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- Subject: Battery Care
- From: "Thomas Wahl" <tvwahl knightsnet com>
- Date: Sat, 25 Aug 2001 22:21:27 -0500
- Delivered-to: tvwahl webtv net
- Reply-to: "Thomas Wahl" <tvwahl knightsnet com>
Battery Care
by T.V. Wahl
Flooded deep-cycle batteries can be expected to last for five to fifteen
years. They have a 25% solution of sulfuric acid in water SG about 1.26. A
fully discharged battery has virtually no sulfuric acid and is almost pure
water SG 1.00.
Use petroleum jelly on all exposed electrical connections to prevent
corrosion.
For flooded batteries a hydrometer is the definitive indicating device.
State of charge= (SOC).
Specific gravity (SG or S.G.) may also be shown 1.275 or 1275.
Tractor pack
Charging Discharge 6x6V=36V
S.G. Comments SOC volts SOC volts Chg SOC V Dis SOC V
1.275 Short life 14.9 est 12.8 est 44.6 est 38.3 est
1.260 Full 14.7 12.6 44.1 37.8
1.222 3/4 full 13.5 12.5 40.5 37.5
1.200 Charge time 13.2 est 12.4 est 39.6 est 37.4 est
1.185 1/2 full 13.0 12.3 39.0 36.9
1.148 1/4 full 12.6 12.0 37.8 36.0
1.110 0 (empty) 12.2 est 11.6 est 36.6 est 34.8 est
<1.110 Short life
30% SOC 38.0 volts (Harry Landis setpoint) 12.7 V equivalent
100% SOC 42.6 volts Harry's 5 minute charge cycle 14.2 equiv
Note: The test for the validity of Harry's setpoint at 38.0 volts is in the
specific gravity measurement. If a series of SG measurements are taken over
time for each cell and averaged we could get a picture where the setpoint
should be. Good batteries should have a normal variation of up to .050 SG.
But a SG variation of .050 or greater means trouble in the battery.
Ref: Home Power Magazine #6 Aug/Sep 1993, #69 Feb/Mar 1999
File:BatCare
PS- I also have a chart with a top view of the tractor battery compartment
and space to record individual cell specific gravity. This can be sent to
anyone that wants it. I cannot put it on the list because attachments are
not allowed (it is in bitmap format- filename.bmp).
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