Did I kill my deep cycle battery ? Also, how to avoid this.

Submitted: Tuesday, Apr 19, 2005 at 01:04
ThreadID: 22181 Views:2347 Replies:7 FollowUps:1
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Went to Fraser over Easter with my brand new van and Delkor 100ah deep cycle battery. Ran the Dometic 3 way fridge on gas while camped, and switched to 12v for the long trip back to Brisbane- via Anderson plug to car alternator and starting battery. When I got back, I discovered that the Anderson plug mustn't have made connection (maybe it was the sand in it from driving around the beach for the week), and the deep cycle had been running the fridge for the whole 7 hour trip back(after running the lights and water pump for the week). It was very low. The smart charger wouldn't charge it (it refuses to charge if the volts are lower than 9 volts- according to the book, if less than 9 volts, then the battery has had it). I "fooled" the charger by connecting up an old charger briefly to show 12 volts, and away the smart charger went. After 3 days, it showed "fully charged", and dropped back to a trickle. According to the charger, it is full and OK.
There is a hydrometer spot thingy on the battery which shows green for "charged", black for "needs charging" and clear for "battery is stuffed". It showed green when we went away, but now only shows black. It has never showed clear.
My question, did I just use up a lot of this battery's life ? Does anyone know anything about those spot hydrometer things ? Any hints on how to avoid this in future ? I just can't tell if a connection to the Anderson plug has been made OK.

Would appreciate your thoughts.
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Reply By: Member - Jimbo (VIC) - Tuesday, Apr 19, 2005 at 07:42

Tuesday, Apr 19, 2005 at 07:42
Any severe discharge of a bettery does have some impact on its life. One alone will not stuff a new battery.

I's take it back and get them to analyse it and replace if necessary.


AnswerID: 107333

Reply By: drivesafe - Tuesday, Apr 19, 2005 at 07:57

Tuesday, Apr 19, 2005 at 07:57
Hi Steerpike, doesn’t your fridge have a low voltage cut out.

If not it would probably pay you to fit a low voltage cut out device at the battery and that way it won’t matter if the fridge or anything else is left on, the cut out will shut down and protect the batter.

AnswerID: 107335

Reply By: Bros - Tuesday, Apr 19, 2005 at 08:36

Tuesday, Apr 19, 2005 at 08:36
Did you let the battery stand for a while before using the hydrometer.
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AnswerID: 107345

Reply By: Des Lexic - Tuesday, Apr 19, 2005 at 09:41

Tuesday, Apr 19, 2005 at 09:41
I had a similar problem with my Delcor and my trickle charger wouldn't do anything for it.
I took it back to the dealer and he put it on his heavy duty charger overnight and hey presto no more problems. That was nearly 18 months ago and it is still going along nicely.
Before I go away, I put the trickle charger on it for 3-4 days to top it up as the alternator won't fully charge the deep cycle regardless of how long you are driving around.
AnswerID: 107351

Reply By: Mainey (WA) - Tuesday, Apr 19, 2005 at 12:04

Tuesday, Apr 19, 2005 at 12:04
Take it back to the battery supplier and ask them to check it out.

It may be faulty, it happens to the best of them, L0L.

They will be able to get it back to full voltage, if not damaged, by deep discharging it to see its actual condition and then charging it with their own equipment overnight.
AnswerID: 107366

Follow Up By: Member - Jimbo (VIC) - Tuesday, Apr 19, 2005 at 20:03

Tuesday, Apr 19, 2005 at 20:03
I agree with Mainey.

I have a quite expensive Lifeline 100 amp AGM battery ($350) that was not getting to full charge, only about 90% but I expected better out of it after 4 months. I took it back and they gave it a discharge followed by an "equalising" charge to get it working right. Has been perfect since.

Not sure if it's the same with wet cells, but get it back to the person who sold it to you to check out. Either they fix it or replace it.


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Reply By: Michael ( Moss Vale NSW) - Tuesday, Apr 19, 2005 at 20:08

Tuesday, Apr 19, 2005 at 20:08
The whole idea of a deep cycle battery is that you can flatten it without damage, unlike a normal battery.... michael
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AnswerID: 107433

Reply By: Steerpike - Wednesday, Apr 20, 2005 at 00:17

Wednesday, Apr 20, 2005 at 00:17
Many thanks for the good info and advice. I'll certainly install a low voltage cut out. Meanwhile, I'll keep it on the trickle charger and keep an eye on the hydrometer.
AnswerID: 107475

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