JiveGirl
Free Member
I had a similar dilemma back in november last year. I went to what I believed was the SW leading battery and solar supplier in Plymouth as I knew my vehicle battery was on its way out as it was dipping low after just a few days off hookupand was 5-6 years old. they tested it and pronounced it on its way out, and automatically replaced it with an AGM battery telling me these were far superior to wet acid batteries and it would outperform and outlast traditional wet acid batteries. I took their word for it. I also asked them to check out my leisure batteries, as they were coming up to 5 years old, and they said they were fine but recommended having the wiring tidied up into junction boxes rather than everything connected to the batteries. My partner offered to pay for this so I booked it in 2 days later and took it in to have the wiring tidied iup. I got a phone call telling me that one of my leisure batteries was actually down to 30% and that I should replace both so I told them to go ahead with like for like batteries, I had 2 banner 110AHa leisure batteries on board. When I picked the motorhome up they had actually replaced these with 2 90ah AGM batteries. I asked why they weren't 110ah and was told that because they outperform wet acid batteries I'd get more from these than the old one.
I took my vehicle home and parked it on the drive for the weekend without hooking up as i didn't think it would be necessary. within 36 hrs my batteries were dropping all 3 of them, and already down to 12.3v by Monday they had dropped to 12.1v all three, and I phoned the battery supplier and said having paid nearly £800 I was a bit concerned I couldn't cope with a weekend without hook up. luckily it started, and I returned it to be told the next day there was nothing wrong they just hadn't set up the Sargent unit properly, so the readings I was getting were wrong. This actually didn't hold true as my alarm also monitors my vehicle battery and I have a read out from my intent connection for the leisure batteries, and these had also confirmed the low reading. I assumed they had done something wrong and corrected it and collected the vehicle. But exactly the same happened within 3 hrs the batteries were falling and kept falling so back it went again. By now, I was researching the suitability of AGM batteries and making phone calls to the battery suppliers and Sargent. Despite being assured that the AGM batteries would work, my research showed that my existing Sargent unit and battery charging systems would never charge them above 80%, which would seriously reduce their life. when I went into my other local supplier to get the AGM batteries tested, he told me he would not put AGM batteries on my vehicle as I need an entirely new charging system to support them, including from the alternator and for hook up and a new solar charger all bypassing the Sargent unit that did not fully support the AGM as none of my systems ever charged above 14.7v.
The people who fitted my batteries couldn't explain why they were draining and just kept saying it must be my motorhome and that they were suitable but in nearly 4 years i'd never had an issue before and been off the grid for a week or so regularly. In the end I told them they could have the batteries back and took it to my local motorhome mechanic to trouble shoot. He was equally baffled and couldn't explain the drain of all 3 batteries with no parasitic drain on my vehicle. The AGms were returned and wet acid batteries fitted, and it still drained! £400 of labour later, and after a comment from me that could it be a faulty diode on my solar panel, he changed my solar control unit, and everything stopped draining. I haven't had any issues since! It seems that when they did the rewire of my leisure batteries, they didn't isolate them before disconnecting, I actually watched them start work on my MH while waiting for my lift home, they did so outside as the workshop was full and they didn't cover the solar panel or go inside the MH to do anything to disconnect power to the solar panel behind the Sargent unit. I didn't know at that time that they should have done that! It was a costly lesson in not taking peoples word for things and pointless trying to get money back from them for the damage caused due to their attitude. After all the research AGMs are fine IF your charging system is new enough and has an AGM profile on it, or you are prepared to spend time independently charging them once a month to achieve a full charge, or spend the extra money upgrading the charging system to ensure the longevity of the batteries and trouble-free use.
Good luck it was a steep learning curve for me. this is an excellent article on AGM batteries https://www.aandncaravanservices.co.uk/agm-batteries.php
unless you mean b2b thing. I thought AGM were the way to go over flooded ordinary batteries but needed a b2b, and now you mention gel ? Wtf is gel and where does it sit in battery benefit as a leasure battery ? I am soo confused.
What did you expect? 12.6V is fully charged.
