Range of my Comutacar 200ah t875 trojans @ 72v versus Lithium?

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rmay635703
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Range of my Comutacar 200ah t875 trojans @ 72v versus Lithium?

Doing the calculations its seems my car runs @ roughly 150-200 amps cruzing (aka50mph or so) I get approximate 25-50miles range (though my speed reduces as I go) 50 miles is at 35ish without much stop and start and the batteries are almost dead. My guess is via peukert I have only about 80amp/hr available and I probably never exceed 60ahr due to the way my controller operates.

So lets say my real range per 60ahr is only about 20 miles (conservatively) that should mean I need 72vx300ahr of lithium batts to go 100miles?

Am I about right? I have seen many discussions of lithium batteries in cars (not counting scooters) But few seem to state decent ranges (better than what I get) and the cost is huge.

On this regard I can possibly get damaged batt sets from wrecked prius and insight setups very cheaply, are they really only 6a/hr 144 or 320 volt? That would mean I need roughly 20 batt sets from wrecked cars assuming all cells function which is unlikely.

Anyone ever go down the road of getting a prius or insight batt set into something else?

I have been watching the so called firefly batteries but according to the white paper they aren't much better than normal lead acid, am I wrong?

Just curious what alternative battery setups are out there, especially in the salvage side of things (I like cheap rather than crippling debt) I have also looked for the military Nicad batteries but they never go up on the govliquidation site.

Also what do you guys think of the thundersky / everspring lithiums? http://www.evforum.net/forums/showthread.php?p=1061

Thanx for any insight
Ryan

andrew
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Re: Range of my Comutacar 200ah t875 trojans @ 72v versus Lith

Your calculations sound about right. The AH available may be slightly more than you calculate. Maybe as high as 100 ah.

Lithium and other chemistries look good when compared to the cost of sealed AGM batteries. A pack wouldn't be too expensive for 2-wheeled vehicle, but still really high for a car. Flooded lead-acid batteries still appear to be cheaper all things considered (including their cycle life).

The issue with floodeds though, is the voltage sags so much under high rates of discharge that the power out is low. So, peukert (reduced capacity), and battery DC resistance (voltage sag), both factor in to reduce the usable energy. This hits the batteries particularly hard in cold temperatures because both the capacity, and the voltage sag get worse, and the available energy drops a lot. It also means high rates of discharge really tend to drastically effect floodeds. This makes sealed AGMs which have a lower DC resistance a better choice for high-rate discharge, and they would probably give you a bit more range at high speeds. They also hold voltage better through the discharge cycle. My experience is that floodeds tend to be weak all around, and their performance starts poor and gradually gets worse with SOC during the discharge cycle. AGMs on the other hand tend perform good, and remain at a fair level of performance until the charge is low (<80% SOC).

Personally, I wouldn't want to ever use floodeds in an EV again, unless it is for a slow utility vehicle. They just have such poor performance, and are so drastically effected by temperature. Then there's the issue of acid corroding everything and getting on clothing, and having to water the batteries. I think flooded are particularly a poor choice for any high-speed road EV, though they are very practical for fork lifts, golf carts (and other slow-moving personal carriers), and airport tugs.

If you wanted a battery with a much lower DC resistance, than something like B&B AGMs, Exide Orbital 34XCDs, or Hawker Odysseys would be a good choice. These would not give much better slow-riding range over the floodeds, but the range when riding at higher speeds may improve by a lot, and the performance would also be a lot better. Unfortunately, the cycle life would not be as good as the floodeds. Some Universal, or "werker" brand may be gotten fairly cheaply. Batteries Plus carries the werker brand and they may give a good discount for a large order.

Trojan carries a VRLA Gel battery that you may check into which is designed for electric vehicles. I'm not sure of the DC resistance, which might not be much better than floodeds. These would need to be balanced somehow, and charged at a lower voltage than floodeds or AGMs. But, they wouldn't vent or leak any acid, and wouldn't need watering.

Have you seen these: Cloud EV LiFePo4 ? They wouldn't give the manufacturer away, but they did say they are not Thundersky. I suspect Cloud EV would probably not sell a product that is junk, but I have no way to be sure on this.

