Flooded battery balancing - soul

http://www.nabble.com/new-battery-break-in-td13294226ef25542.html#a13301565

but from other posts, this Roland bloke does some strange stuff!




Re: new battery break-in
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by Roland Wiench Oct 20, 2007; 02:22am :: Rate this Message: - Use ratings to moderate (?)

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200 amps! That's ok for motor amps, but not battery amps. I been now
driving with my latest battery pack for six years now and the average
battery amps is about 50 amps mostly at city driving at about 30 mph at 5000
rpm at a gear ratio of 13.5:1.

The 200 amps would be my motor amperes that may range from 100 to 400 amps.

The minimum ampere while parking may below 10 amps and accelerating normally
may be 75 amps and accelerating up a slight incline is about 125 amps. Only
one time, I took the battery amps to 250 amps after the battery was broke in
after about 2 years of driving, to see how much shrink back I had at the
post which was about 5 in.lbs.

To break in my batteries, I first torque all the battery connections to 75
in.lbs. Check the electrolyte level to make sure the electrolyte is above
the plates. Do not add water at this time if it looks low. Electrolyte
will be low in a discharge battery and will rise in a charge battery.

Charge the batteries to 1.250 S.G. which is about 90% state of charge.
Check the electrolyte level again. If its not up to the bottom of the fill
well, than add distill water to that level and than continue to charge the
battery to 1.275 S.G. or to 100% S.O.C.

Record the voltages of each battery and record the battery pack voltage
about 12 hours later after rest and record that voltage.

I then pull a 50 amp load for 1 mile and record the battery pack volt drop,
repeat that for 4 more miles and check specific gravity of the batteries,
which tells me how much S.G. per mile I am using. I then re-torque the
battery connections which will lose about 5 in.lbs in the first 5 miles.
This is common for new connections to lose this much torque where that the
surface of the lead is not completely compress.

During these test, it is best to not drop the State of Charge (SOC) of the
battery below 75%. Re-charge the battery at no more the 10 percent of the
rated Ampere Hour of the battery and repeat the test, except check the
battery S.G. after 5 miles and re-torque at 10 miles.

Checking the battery connections at 5, 10, 20, 40, etc. miles, you will find
that the torque lost may be only 1-2 in.lbs per month of driving.

Check the electrolyte level after about one week which will tell you how
often you will have to add distill water. Remember never add water when the
battery is low while it is discharge.

If a battery is setting for a while, it is normal for the battery acid
(H2SO4) will settle to the bottom of the cell, making the bottom read a
higher specific gravity reading while the top portion will read weaker.
Always charge first, add water when need at the 90% charge and finish
charging, which makes this added water mix better.

Another thing to watch out for, which happen to me, is that I had a group of
batteries, that was only partially fill by the factory with 1.275
electrolyte which was still about 3/8 inch below the fill well. Adding
water at a 1.275 S.G. reading only make the electrolyte weaker and trying to
charge the battery, boil off the water anyway. It is best at that time, is
to finish adding 1.275 S.G. electrolyte which you can get at some battery
shops.

After running the EV for a month, checking the electrolyte S.G. and level,
torque, load testing, and voltage, there is a battery conductance leakage
test and battery current shunt test that could be perform.

The conductance leakage test, is the voltage of a battery terminal that is
conducting across the plastic battery tops to either the other post of the
battery or batteries and/or to vehicle ground while charging and not
charging the batteries.

To do this battery current leakage test during charging, apply all the
safety cautions. I use a insulated electrical blankets, that I draped over
any metal portion of the vehicle. Turn the charger on and connect one test
lead to a battery post and the other lead to the battery top starting next
to that same post and slide it to the edge of the battery top, off the
battery case and on to the battery racks or enclosure. If you see any
voltage reading it is time to clean the batteries.

In stead of re-torque of the connections every month or so. I use a battery
connection shunt current test. While the battery charger is on, connect
your volt meter in the milliamp scale and connect in parallel with the
battery links. Do not connect it to the links itself, rather connect it to
the battery post.

