Have had the MH 5 years (2004 model) and the current set of batteries is 3 years old. I run 3- 6 volt(not looking for opinions on this unless relative) and have never had an issue. Today while getting ready to cover I decided to check battery fluid levels. Two were fine and the third was very low. The low battery was the independent battery wired in series. Rarely do I need to add water and MH is always plugged in when not on the road. Any ideas what could cause this?

Internal resistance within the battery. Take a good voltmeter and check when your batteries are under a good load to see the voltage across each battery top. If you find the single battery is dropping more than half of the full voltage from end to end, try moving that battery to a parallel spot and see what happens. Each battery will have somewhat close to six volts across it's tops, but if after moving the arrangement you find the single battery is less than before, it's a sure indication that battery you suspect is indeed causing problems.With a little creative wiring, perhaps you won't have to move the batteries, just the wiring.

You are cooking the series battery while trying to charge the two in parallel.

OK inquiring minds want to know: how did you hooked up three 6 VDC batteries??? And, which one was low?Guess we are all used to thinking of 12 VDC systems, not 6 or 18.

OP is putting two batteries wired in series, the third battery is then wired in parallel.I do not know why anyone would do this!

enblethen wrote:You are cooking the series battery while trying to charge the two in parallel.Yes. Wrong wiring. I think what he meant was the 3rd battery wired in series to the other 2 that are in parallel.

Why would one battery of 3 be very low on water?

53 Replies

wolfe10
Explorer
Dec 13, 2015
OK inquiring minds want to know: how did you hooked up three 6 VDC batteries??? And, which one was low?

Guess we are all used to thinking of 12 VDC systems, not 6 or 18.
enblethen
Nomad
Dec 13, 2015
You are cooking the series battery while trying to charge the two in parallel.
Artum_Snowbird
Explorer
Dec 13, 2015
Internal resistance within the battery. Take a good voltmeter and check when your batteries are under a good load to see the voltage across each battery top. If you find the single battery is dropping more than half of the full voltage from end to end, try moving that battery to a parallel spot and see what happens. Each battery will have somewhat close to six volts across it's tops, but if after moving the arrangement you find the single battery is less than before, it's a sure indication that battery you suspect is indeed causing problems.

With a little creative wiring, perhaps you won't have to move the batteries, just the wiring.

Forum Discussion

Why would one battery of 3 be very low on water?

53 Replies

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