Its getting time to launch and I tested my house batteries and my starting battery with a hygrometer. All the cells are consistent .. but the reading is in the "white" area in all the cells. The instructions with the hygrometer said the batteries need attention. A website I checked said a white reading means the batteries are in fair condition .. so simply charge them and use them for another season. I'd rather replace the batteries now if I'm going to have problems, but at the same time if they are good for another season, then I'd like to defer the purchase. The batteries have seen 3 seasons. Any words of wisdom
White hygrometer readings ... are my batteries ok?
- Thread starter John1558
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No wisdom, just economics
John, if the batteries have been performing well, fully charge them and give them a try. If they fall far from last years performance, replace them. If you are a week end sailor,, you might not notice a difference. If you cruise, it might stick out like a sore thumb. It is your money. If they are not performing, change them, life is short and you don't want problems. If they are performing ( good batteries sometimes work for 7 to 10 years) let them do so, and invest the money elsewhere. I would also charge them and repeat the testing. r.w.landau
John, if the batteries have been performing well, fully charge them and give them a try. If they fall far from last years performance, replace them. If you are a week end sailor,, you might not notice a difference. If you cruise, it might stick out like a sore thumb. It is your money. If they are not performing, change them, life is short and you don't want problems. If they are performing ( good batteries sometimes work for 7 to 10 years) let them do so, and invest the money elsewhere. I would also charge them and repeat the testing. r.w.landau
inconclusive test
1. Toss out the $2 hydrometer, and upgrade to the $10 tester c/w numerical display & temperature compensation chart. 2. For an excellent tutorial on Specific Gravity Testing Goto: “HOW DO I TEST A BATTERY?” by William Darden http://www.batteryfaq.org/carfaq4.htm Sections 4.1 through 4.4 give a step-by-step instruction on how to do a specific gravity test with a hydrometer (a hygrometer measures relative humidity). HTH, Gord May
1. Toss out the $2 hydrometer, and upgrade to the $10 tester c/w numerical display & temperature compensation chart. 2. For an excellent tutorial on Specific Gravity Testing Goto: “HOW DO I TEST A BATTERY?” by William Darden http://www.batteryfaq.org/carfaq4.htm Sections 4.1 through 4.4 give a step-by-step instruction on how to do a specific gravity test with a hydrometer (a hygrometer measures relative humidity). HTH, Gord May
Rule of thumb
If the readings do not vary more than 50 pts between high and low, recharge and perform other tests. The hydrometer is good for letting you know when to chuck a battery out if the readings vary widely.
If the readings do not vary more than 50 pts between high and low, recharge and perform other tests. The hydrometer is good for letting you know when to chuck a battery out if the readings vary widely.
SG Readings
A fully charged lead acid battery should have an SG of 1350 at the end of its charging period. A battery SG of 1210 to 1300, taken at random, is considered to be in good health. As batteries age their internal resistance increases as sulphtion takes place. The only way to accurately test an aging battery is to take it to a dealer and have them test it with an instrument that measures the cell voltage whilst loading it with a heavy discharge current. As a crude rule of thumb, if you can get three repeated engine starts on a cold engine its still got a useful life. But, if the battery self discharges when left standing for a couple of weeks (Check its SG) its plates are shedding material and its unreliable.
A fully charged lead acid battery should have an SG of 1350 at the end of its charging period. A battery SG of 1210 to 1300, taken at random, is considered to be in good health. As batteries age their internal resistance increases as sulphtion takes place. The only way to accurately test an aging battery is to take it to a dealer and have them test it with an instrument that measures the cell voltage whilst loading it with a heavy discharge current. As a crude rule of thumb, if you can get three repeated engine starts on a cold engine its still got a useful life. But, if the battery self discharges when left standing for a couple of weeks (Check its SG) its plates are shedding material and its unreliable.
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