Will our Carbon Gel batteries fry if we use EHU?

[Bonjour Motorhome]

Hello all,





Seeking the wisdom of those on here with knowledge about motorhome electrical systems please and apologies in advance for the length of the post.





We fitted two Carbon Gel 100Ah leisure batteries to our Auto-Trail about four weeks ago along with a Victron Smart MPPT 100/20 which is between the solar panel and the leisure batteries. The van is fitted with a Sargent EC 100 control panel and a Sargent EC325 PSU.





Here's the issue:





For the entire period since fitting, the Victron App has stated the solar panel is producing roughly 21v during the day and the batteries average 13.67v even with 12v lights on, iPhones charging, water pump going and Separate toilet fan running 24/7. The status is 99% always showing as “float”. Happy days?





However, last night the Sargent EC100 started screaming that the leisure batteries were running low, the little useless lights showed two remaining and we suddenly became rather concerned as we were totally off grid. Eventually, despite reducing power consumption to a minimum, the little lights diminished to nothing and the system shut down!





We did the only practical thing and went to bed.





In the morning we had a couple of little lights back but running the water pump for a few seconds resulted in a panic from the EC100 again.





Following various threads on here, some say that the EC325 is NOT compatible with gel batteries so, with the EC100 claiming we have no leisure power and now parked on a family members driveway, can we plug into EHU with the EC325 switched off and the trip switches turned off or will our batteries fry? We really could do with some electric in the van.





Awaiting your superior knowledge.





Regards,


Z.

 

[autorouter]

If the batteries are flat, the first thing to do is to get a charger on them and get them back up to a reasonable state of charge. So I would hook up the charger ASAP.

The unsuitability of the charger for gel batteries is more a long-term thing, they will gradually lose capacity if they are not optimally charged. However for the EC325, the manual says 'the charger can be set at installation for either Gel or Lead-acid batteries'. I don't know exactly how to do that, but I'm sure others will know. I think the Gel setting will be OK for Gel Carbon batteries.

The gel setting has all the voltages the same as the lead-acid setting, but has an extra extended timed absorption stage that gels need. During this time, the gases produced during charging are recombined back into water at the plates. This is required to avoid loss of electrolyte and gradual deterioration. But this is a minor problem compared with leaving the batteries in a discharged state, which can cause much worse deterioration.

Having said that, gel-carbon batteries are particularly resistant to the sulfation that occurs if batteries are left in a discharged state, so less of a worry on that score.

 

[Bonjour Motorhome]

Hello Autorouter and thanks for taking the time to respond, much appreciated.





Firstly, let me explain the very strange formatting of my message. As a severely sight impaired person (totally blind) I use adaptive computer technology to access the internet, etc and unfortunately some website are not truly accessible or text editors perform strange actions when I type in text. Therefore, if there are large amounts of blank spaces this is beyond my control, it is simply an side effect of using a screen reader. On occasions some miserable people have complained about such strange formatting, even go so far as to tell me not to post on their forums as they feel it is an intrusion on their fondness for clarity but I’m sure that most people on here are more understanding and will give me the benefit of tolerance?





Following on from my original post here is an update incase someone else experiences the same issues.





We replaced the old Lead Acid leisure batteries with two Quasar 100Ah Carbon Nano-Tube Gel batteries which can be safely discharged to 10% thus allowing for much longer periods off grid.











At some point the Sargent EC100 believed the batteries were too low and turned off the 12v system as previously described.





I spoke with a member of the Sargent Tech Team who guided us through the procedure of testing the voltage entering the EC325 by removing the front cover and using a multimeter on the corresponding pins. This showed 11.5v and when testing the starter battery, this was at 12.4v. We have a Battery Master fitted BTW.





Therefore the EC100 was acting correctly by interrupting the supply of the 12v system. I asked if the EC325 would be safe to charge the Gel batteries on EHU and was told yes.





Next we visited the battery supplier for advice which involved a one hour journey and they tested the battery voltage which now showed as 12.4 however the EC100 still showed the batteries as being low with only four lights showing, up from the two earlier that morning,.





The Victron MPPT Smart Solar controller was exchanged for a test model and showed the solar panel was generating 22.5v and in the “Float” state, the same as our MPPT was reporting.





Having purchased a Victron Smart Shunt that we will fit this weekend, we departed and returned to the original park up point where EHU is available. However, having read so many different opinions about hooking up to the mains with an EC325 and Gel batteries, I was unsure if this would cause damage. Some state that the EC325 must be configured to charge Gel batteries and some believe it doses’t matter.





As a final check I contacted a member of the Applejacks Electronic Tech Team who instantly understood the whole situation with regards the EC100, EC325 and charging Gel batteries and confidently stated it would be safe to use EHU and allow the Gel batteries to charge.





Big thanks for Ross at Applejacks, definitely a company to be recommended for repairing older electrical systems on vans and boats.





So, here I am, sat in the van with EHU connected and the batteries on charge with no apparent issues. If that changes I shall update this post otherwise, it appears to be safe to run the system in this configuration.





I hope this helps someone else in the future.





Cheers,


Z.