Georgia Mike Posted March 3, 2023 Share Posted March 3, 2023 I replaced my Magnum inverter/charger over a year ago and recently noticed a few times the charge rate is up over 15 volts. It happened for a short time when I first plugged in at a site this last trip and today when I plugged it in it’s up over 15 volts. I made sure my solar charging system is off so that’s not an issue. Is this something to be concerned about? 99% of the time it’s at 13.5 or in that range. Link to comment Share on other sites More sharing options...
DavidL Posted March 3, 2023 Share Posted March 3, 2023 What's the Magnum manual say? I suspect nothing is wrong. Sounds like it's working fine. Link to comment Share on other sites More sharing options...
Rocketman3 Posted March 3, 2023 Share Posted March 3, 2023 A couple of other questions: how cold are the batteries? what kind of batteries? Agm, wet- lead acid, gell, lithium? There is a temperature sensor that should be attached to the charger that registers the temperature of the batteries. When it’s cold lead batteries need higher voltages, when it’s hot - they need lower voltages. If the temperature sensor has become disabled (corroded wire leading to an open circuit), it can cause the charger to think it’s like -40 below - and overcharge the batteries. Check the batteries specs and the Charger manual to find out if your temperature boost is normal for the current battery temperature. 15.3v could be high enough to boil off the acid and cause damage or it could be just fine. When it’s at 13.5v it is in float. That is fine and not a problem- (where it should be at after being plugged in for a while). The question is what is the charging cycle looking like??? Link to comment Share on other sites More sharing options...
96 EVO Posted March 3, 2023 Share Posted March 3, 2023 (edited) I'm not sure BTS affects any charging mode other than float charging 🤔. Does appear a bit high. I usually see about 14.5v in absorb mode. That is set to flooded lead acid batteries. Edited March 3, 2023 by 96 EVO Link to comment Share on other sites More sharing options...
Frank Bergamo Posted March 3, 2023 Share Posted March 3, 2023 Had a similar problem, unplugged battery temp sensor and everything returned to normal. Are your batteries good, how old? That’s where I would start. Link to comment Share on other sites More sharing options...
OhReally Posted March 3, 2023 Share Posted March 3, 2023 Mike, I assume you have lithium batteries since you are using solar. If so, the following information is appropriate. If not lithium, then forget this. What setting are you using on your Magnum? If you have LiFe batteries and are using CV/CC instead of LiFe setting, it is probably not a problem as the information on the display does not correspond to actual voltage or current. It is part of an equation within the Magnum as it sometimes trades off voltage and current in the charging cycle. If you have it set for Lithium, not LiFe, then voltage is a little high but still may not correspond to actual voltage or a problem. Best to get your voltmeter out and check the voltage at your batteries to make certain it is not just an artifact of the Magnum inverter/charger. If you use Magnum's CV/CC setting on LiFe batteries you can lower the battery charge voltage just a little and keep your Life batteries charged while not allowing the Magnum to overheat or input too much voltage or current. Link to comment Share on other sites More sharing options...
Georgia Mike Posted March 3, 2023 Author Share Posted March 3, 2023 Thanks for all the replies. Rocket man asked about the temperature sensor so I went and looked for one but found nothing attached to the batteries. After some investigating I found this wire laying on the bottom of the slide out tray for the batteries. All three ports on the Magnum have phone cords plugged in the yellow one is for the battery temperature sensor so there is a wire leaving there but im not sure what this is. I cut it open and there is two very small gauge wires in the heat shrink that was put on the end. So could this be the temperature sensor put this way from the factory? It looks like it has been here a long time. Also I have all lead acid batteries. Link to comment Share on other sites More sharing options...
vito.a Posted March 4, 2023 Share Posted March 4, 2023 Not sure what brand lead acid, but Trojan T-105 are the most popular. CHARGING INSTRUCTIONS: CHARGER VOLTAGE SETTINGS (AT 77°F/25°C) SYSTEM VOLTAGE 6V Bulk Charge 7.41 Float Charge 6.75 Equalize Charge 8.10 Double these voltages for series parallel 12v applications. It appears you have some incorrect settings or a poor connection. Link to comment Share on other sites More sharing options...
