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Old 15-12-2016, 00:39   #1
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Battery status of Gel batteries

Hi!

Came down to the boat. -5 degrees Celsius now (Winter). House bank at 12,4 V. something like 50-75%. I got a 10 W solar panel connected currently and they were fully charge a few months ago, so would have expected more, if not 12,7 V, at least 12,6 V? The only draw now is an alarm that is blinking. A blinking diode shouldn't drain much?

While sailing last summer I noticed how the voltage came down from e.g. 12,5 V to quite low reading just when turning on a LED light. A 1 W LED shouldn't even change the reading, should it?

Current setup (blame previous owner):

Invac 30 A battery charger. Enabled once shore-power is plugged in. No settings for battery chemistry.

4 x Gel batteries = Housebank = 300 Ah. Text on side of batteries "Euro Gel, max 14,4 V". Installed new 2013.

Seen the Invac producing +15 V.

Invac has been left on for several days on two occasions.

Once the fridge was left on and might have drained the batteries (old fridge always ran on ACU max regardless settings (something was wrong) and turned into a freezer really, replaced the crap with a Non-ACU (only sensible choice) that is also modern and less power-hungry)-

Planned setup:
Am installing the Sterling alternator to battery charger (80 A):
Alternator to Battery Chargers up to 130A | Sterling Power Products

Will connect Invac and Alternator (50 A) to Sterling.
Sterling will connect to house bank.
Will set battery chemistry to Euro Gel (max 14,4 V).

All will be fine so, but might I/previous owner have damaged the batteries? Would like to squeeze a few more years out of them.

Replacing the 4 x 75 Ah Gels with Gel is not an option. Too expensive. I want to have functioning batteries while ARC 2018. Once home in summer 2019 I don't care what happens.

Read about capacity testing. Seems like a pain in the XXX. And you might damage the batteries in the process by draining below 50%.

Problem I got, let's assume the Sterling does its job + the 400 W solar panels I am installing is keeping the batteries ok, I will connect a Nasa BM-1 battery monitor.

Dream scenario would have been brand new batteries. If so, I could have set the BM-1 to 300 Ah and trusted the setting. If I set the current house bank to 300 Ah in the BM-1- Probably not realistic? Will be a false security? Should I set it to 250 Ah? Problem is, I got no idea...

Cheers
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Old 15-12-2016, 01:24   #2
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Re: Battery status of Gel batteries

Charging Gel with a normal battery charger which exceeds 14.4V is likely to kill them fairly quickly.

Sorry to say this, but the odds are that they are stuffed.
No amount of playing around with charging regimes will help now.

Replace them with AGM or FLA.
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Old 15-12-2016, 01:36   #3
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Re: Battery status of Gel batteries

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Charging Gel with a normal battery charger which exceeds 14.4V is likely to kill them fairly quickly.

Sorry to say this, but the odds are that they are stuffed.
No amount of playing around with charging regimes will help now.

Replace them with AGM or FLA.
Ok, my life expectancy need is a few years only. After ARC I'd like to switch to a larger steel boat.

What if I use them next season over here, and replace them prior to leaving for ARC, with regular cheap lead batteries? Those ought to last 1-2 years at least if I give them plenty of love?

As for charging with +14,4 V. If you do this for five minutes on brand new GELs, are they stuffed? How long must they be charged incorrectly, please? Does the amount of Amps matter? E.g. I got a 3 W solar panel in the car with not regulator, keeps the 62 Ah battery topped up while car is parked while sailing for a few weeks in the summer. Doesn't seem to harm the battery. If however we were talking 20 W I would need a regulator.
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Old 15-12-2016, 01:43   #4
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Re: Battery status of Gel batteries

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Originally Posted by Bob666 View Post
Ok, my life expectancy need is a few years only. After ARC I'd like to switch to a larger steel boat.

What if I use them next season over here, and replace them prior to leaving for ARC, with regular cheap lead batteries? Those ought to last 1-2 years at least if I give them plenty of love?
Those batteries will be 5 years old, 6 by the time you get home from the ARC and they appear to be in trouble now.

If they are replaced with FLA now and the batteries looked after they should last 5 years, plenty for the next owner.

However, worth giving them a good slow charge but not exceeding the max voltage to see if they will come back.

Your 10w solar panel won't do much at this time of year especially given your northern latitude. We have 110w of solar which keep the batteries charged but it does take a while if we run the them down. December and January always seem poor for solar charging and it won't improve much until end of February.