[url=/forum-topic/motorcycles-and-large-scooters/587-my-kz750-electric-motorcycle-project]KZ750 Motorcycle Conversion[/url]
[url=/forum-topic/motorcycles-and-large-scooters/588-fixing-my-chinese-scooter]900 watt scooter[/url]
Pic from http://www.electri

PJD
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Re: Range of my Comutacar 200ah t875 trojans @ 72v versus Lithiu

You asked a heap of questions.

There isn't enough info to answer most of them.

I am working on replacing my 40ah SLA pack with 40AH Thunderskys on my e-max. I am expecting a 60$ improvement. Hopefully, I will be able to report my result in a couple months. Any LiFePO4 applications need to use a battery management system if you hope to get good cycle life.

I haven't heard on any homebuilt EV getting more than 60 miles range, so maybe you should set your sights down a bit. Per this site: http://www.electricmotorsport.com/store/ems_ev_parts_batteries_thunder_sky.php

270 AH x 72 volt's worth of Thunderskys would cost 16,000!

The firefly is supposed to be a lead acid battery with very high electrode surface area to create much higher energy and power density than ordinary lead acid - in theory. Bit even if their hype is true, these new battery developers mostly looking for large manufacturers or the deep pocket "defense" industry for which they can be the exclusive supplier for the duration of their patent, in the meantime, patent licenses issued deliberately prohibit batteries large enough for EV's. This is the current case for NiMH batteries until the patent expires in 2015. That's why Toyota cannot offer a plug-in hybrid. This sort of monopolistic, anti-competition behavior that anti-trust laws wer made for, but US courts are packed with judges who rather like monopolies.

Next question, I have trouble imagining finding twenty wrecked Priii, or Insights anywhere - you'd probably have to comb the continent. There are probably specific special rules regarding wrecked Priii - they probably have to taken to a Toyota dealer first for removal of the batteries, so you wouldn't find any in there anyway. They are NiMH's, by the way - and require some fancy charging management.

rmay635703
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Re: Range of my Comutacar 200ah t875 trojans @ 72v

I guess I would never give up floodeds for AGM given their limitations, I prefer cheap versus fancy.

I do use the car 5 days out of a week but to go to all 7 I would need a 100mile range which means either alternate battery tech or a backup generator.

100mi is possible using regular Trojan 6v lead in my paticular car, several have done it but with several caviots.

A. Motor needs to be a smaller more efficient type (my D&D is not)
B Batteries must be the larger trojan 6v batteries (mine are 8v which sag even when they are more AH)
C You cannot drive above 25mph or so

My little comuta has potential but is not paticularly airdynamic or light but it is very easy to modify.

I am wondering if anyone else here has ever tried figuring out how Indias government builds lithium ev powered buses for under $10k. Maybe we should be looking harder for lithium ion traction batteries?

Also on an off topic, I can probably get a non running Insight motor block (should still have the non removable 10kw Perm electric motor intact) for very cheap.

I am curious if anyone knows what type of controller could handle a beasty like this if I lop off the gasser part of the block leaving the shaft. Not sure if it needs the active cooling though

Cheers
Ryan

andrew
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Re: Range of my Comutacar 200ah t875 trojans @ 72v

The insight motor looks like it's 3 phase. Check here:
http://www.insightcentral.net/encyclopedia/enmdm.html
http://www.insightcentral.net/encyclopedia/enmotor.html

My guess is any brushless controller for 3-phase motors may be able to. I expect it may take some experimenting. And, I'm not sure on what type of position sensors the motor has.

In terms of 100 miles with lithium, it would take a lot less than 300 ah at 72v to get 100 miles at less than 25 mph. Maybe even half that or less.I would check into any group purchases of thundersky batteries. Do a net search. I think that's by far the best option for the range you want.

I don't think a generator is a great idea to use regularly because it will probably take cargo space, pollute, and be a maintenance burden. Not to mention a series hybrid is not very efficient because of the compounding losses. 40%? for ICE, 85% for generator, 85% for batteries (when they are charging and the vehicle is not being run), 95% for controller, and finally 85% for motor. Why not just drive the wheels directly with the ICE? I think taking a stock ICE car, and electrifying it for a fair electric range with light lithium batteries may be a better option, and far more versatile with unlimited range.

[url=/forum-topic/motorcycles-and-large-scooters/587-my-kz750-electric-motorcycle-project]KZ750 Motorcycle Conversion[/url]
[url=/forum-topic/motorcycles-and-large-scooters/588-fixing-my-chinese-scooter]900 watt scooter[/url]
Pic from http://www.electri

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