Red Studio

You can connect a standard lead acid battery of similar capacity in parallel with the AGM to charge it on a standard charger. It worked for my older battery but I've bought an AGM charger now too. Interestingly the supplier of the new battery states that the warranty on their Optima batteries is voided if the battery is allowed to fall below 10.5 volts as it will irreparably damage it. They give the same disclaimer on the blue top deep cycle version and the yellow top general purpose and not just the red top starting battery. I may have misunderstood what a deep cycle battery is but I thought they were able to be run down and recharged.

Well a new Optima red top arrived today so will fit it tomorrow. Even though I've pulled the fuse for the fog lights I'm not confident that it's not going to drain another so I've fitted an isolator. Don't fancy forking out another £154! The diesel Cruisers have an Optima AGM battery under the passenger seat as there's no room under the bonnet with the Mercedes diesel engine. The electrics are a nightmare - some is standard and some specific to the diesel so a lot of the books are wrong. I'll try to check for a drain with everything turned off - my main worry is that there'll be a fog lamp relay not protected by the fuse that will still drain it. None shown on the diagram in Haynes but for whatever reason the diesel's fog lamp fuse is in a second box under the bonnet and not in the main fuse box as per standard petrol version so Haynes may be wrong. After four Skodas I just fancied a change - see what happens when you don't drive a Skoda!

Have you tried pressing the ASR button on the dash? If you press it to disable it that puts the ABS light on in ours.

Just as an update if anyone else finds themselves with a flat AGM battery : It will get up to near 10v charging in parallel with the other battery but when I start charging on its own from there it rapidly falls back to 6v at which point the charger shuts off and flags it up as a battery fault. Looks like it's very easy to knacker an AGM by draining it completely - it seems that half the cells have gone down. I'm relying on the old battery at the moment but that was originally replaced as borderline so with the cold weather I've had to jump it off the Fabia twice this week. Going to have to order a new one. Thanks for the input, I think we knew how this would end though.

For sure, that's what it looks like to me too. I've got the old one in there now, 12.67 V in the cold this morning, 14.25 V with the car running at idle. I'll give the flat one another try at the weekend but I think it's had it.

Sounds like the backrest may have popped out of its bracket on one side where it mounts to the floor. They're designed so they can be removed when tilted part way forward. I think you can see one with the rear door open and the other will be visible if you take out the back of the narrow seat. That may give you a bit more wiggle room to free it. I've managed to get mine crooked but never managed to lock them like that. Sorry I'm not very descriptive - I left the car at work Friday so I'm working from memory.

It's nothing so sophisticated. It's a diesel PT Cruiser, the battery's an AGM as it is on its side under the passenger seat. Both new and old are Optimas of the same rating though the old one also has Chrysler branding but as the car is 2005 I doubt it's original. It is correct OEM for the car. I'm charging it out of the car, quite a job in itself as the passenger seat has to come out.

If only! Bought the car 2nd hand and he said he'd put a new battery in it for me. The new battery turned up a couple of months later, looked new but no receipt supplied. I hadn't had trouble before but the car wouldn't start after standing that weekend so I put the new one in and no trouble till last weekend when it happened again with the new battery this time. Fog lights are coming on by themselves so I assume that was the trouble before too. The old battery had stood in my garage since the summer but a friend borrowed it to start a car he had in storage in November and said it was fine when he charged it. I used it to jump start a car after Christmas and there was still plenty in it then too so this is the one I'm pinning my hopes on now. I wonder if the other is getting hot when the charged one dumps its charge into it. If I can get it to 7.5 volts I can get it on the smart charger alone and see how a slow charge goes.

Thanks AGFalco. When I took it off the car it showed less than a volt. It's near 6 now after a couple of goes charging, I think that's mostly from the other battery I was charging it in parallel with. The smart charger won't charge it alone unless it gets above 7.5 volts. It's the heat in one cell that bothers me - I chickened out when I felt that. Now I'm just charging the older battery in the hope of using that. Both batteries are out of the car at the moment so can't check voltage with it running.

Hi I've got a car with an AGM battery which completely flattened while the car was left over a weekend (faulty light switch). I've tried to bring it back up by piggy backing it with another while charging but not having much luck - it just seems to suck all the charge and its voltage falls rapidly once disconnected. One cell also seems warm. If I carry on I think I'll end up with 2 duff batteries. I'm using a 4 amp smart charger, both batteries are Optima AGM of the same rating. The other battery is an older one which holds charge but struggles starting the car. Has anyone any experience of these? Am I wasting time trying to recover the completely flat one? I think it may have been damaged being run completely flat. Any advice I'd be grateful. The flat battery is less than a year old and I don't want to fork out for a new one if I can avoid it, they're a hell of a price but because of where it is in the car it's the only type that fits. Thanks

It's been a while since I did mine but as I recall it didn't need a turn to release - it was just a push fit. I think you're right - check the ends to make sure inner and outer are firmly attached at both and then look for a break in the cable. I've never replaced the cable but if you find it's broken my advice would be don't pull it out until you know how you're going to put a new one in - you may need to use the old one to pull the new one through if it's routed through box sections.

Yep, the cable pops free of the end. I looped a cable tie round the socket, one round the cable end and then looped them together with the third: The tie round the socket/outer alone would probably be fine if pulled tight enough but this three tie solution hasn't gone again in four years.

All I can think is the surge fried something. The serial number matched the book so the code should be right. The book doesn't say anything about shutting you out completely like that, it implies you get unlimited tries if you're prepared to wait an hour each time. Got me foxed, maybe someone else can suggest something.

Sounds right. Mine is SKZAZ8C and a seven figure code then the four figure code is below that on the sticker in a bigger text.

I have just had to enter ours. I think the 1 and 2 May be the number of tries you have had. After you have had 2 goes it locks you out for an hour. There should be a 4 figure code. Once 1000 comes up you use the 1 key to enter the first number by tapping till you get the right one then the same for the second but using the 2 key and so on till you do the last with 4. Once 1000 is replaced with your number press the play button for a couple of seconds and all shoul be fine. (Mine came up LEARN after that but I ignored that and it returned to the radio.