Lets say it reads. 0.005 amps at a torque connection of 75 in.lbs. it may
read 0.009 amps at a lower torque reading and may read 0.001 amps at a
higher torque reading. Use that higher torque reading as a reference and
check the shunt current of every link and adjust the higher shunt amp
reading to match the lowest shunt amp readings. In this way you do not have
to run the torque wrench over every battery connection.

You also can sweep a infer-red temperature scanner over the batteries and
battery connections to a quick test. A good meter will have a heat sensor
to do this type of test.

If you can stand to do all these battery maintenance checks, which I now
been doing for 34 years now. You can a very long life out of your batteries.

Roland

Flooded vs AGM

From EVDL

http://www.nabble.com/Discover-agms---td13508499ef25542.html#a13514772

If you are the sort who looks after your batteries, then it would be difficult to recommend any sealed battery over floodies in terms of cost. You will need a decent charger to hope to approach the rated cycle life for any type of battery. If you need to locate batteries in the passenger compartment or someplace where access for routine maintenance will be difficult, then sealed batteries may be appropriate. If you want a stiffer pack, then AGMs may be appropriate.

Also


A 6V flooded battery is typically rated to about 700 cycles @ 80%DOD, and this will increase dramatically at shallower DOD, just as it does for the AGMs.

Without digging up the Discover specs to fins a cycle vs DOD plot, I would expect them to deliver about 300-400 cycles @ 80%DOD, or about 1/2 the cycles of the floodeds.

hardware for battery boxes

from
http://tech.groups.yahoo.com/group/ev/message/36524

I went to the boat store to buy the flanges and the hose. There's
lots of good stuff at the boat store for hardware to vent bilges
which works well for venting battery boxes.

T-105 suppliers

http://www.batteryguru.com.au/10.html

at $190 each - that is lookign pretty good!

http://www.energymatters.com.au/trojan-flooded-lead-acid-battery-6v-250ah-p-197.html

$240 each

more sealded battery box ideas

Kiwi ev had some good ideas - mentions some waterproof/flameproof/chemical resistant paint for sealing and turbo timers for ensuring that the fans stay running after charging (may be a good idea before charging, but sensing the vacuum may be enough)

nice clips on the battery box as well - but maybe should be locked?

http://www.kiwiev.com/Step%20Fourteen%20-%20Installing%20the%20Batteries.htm

Wet Lead Acid

I think it is time to have a serious look at using wet lead acid batteries.

If I use Trojan T-105 batteries, It will be about $100 cheapter per 12V and I will get 225Ahr instead of 150Ahrs, all for about the same weight.

I also have the peace of mind that these are proven in ev applications (unlike the chinese AGMs that are the alternative)

If I go that way then I need to do some careful battery box design - here is a good article from EVDL mentioning the use of a sensitive vacuum switch - sounds like a good idea to me

http://www.evdl.org/archive/index.html#nabble-td17693571



Re: Battery box fan
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by Roland Wiench Jun 07, 2008; 12:53am :: Rate this Message: - Use ratings to moderate (?)

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Hell Barry,

I do not use 12 VDC to run my battery box ventilation fan. It's a 120 VAC
120 cfm fan that is inline with a heavy duty 2 inch inside diameter flexible
PVC acid proof flex hose that has 1/4 inch thick walls. The fan and fan
blades are all plastic and the electrical fan wires are seal in totally
enclose compartments at the fan connections.

I now have been running 33 years with out a fan ventilating the battery
enclosure while the EV is moving. There is a 2 inch pvc pipe that goes
below the EV and is elbow forward with a screen and 3M filter material in
it. The forward movement of the EV brings in air into the battery enclosure
and exits out the other side.

This fan is used only when I charge the batteries. I install the battery
box ventilation control system, just like we do in gas fire boiler systems.

