commute. That's up from 12.05v, so quite an improvement. I've really been looking forward to Spring Break to get some serious work done on the Toyota. I have a solid set of 6 group 31 batteries for it, and a good supply source. Has it warmed up yet where you are? It was about 70 here yesterday....

It is about 65F today, and this past week is has mostly been raining and snowing. I do have battery heaters though, so they stay at a nice toasty 76F. I am just dealing with two very stubborn batteries that sag like crazy after 12 miles, but bounce back up immediately, so I think they just need some love and more driving to break them in. I did drive 12.8 miles today and only got a low battery warning at the end, which I ignored because I caused it by putting pedal to the metal to see if another problem would come up, but it has been improving. I am not quite ready to the point where I can challenge my 16.8 mile commute, but getting close.

Yeah, I also have Spring Break in two weeks, and I am hoping to get my new suspension installed in the front as the rear was done already.

[vpoppv]

Today was a great day for the EV! This last weekend, I finally broke down and purchased a new battery. This kind of goes against everything this car is about, but I ultimately decided that it was in my best interest to have one good battery to give me a baseline of sorts. All my experiences so far have been with used batteries and I just don't feel like I will ever know what a "new" battery would act under my specific conditions. I believed it would give me a better understanding of batteries in general to have a new one to compare to. In the short term, I had the advantage of taking out my lowest battery and making it my best. I replaced my alum conversion battery. As it turns out, the new battery is still not my "best" battery: that title remains in the hands of Mega-Tron. Anyway, today I showed the highest voltage ever: 79.6v! That is a full volt higher than any previous reading. The car did drive quite a bit spritelier than ever today. On another note, the battery replacement had the advantage of showing me a hidden crack in my battery rack. I welded that up and also put in a reinforcement bar. So last weekend was very productive indeed, even if there wasn't as much done on the Toyota as I would have liked....

[vpoppv]

Ok, I can now confirm that lead/acid batteries can/do explode.....

[TheSGC]

Originally Posted by vpoppv

Ok, I can now confirm that lead/acid batteries can/do explode.....

Oh, now that you left us hanging, there better be pictures. What happened?