Will 130A Alternator in 2019 Toyota 4Runner be Enough to Work with a 40A Charger

Question:

Can my 19 4runner 130A alternator safely support a 40A dc-dc charger at idle and while driving with normal vehicle power draws ? Or do I need a larger alternator or a smaller charger?

asked by: Ralph B

Expert Reply:

It sounds like you're referring to the 40A Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1240D for use with your setup. When it comes to chargers it's a little more about what kind of battery bank you're trying to charge up than how much output the alternator has. With that being said, I reached out to my contact at Redarc and he said that you can typically count on about half of your alternator power being able to switch over to their charger systems so your 130A is definitely high enough for the 40A system.

Since your charger is more related to the battery bank than the alternator the 40A system might be a little high for your application. You should be able to just use the 25A system # 331-BCDC1225D unless you have a pretty substantial battery bank or a trailer that needs to keep something larger like a fridge running constantly. The 40A wouldn't hurt, but it just might not be necessary.

Please note that you're also going to need a fuse kit. If you're going with the 25A kit then you need the Fuse Kit # 331-FK40, but if you're going with the 40A kit then you need the Fuse Kit # 331-FK60 instead.

expert reply by: Jon G