First, I must turn on the fan switch which the fan must run first to clear
any battery venting that may be present. A pressure/vacuum switch detects
the movement of air present and it will then turn on a 2-pole DC contactor
that then connects the output leads of the battery charger to the battery.

The pressure/vacuum switches are super sensitive and you can get them from a
heating and plumbing supplier.

When the fan is up and running and the flow of air is present, a fan
indicator lite will come on, a flow air lite comes on. I then turn on the
charger contactor which also gives me a indication, that I am connected.

I then look at the on board charger panel meters which is a AC volt, AC amp,
DC volt and DC amp. The AC volt meter will indicated that my AC main plug
is contacted and the DC volt meter indicates that I have main battery power
present up to the battery charger output contactor.

Before I turn on my charge, I make sure that the charger circuit breaker is
off and the current knob is at 0 amps. I then turn on the breaker, and
while watching the AC and DC ampere, I turn the current up while watching
the indicators meters.

At any time the battery box exhaust fan fails, the fan pressure/vacuum
switch then turns off the DC contactor which removes the charger circuit
from the batteries. A larger second fan maintains a positive air pressure
in a separate totally enclose charger compartment.

The battery box exhaust exits out the bottom of the EV like a exhaust pipe
does. If I park in the garage with the garage door down, I run out a exhaust
hose either under the garage door or use a garage door port, like you see in
gas stations.

My garage maintains a 70 degree temperature a year, so when I am charging
the batteries, the fans pull this 70 degree garage air through a 3-M filter
which I cut out of a large 2 inch thick 3M filter material and insert it
into the air input side of the battery box ventilation system.

You must be care full not to cross feed the battery box exhaust system with
the air input. At one time, I did not have this fan exhaust system install
this way. Could always detect a battery vent order. I went into the garage
where I was charging the batteries and when I turn off the charger, this
ignited some hydrogen in the charger compartment and blew the charger
bridge.

Roland

fuse possibilities

from RS - either 250A or 325A - 250A should be good good to 325A for a minute

http://australia.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2260894

vacuum switch

EV parts are giving unresonable shipping costs - time to have a look at local vacuum switches

from AEVA
http://www.aeva.asn.au/forums/forum_posts.asp?TID=516&KW=vacuum&PID=4210#4210

Finally have the details about Hobbs Vacuum Pump vacuum switch.

http://www.aeva.asn.au/forums/uploads/437/Vacuum-_Hobbs.jpg

Flexible Drive Agencies, Queensland number 07 32742013
Melb. Hobbs Mgr. Darren Atkins Ph:0393819202
Proximate cost incl. GST and postage aprox $60 au

other power steering possibilities

From aeva forum

http://www.aeva.asn.au/forums/forum_posts.asp?TID=395



Power steering is dead easy to keep - just strap this onto any hydraulic OE system;

http://cgi.ebay.com.au/Vauxhall-Astra-Power-Steering-Pump_W0QQitemZ160261719630QQihZ006QQcategoryZ10404QQrdZ1QQssPageNameZWD2VQQcmdZViewItemQQ_trksidZp1638Q2em122

Pick one up locally at any Holden wrecker

fuse possibilities

http://au.farnell.com/1354651/electrical-circuit-protection/product.us0?sku=littelfuse-157-5700-6251


meant for a forklift - rated to 80V - should be fine for mine but not so sure about mira.

Expensive fuse holder but I think that I can make my own fuse holder.

Battery sizes

I have realised that I may need to make the battery boxes before I buy the batteries. I have checked the size of the three 150Ahr batteries that may be a possibility.

Full river
171(W) x 484(L) x 241(H)

Absorbed Power
172(W) x 485(L) x 240(H)

First Start
170(W) x 485(L) x 241(H)

seems that I can build the boxes based on the max

172(W) x 485(L) x 241(H)

mazda 2 conversions

this mob are converting mazda 2 in armadale

http://www.energetique.com.au/