Dr4Film Posted March 4, 2023 Share Posted March 4, 2023 The most popular current Magnum BTS doesn't look like what you are holding. Is it possible that your BTS is an older version? What you are holding appears to have a sensor on the end which would need to be placed between the sides of two of your house batteries. That's how Trace/Xantrex did it with the Inverter/Charger in my previous Windsor. Here is what the current Magnum BTS looks like and what Trace/Xantrex uses. Link to comment Share on other sites More sharing options...
Tom Cherry Posted March 4, 2023 Share Posted March 4, 2023 only one arm due to shoulder replacement last week soo no caps....too much trouble first, open the magnum setup and verify the parameters. google magnum soft reset and then do that.. while you are about it, read or scan the battery file for a full understanding. you appear to have battery temp sensor not made by magnum. discard and get rid of it.. god only knows what it is telling the magnum. do this before verifying the right magnum parameters and the soft reset. FWIW, you could disconnect all the phone wire and do the soft reset and run the inverter without any of them. but you need the remote to tell it what to do and setup the inverter properly. many have disconnected the magnum temperature as when it dies or shorts, it causes issue. i think your system will work like it ought to after getting rid of the non magnum BTS. if not, call magnum...they will go through and diagnose for free. amazon has the correct magnum and it goes on the back negative pos of your house bank. try the above....i think it will fix it MAGNUM - SETUP REMOTE GUIDELINES - OLD AND NEW (1).pdf BATTERY 101 - BECOME AN EXPERT (1).pdf Link to comment Share on other sites More sharing options...
wamcneil Posted March 5, 2023 Share Posted March 5, 2023 On 3/3/2023 at 3:32 PM, Georgia Mike said: Thanks for all the replies. Rocket man asked about the temperature sensor so I went and looked for one but found nothing attached to the batteries. After some investigating I found this wire laying on the bottom of the slide out tray for the batteries. All three ports on the Magnum have phone cords plugged in the yellow one is for the battery temperature sensor so there is a wire leaving there but im not sure what this is. I cut it open and there is two very small gauge wires in the heat shrink that was put on the end. So could this be the temperature sensor put this way from the factory? It looks like it has been here a long time. Also I have all lead acid batteries. Disconnect the temp sensor phone plug and see what that does to your absorption voltage. Unless you have a relatively new magnum and are using the lithium settings, there’s no way to turn off the temperature compensation other than unplugging the sensor. If the sensor is unplugging the magnum assumes constant 70deg F and temperature compensation is effectively disabled. Cheers Walter 1 Link to comment Share on other sites More sharing options...
Georgia Mike Posted March 6, 2023 Author Share Posted March 6, 2023 We are on a trip to Vogel state park and the voltage has been steady in the 13.5 range since after the first hour when a plugged it in Friday morning. I’m glad to know that isn’t the original battery sensor. When I got the new Magnum last year it came with a new temperature sensor but I didn’t install it because one was already there so I will do that. It’s seems to do it only on startup for a short time after it has been off and it just concerns me a little because I now how sensitive some of these 12 volt systems are with high voltages. When I replaced the Magnum last year I went through the setup screen very carefully and got all the parameters correct and just rechecked them and I have checked the batteries for any bad cells and they are all good so hopefully changing this sensor will help. I will try and disconnect it on startup next time first. Btw first time to Vogel state park and it is one of the nicest parks I have ever been to but a little tight maneuvering this big beast in here. Link to comment Share on other sites More sharing options...
96 EVO Posted March 6, 2023 Share Posted March 6, 2023 (edited) Have you seen it in absorb mode since unplugging the BTS? Most 12v devices are fine with up to at least 16v. Some even more. When I had my Carefree awning replaced, the installer uses a 18v battery pack to test running it out/ in. Edited March 6, 2023 by 96 EVO Link to comment Share on other sites More sharing options...
96 EVO Posted March 9, 2023 Share Posted March 9, 2023 I was just doing a bit of research on Rolls FLA batteries and their charging charts show 15.3v for bulk and absorb charge at 50F. So, you should be fine! Link to comment Share on other sites More sharing options...
Georgia Mike Posted March 10, 2023 Author Share Posted March 10, 2023 Thanks Ben for the info….makes me feel much better Link to comment Share on other sites More sharing options...
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