Before you buy one of those outrageously expensive widgets from Sterling, why not buy the new solar panels and see if they can keep up with your electrical demands.

Pete
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Old 15-12-2016, 02:16   #5
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Re: Battery status of Gel batteries

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Those batteries will be 5 years old, 6 by the time you get home from the ARC and they appear to be in trouble now.

If they are replaced with FLA now and the batteries looked after they should last 5 years, plenty for the next owner.

However, worth giving them a good slow charge but not exceeding the max voltage to see if they will come back.

Your 10w solar panel won't do much at this time of year especially given your northern latitude. We have 110w of solar which keep the batteries charged but it does take a while if we run the them down. December and January always seem poor for solar charging and it won't improve much until end of February.

Before you buy one of those outrageously expensive widgets from Sterling, why not buy the new solar panels and see if they can keep up with your electrical demands.

Pete
Ok thanks. By connecting the Invac 30 A to the Sterling they will be charged correctly, I could try that first.

In parallel, I need a charger for other purposes. What to buy, please? Lots to choose from. CTEK for example claims their chargers charge "all kinds of batteries: GEL, AGM, Lead-acid" etc.

Sounds nice, but should one opt for a charger that is adjustable, i.e. you choose max voltage or choose battery chemistry, with a rotating knob or switch? Rather than trusting its "intelligence"?

Cheers
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Old 15-12-2016, 09:46   #6
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Re: Battery status of Gel batteries

If I were buying a new battery charger, I would definitely choose one with a programmable float voltage. Not a knob or switch, but a semi-permanent adjustable parameter that is set by computer or similar interface. I would also be careful to take into account the typical .3V drop between the charger and the battery terminals. My experience with AGMs is that they are very fussy about float voltage and that one is more likely to undercharge them than to overcharge them. I would also consult the manufacturer to determine the correct float voltage.
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Old 15-12-2016, 10:29   #7
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Re: Battery status of Gel batteries

It does sound like your batteries may be toast. Sounds like they were being overcharged. Do you know what voltage the alternator puts out (was it modified with a balmar etc for the gells) They can vary alot depending on the alternator I have seen a few stock marine alternators put out as much as 14.9 volts. Typically more like 14 but I have seen higher. My old gells called for 14.1 V charging and 13.8 float.

Your boatyard likely has access to a modern battery tester (impedance) while these have issues with house banks, if it fails on one it's likely toast.

You could also run your own less scientific test using the ammeter onboard. Charge the batteries up (at the correct voltage) Let them sit for a bit take a reading, turn on 10-20 amps and see if you get a voltage drop (more then a few 10ths) if not run it for an hour and check the voltage again. Again this is not a real capacity test but based on what you have said it sounds like their gone and this would be a good confirmation.
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Old 15-12-2016, 11:16   #8
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Re: Battery status of Gel batteries

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You could also run your own less scientific test using the ammeter onboard. Charge the batteries up (at the correct voltage) Let them sit for a bit take a reading, turn on 10-20 amps and see if you get a voltage drop (more then a few 10ths) if not run it for an hour and check the voltage again. Again this is not a real capacity test but based on what you have said it sounds like their gone and this would be a good confirmation.
Thanks, mate. Heard US Gels are at lower voltage than Euro Gels.

Anyway, could you please clarify something regarding the test? I should not be getting a large voltage drop, correct? "if not" = just a few 10ths of Voltage drop?

So I get a large Voltage drop = batteries are toast, no need to leave the 10-20 Amps on for an hour.

If I get a small voltage drop, leave the 10-20 Amps for an hour, check Voltage again. Should Voltage be close to original, what to look for here please?

I am getting a smart charger for GEL, featuring temperature compensation. Will charge each battery with it, so will remove the parallel coupling, check a few things while doing so. Trying to figure out if I should charge at boat (cold) or at home (room temperature).

Cheers
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Old 15-12-2016, 12:14   #9
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Re: Battery status of Gel batteries

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Originally Posted by Bob666 View Post
Thanks, mate. Heard US Gels are at lower voltage than Euro Gels.

Anyway, could you please clarify something regarding the test? I should not be getting a large voltage drop, correct? "if not" = just a few 10ths of Voltage drop?

So I get a large Voltage drop = batteries are toast, no need to leave the 10-20 Amps on for an hour.

If I get a small voltage drop, leave the 10-20 Amps for an hour, check Voltage again. Should Voltage be close to original, what to look for here please?

