Island Time 1,249 Posted June 7, 2020 Share Posted June 7, 2020 Some of you might find this interesting. I have a customer who had new batts, alternator, external reg, shorepower and solar fitted by another electrical company about a year or so ago. Recently his house batts failed. They were quality AGM units. Investigation showed they had less than 30% of design capacity, after one year. Further investigation shows the batteries to be badly sulfated, due to charging voltages being too low. The Shorepower charger is a victron Centaur, the Alt reg is a Balmar, and the solar controller an EPever. Investigation of these shows the Victron unit set to AGM. Same with the EPEver. Balmar too. You might think this is OK, but, like I always say, read the PDS for your specific make and model of batteries!! In this case, the Battery PDS wants voltages 14.6-14.8 for Bulk and Absorption, and 13.6 - 13.8 for float. The standard settings provided by these manufacturers for AGM is 14.4 for bulk and 13.3 for float - its not sufficient. So what I did was replace the Solar unit (after batteries replaced with same units again), with a Victron Bluetooth unit with logging. Programmed that to the right voltages under the custom setting, and set it to do an equalization to 15.2v once per month. The Victron Shorepower unit did not actually produce the voltage it was meant to, but now set to LA (Lead Acid) it is within the specs. Still have to program the Balmar unit later today. The jist of this story is; - check your charging voltages, at bulk and at float, for all your charging sorces, and make certain that they are within the specs for YOUR batts. Or suffer premature failure.... 4 Quote Link to post Share on other sites
Steve Pope 243 Posted June 8, 2020 Share Posted June 8, 2020 Good Info. Quote Link to post Share on other sites
Kevin McCready 83 Posted June 8, 2020 Share Posted June 8, 2020 Ta for reminder. Yes. Great info and would be good to get another report in a year. I bought a second hand electric car recently and have been very kind to the batteries. By keeping within the advised levels I've actually been able to INCREASE the range compared to what I bought it at. It's only been a 4.3% increase but every bit counts and I hope to improve on that. Quote Link to post Share on other sites
Island Time 1,249 Posted June 8, 2020 Author Share Posted June 8, 2020 Kevin, if the batts are improving, they are sulfated. A really good discharge then a "robust" charge can help. High rates of charge and an equalization voltage can break up the sulfation. 1 Quote Link to post Share on other sites
Romany 162 Posted June 8, 2020 Share Posted June 8, 2020 IT does that apply to deep cycle AGM too? Quote Link to post Share on other sites
Island Time 1,249 Posted June 8, 2020 Author Share Posted June 8, 2020 Absolutely. That is what the ones in the above example were. Quote Link to post Share on other sites
splat 55 Posted June 8, 2020 Share Posted June 8, 2020 17 minutes ago, Island Time said: Absolutely. That is what the ones in the above example were. Curious IT was the Epever model not adjustable? Quote Link to post Share on other sites
darkside 61 Posted June 8, 2020 Share Posted June 8, 2020 Sulphating an EV battery? Not sure if that is possible for Lithium based batteries. Quote Link to post Share on other sites
Island Time 1,249 Posted June 8, 2020 Author Share Posted June 8, 2020 31 minutes ago, splat said: Curious IT was the Epever model not adjustable? Its adjustable, but it has no logging function. Its also a bit stupid in that it tries to do Bulk charge every day for a set time, regardless of SOC. Quote Link to post Share on other sites
Island Time 1,249 Posted June 8, 2020 Author Share Posted June 8, 2020 14 minutes ago, darkside said: Sulphating an EV battery? Not sure if that is possible for Lithium based batteries. True, It will depend on battery type. But if its gaining capacity with use, it makes me think maybe not lithium?? Quote Link to post Share on other sites
Island Time 1,249 Posted June 8, 2020 Author Share Posted June 8, 2020 Further to this, I've been sent a PM urging caution re equalizing AGM batts. In this case, the NZ agent has insisted on an equalization schedule, and wanted monthly and 15.2v. So this is what this is set to. But again I urge you to read the PDS for your batts, and do what that says. Dont take anyone's word for the settings, the manufacturers know their products, and also carry the warranty! If you are going to equalize, temp sensing is essential! IMO. Quote Link to post Share on other sites
