# '86 Mazda b2000 bad battery? **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** mazda\ **Created:** [November 20, 2021, 10:03am UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757 "2021-11-20T10:03:15Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![dannoflynn\_163057](https://avatars.discourse-cdn.com/v4/letter/d/e274bd/32.png) [@dannoflynn\_163057](https://community.cartalk.com/u/dannoflynn_163057)\ **Post date:** [November 20, 2021, 10:03am UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757/1 "2021-11-20T10:03:15Z")
Hey all, my old Mazda’s battery was dead when I got on it last evening. I jumped it no problem but after a few miles my headlights were very dim. Like dangerously dim. It was a real white knuckle slow drive home. When I turned the car off in my driveway it wouldn’t start back up again. Is this just a bad battery or is my alternator gone too? ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [November 20, 2021, 10:45am UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757/2 "2021-11-20T10:45:46Z")
Yes, both probably need replacing. A failed alternator may kill your battery,. Attempting to charge a failed battery can kill an alternator. How old is the battery? Is the alternator the original 1986 alternator? On a vehicle this old, could be corroded battery cables. You should have had the alternator light show on your dash. Do you plan to do the work yourself? ---
**Author:** ![dannoflynn\_163057](https://avatars.discourse-cdn.com/v4/letter/d/e274bd/32.png) [@dannoflynn\_163057](https://community.cartalk.com/u/dannoflynn_163057)\ **Post date:** [November 20, 2021, 9:09pm UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757/3 "2021-11-20T21:09:34Z")
Yes I plan to do it myself. If memory serves me that alternator is only a few years old. It is no longer my daily driver so goes periods without being driven. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [November 20, 2021, 9:21pm UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757/4 "2021-11-20T21:21:50Z")
You may have fried the alternator when the engine started and the jumper was removed. Alternators are not battery chargers, and asking one to recharge a dead battery can destroy a new alternator. This is the warning that’s included with every alternator I install. ![ALTERNATOR WARNING](https://global.discourse-cdn.com/cartalk/original/3X/8/0/809d7ed626e237cd8e364e71f9f08b5f9a990a49.jpeg) Tester ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [November 20, 2021, 9:50pm UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757/5 "2021-11-20T21:50:28Z")
> [@dannoflynn\_163057](#): > > goes periods without being driven. Suggest you get a battery tender if this vehicle is not routinely driven. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [November 20, 2021, 11:27pm UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757/6 "2021-11-20T23:27:41Z")
I suggest you invest $20 in a basic DVM and measure what’s going on. Lots of sources in the internet to learn what to do with it. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [November 20, 2021, 11:36pm UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757/7 "2021-11-20T23:36:36Z")
Before the first start of the day the battery should measure about 12.6 volts. Then immediately after starting the engine, 13.5 - 15.5 volts. What are you getting? ---
**Author:** ![dannoflynn\_163057](https://avatars.discourse-cdn.com/v4/letter/d/e274bd/32.png) [@dannoflynn\_163057](https://community.cartalk.com/u/dannoflynn_163057)\ **Post date:** [November 21, 2021, 1:38am UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757/8 "2021-11-21T01:38:06Z")
Now I know. ---
**Author:** ![dannoflynn\_163057](https://avatars.discourse-cdn.com/v4/letter/d/e274bd/32.png) [@dannoflynn\_163057](https://community.cartalk.com/u/dannoflynn_163057)\ **Post date:** [November 21, 2021, 1:39am UTC](https://community.cartalk.com/t/86-mazda-b2000-bad-battery/180757/9 "2021-11-21T01:39:19Z")
Right now I’m likely getting nothing at all. Going to borrow a charger from someone and grab my multimeter from work Monday. We shall see.