Another lithium shall I / shan't I thread

[Andacami]

Bear with... and thank you in advance for your sage advice as ever.

We have a 2017-built AS Corinium Duo. It has the Sargent EC500 PSU and EC480 control panel kit, a Sargent PX300 mains charger, and a Victron 75 / 15 MPPT as a direct replacement (I just wired it directly into where the old Sargent cables went) for the Sargent unit that was making some odd noises and I need something a bit beefier for the extra PV I fitted (it had one when we bought it secondhand). I also bought two HLB750 100AH leisure batteries from Halfords back in June 2021. I don't feel I've gained much in terms of off-grid ability and over the last two years, never been able to fully rely on 12v.

Current situation:

• One of the batteries is goosed, it won't take a charge and the CTEK and RING charges/recoverers report it's beyond help
• The other battery reports Ok and seems to take and hold a charge over 48hrs, however, on plugging this one back into the Moho today and turning on the power, it instantly went to 10.7 volts so that's goosed too
• On checking everything (visible and get-atable fuses, fuses inside the charger, and at the starter battery, etc.) I discovered that the EM40 is burnt out on the VB input (as they do). I don't know when this happened, but this year certainly and maybe in the last couple of months

So... I need a replacement EM40, I'll probably get the Apuljack AE EM40 version as I understand it will certainly cope with two LBs and Lithium and should mitigate the burnout issue (I've contacted Sargent but I'm not holding my breath type of compensation). I also need new batteries of course.

The question therefore is...

• Should I decide to splash out on a lithium battery, will the Sargent PSU and Sargent Charger be OK?

I think the Victron MPPT will be fine as one can set a Lithium profile, the AE EM40 will be fine too as I understand, but I think I'm going to need to replace the Sargent PX300 with a new charger as it's a three-stage thing and I don't think that can be changed. I'd like your help please as I don't fully understand the charging profile thing but having read the info on MHF I know that it's important to get it right. It seems if the wise and good can answer the above (PSU and Charger), I'd be looking at three options: 1) a new AE EM40, new lead batteries and be where I was or, 2) a new AE EM40 and new lithium battery or, 3) a new EM40, new charger and new lithium. Of course, these options increase in cost as we move from 1 (which I must do at minimum) to 3 but as I'm forced into doing something, the usual lithium-related benefits appeal (longevity, power, weight) and a bit of future-proofing, ticking the upgraditus box, etc.

​

 

[headlight]

Bear with... and thank you in advance for your sage advice as ever.

We have a 2017-built AS Corinium Duo. It has the Sargent EC500 PSU and EC480 control panel kit, a Sargent PX300 mains charger, and a Victron 75 / 15 MPPT as a direct replacement (I just wired it directly into where the old Sargent cables went) for the Sargent unit that was making some odd noises and I need something a bit beefier for the extra PV I fitted (it had one when we bought it secondhand). I also bought two HLB750 100AH leisure batteries from Halfords back in June 2021. I don't feel I've gained much in terms of off-grid ability and over the last two years, never been able to fully rely on 12v.

Current situation:

• One of the batteries is goosed, it won't take a charge and the CTEK and RING charges/recoverers report it's beyond help
• The other battery reports Ok and seems to take and hold a charge over 48hrs, however, on plugging this one back into the Moho today and turning on the power, it instantly went to 10.7 volts so that's goosed too
• On checking everything (visible and get-atable fuses, fuses inside the charger, and at the starter battery, etc.) I discovered that the EM40 is burnt out on the VB input (as they do). I don't know when this happened, but this year certainly and maybe in the last couple of months

So... I need a replacement EM40, I'll probably get the Apuljack AE EM40 version as I understand it will certainly cope with two LBs and Lithium and should mitigate the burnout issue (I've contacted Sargent but I'm not holding my breath type of compensation). I also need new batteries of course.

The question therefore is...

• Should I decide to splash out on a lithium battery, will the Sargent PSU and Sargent Charger be OK?

I think the Victron MPPT will be fine as one can set a Lithium profile, the AE EM40 will be fine too as I understand, but I think I'm going to need to replace the Sargent PX300 with a new charger as it's a three-stage thing and I don't think that can be changed. I'd like your help please as I don't fully understand the charging profile thing but having read the info on MHF I know that it's important to get it right. It seems if the wise and good can answer the above (PSU and Charger), I'd be looking at three options: 1) a new AE EM40, new lead batteries and be where I was or, 2) a new AE EM40 and new lithium battery or, 3) a new EM40, new charger and new lithium. Of course, these options increase in cost as we move from 1 (which I must do at minimum) to 3 but as I'm forced into doing something, the usual lithium-related benefits appeal (longevity, power, weight) and a bit of future-proofing, ticking the upgraditus box, etc.

​

Do you regularly go on EHU ?
If you don't, you could leave the Sargent PX300 in situ as it has a charge voltage of 14.4v and a float voltage of 13.6v and no desulfation stage.
That is exactly what I did, after taking advice from Fogstar and Vanbitz, as I am only on EHU a couple of nights a year and although the PX300 will only charge my lithium leisure battery to about 90% being on EHU that is not an issue and it won't damage my battery.
If however you go on EHU regularly you should change the PX300 for a charger with a lithium profile.
But if you are normally on EHU I don't see the point of lithium anyway.

 

[Kannon Fodda]

The EM40 should be under a recall, especially if you have the Thetford fridge. Contact Autotrail.

 

[LithiumConvert]

I would suggest the next stage is to find out how to disable the split charge relay ....

.... and when you have checked it is fully disabled then fit a B2B (Battery to Battery charger). - completely by-passing the Sergent unit.

 

[Andacami]

The EM40 should be under a recall, especially if you have the Thetford fridge. Contact Autotrail.

Dometic and Auto Sleepers. But thanks for the tip, I'll contact AS.

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[fishplug]

If you do decide to go down the AGM route, then I've got two 200Ah Victron ones up for sale at a good price with plenty of life left in them.

Then again, the reason I have them up for sale is because I upgrated to Lithium.

Budget v technology - as always....