Battery Failure

[Kimcam]

Hi everyone,

Just pulled my Tvan out of storage, only to find that the batteries appear to have completely failed

Batteries are 2 x Thunder Redback Extreme 100Ah AGM. Age is unknown, but the van was made in 2015 so may be original. Removed both batteries, and each was at about 1.8V. I have stored the Tvan for longer without issue - it is possible that I left something on to drain them but I don't think so.

Battery voltage is so low that they are not recognised by the Projecta charger.

I am about to Google and find out if there is some way I can get the charger to recognise them, but not really hopeful.

My questions to the group are as follows:

- Anyone know a way to get the charger to start charging?
- If I can get them charging, what is the likelihood of a successful recovery?

I know that if I install Lithium replacements I will need to replace both the Projecta and Redarc BCDC for units with a lithium profile, but can I use the existing hardware for now until I have a chance to replace them, and just accept that charging will be less than optimal until I do?

Was hoping to go away this weekend, so I won't have a chance to upgrade the system before then.

Thanks

Cam

[HappyTraveller]

Hi Cam,

I can't give you much good news, but perhaps a little. I had a similar problem a few years ago with my Topaz 2. The AGM betteries, which were only a couple of years old, ran down after I unintentionally left the main radio and TV switch on, meaning that standby power was being consumed. That was enough to run the batteries down over about 7 weeks while I was overseas. That length of time is otherwise fine to go without a charge with AGMs (I never just leave a smart charger on all the time... that can also kill batteries).

When I discovered the problem, the batteries were at 9 volts. Same problem as you, the Projecta charger wouldn't start. I had access to a non smart charger and used that. It got voltage and life into the batteries and then the Projecta would work. I then ran the recondition feature and all seemed good. Trouble was that the battery capacity was only about half what it previous was.

If you can get a basic non smart charger, it may get you going short term. If you can't do that, I'd try jumper leads from the car straight to the batteries. It may work too.

I wouldn't use existing chargers on lithium batteries. The charge rates just aren't taylored to lithium needs which are very specific. Even on a short term basis it could be very risky... not just for the life of the batteries, but for the risk of fire.

Good luck
Andrew

[Kimcam]

Andrew,

Thanks for your reply.

I managed to initiate the charger by using another battery pack to 'jump start' the dead battery. Once the charger sensed voltage and started charging I was able to disconnect the battery pack. Battery has now been on charge overnight and is still charging - will see how it is when I get home tonight.

I suspect that even if it holds charge capacity will be affected At this stage I just hope it will be good enough to go away this weekend, and buy some time to plan and purchase everything needed for a lithium upgrade.

Next question will be which lithium? Lots out there to choose from, with a wide variety of prices. At this stage I am thinking Renogy, but will continue to do further research.

Cam

[HappyTraveller]

Sounds good.

I'd stick with a known brand with lithium... for safety reasons. Renogy seems to have a good reputation. I have Enerdrive in our Trakmaster and as an auxiliary in the car. I'm happy with them.

It's worth noting that the lithium battery voltage is pretty constant until the battery's about flat, so you can't use voltage to tell % full. You need some way of monitoring battery SOC. Usually via a shunt or by having a bluetooth battery. I have a shunt based monitor in the caravan and a bluetooth battery in the car. Both work well.

Cheers
Andrew

[outbacktrev]

A simple trick to "trick" your smart charger is to put it in "power supply" mode for a few minutes, which generally will bring your battery voltage up to "trick" the smart charger then reset charger to appropriate mode for whatever batteries you run. Been there done that.
Can also trick with a 9v tansistor battery if you have one handy.
Cheers,
         Trevor

[Ray]

I have installed a 100ah Renogy battery with the extra bluetooth monitor. Both seem to work well, first real test next week while camping for a few days. I have also upgraded the wiring as well which was too light to run our waeco 50 litre fridge.
I have put the Renogy in a Supercheap battery box to keep it dry and it fits in the front position on our 2009 Mk2 Sport Tvan.

Ray