wheels 543 Posted June 8, 2020 Share Posted June 8, 2020 AGM and GEL are also Lead Acid batteries, but have a different means of covering the plates with Acid. I will start with GEL batteries, because the rule is pure and simple. Gell should not ever be Equalization charged. Unless you have a very specific instruction from the manufacturer that says you can . As soon as Gel gasses, it is shot. Not all AGM's can be EQ charged. As IT said, check with the manufacturer. The battery has to be designed for this to be able to be done safely. It requires specific design in the interplate connections. This usually results in more expensive batteries and thus tends to be found in the Brands that have big reputations and prices. FLA MUST be EQ charged regularly. All lead acid batteries sulfate. This is a natural occurrence every time you discharge. The electrolyte in Lead Acid battery is Sulphuric Acid. A brand new fully charged battery is lead and sulfuric acid. As the battery starts to discharge, a chemical reaction between the lead and acid produces Lead Sulphate and electrical energy. Lead sulfate is a soft material that naturally covers both positive and negative plates. The deeper the discharge, the more lead sulfate will cover the plates. Once the load is turned off and it is time to recharge, lead sulfate is easily converted back into lead and sulfuric acid. This is why it is important to charge batteries back to 100%. If you don’t you will not convert all the lead sulfate back into the active material. If a lead acid battery is not immediately recharged, the lead sulfate will begin to form hard crystals, which cannot be reconverted back to soft Sulphate. Thus the longer and more frequently the Battery is discharged and the longer the battery is not allowed to be fully charged, the less energy the battery will be able to reproduce. Standard recharging will never bring an LA Battery back up to full charge and thus will always be undergoing sulpation and creating crystals, Big heavy FLA batteries can require an EQ charge of up to 8hrs for them to be fully recharged. You can usually tell if your batteries are sulfated when the open circuit voltage (OCV) is low. To measure the OC Voltage, fully charge the batteries. Then leave to sit for at least 10hrs, 24hrs preferable. A fully charged good condition battery should be 12.8 volts or higher. Some can read 13+ Volts. A sulfated battery will be “finished” charging, yet only have an OC Voltage of 12.2-12.5 volts. It will give very little energy back when under load. It is a good point to add, when battery capacity is down, a line is eventually crossed between the economics of energy in and energy returned. If you didn't pay for the Power being pushed into the battery during charge, it isn't so important. But if you do, there is not economical point in supply say 1000Watts of energy in to the battery and getting only 100Watts of energy back out. Quote Link to post Share on other sites
tuffyluffy 76 Posted June 8, 2020 Share Posted June 8, 2020 15 hours ago, Sabre said: Note to self. Dont read posts on battery management. Keep head in sand, cross fingers and all will be well 👍 Ditto, although I'd add another item to my management plan Head in sand Fingers crossed Don't let them go flat So far its working a treat Quote Link to post Share on other sites
splat 55 Posted June 8, 2020 Share Posted June 8, 2020 I see Marine deals is selling 'mastervolt' branded AGM's - anyone have any experience with these re quality, cycle life etc? Are they true deep cycle - product blurb looks a bit confused https://www.marine-deals.co.nz/batteries-and-accessories/mastervolt-mv-12-90-ah-agm-battery Quote Link to post Share on other sites
Island Time 1,249 Posted June 9, 2020 Author Share Posted June 9, 2020 Mastervolt are usually ok. But here is a little test. Ask any supplier for a peukerts number and a PDS (Product data sheet) for that particular battery. If they cannot provide them, then they are low end "consumer" batts, not commercial level. Quote Link to post Share on other sites
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