I am getting a smart charger for GEL, featuring temperature compensation. Will charge each battery with it, so will remove the parallel coupling, check a few things while doing so. Trying to figure out if I should charge at boat (cold) or at home (room temperature).

Cheers
Well this kind of varies depending on the batteries. What voltages have you normally seen when cruising? Your looking for a difference as much as anything. My old gel bank would start off around 12.9 after sitting at the marina for a while and would drop below 12.5 when I would know I had to recharge. But voltage is effected alot by residual effects of a charge , loads applied and temperature. It would be tough to say what yours might be. I would expect going for a resting voltage (having the battery sit for a few hours technically 24) you should not see more then 3-4 10/th or so drop after using 10-20 AH. But again it varies by battery. It really helps if you have a baseline.

What I was really thinking is your batteries have lost most of their capacity then putting a real load with no charging source may cause them to dip a half volt or more in a short time, which would indicate a very dead bank.
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Old 18-12-2016, 07:16   #10
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Re: Battery status of Gel batteries

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Well this kind of varies depending on the batteries. What voltages have you normally seen when cruising? Your looking for a difference as much as anything. My old gel bank would start off around 12.9 after sitting at the marina for a while and would drop below 12.5 when I would know I had to recharge. But voltage is effected alot by residual effects of a charge , loads applied and temperature. It would be tough to say what yours might be. I would expect going for a resting voltage (having the battery sit for a few hours technically 24) you should not see more then 3-4 10/th or so drop after using 10-20 AH. But again it varies by battery. It really helps if you have a baseline.

What I was really thinking is your batteries have lost most of their capacity then putting a real load with no charging source may cause them to dip a half volt or more in a short time, which would indicate a very dead bank.
Went to the boat yesterday .Measured 12.47 V on the house bank (on one of the batteries). The cheap Voltmeter is far away from the bank and is showing less, around 12.40 V.

Decoupled the batteries and labeled them 1,2,3,4. The previous owner had parallel coupled them by connecting each battery to the + and - junctions. He used cables of various length and area.

I will remake all this with 35 mm2 cabling and diagonally across the bank.

When decoupled, each battery measured 12.49 V. Still at the boat. 3C/37F.

Brought them home to 20C/68F. They have rested for 24h. Measurements:

Battery 1 = 12.62 V
Battery 2 = 12.64 V
Battery 3 = 12.49 V
Battery 4 = 12.50 V



As far as I know they're all from the same batch. Year = 2013. Month = August.

"Partsmart Euro Gel 75 Ah max 14.4 V."

I will wait a bit more and charge them each for 48 hours (=8 days) with my new CTEK MXS 5 Amps intelligent charger:
MXS 5.0

I will not choose AGM or Recond. Only the Car symbol = max 14.4 V.

I tried the Recond on my motor boat battery as it's in bad shape. Manual says it's supposed to go to 15.8 V (or maybe that's the AGM + Recond setting) but I only had 14.6 V during Recond phase.

So I suppose the Car symbol won't go as high as 14.4 V. We'll see soon enough.

As for the alternator in the boat. I've never ever seen it go to high voltage. It's usually at 13.5 V or similar, so might not have damaged the house bank?

The Invac 30 A shorepower charger: Seen it go above 15 V, but only used it for a few days, unclear what previous owner did. He wrote a little "manual" for the boat in which he states "never leave the boat on shore power, you might damage the batterier". (Why didn't he sort that then?).

If I have a charger that gives e.g. 15.0 V. And I turn on a lot of lamps to get that down to 14.4 V. Am I home free in that scenario? (I realise this is bad practice, just out of curiosity).

Cheers
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Old 21-12-2016, 13:40   #11
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Re: Battery status of Gel batteries

Little update.

Batteries say on sticker "ok to charge with 14.4 - 14.6...solar panels should not exceed 14.2 V".

Why is that? How can the batteries know if they're getting power from a MPPT regulator or elsewhere from?

Cheers
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Old 28-12-2016, 08:38   #12
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Re: Battery status of Gel batteries

After having charged them +24 h each at room temperature, they rested for day in room temperature. Subsequently, I moved them to our guest house where it is outdoor temperature, currently -3.5C/25.7F. I waited a few days and they are now measuring 13.01 V - 13.10 V.

Batteries 1-2 that were at approx 13.63 V are measuring at 13.10 V, both.
Batteries 3-4 that were at approx 13.50 V are measuring at 13.01 and 13.04 V.

All ok then? Squeeze a few more years out of them maybe?

Cheers
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