Battery test ?

[monkey44]

I believe I have a battery that is not charging - at least it's not holding a charge (Interstate 27 - five years old) ...

I need to see if the truck is charging the battery before I spend the money on a battery. If I charge it at the 110v pedestal, it charges and holds a charge for a couple days with very minimal use once we disconnect... That tells me the camper charger is working?

A few lights, fridge ignite, no heater ... use no electronics, very careful with battery use, bed early, up early. But it discharges pretty quickly, two / three days. We normally get a least a week out of a full battery boon-docking when we limit the use.

How can I test if the truck is charging the battery on the road tho?
It seems to be charging very slowly, if at all when driving. And when we stop overnight after driving all day, it discharges overnight.

I have a line tester - so, if I run the truck, remove the cables, and link one pin to each cable connector, what should it read if it's charging properly -- if that even works? Seems the cable should read power if it's charging, even if the battery is not attached.

It's inconvenient to bring battery in to station for test, but if that's the answer, I'll make that happen.

One more thing: I have a truck camper, so battery raises and lowers the legs. When I tried to raise legs to slide under camper to load it, it tries, but fails and just groans a few seconds and quits. BUT, if I attach jumpers from truck battery to Camper battery, then it will raise the camper easily - I expect that's using the truck charging system and jump power tho, and tells us nothing about the truck charging the battery thru the internal lines??

Any thoughts??

[monkey44]

MEXICOWANDERER wrote:
This is EXACTLY why i recommend carrying a manual battery charger. Now THAT's being smart. Excuse me SMARTER.

Yes, well, I have one but no 110v at the moment ... I'm loading up and outta here next week, will struggle with it until then. Looks like it's charging, but gone battery - just won't hold the charge. 😞

[nineoaks2004]

I have a battery load tester I bought from Harbor Freight for about $20.00, I have used one for years when I installed and trouble shot solar school flashers, It will also tell you if the battery is being charged. I also use a multi-meter
but the load tester is faster and gives me a good idea where the trouble is...

[MEXICOWANDERER]

This is EXACTLY why i recommend carrying a manual battery charger. Now THAT's being smart. Excuse me SMARTER.

[red31]

monkey44 wrote:
if it's charging system problem,

waiting for a voltmeter reading ...

[Lynnmor]

starcraft69 wrote:
Five years???? New battery.

Today I am installing a new battery in my Malibu. The darn thing is cranking a bit slow after 10 years and 7 months.

[Dave_H_M]

Can't you just run the truck at high idle and stick a volt meter on the batt terminals?

[monkey44]

Yes, I would take it to town, but we're a bit isolated at the moment, and if the battery is not charging, I'd like to know if it's in the system (broken wire, or some thing else) then would go buy battery ... if it's charging system problem, then need to fix that first or new battery will not help.

Will get into town next week and get it all checked ... it's never that simple 😞
Thanks for the responses ...

[starcraft69]

Five years???? New battery.

[time2roll]

Dave H M wrote:
when I have that kind of challenge i just take it to town and have it tested for free.

+1

monkey44 wrote:
I believe I have a battery that is not charging - at least it's not holding a charge (Interstate 27 - five years old) ...

Probably enough right there to just get a new battery.

[wa8yxm]

Easiest way to check if the truck is charging is to snag a Clamp On AC/DC ammeter, Sears sells a nice one in th 60-70 dollar range.. I have one but it's not in the Motor Home just now so I can not give you the model number.

Clamp it on the battery cable. Negative is likely the best here and zero it out, Now plug into the truck and fire that sucker up.. Have your partner "Fast idle" and read the meter.. Still zero, or dang close to it, is not good.

A BETTER test, involves the same meter. but find the BATTERY line in the umbilical cord and clamp on it.

the only better test wold require the meter indicate the direction of flow.. I have seen clamp on meters that do this, (But it's been 50 years) but have not the model number... Ford Farm Equipment used them on a 20 HP tractor back in the days when My dad owned one, Furgeson Hydraulics but only FORD appeared on the tractor.

[Dave_H_M]

when I have that kind of challenge i just take it to town and have it tested for free.

[beemerphile1]

1. Read the voltage of the RV battery.
2. Connect the tow vehicle and start the engine.
3. Read the voltage of the RV battery, if charging it will be 13.2 or more.

[Old-Biscuit]

Charging system from truck is better at maintaining a camper battery vs recharging a camper battery especially one that is low.

Charge line wire size is limiting and truck alternator is limited due to voltage regulator

Volt meter connected to batter cables========note voltage at battery
Turn truck on--------note voltage at battery
Increase truck RPMs....note voltage at battery


Then go buy a new battery :B