Campervan Battery Upgrade

[ScubaCollie]

Hi All, first post here therefore please be gentle!

I've just purchased a new campervan and first weekend away, the leisure battery drained/died after 2 days off grid/wild camping, due to only being a 75ah battery installed.

The existing is a Lead Acid and I would like to remove that and install 2 x AGM 160Ah batteries, with both batteries connected in parallel to each other to maintain the 12V and increase the Ah to 320Ah compared with my old lead acid 75Ah.

My question is will the existing wiring loom back to the Sargeant EC176 PSU/Charger be sufficient? And the remainder of the wiring handle the new batteries?

In theory it should be fine as I'm only increasing the Ah available to draw on and not increasing the voltage, just giving myself more power reserve?

 

[Simon47]

That depends on what it is. Doing a quick search for that model, the first hit is this post (on a camping forum) where someone is doing much the same thing.
It sounds like the charger is a basic fixed voltage unit, but there's no indication if it automatically limits output current or goes into overload. On that basis, it's hard to say.
IF the unit automatically restricts its output current to its specification, then it would be safe - it'll simply take longer to recharge a higher capacity battery setup. If not, then there is a risk that with discharged batteries the unit will overload - which "probably" means it will trip out, and possibly auto-reset.

 

[Zerax]

Just so that you know... the AGMs that you are proposing to use are still Lead/Acid in chemistry. They will give you better performance compared to standard wet cells, but nowhere near as good as with Lithium Ion cells.

My experience is with boats rather than camper vans... and if I was to replace the wet cells in my boat... I'd be going down the Lithium route as they are cheaper on an /Wh basis. You'd need to do some research, but the rewards would definitely be worth it.

 

[Lucien Nunes]

In theory changing the batteries has no effect on the necessary wiring loom. The cables from the charger need to be adequate for the charger output which is 12A and limited automatically. Those instructions recommend fusing at 20A which should already be present. The cables to any van loads that bypass the fusing in the EC176 need to be adequate for the loads, and again should already be appropriately fused locally at the battery.

As above, AGM is a lead-acid technology but might require a slightly higher voltage profile for complete charging, compared to traditional flooded batteries. Check the battery specs against the charger curve, otherwise if the charger voltage is too low you will never completely charge the AGMs and they will lose capacity prematurely through sulphation. Some of these general-purpose charger / converters are quite basic and you might get better battery life with a charger upgrade.