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Re: [EVDL] Are deep-cycle marine lead-acid batteries right for electriccars?

Hello Chris,

It is best to use the 6-volt deep cycle batteries. If you use the
Interstate Batteries which I am using now, use the highest ampere-hour ones
that are rated over 235 amp hour. The Interstate 235 AH or less are made by
Interstate they had purchase these 6 volt batteries from U.S. Battery

I found out from my battery dealer that they will order the 251 AH directly
from the U.S. Battery company. These will have only one terminal lug option
which is the tall auto post with a top stud.

Do not use the low profile stud type connector that some battery companies
are using now. The studs are not embedded deep enough which I pull out of
the Trojan batteries. I had to recast all these type of batteries with a
auto post.

When you order these type of battery this dealer or any other dealer, make
sure that the battery manufacture dates are all the same and the batteries
are no more than 4 weeks old. Some dealers like to get rid of there old
stock and may mix the old stock with new stock.

If the dealer orders a pallet load which is about 40 batteries, take a
voltage tester to pick out the ones that all the batteries read about 0.001
volt from each other. If your volt meter only reads 0.01 volt then try to
pick all the ones that may read 6.44 to 6.45 volts or a group combination of
0.01 volt difference.

I use a battery analyzer that reads both voltages and battery capacity.
Many battery dealers use this type of instrument and if they do, then test
all the batteries to the same battery ampere capacity. These batteries are
normally rated for 1000 amp capacity, so it will be normal to have a 50 amp
difference between the batteries. Try to stay in that range.

It will take about 200 cycles before this type of battery reaches full
battery capacity. It took me 435 cycles, because I was only discharging
them daily at 75 amp maximum a average of 1.2 miles a day. All of them
except one went over 1100 ampere battery capacity. The one stay below 1000
ampere, so I return that one for one with the same date and a ampere
capacity as close to the existing ones.

When you purchase a pack of batteries from a dealer, you most make it known
by writing specifications, the date, the post type, the filler cap type and
that the batteries in a pack must be balance.

A battery that has a lower ampere capacity, may have matching voltage will
read good with a load meter or battery analyzer and the dealer will not
replace it unless they have a understanding of the above data.

Use only zinc plated heavy duty copper battery clamps that go around the
auto post. Tighten to 75 inch lbs. I install a stainless steel washer,
lock washer and nut on the stud and tighten that up to 50 inch lbs. What
this does is put a internal force of the lead post against the battery

I use those red and black anti-corrosion pads below the battery clamp and
coated the battery clamp with that rubber tool handle dip rubber compound
which states it can be use for batteries. Being that my battery boxes are a
seal epoxy coated box, I place about 1/2 inch of baking soda in the bottom
of the box for the batteries to set on. This cushions the bottom of the
battery when driving on very rough roads. This helps keeps the battery
clean. So far in 18 months, I only water the batteries twice and never
clean them yet verified by a voltage conductance test from any of the
battery post to the surface of the battery.

After driving the first 5 miles with these type of batteries, re-torque the
battery clamp again. You will notice about 5 inches lbs lost which is
normal which is cause by the brush surface of the post melt back which is
known as shrink back.

One more thing while you do the initial five mile test is to take a specific
gravity test of the electrolyte. Lets say the full charge reading was at
1.275 sg and in five miles it reads 1.270 sg. Therefore 1.275-1.270 = 0.005
sg for 5 miles or about 0.001 sg per mile.

The estimate specific gravity range is 100% SOC at 1.275 sg to 50% SOC at
1.172 or 0.103 sg/0.001 = 103 miles estimate if the voltage remain
constant. Voltage not being constant the range average will be less than
103 miles.


----- Original Message -----
From: "L. Chris Hager" <[email protected]>
To: <[email protected]>
Sent: Thursday, March 03, 2011 10:54 AM
Subject: [EVDL] Are deep-cycle marine lead-acid batteries right for

A neighbor in my near-the-water community is a dealer rep (without
warehouse/shop) for Interstate Batteries. So a Q: If I were to move forward
on a project for a lightweight car at 96 or 108 volts, would the deep-cycle
batteries, made for electric-outboard party barges be the right match. Or
some other-- please specify, as he could probably get anything in their
catalog for me at just above wholesale. Thanks!

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